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Cummins M11 engine Jake brake

Fred is a friend with an older SOB with the M11 engine.  Fred told me he has an engine brake.  I check it out and found Cummins does have engine brake for the M11. 

I knew how an engine brake works, but since I ran across a good description, I also included it below, along with Cummins brake documentation.

Re: Cummins M11 engine Jake brake

Reply #1 –
I have seen a m11 jake at the local Cummins shop.  Owner showed it to me.

Can be added to any m11.

If I could wire it to work like the retarder which works on cruise I might be a player.

Looked on eBay a few years ago for these.1 coach buck plus install.

Afraid of the noise with a resonator.
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Cummins M11 engine Jake brake

Reply #2 –
I have a 2 speed "JAKE" brake on my M11. Works great.
1995 U320C SE 40'
Jeep 4x4 Commander - Limited - Hemi
"The Pack"  Yogi and Diesel our Airedales -  Charlie our Boxer/Akita mix. Gone but NEVER forgotten Jake our yellow Lab.
NRA Law Enforcement Firearms instructor - Handgun/shotgun
Regional Firearms instructor for national Armored Transp. Co.

Re: Cummins M11 engine Jake brake

Reply #3 –
I really liked the jake on 3176 cats. 2,4 or 6 cylinders.  Worked on cruise. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Cummins M11 engine Jake brake

Reply #4 –
My '96 Monaco Sig. with the M-11 had a Jake brake pedal and a 2 speed system. Worked great, too bad the rest of the coach wasn't as good.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Cummins M11 engine Jake brake

Reply #5 –
My joke line to prospective high line rv  customers back then was that some companies should have been arrrested for what they made. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Cummins M11 engine Jake brake

Reply #6 –
I believe that the cruise does not work while using the retarder (to slow down, not just switched on) because the retarder is wired to turn the brake lights on when it is working to slow you down (not when it is turned on).

Do jakes and other engine brakes turn the brake lights on when they are working?

If engine brakes DONOT turn the brake lights on when they are working, why does a Retarder? Is this a Foretravel, Allison, or Legal thing?

Would disconnecting the wire feeding the brake lights allow the use of the Retarder when in cruise?
Wyatt
96 U320 40 WTFE, build 4943
84 Toyota Supra towd
2015 Jeep Wrangler towd
Victoria, BC, Canada

Re: Cummins M11 engine Jake brake

Reply #7 –
Wyatt,

Auxiliary brakes, whether exhaust, engine compression or transmission retarder can be wired either way-- either to turn on brake lights or not turn them on.

Good reasoning behind each.

My personal preference is that brake lights be tied to service brakes-- my opinion only.  Been on too many long downgrades with an exhaust brake or engine compression brake on for several miles at a time.  Brake light on that whole way would send invalid information to drivers behind me.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Cummins M11 engine Jake brake

Reply #8 –
Thanks for you info Brett.

I agree with Brett that I would prefer that the brake lights are NOT activated by the Retarder but do worry that the Retarder can slow the coach as if the brakes were applied such that a following driver could rear end my Towd without the brake light warning. Is there a legal precedent, ie can I disconnect the Retarder from the brake lights without legal ramifications?
Wyatt
96 U320 40 WTFE, build 4943
84 Toyota Supra towd
2015 Jeep Wrangler towd
Victoria, BC, Canada

Re: Cummins M11 engine Jake brake

Reply #9 –
I did a search and see posts by Caflashbob indicating that he modified his Retarder so it can be used while using Cruise Control?
Would Bob mind sharing what that modification was?
Wyatt
96 U320 40 WTFE, build 4943
84 Toyota Supra towd
2015 Jeep Wrangler towd
Victoria, BC, Canada

Re: Cummins M11 engine Jake brake

Reply #10 –
Wyatt,

Can't answer the legal question, but know for a fact that some do not turn on brake lights with auxiliary brake on.

