Skip to main content ↑ ↓
Topic: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison (Read 881 times) previous topic - next topic

Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

I think I want to install (I mean have someone install) an exhaust brake on my U-240.  As the title says, it is is a 1994 model with a 3116 Cat and a 3060 Allison 6-speed.  I read that the Pac PRXB is the current state-of-the-art exhaust brake, and according to the Pac website I need the 4" model.  So far, so good.  I'm ready to order.

However, I have been unable to find anyone qualified or willing to install it on my U-240.  Neither FOT or MOT install exhaust brakes.  They prefer not to work directly on the engines, so referred me to a Cat dealer.  I've called a couple of Cat service centers in nearby Lufkin and Beaumont, but they won't work on motorhomes.

So my first question while I'm asking is do I really want a PRXB, or is there something better?  I want to feel safe when decending a mountain grade whether it is an exhaust brake or whatever.  Secondly, where would I get it installed.  I'd rather have it installed by a qualified shop rather than by Big Jim's Diesel Repair and Bait Shop.

Thanks,
Glen
Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099

Re: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #1 –
Take it to an exhaust shop, then do the wiring yourself. I had a local diesel shop do my 93 U280 with C8.3. Check with your local Cummins Coach care facility.
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT

Re: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #2 –
Quote from: Glockjock –
I think I want to install (I mean have someone install) an exhaust brake on my U-240.  As the title says, it is is a 1994 model with a 3116 Cat and a 3060 Allison 6-speed. 

However, I have been unable to find anyone qualified or willing to install it on my U-240.  Neither FOT or MOT install exhaust brakes.  They prefer not to work directly on the engines, so referred me to a Cat dealer.

Glen,

If you're not already reading it, the CatRV Club has a forum that might be of help CAT RV Club, an FMCA Chapter .  We're at the club rally in Kerrville right now (Steve did their forum migration) so I'll try to remember to ask Brett if he has any recommendations.

Michelle
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #3 –
Yes, you do want the PRXB PacBrake.  We have had one on our coach since 2004.

You can tell them your 3116 has the HD valve springs (which started with engine production in late 1992), so you can use the higher PSI (55 PSI as I recall) brake.

Can't help with the who to install question.  PacBrake has wiring diagrams available online.  It will be wired into the Allison ECM under the driver's foot area.

Brett
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: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #4 –
Thanks for the help, y'all.  I also got a real detailed PM with info about a Nacadoches diesel service shop, but apparently they no longer install exhaust brakes.

I admit I was initially surprised by Dave's suggestion to take it to a muffer shop for the physical installation, but then I read more about how they work, and I raised the bed and took a closer look.  It appears to be a simple bolt-on job to the outlet of the turbo.  After that it's a little exhaust pipe fabrication and wiring.  My mind was making it a tougher job than that.    After further study I called my local mechanic who has worked on my other personal diesel equipment and vechicles.  I've also seen motorhomes and class 8 trucks in his shop.  He told me to bring it on in.  So, tomorrow I'm ordering the 55# PRXB.

Thanks again.  I really appreciate the help.  Hope to see y'all on the road.

Glen
Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099

Re: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #5 –
One more quick question here concerning the wiring for the PRXB.  Brett said the PRXB would tie into the Allison ECM, but of course it will still have to be wired into the PRXB solenoid at the rear of the coach.  The diesel mechanic who will install this brake indicated that just about all the truck chassis use wiring harnesses that have several extra wires running from front to back.  He said he'd be surprised if my Foretravel doesn't have extra wires he can use for the PRXB.

So, I guess I'm wondering if you have any quick tips for the wiring.  Again, I'm probably making this more complicated than it really is, but I just want to make sure it is done right the first time.

Glen

Glen Kenney
Colmesneil, Tx
Former owner of
1997 40' U320
Build # 5099

Re: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #6 –
On my '94 U225 there was a coiled up roll of wires in the overhead cabinet to right of pax seat.  The other end should be coiled up somewhere in engine compartment.  Didn't you already have some type of exhaust brake?  If you did, you can use the existing wires.  Hope your mechanic is better than mine was!!!  Mine was really experienced and highly recommended too ::) .  Mine messed up the cruise control.
1994 U225
build #4514

Re: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #7 –
There were a number of coaches that were not fit with exhaust brake from the factory.

Normal wiring for an exhaust brake is switch to Allison ECM and Allison ECM to air solenoid that "powers" the exhaust brake.

Again, PacBrake has wiring schematics of how it should be done.  But, it does not HAVE to go through the Allison ECM.  It does if you want the transmission to automatically downshift when you engage the exhaust brake.

Can't help you on where extra wires are.  I ran 5 strand wires from front to back when we got the coach, so I just used one of them.

Brett
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: Exhaust brake for 1994 U-240 with 3116 Cat/3060 Allison

Reply #8 –
You should find the extra wires coiled or doubled back over themselves Under the dash just to the left of the steering column and then they should be coiled up at the rear of the coach possibly on the drivers side near the frame somewhere
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins