Problem with RV power steering and brakes.

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#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"?
 
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#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.
 

billr

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#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.
 
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#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
 

nickb2

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#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.
 
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#22
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.
 

jd

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#24
I think that valve malfunctioned in a way that bogged the steering while becoming an orifice that aerated the fluid
 
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#26
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.
 

PC

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#27
Check out the classic car brake restoration outfits, perhaps they can rebuild that valve. Sent out my original master and proportioning valve, they sleeved the master and rebuilt the proportioning valve.
 
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#28
Have no problem with that HR-1 relay valve, my 82 doesn't have one, reason why I wanted an older one, is my toy and felt I needed a break from FI with corresponding trouble codes. Conventional HEI, quad carb, easy to rebuild, brand new engine driven made in the USA Carter fuel pump was only 15 bucks, but did add another electric for boost for 30 bucks. Sure saves on the starter, because that fuel in the carb evaporators. Also EPA law at the time did not required catalytic converters. Two straight pipes with 40 buck mufflers on them.

Put on three new fan belts, alternator and AC had separate belts, even an idler on the AC was easy to adjust, but the PS pump was not to get the proper belt tension, way down there. Wonder if that squeal is a loose belt in that PS pump.

In terms of an accumulator in that Hydro-boost, yes, paying $3.50 a gallon for water sure killed that engine, had no problems with steering nor braking to pull to the side of the road.

Did redo the brakes on this thing, was surprised at my machine shop, only charged me five bucks to clean up the rear drums and the rotors each for this thing. Bring in a tiny rotor, 18 bucks, cheaper to buy a new one. Repacked the tapered bearings and new seals. Master cylinder has a huge reservoir for the front brakes, but only a few ounces for the rear. Super easy to bleed with vacuum, no ABS to trap air. Recently the rear developed a very slow leak, can't find it, but only takes a few ounces once a year to top it off. Carry a can of brake fluid and a small paper cup to keep it full. Even when empty, fronts still work, just fill it up and get a full pedal again.

U-joints plus all the suspension still have zerk fittings and the differential has a drain plug, don't see these any more, wanted all new fluids. Bit low on R-12, also easy, has a sight glass on it. Thermostat is a failsafe.

Is fun driving it as a opposed to a compact car, large SUV's and pickup trucks are afraid of this thing with huge steel bumpers so stay far away. But it does spend most of its time sitting