I am happy with the way I described it.  If lots of traffic and full engine brake/retarder, I lightly step on the service brake to apply brake  lights.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Cummins M11 engine Jake brake

Reply #11 –
Quote from: wolfe10 –
I am happy with the way I described it.  If lots of traffic and full engine brake/retarder, I lightly step on the service brake to apply brake  lights.
As I have your coach, I am happy, too, with the way you wired it. I've followed SOBs down grades and their brake lights were on all the time; never knew what they were going to do!  :facepalm:
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
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                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Cummins M11 engine Jake brake

Reply #12 –
Had this discussion on the forum a while ago. My coach does not apply brake lights when retarding only, but several member told me they all do. Asked Aubrey at MOT, [ex FOT design electrician] and he said Foretravel started connecting them to the brake light circuit back in the 90's due to DOT regs. Schematics for my coach do not show any sort of connection or relay between brake light circuit and retarder, so not sure how it works.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Cummins M11 engine Jake brake

Reply #13 –
On our Foretravel and likely most others:

  • Retard closes a OEM relay on front 12v panel, this does not turn on rear brake lights.
  • Originally without joystick, retard came on at 3 levels by pressing brake pedal.
  • Brake lights are turned when front or rear brake lines are pressurized, with a pair of pressure switches located on top front metal panel in street-side forward compartment.
  • When joy stick was added either as after-market or during manufacturing, (optionally) a NEW relay was added, located next to the two air brake pressure switches.
  • The 12v power that went to the two air pressure switches was extended to the NEW relay, so that any of the three (front brake, rear brake, retard) would turn on brake lights. This NEW relay coil was powered when the 12v front panel retard OEM relay was closed.
  • If cruise control is active when driving down highway AND our joy stick was not in off-position, whenever our coach hit a dip down on the road, throttle would go to zero position for a moment, activating retard, activating OEM relay, activating left-front compartment new relay, turning on brake lights for a moment, which turns cruise off, keeping us from continuing down highway automatically on cruise.
  • So, we ran a pair of wires from the left-front compartment to a new dash switch, that when off will prevent the new left-front relay from turning on brake lights.
  • Now on highway with cruise, coach recovers from zero throttle position by continuing to cruise without operator intervention.
  • When on a long down mountain grade, if we choose to let vehicles behind know we are retarding, we flip dash switch on.

Re: Cummins M11 engine Jake brake

Reply #14 –
Not sure how it's wired only that my buddy in the California Foretravel store set his sold coaches to turn on the brake lights with retarder on and not disconnect the cruise if engaged.

Beaver Marquis 3176 did the same thing.  Cat called it a customer preference software upgrade after it sold. 

Love to have a jake wired the same.

But I assume it would be noisy with only the resonator.

Keeping the motor revs up in lower gears and making sure the brakes are in new condition I am able to drive almost all the western Rockies grades at fairly full speed.

Not wolf creek or Momarch pass.  Slow just for safety. 

Having both operateable at the same time might be a difficult trick but probably doable.

Something about disconnecting a relay? 

Some bmw's have variable brightness rear brake tail lights.

Brighter the harder you apply the brakes?
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Cummins M11 engine Jake brake

Reply #15 –
Quote from: P. Wyatt Sabourin –
I did a search and see posts by Caflashbob indicating that he modified his Retarder so it can be used while using Cruise Control?
Would Bob mind sharing what that modification was?

I had the Cummins engine retarder on my ISX. Regarding use with cruise control, you turn the retarder on, set all three stages and set your cruise at tour desired speed. As you start descending a grade and the truck(coach) gains speed, the retarder activates. First  stage(2 cylinders) at 2 mph over set speed, second stage at 4 mph and the third stage at 5 mph over the set speed.

Jacobs Engineering(Jake Brake) has a similar feature.

Re: Cummins M11 engine Jake brake

Reply #16 –
Ah modern electronics.  Speed variable jake engagement.  Wonder how to do this on our 97. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4