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Topic: Time to go over going down steep grades,  (Read 1920 times) previous topic - next topic

Re: Time to go over going down steep grades,

Reply #20 –
Quote from: oldguy –
I have both and in mountain driving I love the Jake and in town I use the retarder. If I find I'm
in too high a gear with Jake I will use the retarder to get me into a lower gear. Sometimes I don't
want shift down and the Jake won't quite hold the speed I will use the first notch with the retarder.
Show boating. I hope one day to have an operational Jake on my coach. Talk about brake envy. You never can have too much stopping capability and more options is great. IMO.

Re: Time to go over going down steep grades,

Reply #21 –
Quote from: oldguy –
I have both and in mountain driving I love the Jake and in town I use the retarder.

How did you wind up with both?  Did you add the jake or did a previous owner?

Re: Time to go over going down steep grades,

Reply #22 –
George,

Not Perter but he DIY the job. Here is a link to the thread what will help you out.
Adding a Jake brake

Mike

Re: Time to go over going down steep grades,

Reply #23 –
Quote from: kgrover –
I haven't had to do any really big grades in the GV yet, but the few I have I've used the trans retarder and brakes without issue. I was taught when getting my CDL, that you apply the brakes firmly and drop your speed 10-20 mph and then let the retarder/engine braking work until the speed climbs back up, Then apply the brakes again. This gives the brakes time to cool in between applications. That's if your retarder/engine brake isn't enough to keep your speed where you want it. Riding the brakes for a long time is bad, just builds up heat, but on and off applications give them time to cool off.

This was our procedure in our '95 and our '02 coaches.  I watched the Silverleaf and monitored temps while heading up and down the more acute grades .  We never had an issue with getting too hot while the brakes and retarder worked in tandem.  On our '93 there was a Jake brake.  It almost never worked properly.  Finally, at a balloon rally in Albuquerque, we had a skinny little tech look at the issue.  He managed to find a broken wire somewhere in a ridiculous place and we were in business.  (He said that you always need one skinny guy on the crew.) I have to say that we much preferred the retarder.
Heading to Leadville, CO to see our son, I watched a truck with its brakes on FIRE because of poor grade management by the driver.  This was somewhere in the Eisenhower Tunnel area.  Costly and dangerous!

Re: Time to go over going down steep grades,

Reply #24 –
Not sure about the coach brakes total ability to absorb and/or to dissipate braking energy input to the rotor but I did replace the front two steel oem rotors with ductile iron Meritor rotors. Way stronger braking action. Much higher coefficient of friction it seems. The steel rotors were on my coach with 130/110? D2 valve setting were too cold blooded in my opinion. Versus rely on the retarder when cold I used to regularly apply the brakes repeatedly to warm them up when in-town driving to give me a stronger response. Did not do this on higher speed more open roads.

On an early trip after buying the coach I had a fedex van panic stop 200 yards in front of me towing to avoid missing a left turn for him. Total panic stop. The pre warmed up brakes along with a full application of the retarder  narrowly avoided a crash.

The grey iron(ductile) is so much more aggressive cold that I decreased the retarder use in town as the brakes now stop like the steel rotors did with a 2 click retrader input.

Much more confident feeling to me.

The ductile rotors may or may not have increased the brakes capacity as I stated but the stronger action cold has eliminated my application of the brakes regularly while driving just to increase their response level.

I tried softer pads. I tried aftermarket pads to increase the brakes cold action.

Ah the rotors fixed it. Fronts only were enough for me.

Anyone else noticed my braking issue?  Total system rebuilt twice. Then the rotors. Correct clay based grease. Rebuilt the calipers pad pin holes as they were worn larger. Experienced Cummins dealer shop that does the local fire engines and military base work.

My understanding is that a m11 Jake is about 40% of the retarders retardation if the retarder is fully on. 

My coach will retain its cruise control operation when the retarder engages. On and off cruise still on.

Handy speed reminder in heavy enforcement areas as non visible downgrades do cause the coach to pass the selected mph. Tug at the coach then off.

I understand the brake lights do come on when the retarder is being used.

