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Problem with RV power steering and brakes.

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    MAKE:pace arrow
    MODEL: Class "A" 37j
    YEAR:1994
    MILES:???
    ENGINE: Methinks a 454.
    DESCRIBE ISSUE....

    Loss of power steering and brakes when put into gear.

    We have at the shop at this time this RV and it has been there for the past two weeks or more. Client is irrate, the Tech working on it is irate, my boss is irate and they have now asked me to look into it as I am bi-lingual and often flaunt that I am a proud member of Bat auto.

    So, here is what the other tech has done..

    He replaced the hydro boost, the power steering pump. New (rebuilt) hydro boost leaked, so another one was installed, same problem, but no leak.

    PS pump whines like a bitch once put into gear. Also whines like a bitch once brakes applied in gear.

    After being stumped, my co-worker came to me to ask to help him bleed the system. I noticed it bleed better in neutral and whine went away. In park, bleed was not as good. Once the engine is turned off, the fluid spills out the reservoir like no tomorrow.

    Thursday, we had almost got it perfect, I mean almost. Boss goes to drive it around town, came back saying steering went stiff again and loss of brake boosting. Mind you, kind of alarming with a class A RV to say the least.

    So I did some research and found that this unit has a HR-1 relay valve. I also found two bleeding procedures. One is in fact to bleed the unit engine running in NEUTRAL. Which is also what I found worked better.

    Here is a copy paste of a link I found describing EXACT same issue. Plz take time to read it and give me your thoughts if you are so inclined. What are we missing here? My next step is to tell my boss to get a new HR-1 relay valve. That is the only thing I can see at this point.

    https://www.justanswer.com/rv-motorhome/5lv9i-1993-pace-arrow-chevy-chassis-454-engine-power.html
     
  2. I didn't know if this went into the heavy equipment forum, but thought it more suitable for the domestic forum as it is a chevy chassis. Maybe an admin can decide which is better, but for now I am going for the domestic forum.

    Again, thx to any one for any ideas.
     
  3. Hydro-boost with a 454 gasoline engine? What an annoying way to make two simple systems (PS and PB) complicated. I'll have to study that quasi-schematic in the link; any chance there is a better one? Obviously, I know near-nothing about this vehicle or system, but will try to help with "general purpose" ideas.
     
  4. Thx bill, here are a few more schematics I was able to find without paying for the whole service manual. In the following link, we see better the relay valve that seems to be the issue.

    https://www.justanswer.com/rv-motorhome/2c6qw-1991-pace-arrow-33-motorhome-454-engine.html

    My understanding is that this HR-1 relay valve unit is probably faulty seeming as it interacts directly with the parking brake hydraulic system. Hence maybe why it is overflowing once engine is turned of. A stuck valve maybe letting the reserve fluid pass back through the fluid reservoir. I read somewhere that this vavle actualy permits to have residual pressure for a few seconds once the engine is turned of, so my thought is that is what is causing our root issues. And the first link I linked seems to confirm that as the guy did say, that if we are sure the system is bled properly and system is still not functioning, most likely a relay valve.

    There are two reservoirs. One for the power steering pump which can be check as any normal vehicle with a depth gauge, and another for the power brake assist assembly underneath the truck which has the actual bleeder that is used to bleed the system in neutral engine on.
     
  5. I have grandchild duty today, will try to study later.
     
  6. Yeah, no nude chics things. LOL. On the other thread, yeah, I was 10 over, so your right, no fear for that, but still, a concern. Have fun with the kid. Granfathers are the best.

    Although I do not wish to be one soon, my son will 14 soon, so that may be in the next decade or so.
     
  7. Wondering if somebody on the Class A or Tech Issues forums could help you. gOOgle "rv.net auto park." Or there are "Chassis Clubs" on the IRV2 Forum. I got a few hits on gOOgle "irv2 auto park" and one of those might help. I was only part way through your text when I thought "Oh No Auto Park!" Somebody may be able to help, will likely want the Model of this Chassis, like P30 (Chevy), W32 (Chevy sold as Workhorse).
     
  8. This is the exact same system used on school busses made by Chevy of that vintage. Have not run into that same problem that I recall but will check with some friends and see what they say.
     
  9. As I recall there were 3 or 4 different units for that vintage all looked alike but were different had to order by vin
     
  10. Also one of my buddies asked if when you were purging the air did you have the front wheels off the ground? We always did that with our buses as well. Is the PS fluid aerated at all?
     
  11. Yes, I purged off ground and 40 ton jacks off rv.

    Like I said before, I inherited this from irate boss and co worker. I like the ideas back and forth, it keeps me grounded.
    Yes, the fluid is like foam from the sea.
     
  12. What we need to know, is: "What's Making the Fluid Foamy?" I know we are not supposed to take Brake Fluid that has been "Bled" through the bleeder valves, through the piece of hose, and caught in the Coke Bottle. That process is claimed to add air bubbles that make the fluid compressible. What I don't know, is: "Does same apply to hydraulic oil like transmission and power steering fluid?"
     
  13. I'm kind of thinking like jd... how is it getting foamy, why is the reservoir puking when you shut it off? I don't think bleeding is the problem. Hydraulic systems with a pump usually self-bleed fairly quickly. I think that pump is sucking air somehow.

    A wild thought: did the 454 ever have reverse-rotation accessories from changing from V-belts to serp belts?
     
  14. No this engine has only v-belts and nothing was changed. The system has a bleed screw much like a brake system. It sit atop the fluid reservoir of the park brake actuator as seen in following snapshot. Read paragraph that starts with "with the shift selector in park" Screenshot (87).png
     
  15. No help to offer, but is there no accumulator in this system to provide a stop or two if the engine /belt/pump fail?
     
  16. Nick said "There are two reservoirs. One for the power steering pump which can be check as any normal vehicle with a depth gauge, and another for the power brake assist assembly underneath the truck which has the actual bleeder that is used to bleed the system in neutral engine on."
    Is this correct? TWO reservoirs? POWER brake assist assembly underneath the truck? Do you mean "parking brake assembly"?
     
