P32 - Auto Park - I'm very worried reading posts here

[Alfred622]

I'm new to Class As and purchased a 2005 Winnebago SightSeer in June. I've put almost 3,000 miles on this year and it is working fine. However, it has a P32 Workhorse chassis (manufactured 11/2004) with the Auto Park brake assembly. Auto Park has worked every time for me so far, but I'm extremely nervous after reading the posts here about lockups in the middle of the highway. I drive some highways where, with construction, I would be extremely concerned about an auto-park lockup/failure.

People talk about a booster pump pressure switch that fails, fills with oil, and triggers the lockup. Can anyone tell me where that switch is found (or a photo of what it looks like)?

This forum makes it seem like these Auto Park failures are common - is that really true? While I was on the highway driving the RV home last weekend I noticed the Auto Park light blinked, after a couple of minutes it blinked again, then once more several minutes later. The brakes never applied until I got home and shifted to Park. Is there anything I should be looking at or checking?

I did check the Power Steering reservoir and that is full. I don't know where the brake reservoir is located. (How do you learn where these things are found - I don't know a whole bunch about this sort of stuff)

Thanks!

[Alfred622]

I'm new to Class As and purchased a 2005 Winnebago SightSeer in June. I've put almost 3,000 miles on this year and it is working fine. However, it has a P32 Workhorse chassis (manufactured 11/2004) with the Auto Park brake assembly. Auto Park has worked every time for me so far, but I'm extremely nervous after reading the posts here about lockups in the middle of the highway. I drive some highways where, with construction, I would be extremely concerned about an auto-park lockup/failure.

People talk about a booster pump pressure switch that fails, fills with oil, and triggers the lockup. Can anyone tell me where that switch is found (or a photo of what it looks like)?

This forum makes it seem like these Auto Park failures are common - is that really true? While I was on the highway driving the RV home last weekend I noticed the Auto Park light blinked, after a couple of minutes it blinked again, then once more several minutes later. The brakes never applied until I got home and shifted to Park. Is there anything I should be looking at or checking?

I did check the Power Steering reservoir and that is full. I don't know where the brake reservoir is located. (How do you learn where these things are found - I don't know a whole bunch about this sort of stuff)

Thanks!

[YosemiteBobR]

Alfred622:

Auto – Park Brake Reservoir P–Models

The Auto – Park brake hydraulic motor reservoir on P-Models should be checked during normal scheduled maintenance to make sure that it has not collected moisture or become contaminated with water.

Water can freeze in the reservoir blocking the motor from picking up oil. This can result in a non – wanted parking brake apply or parking brake that will not release.

When contaminated, the reservoir should be cleaned and new oil (transmission or hydraulic oil ) installed.

This is the first electronic installment of the Technical Advice column provided for the club by Chris Christy. A big thank you for all these great tips and we'll look forward to the "Technical Tips" column in the next WCMC Newsletter


There are many tips and more like these on the forum. Under 'Find' just put in Auto Park and see how much comes up. I can not respond to this as I do not have the P32. But here is some help and I'm sure someone will post as well.

[W8RLM]

Alfred,

I have a 2003 32V Brave on the P32 chassis. When I park my motorhome in the driveway, it is on a grade, nose down. I have to raise the front fairly high to get the coach level enough to run the refrigerator and open the slides. I block the rear wheels, but also depend on the Auto Park.

I also have the dealer check the fluid level and the switches in the system when I have the oil changed. They provide that service as part of the lube and oil service.

In over two years, we've put over 33000 miles on the Brave incuding the Alaska tour this year. That added 9900 miles to the coach. We have never had a problem with the Auto Park.

Enjoy the motorhome.

W8RLM - Bob

[max49]

Alfred, I don't like this parking brake either. I just don't trust it and don't know why puttinp the gear shift in park does the same thing as the park button. I have'nt had any touble with it tho, not yet. Don't turn the key off while moving.
If you have the same WH owner manual as me , you'll find where it is located on page 4-52 "under the vehicle, behind the transmission on the passenger side" it takes Dexron 3 automatic tranny oil.
If you're not scared of the auto park, you will be when you see all the warnings in the manual.(over and over again)

[Alfred622]

Thanks, everyone, for your postings. I value what you said.

I'm also amazed that there were so few replies. I'm thinking that maybe this Auto Park problem is not as bad as I thought it might be. Over 60 folks have read this thread but most didn't reply. Perhaps they were all looking for information too.

None of the moderators chimed in either. I don't know how to take that- is it because the problem is real with Auto Park and they don't have any solutions to offer, or is their silence indicitative there is not a problem.

I was hoping for dozens of people to indicate they had been stuck in the middle of traffic with an auto park lockup (in which case I'd really be nervous) or dozens of folks to say they have thousands of miles on their P32 and no problems (in which case I'd relax).

Perhaps if anyone else with experience on a P32, with or without an Auto Park problem, reads this they might be inclined to reply.

Thanks all!

