Just getting into readying my coach for a nice trip in the spring and last year I had a problem just before I put it away for the winter. When I bought the coach back in 2013 the previous owner had his transmission removed to replace the rear main seal on the engine. Almost a week later he took it back and told the shop the Pac Brake did not work. Well they said it needed a switch on the dash and put in a spst toggle switch next to the ignition switch and a complete wire assy. to the Pac Brake. They then charge him almost $900 for this. Now the screw connections have come loose and almost completely undone. I think that when they took the transmission out they either forgot to reconnect something or damaged the wire and did not repair it, just my speculation. Why would Foretravel not have a rocker switch already on the dash for this? I have a rocker switch right beside the Ether control that does nothing but is powered. As I was reading in the manual that was for the optional retarder but to my thinking why would Foretravel not use that rocker switch for the Pac Brake if that was not used for the retarder to keep things consistent. Also, if it is not used why would it be there wired and powered as the light comes on when the rocker is activated. There is no labeling on the dash as with all other rockers that signify it purpose? If it is for the Pac Brake put in at the factory I will rewire to that switch as I don't like the type of connections at the toggle switch and doing it properly through a rocker switch would be much more preferable with the light activated when on. In any case I think I will avoid the shop that did the work.
The next time I'm at the coach I will try to trace the wiring from the switch since the wiring in the manual does not cover any switches nor the Pac Brake. If the Pac Brake had not stopped working I would not have asked this question thinking that the rocker switch was for an option I did not have. I have a strong feeling it was for the Pac Brake originally. It has a black ground wire (about 16 ga) and a light green wire (about 14 ga) to and from the switch. Anyone that might be able to shed some light on this, it would sure be helpful. It will save me a lot of scratch marks on my head trying to figure out the purpose.
Thanks,
John
The PAC brake on my rig is powered from a step on switch that is located on the floor to the right of the steering column. I have a couple of extra switches on my dash also, so I;m not sure that any of those were ever intended for a PAC brake. I don't have any wiring diagrams that show a PAC brake. FT may be able to shed some light on this for you. ---- Have a great day ---- Fritz
Thanks Fritz!
It is good to know that I may have an extra rocker already in place. I'll see what James Triana has to say when he gives me a call back on that. I know that the coaches configuration may change quite a bit depending on model and options. It is nice to have an illuminated switch to remind you that it is active so you don't leave it on when trying to coast. It has worked well for years but when it stopped functioning it made me look into the past owners receipts. I had made sure everything was free on the engine side and lubricated it at the start and end of each trip so I knew that it was not a seized gate. I was surprised to find multiple loose connections and they are not that easy to get to without removing the radio and cigarette lighter housing. I was hoping that it was a simple mistake that can be corrected easily which yet may well be. I had been eyeing that rocker for some time wondering what it was for and if it could be used for something in the future like the Pac Brake. I did not think that Foretravel would hard wire the Pac Brake to be on all the time as was suggested by the shop that had previously did the work.
Thanks for your enlightenment and reply.
Regards,
John
Maybe Mike Leary has a wiring diagram for a pac brake. My exhaust brake has a master switch to turn to automatic mode, let off completely on the accelerator pedal and the exhaust brake engages. Can still coast down hills be just resting my foot on the pedal.
John,
Do you have some paperwork that indicates your exhaust brake was installed at the factory? I don't see any mention of it in the beamalarm spec sheet for your coach. I am wondering if it was added after the coach left the factory, by one of the prior owners. In that case, it is anybody's guess how it was wired.
1994 Foretravel U280 Specifications (http://beamalarm.com/foretravel-links/models/1994_foretravel_u280_specifications.html)
I apparently don't have the "extra" unused switch on my coach. My exhaust brake is operated by a add-on switch on the wall next to driver seat. See photos below. On my brake, which was added by a prior owner, when I turn it on (arm it), then it operates automatically. If I release pressure on the throttle pedal, brake closes. When I apply foot pressure to throttle pedal, it opens.
I suppose it is possible the extra switch on your dash was used to operate your exhaust brake. Good luck tracing the wires!
Mine is quite similar to Chuck's, let totaly off the gas and engages and can also be switched to show brake lights while engaged. Will attempt to post a photo tomorrow. Red indicater lights for both functions. Best bet would probably be Mike Leary for wiring diagram as his coach is very documented.
