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Driving with parking brake on


westlynch

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1994 Fleetwood Southwind Class A; Chevy 454

 

Yesterday I drove for a stretch with the parking brake on. I didn't see any smoke out the back window or through the side mirrors, nor did I feel any drag. Nor did anyone try to signal me. I may have gone about 30 miles before realizing it was on and disengaging it.
I drove for several more hours, stopping as necessary for gas and rest stops where I engaged/disengaged the parking brake with no issue.

However, when I arrived at my campground last night, put the coach in park and applied the parking brake, when I turned off the engine, the coach coasted forward on the slight incline.

A mechanically inclined friend thinks I might have a glaze on the brake pads and may the drums. He said that a light sanding could remove that so I will be ok. I do get the brakes checked often and they have been deemed all right.

He also suggests that since I need to push the parking brake pedal almost to the floor, which has been this way for quite a while, that I should have that adjusted. He said it should engage at the halfway point.
I'm going to be checking reviews for a mechanic in the area. I'm in Advance NC. Does this sound right or is there anything else I should be considering? I don't want to get hoodwinked, taken for a ride, etc.
Thanks!

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Do you mean that it actually rolled while in park? Or did it just move an inch or so to come against the transmission lock? If the first you have more problems but I'd guess that you mean the second, which should not happen if that parking brake is holding as it should. How long has it been since the parking brake was last serviced? Since the parking brake is a brake that applies to the drive shaft, if it were to lock it would not allow even the small movement that is normal with the transmission in park and if it were locked against the drive line solidly, you probably would have noticed and it clearly would have gotten hot and you should have smelled it.

 

It probably at the least needs to be adjusted and isn't actually applying any significant braking to the drive shaft as it should. In this case, that may be a good thing. With an RV that is now 22 years old, it probably is time it had some attention.

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Yes, it actually rolled in Park and in Park with the Parking Brake on but only when the engine was off.
I have in the past noticed that there has been a slight roll when I first stop and put the coach in Park, but this is significantly different.
I had the Parking Brake serviced when I first got the rig in October 2014. I assume that anyone who checks the brakes would also check the Parking Brake but I can't really be positive that that is the case.

When you say 'more problems', what are you referring to? Knowledge is power. Thanks.

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I assume that anyone who checks the brakes would also check the Parking Brake but I can't really be positive that that is the case.

When you say 'more problems', what are you referring to? Knowledge is power. Thanks.

I highly doubt that the mechanic checked the parking brake if he was just asked to check the brakes. Most do not unless you also specify the parking brake.

 

What I mean by "problems" is that the transmission is locked when placed into park and a very small amount of play is not unusual but it should be very little actual movement. If the RV moved several inches along the pavement after the transmission is put into park, there is probably something slipping inside of the transmission. I'm no transmission guy and my knowledge of their working is pretty limited but I have owned automatic transmission vehicles and motorhomes and some small movement to come against the transmission lock is normal, but not enough to actually move over the ground. There is some play in the mechanical parts and the motion is must a matter of taking up that slack, unless there is some sort of excessive play the transmission. As I read your post, if you are saying that the motion when placed into park is now more than it was before driving with the brake on, then I really think that you need to have someone who is qualified take a look at your transmission and probably the parking brake as well. It isn't unheard of for the transmission lock that is applied when placed into park to break and allow the vehicle to roll.

 

Hopefully, someone on the forums who is more of a mechanic than I, will join in to offer better advice.

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Yeah, I'm with Kirk - time to have someone take a look.

 

Based on your description there are two separate things going on, the park lock in the transmission and the parking brake. The transmission parking lock not engaging is more likely to be a simple linkage adjustment than anything else. It's possible for the park lock pin to break inside the transmission, but unlikely.

 

I lost my parking brake last year (manual transmission) and when we would stop my wife would have to get out and chock the wheels before I got out to stop it from rolling.

 

Good luck!

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1) By the year of it, if it has a foot applied brake pedal, then it has brakes on the rear axle. You would like your friend stated have glazed the shoes/pads. coarse emery cloth will scuff them up also check the brake drum/rotor surface for overheating (bluish/black) instead of shiny metal surface and cracking; Replace if that be the case! Otherwise scuff the metal surface!