Re: Time to go over going down steep grades,

Reply #25 –
Speaking of Jakes and retarders, how many know that Clessie Cummins was not only the founder of the Cummins Engine Co. but also invented the Jake brake? He also had 33 other patents.

Pierce

Re: Time to go over going down steep grades,

Reply #26 –
Has anyone here or heard of electric trailer brakes getting burnt up because of the retarder activating the brake lights? This was a concern of mine so I disconnected that feature. I just felt I didn't want to be replacing trailer brakes due to retarder activation. But towing a 9,000 lb trailer would seem to contribute to the retarder temps going up. I'm now thinking replacing trailer brakes should not be a concern over retarder temps. Steep grades can be very stressful. I have used a few different techniques to keep speed down and have learned to just go slow. The Allison trans won't up shift under deceleration so overrev is a concern. All these mechanical systems have the possibilities of failure so these situations have my utmost attention. Jim.   

Re: Time to go over going down steep grades,

Reply #27 –
Some have wired a dash toggle switch that optionally prevents retard from turn on brake lights. Additional advantage is cruise control does not turn off on slight highway dips when joy stick is not in off position.

Re: Time to go over going down steep grades,

Reply #28 –
Does anyone have info/diagrams on the toggle used and how it was wired to optionally cut out the brake light for the retarder?

Re: Time to go over going down steep grades,

Reply #29 –
I use an adjustable inertia based brake controller as i assume most do.  Braking is braking so even if it's the retarder, you're trying to decelerate so some level of trailer braking is appropriate. The trick is how to set it.  With a pickup truck (or any typical tow vehicle) the recommendation is to get up to about 30mph and manually apply the trailer brakes only and set them so they are just on the verge of lock up.  Of course that is easier said than done with the coach since i can't really see the trailer wheels. In any case i generally set them on the lighter side and figure any braking assist is helpful. I do want them to engage with the retarder and if i find them running too hot i will simply dial them back a little bit.

Re: Time to go over going down steep grades,

Reply #30 –
To Fourdayoff, I install diodes to keep the retarder from activating the trailer brake controller. Or you can install a separate brake light switch that only does the trailer brake controller.

Re: Time to go over going down steep grades,

Reply #31 –
I put in separate air switch for the trailer controller so the trailer brakes only come on with the
coach brakes. 

Re: Time to go over going down steep grades,

Reply #32 –
Quote from: red tractor –
To Fourdayoff, I install diodes to keep the retarder from activating the trailer brake controller. Or you can install a separate brake light switch that only does the trailer brake controller.
That's what I did. Retarder never operates trailer brakes. Stepping on the brake peddle operated trailer brakes. On my coach retarder and brakes both operate cooling fans on hi also. Additional parasite loads do add up and again more is better 

Re: Time to go over going down steep grades,

Reply #33 –
Quote from: dsd –
That's what I did. Retarder never operates trailer brakes. Stepping on the brake peddle operated trailer brakes. On my coach retarder and brakes both operate cooling fans on hi also. Additional parasite loads do add up and again more is better
Scott, this is what I have and I'm wondering if the extra 9,000 lbs pushing on the coach contributes to higher retarder temps. Maybe replacing trailer brakes would be better. Jim. 

Re: Time to go over going down steep grades,

Reply #34 –
I would think a lower gear would be better as on a long hill you could completely toast your trailer brakes.

Re: Time to go over going down steep grades,

Reply #35 –
Quote from: oldguy –
I would think a lower gear would be better as on a long hill you could completely toast your trailer brakes.


Yup, and higher engine RPM also means that the water pump turns faster, so coolant circulation through the transmission cooler is increased.

Re: Time to go over going down steep grades,

Reply #36 –
Quote from: oldguy –
I would think a lower gear would be better as on a long hill you could completely toast your trailer brakes.
Peter, this was my thought in disconnecting the retarder activating the brake lights but am I now causing more retarder heat? Also I've had complaints from WS6 Keith following me about running up on me with no brake lights while slowing with just retarder. 2 issues I'm contemplating. Jim. 

