I bought a Roadmaster Brakemaster 9160. The car install is done, now I am working on the coach side. Looking at page 10, Step 3 of the directions, https://www.roadmasterinc.com/pdf/85-1809.pdf it says find the air brake relay valve and either use an unused port or tap into an existing with a Tee.
Question
1- Where is the air brake relay valve? On the diagram, is that the Spring Brake Relay Valve?
2- From the right side rear wheel, I took 2 photos, the first is rear, just in front of the axle. You can see the driveshaft in the photo. The second is about 3-4 feet forward. What are these two? If I had to guess, the rear one is the Spring Brake Relay Valve and the front one is one of the SPS valves (what does SPS stand for?)
3- Which should be tapped into and is there a free port or do I have to use a Tee.
TIA, almost there!!
The main thing to note is NOT to Tee into your spring brake air supply. That is unless it is somehow configured exactly opposite to the Airforce One aux braking system. When you release the parking brake, full air is delivered to the spring brake port to keep it released. I would think that your supplemental braking system of whatever brand should use the service brake supply to apply proportionate barking force in the towed vehicle. I had an install that was done improperly by an authorized installer at the "Q". Flatspotted four new tires on the towed. The canisters are stamped as to function (service, spring), but you have to clean the area and get up close and personal to read it.
Note: The picture with the brass TEEW is improperly installed. I took this picture after cleaning the area and sent it to the AF1 head honcho to get him to make the installer reimburse me for four new tires. Small satisfaction for all the time wasted and aggravation felt because of this installer's incompetence.
Don
I am always leery about making a toad air brake connection.
What do we think happens to our coach braking capability when the air line between motorhome & toad, breaks allowing braking air flow to the atmosphere? Seems like it would be an air leak on a critical hose we would not want.
With so many toad braking systems that do not need us to tap a motorhome brake air lines why not choose them. Air Force taps into an air line, but does not send braking air pressure out to toad, but I prefer simpler systems like iBrake. Understand that some inertia systems will activate with retarder.
Barry , I believe the above statement is incorrect. While the AF1 uses a small air cylinder actuator to mechanically apply the braking force via the towed's brake pedal, the force is modulated via the metered air from the service brake to give fully proportional braking to the towed. When the AF1 control input is incorrectly Tee'd into the spring brake supply and the parking brake is released, full wet tank pressure is applied to the AF1 control module resulting in completely locked towed brake. IIRC, the AF1 also Tee's into the wet tank for system air pressure and there is a module mounted on the coach side which uses both the service brake metered air and the wet tank but is purely mechanical in nature. From this module which is a sort of regulator and a small reservoir (buffer), a single air line runs to the towed connection.
Don, I have not installed AF1 and also do not prefer them, but I thought one of the advantages ( & additional complexity) of AF1 is it installs with a relay/safety type of device that as you said, gets air from wet tank that flows out to toad under control of the modulated air brake pressure.
Air brake line being only used to open the 'relay's' air line from wet tank. So if when there is a leak from the air line to toad, the source of the air is just the wet tank, which of course will reduce system air pressure, but will not dilute the air going to the coach brakes.
Or are we both saying the same thing.
BTW, with coach/vehicle weight difference being so great, I think modulated toad braking is over marketed.
With a toad air pressure regular set optimally, the toad will never lock up. Toad air cylinder can do a good job by flowing constant coach air whenever coach air brakes are applied. And with portable toad braking systems with integrated air pump, that air pressure can be used in place of coach air.
Thanks Don, pictures are worth a 1000 words. I was able to see the two on the brake chamber. From the left rear, the one pointing to the center is the Spring (Type 30 port), the one on top is Service (Type 24 port). I'll Tee into the Service.
Barry & Cindy wrote "What do we think happens to our coach braking capability when the air line between motorhome & toad, breaks allowing braking air flow to the atmosphere? Seems like it would be an air leak on a critical hose we would not want."
The same thing that happens when an air line, quick exhaust valve or air motor/canister fails: The braking system splits into two and the remaining braking system provides stopping power.