[max49]

Alfred, I told you where the book says the reservoir is. I had never seen it but put the Damon up on it's jacks and climbed under to find the mastercylinder and while I was at it look for that resevoir for the auto park. I could'nt find any thing that looked like a reservoir back by the autopark mechanism.
I did find a white, tranluscent tank that was labeled "dexron" under the hood. It's not the power steering tank, but close to it. I wonder if that's it.
Let's just hope we don't have trouble with the autopark. I worry it might lock up by it self , going down the road, and it is the ONLY thing holding it and my boat on the steep boat ramp while I'm behind it lauching the boat. It just seems to be an idea from a mad scientist to design a brake that needs electricity to disengage and no other back up brake like a park pawl. I know air brakes need air but they are obviouly very reliable, since every truck in the world has them.

[Freddy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Alfred622:
I'm also amazed that there were so few replies. I'm thinking that maybe this Auto Park problem is not as bad as I thought it might be. </div></BLOCKQUOTE>

I think - not sure - that the Auto Park brake is for some reason unknown to me only on the Sightseer.

I had a 2000 Sightseer (or, 2001; can't remember which but it was second year they were out. Within a few months the Auto Park brake locked up at a railroad crossing! Fortunately, we were not first in line, and were on a 4-lane US Hwy, so traffic could get around us.

That day I traded the Sightseer for the Brave.

My advice is to have lots of flares and triangles, know your precise location (Good Sam sometimes has problems finding you on a map), and evacuate the bus until the tow truck arrives!

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by max49:
It just seems to be an idea from a mad scientist to design a brake that needs electricity to disengage and no other back up brake like a park pawl. I know air brakes need air but they are obviously very reliable, since every truck in the world has them. </div></BLOCKQUOTE>The auto brake has been and continues to be a reliable system. It does not generally have any more or less failures than the equivalent fleet of vehicles that use air brakes.

The auto apply brake is basically the same technology as a air parking brake. If the auto apply brake fails it locks up. If the air brake system fails it will also lock up.

Let's talk about the "reason" for an auto apply brake. This brake wasn't devised by a mad scientist and there is a clear and distinct reason why it exists and it has "nothing" to do with the chassis builder.

Let's take it down to the lower GVW. GM will not provide a parking pawl in a 4L80E or 4L85E due to the GVW of the vehicle. GM says that a either the pawl or the case will break affording the owner of the vehicle a broken transmission case and no brake. Only solution is an auto apply brake. Why???, Ask Uncle Sam he sets the motor vehicle standard for braking devices on heavy vehicles.

Let's consider the W20 & W22, these vehicles have parking pawl in the T1000 transmission. Why?? because Allison said it could be done. Therefore a mechanical foot parking brake is provided to supplement the pawl. Now there is a technique to setting this pawl. You have to set the parking brake, allow the vehicle to unload on the brake by taking your foot off of the service brake and then shift to park. The pawl if you will is a secondary device to the foot brake.

The third and final scenario applies to the 24K GVW W24 with the Allison 2100MH. Surely this transmission should have a parking pawl but no it doesn't. Why? because Allison won't install a parking pawl in one of their transmission that has to hold back 30,000 pounds. The only solution acceptable again to U.S. is an auto apply brake.

The auto apply brake is quite extensively used in both motorhomes and commercial chassis and it is approved by every government body that control or certifies motor vehicles for operation on the highways.

Now if an 18 wheeler dumped its air on a rail road track and the brakes automatically set and for all the reliability of the air brake system you had better call Maaco because that truck's gonna need a paint job.

The best thing that an owner can do to assure the reliability of the auto apply brake is routine service and maintenance.

Commercial trucks over 30K of GVW do not have parking pawls if they are using an Allison automatic or generally any other automatic transmission. If they are using a manual transmission these units don't have parking pawls however they can be left in gear but this is not considered to be a reliable brake by automotive designers. The only approved braking solution for air equipped trucks is when the absence of pressure in the air brake system is sensed the brakes become automatically set.

The auto apply brake works the same way, if an absence of pressure is sensed in the hydraulic system the brakes become automatically set.

If a parking pawl is required in all automatic transmissions then the solution rests with the transmission builder. The auto apply brake is a solution provided by the chassis builder that works until such a time as everyone can have parking pawls.

[max49]

Driver, I know you always defend Workhorse. How can you possibly defend the autopark system? Nobody can defend that system except to say something like "uh well , it works until we can think of a safer more dependable way". You know like a foot /cable operated parking brake and a Park pawl in the transmission for a back up.
You seem so well connected with Workhorse, why don't you lobby WH to do the right thing and recall all those dangerous MH's they sold with the autopark before someone gets killed because of it. They don't have to wait for that and a good lawyer to help them do it.
Air brakes don't come on just because the electricity is taken away from it. Air brakes out number autopark system by a million to one and are proven reliable.
Don't let your keys get caught on the gearshift as you shift from Drive to 2nd or overdrive because if that key gets turned off while you're driving down the road. You will come to a screeching stop and /or tear your auto park or driveshaft out of the vehicle.
Air brakes , apply the normal wheel brakes, not a driveshaft brake.
What kind of "routine service and maintenance" are you suppose to do to a parking brake? Adjust the cable?
My HH does have P for park on the gearshift. I thought it was a Park in addition to the yellow button parking brake. All it does is apply the auto park. Why it needs 2 different things to do the same thing, apply the same driveshaft brake, who knows. I feel it was deception. "fool me once, shame on you."
I had no idea what a "autopark was when I bought this MH but I certainly thought I had a Park in the transmission.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by max49:
Driver, I know you always defend Workhorse. How can you possibly defend the autopark system? </div></BLOCKQUOTE>Well I didn't know that WCC and the auto apply brake were one in the same company. Now I clearly recall renting a large straight-job moving truck from Ryder a while back and this thing had a diesel engine, hydraulic brakes and an auto apply brake.

