Workhorse P32 auto park brake

[Mark_K5LXP]

Man, that's great news.  Disaster averted.

I cringe every time I hear my auto brake pump run.  It seems such a complicated system just to actuate a brake.  There's a reason this came to be, but you'd think it could be solved more elegantly and reliably.  Your post has motivated me to check and see if my 'rotten green switch' has been replaced, and sourcing spares for the toolbox.  When these things go south you're stuck, so better to have some spares plus the tools and knowledge to disengage if needed.

The workhorse W22 chassis service manual has a very informative chapter on the J72 brake, and the information by 'oldusedbear' on troubleshooting and fabricating an indicator panel are bookmarked.  <http://www.rvautopark.com/>

Mark B.
Albuquerque, NM

 

[Isaac-1]

Its not just has it been replaced, but has it been replaced recently.  My rotten green switch was replaced by the previous owner of my coach in 2014, or 2015, still it was showing signs of oozing when I replaced it with the Brazel's upgraded switch in 2019.

 

[Henry J Fate]

I replaced my rgs almost one year to the day. It wasn't leaking but was not shutting the pump off. It happened while backing in to a campsite. I had the coach in neutral and pulled the park brake knob and went out to see how the coach was positioned. Came back in to move the coach back ever so slightly. Disengaged the park brake and the pump kept running. I pulled the knob and shut the pump down and left the coach where it was. I figured it was the rgs so I found one at napa and put it in and all was fine.

Amazingly it went bad during a back in to a camp site. Any other time would have been a serious problem. The switch showed no sign of leaking. Just stopped shutting the pump down at pressure limit. Crazy how bad things can work in your favor sometimes. I paid $85 for that switch. I looked at the invoice today.

 

[Johnl89166]

Sorry about being late responding, spent my morning in the doctors office doing my every 6 month check up.

When mine failed I replaced it and the Rotten green switch with the Brazel's upgraded switches, so that I will hopefully never have to deal with it again. US21 - UltraStop P32 Park Brake Pressure Switch Upgrade Kit

 

[Johnl89166]

Its not just has it been replaced, but has it been replaced recently. My rotten green switch was replaced by the previous owner of my coach in 2014, or 2015, still it was showing signs of oozing when I replaced it with the Brazel's upgraded switch in 2019.

Greetings, is the the RGS? Its leaking and I wsnt to make sure I get the right part....it appears the previous owner wrapped it with electrical tape...

 

[Isaac-1]

That looks right, but the gray switch looks almost identical and functions differently so can't be interchanged. Generally most experts agree the brown switch and the green switch are interchangable


p.s. based on how it is mounted I think that is the gray switch, but am not sure as there are several variations on the pump

 

[Johnl89166]

That looks right, but the gray switch looks almost identical and functions differently so can't be interchanged. Generally most experts agree the brown switch and the green switch are interchangable


p.s. based on how it is mounted I think that is the gray switch, but am not sure as there are several variations on the pump

Thanks Issac! Based on your info, i ordered the exact part based on the part #15034355 i saw on the existing part. It seems to be the brown switch.

 

[Henry J Fate]

re-booting this post.

my auto park brake light will not turn off when the brake is disengaged. which switch (there are 2) is responsible for shutting the light off once the brake is disengaged ?

 

[Isaac-1]

This will be the gray stop switch which is most likely located near the actuator under the coach.

p.s. don't ignore it, I had one go out on the drive home from a 400 mile trip, it made it home, barely then dumped all the fluid on the floor of my storage shed a couple of days later.

 

[Henry J Fate]

thanks buddy. i picked up both switches today. gona replace both tomorrow. guess i will keep the used rotten green switch for an emergency spare and toss the other. heading outa sc monday then to tampa, dallas then houston. needed to solve this before departure and i couldnt remember back when i replaced both, which killed the light.

any idea where i could get a backup drive belt for the 8.1 vortex ?

 

[Mark_K5LXP]

any idea where i could get a backup drive belt for the 8.1 vortex ?

I would think most anywhere. Base p/n is GM 12569440, I just put on a Gates K061031HD I got from Rock Auto.

Mark B.
Albuquerque, NM

 

[Isaac-1]

When changing out the green switch be careful and use a backing wrench so as to not unscrew the soft Aluminum fitting it screws into. You may need an extra thin open ended backing wrench to fit and hold the Aluminum fitting.

 

[Henry J Fate]

thank you. i will look at the fitting for the rgs. did not have a problem last time. thanks for the gm part number. i will check around tomorrow. off to sleep. i will update.

 

[Henry J Fate]

replaced both switches. everything normal. the rgs switch was good. keeping the one i took out for a spare. gona pick up a back up switch for the switch on the chassis actuator. that switch was beginning to leak. did not get the back up drive belt will work on that this weekend. put about 1000 miles on the clock with another 1200 to go. thanks for all the help.