Now this gives me more to ask James Triana when we talk. To bad they did not do what most car makers do including build sheets all through out the interior of the car. I looked at all the documentation and it does not show anywhere either being built at the factory with nor added late on, so Chuck you are quite right it could be anyone guess. Mine operated fine when left on and just operated when taking your foot off the accelerator and disengaged when throttle was applied. My dash is identical to yours except for the one extra illuminated rocker between the Ether and the Park Brake and the one you just added for your Battery boost setup.
Old Phart Phred has given me another avenue to go as far as getting wiring info on the Pac Brake from Mike Leary. Even if it is factory installed I would like to have at least a basic wiring diagram on how it is supposed to be wired. One note I found is that when the previous owner took delivery of it, it was gone over by FOT and they showed him how to operate the Pac Brake but even then there was an issue that he was to deal with at a later date but I had no paperwork for that if it was performed other than the switch added before I purchased it.
I want to thank you both for your response and help on this one. When it is rectified it will certainly ease my mind knowing it is done to a better degree that will not fall apart later going down the road with a positive wire floating around under the dash looking to cause problems. As I get older I need all the help I can get as in seeing a bright light on the dash telling me the Pac Brake is on or when I forgot to turn it off. I guess too I will have to look on line to see the proper function and operation of the Pac Brake. I had thought about getting a 2 stage unit until I looked at the price. The reality is that the one I have does enough to help on slowing things down in the mountains now. I have been looking for a large anchor, even if it is wood and painted like a ship anchor, to mount on the back with a chain attached and a sign that reads, please stay back at least 50 feet, emergency brake activated. It should get a laugh or 2 and less people tailgating.
Thanks to all for the help,
John
I have the pac-brake on mine. It is wired into a spare rocker switch in the dash to the left of the 2 dock light switches. Foretravel never installed a pac-brake on any motorhome that I know of. As far as I'm concerned, and this is my second Foretravel with a pac-brake, it is worthless.
I'll check my files today for a any wiring schematics. Here's mine, with the custom console (done by Brett, natch!). The PacBrake on/off is at the bottom of the shifter. BTW, I LOVE OURS! ^.^d ^.^d ^.^d I show our's was installed in 04,"PRXB New Generation", serial # 082658. It was made for the 3116/3126 CAT engines.
I found the files! There a quite a few pages, so I can make copies for anyone. The print is so small, that would be a challenge to read on a computer screen. Any one can send me a PM with their address, and I'll have our local printers do it and mail it out. ^.^d
I notice the files for the '94 280 mentioned having a Cummins engine, but the same 3060 Allison MD World 6-speed as ours. I'd think a call to PacBrake would be in order, just to make sure my files will be of help. ^.^d
First off, this morning I received a much awaited phone call from James Triana. He mentioned that my coach came without the Pac Brake and that it must have been done by a previous owner, which would have been the original owner. As far as the spare rocker on the dash that would have been an after purchase add on for, a big question mark, but I getting the assumption it may have originally been the Pac Brake On/Off master switch. Now I just have to trace the wiring as it does not look to be by Foretravel at this point in time.
In the response from Twigg. I concur with you in that it does not have much strength but any assist which I have noticed on a 6% grade is helpful and lengthens the life of the service brakes by a little as well as using a lower gear and running below the speed limit. I don't like it when it exceeds 80 mph which I did only once. It is abuse of equipment and I gave my head a shake afterward plus a kick in the butt. I've seen the aftermath of too many accidents from people doing stupid things in my day and don't want to add to them. I don't need to get anywhere fast or in a short period of time. I got myself out of the military habit of "hurry up and wait".
Thank you Mike for joining and responding to my request. Yes, I will get a hold of Pac Brake on the phone and try to stop by their office this week to try to get further info. I'll hold off on the wiring request, Mike, until I talk to Pac Brake to see what I can get out of them first. Thank you immensely for effort in finding your documentation. By the way I do have a big magnifying glass for the computer screen too, just kidding. It seems that a lot of manufactures are going to micro-fine print that is bordering on microfiche in their printing.
I will dig in to the tracing of the wires next week and post what I come up with. Thanks to all for the help and suggestions, now it is up to me to get 'er done. At least now I feel like I'm not chasing a wire needlessly and that I have a game plan and resources at hand. :)
Later and many thanks for your responses,
John
I don't want to get into a debate on the value of a exhaust brake, BUT, Twig's opinion (that the Pacbrake is worthless) does not match my opinion (of our exhaust brake). I know they are two different brands, but they seem to operate in a similar manner. We have been over the Rockies several times, and I have found our exhaust brake to be a great help in descending long, steep grades. Of course, a exhaust brake will never match the performance of a hydraulic transmission retarder, but if I had to choose between having our exhaust brake or nothing at all, I would certainly rather have our brake.
