Chevrolet Auto Park

[jmstromquisst]

I didn't think thoroughly enough about the downfalls of the Chevrolet chases when I bought my last motorhome. I've sure thought enough about it since. The previous owner had disabled the system (I still don't know how) so that it does not/cannot apply the brake. Instead of a functional Auto Park, I got a sticky note on the dash reminding me to disengage the brake before I drove off. After missing that step a few times and getting tired of brake smoke, I build an electronic alarm to remind me to take off the brake when shifting out of park . . . and to apply the brake when shifting back into park. The alarm works perfect, ever time; and now I've got the routine down real good. I wish I'd had the alarm sooner.

Now I've go an emergency brake pedal that goes to the floor and a brake that does not hold so good. I'm suspecting that my shoes are toast, so I'm looking at opening the brake up and having a look. Anyone had a go at this? Also, are there parts (such as shoes) available, or should I rely on the local clutch and brake rebuilders? I would really like to see this thing grab really good so I can trust the motorhome to stay put when I've applied the brake.


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[moisheh]

THE APB is a big piece of Junk. Adjusting is the worst of your worries. There are some mods that will help but the whole system never worked properly. Brazell's has an air version that would eliminate 95% of the problems. About $1800 plus installation. Some of the APB parts are no longer available. Brazel and a few others have some parts but be prepared to pay dearly. I had the APB lock up on me on I-10 in Tucson in 4 o'clock traffic. Scary. I would never buy a MH with that system again.

Moisheh

[wolfe10]

10th digit denotes the year. P= 1993

[tropical36]

wolfe10 wrote:
According to the VIN (16BKP37N4P3307675), the chassis is a 1993.

That you don't see often with the chassis year being the same as the house year and title.

[wolfe10]

According to the VIN (16BKP37N4P3307675), the chassis is a 1993.

[tropical36]

Gjac wrote:
With your model year there is also an adjustment on the foot pedal cable, if I remember correctly there is an adjustable clevis pin that attaches to the end of the foot pedal cable and the clevis attaching to the transmission shift mechanism, that can be adjusted also along with the star wheel I previously posted. When you go from park to drive do you hear a hydraulic pump coming on? If so your auto park system is still hooked up. There is a green switch inside the metal box that surrounds the system.Remove the inside plate closest to the drive shaft you will be able to see and access all the components of the system. Remove the electrical connection and see if there is any transmission fluid inside that connection fluid. Also check the fluid level in the reservoir it may me too low. If you post back your findings you will get more help in diagnosing the problem. Good Luck.

Probably a 92 chassis at best, so no self contained system and no steel box with fluid reservoir, so this is most likely a version II and relies on the power boost pump that supplies brake and power steering power. Gonna have that pesky cam sw. as well and not the tranny mounted version, that connects to the shift lever. Once one mounts a momentary bypass button for the cam sw. for when it's needed and usually for reverse, this system is fairly reliable.

[jmstromquisst]

My VIN: 16BKP37N4P3307675.
As stated in my original post, I do not know why it was disconnected. Without hands-on testing, I cannot say exactly how it was disconnected, nor can I know what is wrong with it. I am a bit leery about the design, I'm convinced it was not one of GM's best ideas. There is also more than one owner who has retrofit the auto park with a linear actuator, which gets rid of the hydraulic cylinder, the RGS, the original pump relay, and off course the pump and reservoir. It eliminates about eight hydraulic leak potentials and greatly simplifies the brake. All this still relies on the drum brake, which is why I insist in giving that a good look ,,, regardless of what else I do. It is nice to know that there are owners out there who have auto parks that they still trust. I also agree with the post that says my foot brake should hold the vehicle well enough so it should be at least obvious it's still on when I attempt to drive away, making the alarm system no essential; but it's never worked that well since I've owned the vehicle.

