Community Forums

snowman8383 · 06-04-2021, 03:01 PM

Hello,
New to rv world, I have a 2000 winnebago itasca sunriser and the auto park is on and it will not run the motor I have been searching the web and can not find a good wiring diagram to diagnose it ( I am a Tech in the ag industry) If i could just find a good diagram to tell me where power comes from and what switches have power with key on etc...

Jim_HiTek · 06-04-2021, 03:32 PM

Is your autoparkbrake a drum brake around the drive shaft? If so, you can just adjust it so the brake pads are not making contact with the drum. Or you can disconnect the linkage and zip tie it up out of the way so the brake isn't applied.

Since you're a tech, I won't go into how dangerous doing that is so make sure you have some wheel chocks to chock it when working on it. I undid my brake drum while waiting for parts, but had to drive it anyway. Still had regular brakes even with the engine off but no parking brake so had to chock it when stopped.

Can you explain what motor you mean? Maybe describe what you know of your park brake system? They come in several flavors...depending on chassis, so what's your chassis manufacturer? Also, is your RV a Sunriser or Suncruiser?

snowman8383 · 06-04-2021, 05:50 PM

When I meant motor I mean the hydraulic pump motor for the activation of the brake and yes it is the drum on the drive shaft

astrnmrtom · 06-04-2021, 06:37 PM

This link should help you. Note that the original owner of the site is no longer involved, but the site does contain a lot of information on the systems.

AutoPark parking brake system help, troubleshooting, and repair

Jim_HiTek · 06-04-2021, 06:40 PM

Well, after some digging I find there IS a Sunriser model. Google kept suggesting Suncruiser. And it has a Workhorse chassis.

If your chassis used the RGS (Rotten Green Switch) to activate the park brake, you want to read up on it on OldUseBears web site here: AutoParkBrake. There's all sorts of help for the issue there. Even has part numbers for what you likely need.

If your era Workhorse had switched to the Bendix system by 2000 or not, I have no idea. But it's the better system and your symptom reminds me of a bad TW-12 valve...IF you have that system. The Bendix system on many RVs have a motor that runs when the engine is OFF, and you step on the brake. What it does is apply ATF to the brake cylinder if the engine dies when you're still rolling. Or if you're on a hill and forgot to set the P-B.

How both systems work is the chassis hydraulic system has a pump for the brakes that when applied to the P-B system, force a spring loaded canister plate to move and compress the spring. That relaxes the linkage that relaxes the brake shoes from the drum. Now when the engine dies, or you put the shift lever in P-B, it releases the pressure and the P-B applies pressure on the brake drum. The large spring passively applies the brake. The hydraulic system retracts it. That's a safety thing.

Now in your case, since it's a Workhorse perhaps with the not so good system, I'd suggest following OldUsedBears instructions on narrowing down the issue. I'd wager it's the RGS. I know my Bendix system pretty well, but not so much the Workhorse. I'm not sure if the RGS was still used by the 1999 chassis. I'll let you find that out.

snowman8383 · 06-04-2021, 07:49 PM

Ok everyone thanks for the advice I was doing some troubleshooting tonight and I found the issue, It was the relay down by the RGS now I need to find one and we will be ready for our next adventure

donr103 · 06-04-2021, 09:47 PM

relay needs to be the best you can buy, you need to keep 2spars and it needs to be changed every 5 yrs.. when is last time you changed A/P oil?? and for that matter flushed your brake fluids?? needs to be done every 2yrs.. good luck , and dont forget to change P/S oil,

edgray · 06-05-2021, 08:20 AM

Quote:

Originally Posted by snowman8383

Ok everyone thanks for the advice I was doing some troubleshooting tonight and I found the issue, It was the relay down by the RGS now I need to find one and we will be ready for our next adventure

You can find upgraded J71 AAPB parts HERE: www.urvp.com

LETMGROW · 06-07-2021, 08:00 AM

Quote:

Originally Posted by edgray

You can find upgraded J71 AAPB parts HERE: www.urvp.com

Good recommendation. Don't just replace. Upgrade.

Mitzlplik · 06-13-2021, 10:21 AM

Let me tell how I got to this level of confusion first.
We have an 2002 winnebago sightseer with the 8.1 and the j 71 system with the pump and RGS mounted under drivers side.
I have replaced RGS and I'm waiting on the GRS to arrive. Pulled relay a confirmed pump will run so I ordered a new relay. So jumping back to leaving.
Left place we were camped at 20 miles down the road auto park light comes on pull over turn rv off parking brake engages I can hear it so not too worried.
Next week left home after mounting a motorcycle carrier an decided to try a known hill about 25 miles away to make sure braking would be ok.
Nope caliper stuck brakes heated up an parking brake light came on. Changed all calipers and pads. Is there something I'm missing to get the brake light on the dash to turn off? I've gone thru oldusedbears threads an downloaded everything I can find an seems I can't locate a problem like this. Sorry to piggyback on this thread but I'm at a loss trying to find a solution. Any help would be outstanding an that person would have my gratitude forever.
Thanks. Bill

Jim_HiTek · 06-13-2021, 11:29 AM

Quote:

Originally Posted by Mitzlplik

Let me tell how I got to this level of confusion first.
We have an 2002 winnebago sightseer with the 8.1 and the j 71 system with the pump and RGS mounted under drivers side.
I have replaced RGS and I'm waiting on the GRS to arrive. Pulled relay a confirmed pump will run so I ordered a new relay. So jumping back to leaving.
Left place we were camped at 20 miles down the road auto park light comes on pull over turn rv off parking brake engages I can hear it so not too worried.
Next week left home after mounting a motorcycle carrier an decided to try a known hill about 25 miles away to make sure braking would be ok.
Nope caliper stuck brakes heated up an parking brake light came on. Changed all calipers and pads. Is there something I'm missing to get the brake light on the dash to turn off? I've gone thru oldusedbears threads an downloaded everything I can find an seems I can't locate a problem like this. Sorry to piggyback on this thread but I'm at a loss trying to find a solution. Any help would be outstanding an that person would have my gratitude forever.
Thanks. Bill

Do you have that drum brake setup around the shaft? If so, the brake force is adjustable like in olden days. You stop the engine without setting the P-B, chock the RVs tires with several chocks, on a flat area of course, climb under the RV, slip an unneeded business card, say from your BIL, between the drum and the brake pad, then turn the adjustment screw so there's a bit of pressure on the card but you can still pull it out. Those friction pads wear out but there's no 'auto-adjustment' on the older systems like on cars with drum brakes.

It's a once a year maintenance item. At least it was for mine. Originally, when I bought the Bounder, I found that the PO or their mechanic had loosened the adjustment screw by 1"! Outrageous thing to do with a safety item. They had the P brake light coming on all the time though most likely, due to 2-3 other issues. One was the TW-12 valve was going bad, 2nd was the P-B cable up next to the driver would slowly slip out of it's clamp, 3rd was the Master Cylinder was leaking and the brake system fluid would get low.

In other words, the P-B warning light could come on for other reasons besides the system applying the brake. In my case it was usually low fluid, and the cable slipping. Years past before the TW-12 failed outright.

In your case, OldUsedBears drawings should help narrow it down. Does your RV have a manual cable link from the shift lever next to the driver to operate the P-B? If it does, make sure it's clamped correctly.

Good hunting.

Mitzlplik · 06-13-2021, 06:50 PM

Thanks for replying.
I have the drum brake on the back of trans.
Adjustment i will try to see if that corrects the not holding process.
Now enlighten me on tw12? Yrs ago it was related to an air valve now a day not sure.
Master cylinder doesn't leak no other plug in I can see to indicate low fluid.
I'll ck the cable near trans. No mine the yellow knob.
Would the GRS cause the brake light to stay lit?
We need to leave out in the next few days and I'm running low on ideas.
Is there a switch I'm missing?
From what ive read my system only has the GRS and the grey one on the chamber under the rv.
Thanks maybe I can get it figured out soon.
I might not have added but my auto park is not engaging hence the brake light being on so adjusting won't be possible till I can get it to work.
Thanks for your reply

Jim_HiTek · 06-13-2021, 07:47 PM

The TW12 is a manual hydraulic valve that is used with the Bendix P-B system generally on all the worlds heavy duty truck chassis EXCEPT the Workhorse. It's a proven reliable device that does go bad occasionally, like mine did, but I don't believe you have one. So not to worry about that. You mentioned above you have the RGS and if so yours is a different system then the Bendix. OldUsedBear has all sorts of drawings you could check out for ideas on your system. I mentioned the TW12 for lurkers that might visit this thread in future.

Here's what it looks like removed. There's a steel cable connected to that control arm, and that comes from the shift lever next to the driver, around 1/2" in diameter, and when the shift lever is in P-B position, and the engine is running, it applies hydraulic fluid pressure to the brake spring cartridge. Which pulls the cable releasing the brake. When you park, put it in P-B position, then the TW12 allows the fluid to return to the tank, the spring pushes the plate, and that applies the P-B around the drive shaft. Once the P-B light goes on, then the engine can be shut off. Shut off the engine too soon and the brake won't apply. In the Bendix system, I don't recall where the switch was because mine never failed. But it might have been inside the TW12 as I can see what looks to be a connector in the picture below.

donr103 · 06-14-2021, 10:58 AM

to Mitziplik.. you are trying to confuse two seperate independent systems.. the chassis brakes and the parking brake.. aka a/p auto park.. 1st do a search in up part of this forum and use the words genie light for a/p .. put this on.. now for a/p the a/p light sw is mounted on the pressure sw and it will make the a/p light stay on.. all a/p relays and sws should be changed every 5yrs even if good. unless you go to ultra rv and get lifetime sws.. the caliper pads will not turn on a/p light which on some mds rv are combined they read brake/ auto park.. that said when was last time you flushed the chassis brake oil?? on chassis brakes which caliper stuck?? you may need to replace a abs wheel sensor.. they can melt or get heated up.. may just need cleaned.. when was last time brake caliper pins greased?? do a search on workhorse caliper pins.. there is a great youtube vid on this.. recheck oil level in chassis master cylinder.. now back to a/p.. when was last time you changed the oil in a/p res.. ?? now you could have burned up the a/p park shoes maybe.. 1st get chassis brakes sorted .. then try a hill and see if a/p holds.. if not you got to find out why.. warning untill you confirmed that the a/p is working you must chock all!!! all !! wheels.. there is no parking pin like a car to stop mh from rolling.. it could kill you or some one you love or just make alot of damage and guess who is going to pick up the check.. now that is over..the a/p has 2 adjustments on it.. one at the shoes in drum on trans and one back one a/p cable system. you can try both.. the best indicaton i have found is that if the drum is very dis-colored on trans.. then you will need new shoes.. there are a few vids on youtubes.. or search workhorse a/p shoes on forum.. let us know how you came out.. good luck.. better members than me will chime in and help you if you come back and ask.. that why they are here.. they have helped me soo much and i that them all.. they work so hard to find the answers and take thier time to get back to us.. again thank youall!! bazles rv give them a call have your vin and they will give you great info..