We have descended many long downhill roads with SOB coaches in front of us. They are riding their brakes all the way down the hill, while we coast down serenely in 4th gear at about 2000 RPM and our exhaust brake activated. In many cases I never have to touch the service brakes. A properly maintained exhaust brake, that is functioning correctly and operated properly, will take a big load off your disk brakes when driving in the mountains.
That is only my opinion - take it for what it is worth.
You can get wiring diagrams for installing a PacBrake from them.
Generally, it is wired through the Allison ECM so it achieves a downshift as well as exhaust brake application.
Having had a PacBrake installed (and maintained) since 04, is the BIG reason our drum brakes have lasted so well. I would add, both previous owners KNEW how to drive slopes!
Thanks Brett for your input as I have never seen any documentation or wiring for the Pac Brake but it is very important to know. I had no idea that it went through the ECM so that is good to know so I can narrow my wire tracing as well. That is why I'm trying to get mine in service again as I cross the Siskiyou Mountains enough to enjoy the added help of our Pac Brake. It is an advantage and used right a very big safety feature. I too would rather have the Pac than nothing as it gives you peace of mind and it does not raise the transmission temp while in use. But as I mentioned that I'm not in a rush to get anywhere in retirement as the final resting place is coming up too fast anyway and I don't want to meet it half way there.
I also totally agree with Chuck & Mike that you have to maintain (lube the proper points) so that they don't seize in the exhaust. That was one of the things I first got when I bought my coach was a bottle of lubricant for that specific purpose. It is much nicer to descend at a slower leisurely pace than find yourself between a rock and a hard place in a sharp corner with items cascading through the coach or worse. That is why I want the added feature of knowing via the illuminated rocker that I have it activated and that I did not forget it in my old age or just watching the scenery.
I was feeling almost ashamed of bring this matter up on the forum. Now I know more and maybe others might change their opinions of this sometimes poo pooed item if used properly. I feel I'm always learning and never regret even the smallest or seemingly most insignificant item can be given it's true value with a little knowledge. I really appreciate all the input from everyone.
Thanks, ^.^d
John
These are the best I could get since they are not originals, but FAX. Hope they can help.
This is more than what I expected, thanks Mike! Now, this gave me another possible avenue to look into as I had my ECM redone about the same time but I had not done any mountain travel for quite a while afterwards and since not really going fast and I did not bother using the Pac Brake. I'm wondering when it was rebuilt, if the settings had been changed and would need to be activated again, just a thought? I had it redone by Transmission Instruments so I may just give them a call to see if the setting may have been changed. I will be able to start looking for what is what and also to go out for a test drive first just to see if tightening the connections had done the trick. If not I will place a call and start checking all the connections and wired that I can.
Get that end solved, then tackle the other moving the wires to an illuminated rocker switch.
Thanks, Mike, for the 2 pics as it gives me something to ponder on so I can have a better point of reference as to what is happening and where to look.
Regards,
John
I checked the location of Pac Brake Corporate Headquarters is only 20 minutes from my home so that is very convenient and if I have problems then I can always take it to them if they are can do further diagnosis. That is lucky for sure to be so close. One of my neighbors is or was a sales person for them but he moved out of my area unfortunately. So that is a Monday morning trip on the way to the coach and shopping.
John
How often does THAT happen to any of us? b^.^d
My exhaust brake (haven't looked at the brand) is commanded by the switch marked retartder but only lights up and activates when switch is on and brakes are applied.
I have to add on to this. My PacBrake is a foot pedal to the left of the steering column., no additional switches on the dash. I have found it great for 6% & 7% grades when shifted down to 4th (feels the best for speed and control). It will slow me down at exits (not quite to a stop, but in combination with the brakes, gets me stopped a lot faster with less effort). Replaced my frozen one about 1 1/2 years ago and feel much better taking long steep grades.