Houston, we have a problem!
I was putting the adapter on and it needed about 2 mils more, it was hitting the 2 piece C clamp around the brake. I started loosening them to see if I could push it over a hair. Well, I ended up loosening too much and the spring popped apart! I have the diaphragm. It looks like if I can get the rearmost piece(piston?) that pushes the front side I can reassemble, but how do you get that piece to retract? What doe the Press Here on the back side of the housing do where the rubber cover is?
If someone has experience with this and can talk, DM me your phone # or vice versa. Thanks in advance.
People have been killed doing what you did. When in doubt: Don't. Stop and ask questions first. (PM me)
You need to take the can off, then "key" the spring brake to get it back together. Use google or Youtube to see how this is done.
Congratulations on not getting hurt.
I really don't like dealing with springs. I spent a lot of time designing around the need for springs.
Here's a YouTube video with dirt and stuff on how to cage a spring brake:
https://youtu.be/dwmt3zuRoYA
Here is where I am. Good news is I undid the forward clamp and not the spring brake part it seems, which I now know can be dangerous.
You must block the coach and cage the spring brake to pull the flange back so you can install the other half of the can.
When caging, how far back does the piece need to be pulled back? And then on the front/left side, how do you bring the spring back so it stays?
I have looked at new ones, but my concern is that I will still be in the same situation with the adapter that will not clear the nut.
Cage it and tighten until the nut stops, then you can put the can together, the light spring compresses easy.
Called around, people tend to want to replace this instead of fixing, since they are not too pricey. The pancake is cracked so I am considering getting new ones and letting a mobile mechanic do this. If it is like this on one, the other is probably the same, so may as well do them both.
The mechanic said to upgrade to 3030 over a 2430. Any input on that? Will putting on larger rears impact the fronts? I know they should be done in pairs. Before I have them come out , I'd like to figure this out so I don't have to pay for it twice.
Also, regarding brand, I have MGMs but does it matter what brand? I can get these tomorrow if going with a 2430 https://www.napaonline.com/en/p/TWDHD2430C
Has anyone experienced a brake can failure? (https://www.foreforums.com/index.php?topic=42035.msg421474#msg421474)
These cans are not difficult to work on. Ive read that people have gone to larger cans but I personally don't see a need currently for me. With the spring brake pressurized to about 60 psi locking is effortless. If you manually retract the spring brake spring with the caging tool on the side of the can make sure you lube the treads to prevent damaging them. Interesting once spring brake is caged it only takes minimal psi to start moving the primary diaphragm setting the brakes. Please post a picture of your damaged cracked part.
Scott
Stick with the 24/30 Your system is set up for it. Changing to the larger 30/30 might cause the rears to lock up.
Pics attached. Oddly, the pancake says long stroke, but I thought they were regular?
I have tightened the cage nut, it's pretty darn tight and I don't want to overtighten it. You can see where the bolt is on the back side as well as the rod on the inside which is about even with the edge of the can. But there is no way I can push the can on the spring on the front and tighten the clamps, I don't have that many hands not to mention the effort is high (I am not a small or older guy!)
look at reply # 16 and you will see how far back the shaft should go into the can. Have you hit the shaft to see if it is stuck. If it bounces the spring isn't caged enough.
I cannot clock it back that far, the tension/torque to do it is very high and I don't want to break something. I tapped on the shaft, no play, it's very tight.
Buy a couple of new cans if the shaft is frozen, they won't let you kill yourself. They sealed the band on the spring brake side of the chamber.
Yep. X2 If in doubt toss it out.
Scott
That's because this is a life safety part. Remember that you're driving a 30,000 pound truck. Stopping is important.
Appreciate the helpful replies today
@craneman and
@dsd. I was trying to get away this weekend but that doesn't look like it's happening now. I am going to get new rears, may get them by Friday otherwise next week. I do not feel comfortable at all cranking it any tighter as I mentioned.
I will look for a write up/vid on installing new cans and adjusting and decide if I want to tackle it or call it in.
