Community Forums

Markstal · 02-12-2025, 06:35 PM

Has anyone found a place to buy parts to repair J 72 prop shaft parking brake ?
I am a tech , this is not hard to fix , some o ring seals and a friction disc and it is repaired, everyone wants to replace unit $3000.00 , I’ll convert to something else before I spend that , HELP

D Gardiner · 02-13-2025, 11:23 PM

Assume you are talking about the auto park brake system.

If so,
Chevy P-30 Auto Parking Brake (welcome to our nightmare)

https://www.ultrarvproducts.com/Auto...uG4PWcHr8QbQeF

https://www.irv2.com/forums/f22/okay...em-195374.html

edgray · 02-14-2025, 08:55 AM

Quote:

Originally Posted by D Gardiner

Assume you are talking about the auto park brake system.

If so,
Chevy P-30 Auto Parking Brake (welcome to our nightmare)

https://www.ultrarvproducts.com/Auto...uG4PWcHr8QbQeF

https://www.irv2.com/forums/f22/okay...em-195374.html

Yes he is, but your links are about the "original" J71 AAPB. He is asking for help with the J72 AAPB system. The J72 was a much improved version first introduced by WCC for their 2005 model year P-32 series chassis. I think it MAY have also been used on the 2005 and 2006 W-24 series chassis. NONE of the W-22 series chassis used either of them, always relying on a foot-applied PB.

Markstal · 02-15-2025, 02:48 PM

Yes , but it a j72 , it is a hydraulic unit , not brake shoes , but I wish it was , don’t understand why parts not available to fix this , only need 2 o rings and a friction disc to repair it , not interested in spending over $3000 to replace the complete assembly, I think it would be cheaper to convert to a older system

Markstal · 02-15-2025, 02:52 PM

Yes , that is correct, does anyone know where to get parts to fix j72 ????

Markstal · 02-15-2025, 03:43 PM

Does anyone have the list of parts needed to convert this to the manual pull handle brake like on a P30 step van ?

David 70 · 02-15-2025, 07:09 PM

The P30 system is not like the J72. The only place I would know to look is Ultra RV, but I don't know if they will have separate parts. The J71 used a drum brake and shoes like the old drum brake on cars. The J72 uses a disc type brake. It is a spring applied disc that clamps the two sets of discs. it uses hydraulic pressure to release it. I don't know if you could overcome the spring pressure with a foot or hand lever to release it. The J71 one would be applied with the foot or hand lever like on most other park brakes. The difference is that on the J72 the hydraulic cylinder is an integral part of the brake assembly whereas the J71 the hydraulic cylinder is a separate part. My 2004 W24 has the J72 setup.

I looked on Ultra RV website and, in their comments, it states they are not rebuildable. Therefore, I don't believe the parts are able to be found. The O-rings should just be standard O-rings, but the disc is probably nowhere to be had.

l1v3fr33ord1 · 02-16-2025, 04:19 AM

Markstal-

First off, welcome to iRV2!

Second, it is possible/likely that I'm completely off-base, and I expect and hope the Workhorse experts will correct me, if I confuse the J72 system with the Auto-Park system for which there has been much electronic ink spilled over the past ten or fifteen years.

I looked at Workhorse-chassis coaches when I moved from Class C to Class A, and read many a thread on the Auto-Park system. One of the threads detailed a home-built replacement for the Auto-Park system:

Okay ... I SOLVED THE AUTO PARK BRAKE PROBLEM!

by iRV2 member Jerry Peck. The thread is very long now, 196 posts, but I suggest reading it, unless the J72 system you have is completely different and none of what is posted there applies. As a strategy, you might read the first 20 posts, look at Jerry's write-up (downloadable), read the last 20 posts and then the "middle" posts.

I liked what I saw. If I had bought a coach with the Auto-Park, I would have replaced it after the first or second failure with Jerry's system.

Finally, you should add a "signature" to your profile. It contains whatever info you want; most people put info about their coach there, so they don't have to type it into each message. Instructions for adding a signature are here.

Edit: I understand the difference between the actuator, which Jerry's replacement addresses, and the actuated device- the brake. My post addresses the former, and your problem/questions may address the latter. I apologize in advance if my pushing an Auto-Park "solution" forward doesn't help you at all!

Markstal · 02-16-2025, 03:51 PM

Hi , yes I am well aware of how the system works , I have it apart and cleaned up ready to find the items I need to fix it , or the parts to convert it to something more reliable and serviceable, spicer makes the accouter , someone has parts for it , that is the issue

David 70 · 02-16-2025, 06:34 PM

I had no doubt that you knew how it works. I was trying to explain the difference to the ones that kept talking about the J71. As we both know the two are completely different and it would be hard to make a hand or foot applied one out of it. I don't know if the Allison ever had a J71 on it.