I visited Pac Brakes Head Office in Surrey, BC yesterday looking for info on my Pac Brake for 8.3 Cummins/MD3060 Allison. As it turned out the gave the info freely to me printing it out there on the spot which was quite nice of them. When I got home I read the material showed me that I knew far less about the operation than I thought and the different configurations of installation in the coach and how they are set up according to the owner and installer, so it can differ quite a bit. So this morning I got hold of Chris Lacey at Pac Brake again but on the phone and asked if he could possibly send me .pdf files to me so I could get them to interested parties on the Forum. He was more than happy to do that and now I have them in my possession. Now, I don't know the best way of posting the .pdf files here so they can be shared with interested parties and they also have many links on operation so the Pac Brake can be used more effectively which I learned a lot. I know others are probably in the same boat in that way which a little nudge in reading this info would certainly help. Also, Chris included a trouble shooting guide, also helpful and one that he did not include was the "How An Exhaust Brake Works / Exhaust Brake Driving Tips" which is easily downloadable from the Pac Brake site.
On my coach the Pac Brake was put on by the original owner just after he purchased it from what I can tell, but the configuration is still unknown. The second owner, I think, did not use it enough and had problems with it at which point someone added a switch that was supposed to operate the Pac Brake but lately it stopped working and that is the reason I'm doing this search of answers to bring it to life again. I had maintained it over the years that I had it and seemed to function alright but not to any great degree of stopping power for such a expensive item. Well, that I can blame on me for not knowing how to use it properly and the way it is configured in my coach at present is not the best way but the easiest or possibly the cheapest way and yet not the most efficient. Now I have to find out what was on the original configuration if I can and go from there but with this new info from Pac Brake at least now I have a good starting point and the reasons for doing each configuration.
I hope that this info may be able to help others and find it's way into the permanent files where everyone may make use of them in the future. Now, I just have to find out how to get it loaded here.
John
That's great to be able to bond with the factory, John! Our's was installed in '04 and called the "PRXB' New Generation". Serial # 082658. It was last lubed in 2015, so I should check when it needs service. I sure like it, but as we've talked about, it takes some experience before one goes chargin' down a 7% grade at 65 and expects the PB to act like a 'Jake'.
John,
You can upload .pdf files within a post just like you do a photo. Use the "Add Files..." button at the bottom of the page, find the .pdf files on your computer, and click them to upload.
OR, you can add them to the Forum Library. Use the link below to the Library. Pick the folder that seems most appropriate to you, or start a new folder. Move to that folder, and then use the "Add Item" button at top of page to upload the .pdf files.
http://www.foreforums.com/index.php?action=media;sa=album;in=165
John's going to send them to me, as well. Still not sure how many of the members have them or when PB upgraded to the 'new generation'. More research is needed, on my part. Maybe you who have these will bookmark this thread and we can share questions/info? b^.^d
Thanks Chuck,
I was just too tired to think on my own to get it done, so thanks for the help. I hope this helps and gives some pointers on lubrication for those whom may not know. I bought the synthetic lube a while back on Amazon so it may be a good bet that is a good place to get it quickly.
Toby's setup was what I had thought was originally done with mine on the rocker panel (in place of the retarder) but the wires have yet to be traced. Also, as Balcantrez mentioned about the foot switch, that was one of the options mentioned and too as Brett had mentioned about the transmission gear reduction as well could be added. It is all in how it was setup and purchased and with what options. I hope to find one of these options in my rocker switch that may have been bypassed but only time will tell. At least we now have some factory files to look at and go by and as I mentioned these can be upgraded as you wish and they give all the listings with the engine and transmission combos possible.
I know that the guys at Pac Brake will do everything possible to help in repairs to upgrades or new installs. A few days ago I felt out in left field someplace but now I have a whole library and plenty of people to help and draw info from when needed. Thanks to all and I will keep you up to date on my own outcome.
Thanks ^.^d
John
Here was another one that I missed. One of the must have files.
John
John,
About the interface with the transmission. My exhaust brake was originally set up with this option. There is a sticker on my Allison ECU (brain box) indicating that the "automatic preselect" was adjusted to 2nd gear at request of the owner. I think the way this was supposed to work was when the exhaust brake was activated (in 6th gear) the transmission would start automatically downshifting as engine RPM/speed would allow, and work its way gradually down to 2nd gear as the coach slowed down. I say I "think" because this feature has never worked since we got the coach. That's fine with me! I would rather be in control of gear selection, and decide what gear I want when I want it.
As I mentioned in a earlier post, I have found our brake to most useful on the highway, and the best braking combo to be 4th gear at a maximum "comfortable" RPM (around 2000 to 2200). This equates to about 45-55 MPH, and is a good useful speed for descending long steep grades on the highway. I can't imagine ever needing the brake in 2nd gear, because in that gear the coach would be at crawling speed. I also never bother to use our brake in town, because it is ineffective at low engine RPMs.