Is there any problem with me disconnecting the spring brake line on the busted one? And it's blocked up but I'd like to remove the blocks until the parts come in(we're living in it temporarily and it's a tad shaky). Will I still be able to raise and lower? I'm guessing yes since it's a different system?
There is no pressure on the spring brake release port unless you release the parking brake.
No, the yellow button automatically popped when I got to around 30psi, so it's engaged.
When the yellow handle pops out it engages the spring brake by dumping the air in that line. You have to have over 60 psi. to push the handle in to add air the that port and release the spring brake.
I removed the back can by undoing port 30. 2 chambers on order, will be here tomorrow.
Any concerns if I start the rig and raise the coach to remove the blocks?
If you still have one can on, you have a parking brake on that wheel. Chocking the coach and raising it to get the blocks out is no problem. Remember to put them back in before working on the cans again.
Thanks. Is it possible to drive to a shop to get fixed or is this strictly mobile now? If I could drive, is anything needed, ie clamping the lines, etc?
You would not have a rear brake on the wheel without the can not a very safe idea. You shouldn't have a problem installing a new can.
So your airlines are also in there golden years and probably not as pliable as they were new. Clamping to seal off could crack the inner hose and start a entire new problem. Yes I would do to clear the road but would also be proactively changing that line because it may be damaged. They like all rubber products they have a life and if moved to excess will fail. That being said undisturbed may last your life time. Your results may vary.
Scott
Ok. I had a mechanic suggest clamping and driving. Definitely not what I wanted to do, but wanted to confirm.
I would not clamp the hose scrwe the fitting out of the can and put a pipe cap on the fitting then it will hold air b
New chamber in hand, I got the NAPA one, looks nice, not much info on the site but it's a 2430. Hopefully I can get a mechanic to come over and swap it out today.
The manager there said something that has given me pause- he said adding an adapter on the chamber changes the way the brakes work. He took some classes on them and I suppose that is where he heard that. Any input here? I can continue what I had planned to do, move to another location besides the chamber (IDK where) or scrap this system all together and go with a non-air solution.
Jason, I use the Ready Brake system. It comes in a Ready Brute tow bar or just a device between the coach and the tow bar. It is not invasive of either the coach or car systems. Plus it is not very expensive.
I can take my Ready Brake, my tow bar and hook my car to your coach or any other coach and have towed brakes. KISS
But it is not as elegant as Air Force One and others. But works just fine as does the others.
That is really the other one I was contemplating, specifically the Hercules because I want a 10K tow bar/capacity and this is 12K. I was trying to avoid drilling into the firewall on the toad, but given this experience, I am kinda over that ....
I do have a car trailer I can use in the short term, just adds 2K lbs of trailer as well as the complications when at a campground.
I would be interested in how teeing into the service port of the brake could change the way the brakes work. It would be no different than teeing into the output of the brake relay valve. The relay valve has full pressure supply going in it and the brake treadle valve throttles it. The brake can will have the same pressure with or without the tee. He could be referring to the fact that if the line going to the toad were to break, that can would have less stopping power than the other. You would not see a big pressure drop on the gauges as it would only leak when the brake was applied.
I talked to another very knowledgeable mechanic, he said to disregard what the napa guy said.
I am not sure about where you live, but I am having a heck of a time finding a mobile mechanic here in the Austin area. They are days out at least, if they work on them at all or accept retail work. HD truck mechanics is a great business to be in apparently!
I checked the clearance on the clamps, it clears the adapter with ease, so no clocking needed. Debating if I want to tackle this. It looks like 2 bolts to hold it on, putting the clevis on, and cutting the rod. Watching some vids, it seems there are a couple ways to measure where to cut the rod. And do you push in the parking brake when it pops out at 30 PSI so the shaft is extended?
A creative toad brake that uses a removable air cylinder to press toad brake pedal, that does NOT need taping into coach air brake line.
- Air hose from wet tank (tap tire filling hose) to air tank located in to ad. Nice to use quick disconnects on both ends of air hose between coach & toad.