[Gjac]

With your model year there is also an adjustment on the foot pedal cable, if I remember correctly there is an adjustable clevis pin that attaches to the end of the foot pedal cable and the clevis attaching to the transmission shift mechanism, that can be adjusted also along with the star wheel I previously posted. When you go from park to drive do you hear a hydraulic pump coming on? If so your auto park system is still hooked up. There is a green switch inside the metal box that surrounds the system.Remove the inside plate closest to the drive shaft you will be able to see and access all the components of the system. Remove the electrical connection and see if there is any transmission fluid inside that connection fluid. Also check the fluid level in the reservoir it may me too low. If you post back your findings you will get more help in diagnosing the problem. Good Luck.

[jmstromquisst]

Looking up the title was a good idea.
It's a '93.
The title says it's an 18,000# vehicle.
I definitely do not have the yellow switch on the dash.

[tropical36]

jmstromquisst wrote:
I think it is a '94.

Do you not have a title?

Also, the chassis manufactured date should be on an exterior side plate, near the entry door. Note that the chassis will most likely be a year older than the house and maybe even more.

[tropical36]

enblethen wrote:
Should find the weight chart. It should be in a closet or cabinet.
My late 93 does not have the problematic auto park. It could be an early style.
When I put in park, it does apply the drum brake on the transmission. It has the foot pedal for manual operation.
The adjustment is easy like earlier posted about slotted opening on the top of the backing plate. I had the shoes replaced because they were separating between friction material and the steel. There was signs of rust so they replaced the spring assemblies.

If it engages the brake in park or with shutting off the ignition, then it has autopark and most likely version II like the OP. Which was more problematic is up for grabs, but the best was the very last one, that had a disk plate and a hydraulic line, rather than a mech. cable for actuation.

[tropical36]

jmstromquisst wrote:
I've been doing a lot of study, and I think I have the type II system because there is no yellow knob and I still have the emergency brake pedal. I have crawled underneath (before I studied up on Auto Park) and could not figure out much. With a lot more knowledge and some diagrams and pictures in hand, I'm ready to return "down there." However, at this movement there is a lot of water and mud over the campground due to a recent storm, and winter is about to beset us. It's not looking good for more work soon. The post is part of ongoing research so I can be fully prepared when when I am able to get back to it. To be honest, I'm not sure there is anything wrong with the Auto Park system, the previous owner may have just defeated it just because they read some of the nightmare stories I have been reading. At this point I am undecided about if I really want to fix it, or if I just want to verify that it has been properly disabled. My most urgent repair is of the drive shaft brake; I want to disassemble it and check the shoes and drum to make sure it is not totally toast inside; I don't trust it to hold the RV. At this point I'm glad to have the alarm I put on the vehicle so I can intelligently operate the brake manually, that alarm also made it easy to explain the brake operation to my daughter, who may assist me to move the vehicle from time to time.

OK, do understand now that you have one of the earlier ones and also with some of the few that had the brake pedal, as well.
Better if you mention the particulars and year of your coach, with your posts, for better responses. I'm now understanding what you actually meant by releasing it manually, which is what a lot of people would like anyway and some have even converted to such. Not a good thing really, as the tranny probably doesn't have a parking pawl, as that would be quite rare, so not good depending on a foot brake only. As has been said, different strengths will engage the brake at different levels and a cable breaking would release it, so you should always block the wheels, without fail, until the thing is repaired.
Most likely the previous owner just disconnected the lever clevis that comes from the spring actuator. I'm also thinking that it doesn't have it's own reserviour and uses the power boost pump, that is also used for the power steering. Yes, this would qualify it, as a version II, as far as I know.

[T18skyguy]

Our resident expert on Autopark is Oldusedbear. If you can find him I'm sure he can help. He knows every system. Last I heard he had prostate cancer so I don't know what his status is

[enblethen]

Should find the weight chart. It should be in a closet or cabinet.
My late 93 does not have the problematic auto park. It could be an early style.
When I put in park, it does apply the drum brake on the transmission. It has the foot pedal for manual operation.
The adjustment is easy like earlier posted about slotted opening on the top of the backing plate. I had the shoes replaced because they were separating between friction material and the steel. There was signs of rust so they replaced the spring assemblies.

[wolfe10]

Post the VIN, then there will be no question about the model year of the chassis.