My brake has a "exercise" feature that is handy. Each time we start our engine (assuming the system air pressure is 60psi or better) the exhaust brake cycles closed/open twice. This ensures that the mechanism gets operated regularly, and goes a long way toward keeping it freed up.
Yes, if properly wired though the Allison ECU, the transmission will downshift as speed drops to/toward the "pre-select gear".
2nd and 4th are common options, but any gear can be programmed in. I had ours set to 5th.
At highway speeds, it does NOT downshift to 2nd, any more than at a stop light with selector in 6th it is in 6th gear. It is the "go to" gear.
I also have no problem in not wiring through the Allison and letting the driver use the down arrow to select the proper gear.
Be aware that the PacBrake PRXB is quite a lot stronger at lower RPM than the older design exhaust brakes.
To 'pre-select' (which I've never done), how is that done? BTW, I use the toggle all the time driving in town, work's great!
Mike,
An Allison dealer has to reprogram the ECU using an Allison proprietary device. Not something an owner can do. Takes about 10 minutes.
So, (unless the PO changed it) we are going to assume it's still set for 5th gear? ^.^d
Mike,
Correct. But, easy to confirm. Next time you drive it, turn on the exhaust brake switch and look at the LEFT shift pad window. That will indicate the pre-select gear.
If it as I had it programmed, that window will go from "6" to "5". Remember, left window is the pre-select gear (gear toward which the transmission will go), the right window the actual gear the transmission is in.
Yes, there are some years with only a single window (thanks, bean-counters). That window indicates the pre-select gear, NOT the gear you are in.
Thanks, I have seen different numbers left & right, but never understood what was what. As I said, I drive in town with my hand (ergonomically placed, thank you) on the toggle switch. Only use the mains for a full stop. Are you sailing or sitting in a salior's bar? b^.^d
Update on the sailing trip: Not on the boat-- sailing a "small craft" on a time schedule is an oxymoron.
Thanksgiving to Christmas the boat was stored at Port LaBelle FL on the Okeechobee waterway-- staged to cross the Okeechobee, down to West Palm Beach and across to West End, Grand Bahamas. Arrived at the boat 12/28, ready for the 3 day trip to West Palm to await the first good weather window to cross the Gulf Stream. Neal Pillsbury was kind enough to ferry us from return of the rent car at the Ft Myers airport back to the boat. Weather looked good for a 1/2/2019 crossing.
So, 12/29 ready to head east. BUT (HUGE BUT) taking the boat across the Okeechobee requires the services of "Billy the boat tipper" to tip the 53' mast to go under the 49' Mayaka RR bridge. 26 degrees of heel and we are good to go! Billy has tipped this boat 3 times so far-- so, no big deal (we ASSUMED). Billy cancelled at the last minute-- his outboard is "broke".
This forced us to backtrack to the Gulf of Mexico and sail down through the Keys. That extra 300 miles (at 6 MPH) we had to do going through the Keys instead of across the Okeechobee Waterway ate up an extra 9 days. But, we had a great time, visiting some of our old haunts: Ft Myers, Ft Myers Beach, Marco Island, Indian Key Passage anchorage, anchorage off Little Shark River, anchorage off Matacumbe Key and in Biscayne Bay.
When we came north from the Keys and arrived at Biscayne Bay, we started looking for a weather window to safely cross the Gulf Stream to West End, Grand Bahama and on east to the Abacos. As is common this time of year, there are limited "weather windows" to safely cross both the Gulf Stream and then the 125 miles from West End, Grand Bahama to the Abacos. If we crossed on the next weather window, we would be stuck in West End at an expensive marina for at least 7 more days due to a strong cold front with 25+ MPH winds.
Our flight from Marsh Harbor was set. Unlikely we would even get to the Abacos/the island from which we had our reservation before our flight.
SO, Dianne and I got off the boat in Miami and got a rent car to drive back home. Visiting friends here before hitting the road. My brother and his wife who are not on a schedule will continue east as weather permits.
Yes, he is all set to do damage to the Lobster population.
Thanks again everyone as this is great food for thought and now know what I'm looking at when digging and tracing. I checked my photos of my ECU that I had rebuilt and it has no reprogrammed features as in Chucks marked on it so I know that was not included. It is great how much we learn from one another on these items. I really appreciate Brett jumping in when he has got so much on his plate, his words to many of us are like Yoda's. Have fun Brett!
