J71 Auto Park Issue History Collection

[is.chowa]

Just Wondering?
How many of you have had an A/P "experience" and what were the "fixes"?

The J71 has in infamous history, having had my own experience. If any of you have had such a failure, it would be "of interest" to collect such info.

Do not need the experience, but the "fault" and "fix", eg: the infamous RGS, "green", "brown" or "gray", the solenoid "dump" valve or relay, or any other problem. On second thought, an "at speed failure" and how you managed that would also be of benefit to others.

There has been volumes of discussion on this issue and it would be nice to put it to bed..

Welcome your responses,

Steve

[greenproduct]

still waiting for mine to be fixed, meanwhile putting jacks down at every stop. would welcome all suggestions, cc does not work either.

[glasair]

After being stuck six times and thousands of $, I disabled mine and use chocks.
A real P.O.S.
Joe

[DaveFL]

Mine went bad two weeks ago, moved it 30 ft in driveway, brakes applied wouldn't release.
No previous indication of a problem. Released by undoing the adjustment nut at the unit.
Sent hydraulic part out to Oregon for rebuild purchased both green and grey switches hoping Oldusedbear has it already heading back to me. Cost $102(including shipping) hydraulics, 30+18 switches(Amazon), 10 for ATF and time.(will estimate 8 hrs including cleanup of parts)
Chevy quit making and passed it on to Workhorse, if this doesn't solve it I will be ready for the manual hand brake Steve it will be interesting to see how many respond.
According to Oldusedbear hydraulics only last as long as tires, same rubber(plastic) breakdown and should be expected by owners.

[is.chowa]

I have put in Brazel's switches in mine as well as the steel bushing and 75A relay so am good to go. The Hydraulic dump valve was replaced as this was causing intermittent lock ups. Dave since your and mine are the same year, gonna keep an eye on for a leaking actuator. Wish I had the part numbers for the O ring for the actuator. Just in case.

Steve

[DaveFL]

Originally Posted by is.chowa

Wish I had the part numbers for the O ring for the actuator. Just in case.

Steve

I didn't see any numbers on my actuator or who the manufacturer was.
I would guess a good hydraulic shop could measure and determine right size. Problem is Chevy's fix is to replace actuator not rebuild it and I would guess workhorse is doing the same thing.

[is.chowa]

Someone did a self rebuild for about $6.00 for the o rings, can't recall if it was on this site.

Steve

[Airstream12557]

My 2005 has the "rotten green switch" by the cylinder near the frame rail and just behind the step. There is a similar looking pressure switch at the pump unit under the hood beside the leveling jacks hydraulic unit. Are both pressure switches the same model number and thus interchangable?

Sam

[woodytwo]

Originally Posted by Airstream12557

My 2005 has the "rotten green switch" by the cylinder near the frame rail and just behind the step. There is a similar looking pressure switch at the pump unit under the hood beside the leveling jacks hydraulic unit. Are both pressure switches the same model number and thus interchangable?

Sam

Hi Sam.

read somewhere recently but can't remember where that the 2005 model year has the J72 version of the auto park brake. So not the problems of the J71. For what it's worth.

[Airstream12557]

I would suggest that everyone with an AutoPark on their motorhome carry a spare "rotten green switch" in case your switch fails and the emergency brake locks up. The switch is fairly easy to access -- it is under a panel that has to be removed by the frame rail just inside the step. If you cannot replace it, any roadside service technician can. The definate sign of failure is leaking hydraulic fluid (small amount) from the switch and around the access panel. The switches can be ordered from any GM dealer (Don Wood Automotive -- www.donwood.com has a good price. Also, Amazon has the switch listed for even less). You need a spare switch in your motorhome!

Lots of information on the Internet on the AutoPark system.

Sam

[DaveFL]

Originally Posted by Airstream12557

.... The switch is fairly easy to access -- it is under a panel that has to be removed by the frame rail just inside the step. If you cannot replace it, any roadside service technician can. ...

Sam

BUT only if he knows the difference between inch pounds and foot pounds.

109 inch pounds and the o-ring does the sealing, more and the aluminum threads will strip, and the part it screws into has to be kept in place or he will lose a spring poppit valve it holds in place.