Re: Time to go over going down steep grades,

Reply #37 –
Check these out to keep retarder from turning on brake lights sometimes. Let us know if you need more info: ----------- Add a dash switch on the wire from main retard-relay mounted on dash 12v breaker panel in front of copilot chair to retard brake light relay. Or add the switch on this retard brake light relay's wire to air brake switches. Our coach is different, as the air brake switches and retard brake light relay are mounted on front panel in street-side front compartment. Switch is VERY handy to keep cruise control from turning off on highway dips when retard joystick is not in off position. Dip causes throttle to move to idle position allowing retard to come on, and at bottom of dip throttle will accelerate coach turning off retard, if cruise control is still active. ------------ We put in a dash switch to optionally not turn brakes lights on when retarder is active. We did it for freeway driving to keep retard from turning off cruise control. If driving on cruise with joy stick not fully off, and the highway goes down even a small hill, the throttle goes to idle position, retard will kick in and when the highway goes level or starts to climb again, we used to unexpectedly find cruise turned off. With the new retard/brake light switch, we can prevent cruise from turning off. Always driving with joy stick off eliminates the need for the switch. On our coach there is a retard brake light relay next to the two (front & rear) air brake pressure switches, all of which are located high up on the front panel of the forward street side bay (just behind the headlights). Running a pair of wires from this retard relay up to dash gave us our option. Some coaches where joy stick was added post-production, the retard brake light relay was not added, so these coaches do not ever turn on brake lights when their retarder is activated. ------------

Re: Time to go over going down steep grades,

Reply #38 –
I added a air switch by the brake light switches and powered the trailer controller so it works
from that switch instead of the brake lights, that way the retarder works separately from the trailer
bakes.

Re: Time to go over going down steep grades,

Reply #39 –
Quote from: Barry & Cindy –
Check these out to keep retarder from turning on brake lights sometimes. Let us know if you need more info: ----------- Add a dash switch on the wire from main retard-relay mounted on dash 12v breaker panel in front of copilot chair to retard brake light relay. Or add the switch on this retard brake light relay's wire to air brake switches. Our coach is different, as the air brake switches and retard brake light relay are mounted on front panel in street-side front compartment. Switch is VERY handy to keep cruise control from turning off on highway dips when retard joystick is not in off position. Dip causes throttle to move to idle position allowing retard to come on, and at bottom of dip throttle will accelerate coach turning off retard, if cruise control is still active. ------------ We put in a dash switch to optionally not turn brakes lights on when retarder is active. We did it for freeway driving to keep retard from turning off cruise control. If driving on cruise with joy stick not fully off, and the highway goes down even a small hill, the throttle goes to idle position, retard will kick in and when the highway goes level or starts to climb again, we used to unexpectedly find cruise turned off. With the new retard/brake light switch, we can prevent cruise from turning off. Always driving with joy stick off eliminates the need for the switch. On our coach there is a retard brake light relay next to the two (front & rear) air brake pressure switches, all of which are located high up on the front panel of the forward street side bay (just behind the headlights). Running a pair of wires from this retard relay up to dash gave us our option. Some coaches where joy stick was added post-production, the retard brake light relay was not added, so these coaches do not ever turn on brake lights when their retarder is activated. ------------

Or the relay was disconnected. My Foretravel salesman/friend  Roger T. who worked at and then ran the sales at the Foretravel  of California store after I left mentioned how this was a popular mod. Seems mine must be disconnected. So maybe my coaches brake lights do not come on when the retarder operates on cruise.

I had following people I thought told me that they did come on. Seems unlikely. I will have to be careful if being followed closely it seems. Lots of good mods to allow the retarder to work on cruise which is one of my favorite things when driving the coach.

A lot of owners here were holding back this info it seems. I casually posted many years ago that that was how mine was setup. Either some read my posts or like thinking of great minds took over or their coaches had had the mods long ago.

Great info as I said. I hope this can be pinned for future info both for the mod and to warn that the brake lights my not be on when on cruise and the retarder operates or does the taillights never operate on retarder cruise on or off?