This has given me a much better understanding of what is what and how things interact as in all the interlocks (relays) in the Pac Brake wiring, Cruise control, Air brakes, and the optional ECU settings. As mentioned I'll stick with the current install until I get it sorted and then look to maybe an upgrade. I would rather get things running properly first and to understand it and go from there. Chris at Pac Brake mentioned to "test the Pac Brake by disconnecting the power side of the Pac Brake solenoid on the engine firewall and putting power to it", only with the engine off after you have built up air in the system to see if it is closing the Pac Brake when actuated. Also, to make up a small powered test wire with a sealed illuminated switch for the test purposes from the battery and I'd probably throw in a fuse just in case and alligator clips on both ends. Then you can toggle back and forth to see if it works and you have a nice test lead afterwards. All good things to know and I feel much more knowledgeable now of what I'm looking at. I think a lot of the people that buy there coach have little understanding of this and usually don't want to admit that until they run into problems, myself included there. At least it is still fun to learn at 72 but then I may have to learn it again a few days later, memory, whats that! That on my hard drive! :))
Thanks,
John
Does your shifter look like this?
Yes Mike, it is the same unit there and just been serviced with the ECU last year. Still works great!
John,
Lots of "always hot" and "hot with ignition on" sources in the engine room. Be sure you disconnect the harness back to the dash/switch before applying 12 VDC positive to the PacBrake solenoid. You do not want to back-feed that circuit. You may want to cut the positive wire and install insulated male/female connectors to make testing and activating for lubing (IMPORTANT) even easier.
Great point Brett, that is what I had in mind but I did not know if it was plugged in or hard wired as you suggest. I know better than to back feed a circuit, it brings out the nasty surprises you don't want. I will take your comments as sage advice and a good reminder, thanks. After my last response I had given it some thought too in that manner as I was not sure of how the connection to the solenoid was made as I did not see any connectors in the photos of the solenoid and wiring.
Here are photos of the switches I have been mentioning. Current toggle sw. to right of ignition sw. & lighter. Also the rocker switches with the one between the Ether and Parking Brake.
John
Yours is all different than mine; any clue when it was installed?
Well--- different engine (Cummins C vs Caterpillar 3116), different cruise (his is the OE Bendix cruise, yours has been upgraded to the King Control electronic cruise) and different exhaust brake (his is the original PacBrake vs PRXB on yours).
So, yes, DIFFERENT.
I'm not sure Mike on when it was done as nobody has any paperwork or receipts for it now and nothing came with the coach from the previous owner who kept all his receipts. I believe it was done by the original owner as the second owner did not take delivery of it until 2003 which would have made it the late model Pac Brake. I know that it was based in or around San Antonio, TX until the second owner got it and then it made it's way to the Seattle area. I just assume that it was done a short while after originally sold in '94.
Hi Everyone,
Here is the update on my PacBrake malfunctioning.
Finally got it all sorted out and it is working again as it should as I had a place to work and enough time to dig into the wiring. I found out that the second switch installed to activate the PacBrake was not necessary work done for the previous owner. I traced the wires and found that they were perfectly intact and functioning to the illuminated rocker switch by the Parking Brake. All that was needed was a new switch as the original throttle switch by the fuel pump had come close to seizing buy still worked if you used pliers. The previous repair by the previous owner could have cost much less if they had done the switch replacement instead of freeing up the switch, but they installed a new multiconductor cable front to rear that was unnecessary plus the toggle switch on the dash. I can possibly find a use for the wiring but the switch will disappear and something else will go in that hole in the dash. I bought a new switch which is a different type from PacBrake to activate the air solenoid to the PacBrake at the rear. The actuator assembly is now on the accelerator pedal and engages the PacBrake when your foot is lifted off the accelerator and as soon as you press the accelerator pedal disengages. It was an easy thing to do once I gave it enough thought and found out the wiring was all there and just needed to be moved to accommodate the new switch on the accelerator. Now I feel that I can safely go into the mountains and know that the PacBrake is there when needed.
I also found hidden was a broken return spring on the throttle cable on the fuel pump and have a new pair coming from FOT to replace them both.
I want to thank all, Chuck & Jeannie, Mike & Pamela, Brett Wolfe, Mike Leary, and Old Phart Phred, who stepped forward to help with ideas and suggestions. The Forum is always a great help when help is requested. It gives us confidence and knowledge to get it done. It was all very simple once I got past the creative unnecessary creative wiring and removed all the old setup at the fuel pump.