If it has a hand pull lever; then the brake is attached to the back of the Transmission, check and repair or replace. 2) Brake cables stretch over time underneath there is an adjuster where the single cable meets with dual cables. adjuster is two nuts tightened to each other. lefty loosey with two wrenches and tighten the slack until the inside pedal holds the vehicle or about 1/2 pedal.

3) The shift cable on the transmission side has a lever that goes in the case; when in Park there is a piece of metal that looks like a dog ear, it can break and you have no Park to stop it from rolling. Doubt this is the case. it is normal for some play,causing a slight roll in the drive lines-a couple inches at most in bigger vehicles. If your shifting between reverse and Park with the engine running at normal idle with your foot on the brakes you should only get a slight movement; if excessive play then the Universal Joints on the driveshaft are worn or gear lash in the differential gears (RearEnd) are worn.

4) If this is too confusing; take it to a driveline specialist and have it checked. Safe beats, sorry!!

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As I recall, the P30 chassis/Chevy engine combo does not have a "Park" pawl in the transmission. Instead, the drive shaft mounted parking brake is automatically applied when the gear selector is put in park. I believe there's a switch that's a fairly common failure point, but I have no experience with it. A Google search on "p30 auto park" will turn up a lot of information.

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As I recall, the P30 chassis/Chevy engine combo does not have a "Park" pawl in the transmission. Instead, the drive shaft mounted parking brake is automatically applied when the gear selector is put in park. I believe there's a switch that's a fairly common failure point, but I have no experience with it. A Google search on "p30 auto park" will turn up a lot of information.

 

Ah, I did not know that! Good info.

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He also suggests that since I need to push the parking brake pedal almost to the floor, which has been this way for quite a while, that I should have that adjusted. He said it should engage at the halfway point.

1) By the year of it, if it has a foot applied brake pedal, then it has brakes on the rear axle. You would like your friend stated have glazed the shoes/pads. coarse emery cloth will scuff them up also check the brake drum/rotor surface for overheating (bluish/black) instead of shiny metal surface and cracking; Replace if that be the case! Otherwise scuff the metal surface!

If it has a hand pull lever; then the brake is attached to the back of the Transmission, check and repair or replace.

That makes it sound like he has a foot pedal. But I was not aware that GM chassis went to using the normal brake pads for parking. I would think that if that were what he had, then driving with them set should have also effected his normal brake application? Or do you mean that he has "brakes on the rear axle" that are different from the rear wheel brakes? He said that it was a 94 model. As I said before, a mechanic I'm not..... My only P series motorhome chassis was an 87 and it did have the parking brake on the drive shaft, set by a foot pedal.

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Only trying to be helpful take it for what its worth!! been a long time since I worked on any big trucks or motorhomes!! Like I stated if all else fails: LOCATE a good Driveline Technician!! and from now on I will keep my 2 danged cents to myself!! You want to argue go argue with some one who care! Maybe I will just unsubscribe fro this crap!

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Thank you all very much for this info. I took a lot of notes.
Pieere, I'll ask about a driveline mechanic.It's helpful to have terminology to use.
Same to you pugsly with regard to the trans lock.
I'll be googling P30 auto park, Dutch-12078.

Thank you Kirk for all the info, too. Very useful to me.
I'll report back when the solution is found. I appreciate this information bc I hopefully can speak intelligently to the repair folks.
To clarify some points that came up:

When I push the regular brake pedal, it works just fine so I'm having no issue braking the rig when I'm driving.
I apply the Parking Brake by pushing my left foot down on a small pedal. It releases with a pull of the handle.
I'm a she, not a he, and that has a lot to do with being concerned about getting ripped off and that's why I really appreciate all your information.

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Pieere: don't be to upset. Lots of folks her are very EXPERIENCED in solving problems concerning RV's.

 

Unfortunately, some here have only book knowledge or second hand information on some of the questions asked and feel necessary to make a post from no experience. There is a big difference between knowledge and experience, ask any electrician, plumber, auto mechanic.

 

Sadly, Captain Nemo posts seem to indicate you are incorrect, you are not,your just trying to help......I can understand completely it's happened to me. Calling them out, reply is silence.

 

Since I have never had this braking problem, my first feeling was what you stated in ur post. Hopefully we will find out the solution. Lots of knowledge and applied experience will be found here.

 

Hang around---Trucken

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Only trying to be helpful take it for what its worth!! been a long time since I worked on any big trucks or motorhomes!! Like I stated if all else fails: LOCATE a good Driveline Technician!! and from now on I will keep my 2 danged cents to myself!! You want to argue go argue with some one who care! Maybe I will just unsubscribe fro this crap!