Under the hood there arose such a clatter that we pulled off into a rest top just to see what was the matter.

There we were, stuck on I-89 in Vermont in a rest stop. I believe a fan belt idler failed that caused the fan belt to slip and we couldn't get the auto apply brake to release. The tow truck driver dropped the driveshaft and we were towed to a service facility. The failed part was replaced and we were on our way.

Clearly WCC isn't the first to use this type system and it won't be the last. Now don't look now but when FL goes with a 2000 series transmission in their new "FRED" it's "not" going to have a parking pawl either because Allison doesn't install a parking pawl for the 26,000 pounds of GVW that the transmission has to deal with. They are going to have to come up with something to brake the vehicle when it's stationary. The FRED will most likely have an AAB system.

A mechanical foot brake by itself is not a reliable device when used without a parking pawl because it largely depends on the strength of the operator to push on the pedal. Each and every one of us will push the pedal differently. I'll push the pedal to the firewall where my wife can't push the pedal much past 1/3 of the way. The parking pawl is a necessary secondary device that will hold the vehicle's weight when properly used in conjunction with the mechanical foot brake. The AAB makes up for inconsistencies in drivers and is certified to hold the weight of the vehicle without a parking pawl.

I can't comment of your key scenario unless to suggest that perhaps you need to have fewer keys on your key ring. Even you would have to admit that the event you describe is going to be somewhat difficult to repeat using scientific method.

I was speaking with 2 - P32 owners here in the fairground that have AAB systems and although they voiced concern from what is written here both agreed that their systems were reliable and so far touble free.

[Alfred622]

I apprecate all that has been said. I'm not concerned about why we have AutoPark on the P32 chassis - the rationale is nice, but it doesn't help the basic question:

Does the auto park system, as implemented by Workhorse on their P32 chassis, have a liklihood of unintended lock-ups?

If the answer is Yes (as it seems to be), then the second question is:

What preventive maintenance can be performed to minimize the liklihood of an unintended lockup?

Some have suggested the lockups are due to hydraulic fluid leaking into a pressure switch - and that the switch should be periodically inspected.

I've emailed Workhorse Customer Service, who normally responds to my questions promptly, with these questions and I've not received a reply yet.

DriVer, you seem to know a lot about Workhorse - is there anyway you can help us find out about the failure rate of the P32 Auto Park braking system and find any suggestions for preventive maintenance to minimize an unintended AutoPark activiation?

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Alfred622:
- is there anyway you can help us find out about the failure rate of the P32 Auto Park braking system and find any suggestions for preventive maintenance to minimize an unintended AutoPark activation? </div></BLOCKQUOTE>I've generated a lot of ink toward this issue is this thread however the best resource to learn all about your particular system is in your "WCC Owners Manual". Another good resource regarding both the J71 and the newer J72 Auto Apply Parking Brake system would be in the 2006 Workhorse Gas Motorhome Chassis Guide. There are 10 pages dedicated in the publication that completely describe the system and WCC has included all the schematics for the circuits and have clearly explained all the components and how they are designed to operate with one another.

I'm sure that this will be a invaluable resource that will increase your knowledge of the system and thereby giving you a text book incite as to how the AAPBS works.

Re: Preventative Maintenance on the AAPBS on Page 93 of the 06 WGMHCG, Preferred Maintenance for Trouble Free Operation, Schedule "D" reads as follows:

Schedule D is to be completed at all engine oil change/chassis lubrication (3,000 miles or 3 months)

The schedule D procedure as applies the AAPBS is as follows and it also includes additional component and procedures that require attention other than than the AAPBS,

Auto Park Brake - General inspection, check adjustments and fluid level when equipped (16.5K, 17K, 18K, and 24K lb. chassis)

The failure rate if it exists can not be substantial because we would have seen some type of movement toward developing a Service Bulletin and in the "guide" there are none published for the AAPBS. There is one TSB (80101-T) re: 2001 P series that deals with resolving a ground connection however it's been resolved and doesn't involve any other model year chassis.

[KD4AO Bob]

In addition to what is stated above, by research I have discovered that the implementation of Auto-Park in the P32 is different or doesn't exist based on the GVWR of the vehicle and the year of the chassis. Under 16000lbs appears to not have Auto-Park although some use the same driveline drum assembly for the manual park. As stated, check your Workhorse owners manual and the service manual.