John Smith
PS: I just gave my coach it's name today, Roamer, after the friendly neighbors cat stopped by to say hello and was killed shortly thereafter by a careless driver. Here's to Roamer, he will always be loved and remembered by us!
John,
That looks a lot more proper than the other activation switch that you had. With this one in the clean/dry environment where it is mounted it should work for a long time. That is a very good idea for a mounting box also.
Mike
Excellent photo report, and nice clean installation of the activation switch! Now you can check this item off your list, and move on to the next project. There is ALWAYS another project!
PS: Exhaust brakes like to be exercised. Even if you are not driving in the mountains, try to operate the brake several times on every drive. Doing so will keep the parts in good condition and ready for the times you really need them.
Do you still have a way to turn off the exhaust brake (like a dash switch that then powers the switch on the accelerator)?
To me, that would be critical, as without it you miss my favorite "gear"= COASTING. Said another way, you don't want the exhaust brake to come on every time you close the throttle.
And, it the exhaust brake wired through the transmission so it automatically downshifts when the exhaust brake is activated?
I agree that coasting is an important part of going downhill too. The way it was configured was the same way that I wired it until I can either find a way of wiring it the way you mentioned but for now I have a nice big red light that is come on on the dash that will not let me forget to shut it off as I had done in the past when not needed and I may put a flasher on the indicator light if needed. If I could get some info on the way it should be wired I could easily wire it to suit but there again I would have to check the ECM to make sure the unit is configured to operate that way. I have just been down shifting till this point as needed.
To this end, now it it is operational and a little safer and easier on the service brakes descending steep grades. As you very well pointed out Brett it would be better done the way you mentioned and it will get there. At least, until I can get further info I have something useful to use in a manual mode. Right now I'm just happy having the wires sorted to the point of knowing what I have is functional and a basis for any further mods. I found if modifying a non functioning item you are guessing at the outcome if it doesn't work the first time. That I found on the wiring I did this time after testing all the wires and hooking up the new switch and not looking at the contact point on the switch as it should have been NC contacts and the switch was wired with NO contacts. I knew right where to look and it took me about 10 minutes to rectify the problem but at least I understood what had happened. So if someone does buy that switch from PacBrake for the same use as I had then they will have to remove one contact screw and move it to the opposite side of the switch to function properly. If I had not checked things out to start with I would have been guessing again as to what happened. So as I found out years ago it is better to start clean with a good base and proceed from there. Now, I'm good to go again for any mods that I can add to make it better.
Thank you again Brett for pointing that out as it will keep me doing something in my spare time. I appreciate all the comments everyone have given. You never know where they may lead you and sometimes someone may discover a better way to get things done and that way we all can learn. If I can't learn I'm dead!
John
One thing I forgot to mention is that the main shut off switch is the same rocker switch in the same location as most coaches that is used for the retarder activation on the dash but is unlabeled at this point in time. So yes, you do have the ability for coasting as long as you have the slope. I'm hoping that there is a single wire hookup to the transmission ECM that can be used as it is very close to the switches on the dash and by the accelerator pedal. If anyone knows please chime in with your opinion in as it would be much appreciated. I had thought about a secondary switch that could be inline to the transmission so if I decided it was not necessary I could override it but that is just an idea at this moment as it may not even be necessary.
John,
Pacbrake's website has those diagrams.
But, interface with the Allison ECM is not necessary-- some may even say detrimental. There is no ideal "pre-select gear" for exhaust brake use.
Going west into Albuquerque on I40, 5th gear is perfect. Coming to a complete stop, 2nd gear is perfect.
You certainly have the option of not interfacing with the Allison and just using the down arrows to select the proper gear.
Thanks Brett, I'll leave well enough alone for now. It has worked fine for me in the past.
The pac brake switch is wired on top of the throttle in the engine compartment. Hot and ground, that's all. It causes the air system to open and close the butterfly to cut off exhaust. In order for it to work it's necessary to step on the brake pedal. If the dash rocker is on and lit up, then the pac brake is activated. When you apply throttle the pac brake opens until you let off the throttle again. It won't work at all in cruise control unless you tap the brake pedal to kill the cruise. The higher the rpm's I guess the better it works. Hope you like yours better than I like mine.
I ripped out the switch on the engine and used a new switch shown in the previous photos on the accelerator pedal. It is wired basically the same as it was before but in a much cleaner location up front. Someone had rewired it exactly the same as the original wiring, duplicated more or less and there was nothing wrong with the original wiring except the original PacBrake switch at the fuel pump was sticking from dirt or corrosion so it is now gone and returned back to the original wiring. Now it is functional as before.