Not arguing, just trying to learn. As I said before, I not a mechanic at all and know only a little about the brakes. I asked the question because I do not know and wasn't sure that I understand what you were saying. How do the parking brakes work since they stopped putting them on the drive shaft, as mine used to be. I think that they were that way on my 98 Ford chassis, but could be wrong and don't own it any longer. Your knowledge is appreciated.

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It sounds like even if we figure out how the system is designed, you won't be able to work on it yourself. "Talking the lingo" takes a lot more than "Where do I get a map?" or "Can you tell me where the Eiffel Tower is?". :P

 

Find yourself a competent repair shop. I know, easier said than done.

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Finding a good shop that's familiar with the P30 auto-park system may be a bit of a challenge, but at least she'll know what to ask for.

So how does the autopark lock the wheels? I've not owned one of those but have wondered how they work. Do they apply the rear brakes or......?

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: ) I can guarantee I won't be doing this myself!
True about the lingo but I've found that if I at least sound like I understand how things work that they are less likely to try anything and I'm more likely to find a person who can do the work. Thank to all of you, I can do a better job of that now.

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Lot of information on the web! Just type in the year make and model with Parking Brake as the Topic! It has a lot of reading! What I read it is called an AutoPark that is fluid activated from the power steering pump! Best of luck, Westlynch.

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Lot of information on the web! Just type in the year make and model with Parking Brake as the Topic! It has a lot of reading! What I read it is called an AutoPark that is fluid activated from the power steering pump! Best of luck, Westlynch.

Thanks. I'll be spending some time reading it looks like. ;)

 

What year did the autopark come into use?

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Thanks again for all the info everyone. I called several places today and heard 'we don't do chassis work' and 'our place is too small to handle that size vehicle' and so on. A guy named Reggie happened to be working in the park and came over to check. He said he smelled nothing at all stating that there would be an odor had the damage been bad. He told me I would have smelled it, too. And I would have seen smoke. He also looked and said there was no sign of cracking or damage that he could see.
Good to know but still kept up the search for an expert to check it all over. Late today I called a Chevrolet service department and they can do it so I'm taking it in tomorrow morning. They will also do an oil change and chassis lube, which it's due for anyway. I told them I'm ok as long as I'm not on an incline and he said that's not a problem.
I'll update again once I have more info.

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So how does the autopark lock the wheels? I've not owned one of those but have wondered how they work. Do they apply the rear brakes or......?

 

Similar to the F53, the P30 uses a drive shaft brake assembly as the emergency brake. The auto-park system uses a hydraulic cylinder to activate the brake when the gear selector is placed in park. The hydraulic pressure comes from the power steering pump in older models, and from an independent pump in later models. I don't recall what years used which setup...

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Similar to the F53, the P30 uses a drive shaft brake assembly as the emergency brake.

So the auto park does still apply the brake to the drive line, same as my old 87, P-30 except for the way that it is engaged? That one had a foot pedal with a cable and mechanical linkage.

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Doing a little research, I think I have the timelines roughly figured out for the various auto-park configurations used on the P-30 chassis.

 

The J71 AutoPark systems built between '89 and '94 all utilize the power steering pump as a source of hydraulic pressure. They have a "PARK" position on the gearshift lever that automatically applies the parking brake. Most of these units also have a manually applied foot pedal, located to the left of the steering column, that will also apply the brake, a drum type brake located on the driveshaft right behind the transmission. Within the same timeframe, there were a small number of units that DO NOT have the foot applied brake, but instead have a yellow knob on the dashboard that will apply the parking brake. As with all of the units, the brake can also be applied by putting the shift lever into PARK. Apparently very few of these were built.

 

At some point in '94, (the date info is a little soft), use of the power steering as a source of hydraulic pressure was discontinued, and a dedicated pump and reservoir were added. They also have the foot pedal for application of the parking brake, as well as the "PARK" position on the gearshift lever. Around '98 or '99 they discontinued the provision of the foot pedal for application of the parking brake, and went back to the yellow knob on the dashboard.

 

I should also note that these brake units operate similar to air brakes, in that the hydraulic pressure is used to release the brake, not to apply it.

 

I don't know if that clears anything up, but it's the best I can come up with at this point...

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