- 12v 3-way pneumatic valve in toad that responds to coach brake lamp circuit by opening toad air tank valve to push brake pedal.
- Pressure regulator on cylinder air line to prevent locking up toad brakes.
- Coach brake lamp circuit can be wired so it does not activate toad when retarder-only is active, even if retard turns on coach brake lights.
- For brake away, use brake away switch to connect toad battery to 3-way valve, keeping coach brake lamp & toad battery circuit separate with diode.
As previously mentioned, not a fan of Air Force braking system or any system that ties into coach air brake line, just to get proportional braking. Today's problem is just one of many. Also find hitch-activated pull-cable through firewall to be problematic.
Well finally have success on both fronts. The second Napa chamber came in this morning and I had a mobile mechanic swap out both chambers. The adapter was put on the one and all systems were good. Later, I went ahead and hooked up the Brakemaster system, it all works. A couple small leaks that were fixed by tightening the nut around the compression fitting.
Since I am invested in the Brakemaster, I am going to give it a try. I can always switch later. I do like the NSA Hercules. I learned a lot about the coach and appreciate the advice given.
Jason, I'm happy to hear all went well with your BrakeMaster system. I originally installed as it was recommended to me by a respected tech I know. He stated he never had a "come back" on one. I've bought a couple units, and used them on several vehicles, with never a misstep. You might want to buy a spare air coupling connector, as they are proprietary. If one gets damaged by say draging on the ground or anything else, you will be glad you had a spare. ETRAILER carries them: Roadmaster Quick Disconnect Kit for Brakemaster, Price: $38.45 and in Stock
https://www.etrailer.com/Accessories-and-Parts/Roadmaster/RM-921004-80.html?feed=npn&utm_source=google&utm_medium=cpc&utm_campaign=Google%20%7C%20Smart%20Shopping%20-%20Accessories%20and%20Parts%20-%20Maximize%20Revenue&adgroupid=78445819423&campaignid=6893256689&creative=395353250592&device=m&devicemodel=&feeditemid=&keyword=&loc_interest_ms=&loc_physical_ms=9059806&matchtype=&network=u&placement=&position=&gclid=Cj0KCQjwssyJBhDXARIsAK98ITR0kcVR0GB9aKaHRWyWL1NNCdTt0CDYhuJJ0Al9SsXkR_T5MJKjxHYaAtC0EALw_wcB
Barry & Cindy wrote;
"As previously mentioned, not a fan of Air Force braking system or any system that ties into coach air brake line, just to get proportional braking. Today's problem is just one of many. Also find hitch-activated pull-cable through firewall to be problematic."
So I am asking, how do you feel about the combination units traveling our public highway system with the trailer brakes tied into the tractor brakes?
That is an apples and oranges comparison. The semi trailers have their own air tank, relay valve and check valves to the tractor. They can even be manually applied without the truck brakes. You may have seen skid marks on freeways where trailer brakes locked up because of a broken air line. The truck still has brakes and the skid marks go to the shoulder where it finally parks. But as for the the fact I see no problem tying into the coach's air system for toad brakes personally.
One-Way Check Valves | CDL Air Brake Valves | CDL Air Brakes | Pass CDL License (https://www.smartdrivetest.com/air-brake-valves/one-way-check-valves)
I mentioned to James T. at FOT that I was thinking of installing an air brake system on my toad a couple of years ago. He gave me a drawing on where to attach the air line. See atch drawing. I never completed the project; still using the Brake Buddy and hating it.
I am not certain but, that is probably a DOT approved method.
I called MOT and asked James J where to tap into it and he said they use the brake chamber. I will say that the Brakemaster has worked well so far on our inaugural trip, which has included some mountains.
It does eliminate cutting and splicing a brake line. That's for sure.
And eliminates lowering pressure on a single can. The only way that I see it could be improved would be to install a separate relay valve with supply coming from the wet tank and teeing off the output of the treadle valve. A lot of work for little gain from using an unused port on the rear relay valve.