As everyone notes it is not a jake brake but more an assist only much the same as my car has. If you plan far enough down the road it works well but for quick stops not so much. In any case that is why we have good service brakes and try to keep them that way.
John
I assume you have a 'PRXB" model? Here's one in our CAT: Brett did a cool thing when he modified the shifter console; the toggle switch is on the bottom, perfectly placed for my left hand! I've got some files I'll dig up about the lube type and locations, maybe someone else will chime in. BTW, I LOVE ours! ^.^d
PacBrake Lube: SuperLube - Exhaust Brake Lubricant | Pacbrake (http://pacbrake.com/product/c18037-superlube/)
Picture on the right shows where to lube. If not a PRXB brake, lube only the "places" that your exhaust brake has.
Ya gotta love them 4 wheel discs. ;D
Thanks but I already have the info from PacBrake on all the lube points and have been doing it religiously for 6 years now even when it was not working so it did not become a boat anchor. I do it before I take it out and also when I put it in storage just to be safe. Lube is cheap and a lot less work than replacement of parts.
John,
You are the rare exception-- most exhaust brakes are NEVER lubed and just seize up.
X2 John! For those who need 'em here's the scoop:
My exhaust brake shaft slides up a down out of the exhaust airstream will dry Teflon spray lube gum up? Valve body will eventually heat up to approach normal exhaust temp's of which I have no clue. Donaldson shows my peak temperature at 850. No pyrometer or boost gauge, probably will add the boost on my coach to help judge fuel use. Do have an exhaust manifold pressure gauge redlined at 29 psi.
I'm learning, too. Things I did not know about our PB:
More good PB stuff:
We were really interested in a pac brake when we first got our coach. I talked to the guys at pac brake and they didn't want to sell us one because they believed that with our transmission (MT647) the performance would poor enough as to not justify the expense. We were also having trouble finding a shop that would install it due to liability issues.
Looks like they make a by-pass for the Allison. See my post above. ^.^d
I'm thinking that I'll just forget about the Allison wiring as I did not need it before and I would only be using it on the steep downgrades which is all I had used it for before and it was just fine. The Super Lube is in the coach at all times under the bed, handy. I think I might throw on a flasher on the rocker switch illumination as I have about 6 of them and that would make sure I don't forget to shut it off. It sure beats that darned toggle switch that was put in as that would get left on a number of times as it is so small that you don't notice the position and it is not in plain sight. I'll see how it goes as the ECM switch is pretty much what I was thinking of doing but I'll see how well it and myself operate first on the new setup. It is funny that they already have the switch for those who might want it so the call for it seems great enough they had to make it. It all comes down to operator errors in the end anyway for the most part and I'm no exception. If you are operating it in low speed conditions as Brett noted that puts a whole new issue on the table for manual selection. I had never thought about using it for traffic conditions myself but if it works that is great as the service brakes would see a lot of use otherwise, especially in Seattle rush hour traffic which starts at midnight and ends at midnight, almost. Thank heaven for the express lanes!
John,
Unless your PacBrake is a LOT more effective than mine, I think you will find it has very little discernible effect when driving in traffic, because most of the time engine is barely above idle. Leaving it engaged all the time won't hurt anything, but don't think it will make much difference in your brake usage (in normal city driving).
Exhaust brakes work best at high engine RPM. Yes - I know - the PacBrake uses a design that increases the efficiency over a wider range of RPM. My Super Duty exhaust brake has the same basic design feature. Still doesn't do much, if anything, driving around town.
D-Celerator Diesel Exhaust Brake (http://www.usgear.cc/dcelerator.htm)
The GOOD thing about having it ON all the time (should you do so) is it keeps it exercised and freed up and ready to use in the mountains.
Unless I have to come to a full stop, I toggle the PB back and forth in downtown traffic; works great!. The model I have will provide braking down to low RPMs. ^.^d
Being that mine is the early model and not the new two stage I have to agree. I think that was the case but I have not used it in while and that stands to reason as you seldom get above idle, especially if you get caught in Seattle rush hour going the opposite the express lanes depending on the time of day. I guess for that the anchor on the rear works best for that.
Pacbrake has a web site and is on Face Book with quick service for questions. I'd wonder what the upgrade using your existing would cost? I also saw, on their site, a list of authorized service outlets. Heck, the factory is just up the I-5 from Seattle! ^.^d