[Airstream12557]

Good point DaveFL. The o-ring and small diameter aluminum thread should be a clue that the mechanic doesn't need a cheater bar to torque in the switch. ;-(

Point still is that if you have an AutoPark, you should carry a spare "rotten green switch".

Sam -- See you down the road

[Bella123]

New to landyacht and P30, so I looked mine over very carefully as we could not hold 1500 rpm, for 5 seconds as per the test procedure. Easy test , does not hold, rolls down the hill. So, I checked, our bus has a J71 system, and is a 2005.
Changed the atf. Looked at the green switch, no sign of leakage. Checked the actuator and no sign of leakage. The cables looked OK. Adjusted the shoes till locked up and then backed off five clicks. The last step was adjust the cable at the actuator so the travel was 1.25".
We now don't roll down the hill.

Finally, if there is a issue of hydraulic pressure failure on the road, I would as a last resort, cut the cable to be able to drive to a safer repair location. I ordered a spare cable for 30 dollars from stepvanparts.Com and so can fix it with out waiting for parts should the need arise.

Now carry a spare motor control switch, 30 dollars at Amazon, as rvautopark.com says 80 percent of the failures, are this switch, as a failed switch is a hydraulic leak potentially causing lock up.

From you experienced LY owners, or P30, any thoughts?

[Airstream12557]

Bella123, I just received two "rotten green switches" from Amazon; was just under $50 at my door (free shipping). The Amazon switches were in the identical sealed General Motors package as a earlier switch I had ordered on line from a GM parts supplier. His price for one switch was about the same as for two from Amazon. Local parts stores, including GM dealers were about twice as expensive as the on line GM parts supplier.

Good point about cutting the cable.

Sam

[DaveFL]

Originally Posted by Bella123

The cables looked OK. Adjusted the shoes till locked up and then backed off five clicks. The last step was adjust the cable at the actuator so the travel was 1.25".
We now don't roll down the hill....

Finally, if there is a issue of hydraulic pressure failure on the road, I would as a last resort, cut the cable to be able to drive to a safer repair location...

From you experienced LY owners, or P30, any thoughts?

If your cable connection adjustment can free your brake contact pressure there is no need to cut the cable. I backed off the cable adjustment before moving the rv to the repair pad. It was only 50 ft of backing but readjusting much easier than cutting and replacing. Except when you back off the adjustment and it disconnects, pia to reconnect but was less work than replacing cable. As always having the parts with you on the road will make it possible to fix by any mechanic or shop that will use your parts. My local RV dealer has a sign that reads "We only install our parts not yours"

[Bella123]

Thanks for the input.

Did you adjust the cable at the actuator, and there are enough threads to unload the giant spring? Did you have hydraulic pressure on to give you slack, engine on and in neutral? I tried it, and it seemed really heavily loaded with out hydraulic pressure. That would be great to know for sure. If so, how did you keep the shaft from turning, I don't see any flats or any retention device, if you scar the surface then seal issues even if the actuator was not the problem to begin with.

Good point about repair shops parts policy, but we have never had a shop available when we needed one, so I really want to be able to save myself for the items that are possible for me to do if necessary. We kitesurf, and if you are all alone down a dirt road a broken bus and no phone coverage is a really lonely feeling......

Thanks again!

[DaveFL]

I was able to back the tension adjustment nut off the the actuator bolt, lots of load and not easy, used crowbar and vice grips. When actuator was operating it was easy to put the actuator nut(adjuster) back to it's original position. Yes and no on enough threads, I had seen the leak was in the actuator not the RGS so I knew the actuator was going to be removed for service. I didn't test to see if brake was completely released while it was still connected on the threads but I did have enough to backup the 50 ft. Problem is you can't tell how much thread is left holding it on. and the spring has a lot of pull to the end of the treads. I would guess actuator has two inches of movement under pressure while the adjustment nut has about an inch. I didn't know the actuator hydraulic cylinder could be removed without bothering the spring load until I was ready to take off the cylinder.

[Bella123]

OK, good to know, thanks!

Robert

[92landyacht]

Hearing all of these horror stories I'm feeling much better at having a pre-94 P30 with the power steering driven Auto Park with no Rotten Green Switch.