  17. Is it possible that fluid lines somewhere in the system are "reversed"?

    Looks like shift lever is moved to Park, high pressure fluid will be released from parking brake assembly and the giant spring inside will pull the giant cable to apply the parking brake. This would sent fluid back to the reservoir. The amount of fluid would vary according to how far the cable moved as the parking brake shoes went from released to applied. Worn out shoes might give you lots more fluid return to reservoir.

    If fluid amount needed to compress giant parking brake spring is a large amount, fluid level in the reservoir might drop too low as soon as shift lever is moved out of Park. Then whine, foam, foamy fluid has too much volume to fit in the system once the shift lever moves to park, because fluid in the parking brake suddenly comes back into the reservoir. Messy. Now you've got foamy fluid again.

    Possible fix...remove all unnecessary slack from parking brake cable and shoes. Get foamy fluid out of system. Set fluid level in reservoir so that it does not get too low when shift lever is moved out of Park and some of the fluid goes down into the parking brake assembly.

    The parking brake setup is kind of a brain twister, because all the switches, valves, pumps and hydraulic work together to RELEASE the parking brake. The giant spring applies it. The spring wants the parking brake to be on 24/7/365. All the rest of the system is there to compress the spring and hold it back so the vehicle will roll.
     
  18. It seems that schematic posted (via link) is woefully inadequate. Worse yet, it may not even apply to this system since we have been advised (by dabunk?) that there are several variants of this system.
     
  19. Foaming means air in system or air entering. So if you are not leaking? How far have you or anyone actually driven it? I had one bus that I finally had to drive almost 100 miles before it purged all the air pocket. my .02 worth
     
  20. Update. Well, I seems, actually, I am pretty sure it was the HR-1 relay valve but could not test my theory.

    Sadly, the part is discontinued, so I ended up just bypassing it by way of disconnecting the shift lever to the HR-1 valve, and also disconnecting the parking brake actuator cable at the emergency brake lever beside the trans also. So he can use his emergency brake in lieu of the hydraulic park brake actuator and the HR-1 is no longer in function as the shift lever does not open the hydraulic side to the park brake actuator.

    System works flawlessly until you hook up the HR-1 valve. Has P/S and brakes all day when set up like I did with no whine, no foam/air. Also no spewing when shifting back into park. :D

    Client seemed happy with the result and says that if he goes to the states on his next vacation which is soon enough. He will try to maybe find a HR-1 valve down there. Maybe more luck there than in Montreal. But after testing out the park brake with the emergency pedal, he was happy with the bite of it and felt secure. SO he can now go on vacation which was belated due to trying to find out why this system kept gushing and and when put into gear we would loose P/S and brakes.

    We, at the shop were just happy to see this big old Class "A" leave the lot.

    Thx for all the responses.
     
  21. I have one of these, and the shop manual. Same problem, practically no PS or PB's. Shop manual said to remove that hydroboost, not that my shop manual can listen, told it, you got to be kidding, Pace Arrow built a motorhome on top of this thing.

    So I suctioned out all the PS fluid out of its reservoir and filled it with Lucas power steering conditioner. After running it for a couple of minutes, everything was good again.

    Other problem, my brake pedal wasn't coming up, grabbed my can of Liquid Wrench Lubricant, sure has a long ride from the brake pedal to the hydroboost. Put a lot of spray on all the linkage. Then the brake pedal popped up instantly. Did all this in less than 20 minutes.

    Was watching program on Discovery, bunch of guys decide to take their motorhome from Alaska to San Diego, guy driving it never looked at this temperature gauge, was over heating and burnt out his engine. Stopped at some RV joint after being towed. let them use one of theirs for that trip. When they returned, said they had to cut the front of their motorhome off to drop in an engine and good to go again. But never said what the bill was.

    This happened to me but always watching those gauges, temp was rising. Stopped in a town at a public library, was a parts dealer two blocks away, purchased a new thermostat, this time paid extra for a failsafe one, gasket, and a bottle of antifreeze. Carry a tool box, about 90 minutes later, we were good to go again.

    Another problem last fall, went up north to Lake Superior, daughter got sick, had to cut our trip short, sure stopped at the wrong gas station, got water in the tank, thank God was in a spot with a wide shoulder on the road, and also stuck in an auxiliary electric fuel pump. 1:00 AM in the morning and raining. Crawled under, disconnected a fuel line, had my wife switch on the fuel pump, had to train her, pumped all that water out, reconnected that fuel line and good to go again. Wonder why I never filed a dispute on my credit card for about five gallons of water. This added 45 minutes to our trip, good thing we have a shower and I had dry cloths to wear. RV dealers around here charge 125 bucks an hour to work on these things, in a way, a PITA, but like having it. Use it as a moving van.

    Sure getting a lot of rain up here, power went out, started the generator to keep my sump pump working or would ended up with a flooded basement.
     
  22. Mine only has one reservoir in the PS pump.
     
  23. I think that valve malfunctioned in a way that bogged the steering while becoming an orifice that aerated the fluid
     
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  25. All I can add about these things, ease of maintenance was not a priority in its design, sure not safe to drive without PS or PB. Even have to be a contortionist to add brake fluid to the master cylinder reservoir. No wonder craiglist are loaded with these things at giveaway prices.

    Does have one element of pleasure, when I drive my compact car, SUV's and pickup's scare the heck out of me, but when I drive this thing, the tides are reversed.