1984 Minnie Winnie Poor Brake Performance - Hydroboost

[EndorphinJunky]

So, I picked up this vintage motorhome from an elderly gent who was a big nascar fan and kept a pretty good eye on his Minnie Winnie..

Check out this ad straight from '84 with the dad & son complete with missing front teeth & their fish..It's pretty amusing! Mine has the exact same flower wallpaper and brown/blue upholstery everywhere.

http://media.gowinnebago.com/models/...Winnie-bro.pdf

But I'm having a bit of trouble with the brakes in this boat..It's a Chevy G30 van chassis with hydroboost. I was unfamiliar with hydroboost and was puzzled at the jungle gym underneath the hood/master cylinder.

Problem: The pedal is extremely hard and has little travel. When I jam them on the giant couch stops but jerks to the right pretty good. Making for a pretty unsafe situation.

I checked out the rotors (it has dually rear drums n front rotors) and they don't look bad in any way. I replaced the master cylinder, bench bled correctly & found no improvement.

I have a new hydroboost unit from autozone waiting to go in but I'm having second thoughts. Could the problem be the power steering pump instead? The steering works fine..?

As far as the jerking to the right condition, I don't see anything it could be other than a warped right rotor or a bad left caliper..?

I read most of the brake bible and Vanco hydroboost install.

Any thoughts?

[87manche]

it could be the power steering pump

Have you identified what hydroboost system it is? Many of the manufacturers have PDF's for troubleshooting at the website.

If it's the Bosch Hydromax system here's the information you need. This is what's on my IH uhaul toter.

http://rb-kwin.bosch.com/pool/usa/pd...ter_Manual.pdf

it seems to have been a popular unit in the 80's.

does it have some sort of brake pressure warning system?

[RanchTruck]

Pulling to the right is a separate issue, the master cylinder or brake booster can't cause that. That's either stuck brake pads, seized caliper or slide pins, or mismatched pads from side to side. It could also be oil contamination on the rear brakes.

If the power steering works, and works well, then the pump is still good. Pressure comes from the pump, goes to the hydroboost, then down to the power steering box. Both the box and the hydroboost should have seperate return lines to the pump. So if the steering is working, that means hydraulic pressure is making it through the hydroboost to get to the steering box.

Pump the brake pedal a few times with the engine off, then stand on it and start the engine. It should sink towards the floor a couple inches. If it doesn't, you have a booster problem.

[EndorphinJunky]

No, this is the unit..

http://cgi.ebay.com/ebaymotors/Cardo...Q5fAccessories

RanchTruck,

Ya, that's what I figured because the power steering appears to be working A-OK. I will try the pumping procedure you mentioned.

And I'll double check the calipers and lube them up. It's got brand new pads up front..

I haven't had the chance to get the rear rotors off yet..that'll be next if I don't find anything..

[odee]

I would check the front brake hoses also. How are the front wheel bearings, if either side has play it will cause a pull also.

[370]

replace BOTH calipers and hoses. my dad was telling me at work they've found if you replace 1 caliper you usually get a pull when braking.

[BIG-O]

I've got a similar problem with my hydroboost brakes on my 93 p30 chassis fleetwood flair motorhome. How do you test the output from the pump? Should you be able to turn the wheels back and forth at a stop, I can't. the steering has that noise when you turn like it is low on fluid,it's not low. I've bled the brakes and get the same amount of fluid out of each cylinder. It has a hard pedal. I took it to a mechanic and he said it's supposed to be like that.

[87manche]

Originally Posted by BIG-O

I've got a similar problem with my hydroboost brakes on my 93 p30 chassis fleetwood flair motorhome. How do you test the output from the pump? Should you be able to turn the wheels back and forth at a stop, I can't. the steering has that noise when you turn like it is low on fluid,it's not low. I've bled the brakes and get the same amount of fluid out of each cylinder. It has a hard pedal. I took it to a mechanic and he said it's supposed to be like that.

only way to test the pump is to put a presure gauge somewhere on it with a tee fitting.

I can easily turn the wheels on my uhaul toter parked, so I'd say your pump is weak.

[RanchTruck]

Originally Posted by BIG-O

Should you be able to turn the wheels back and forth at a stop, I can't. the steering has that noise when you turn like it is low on fluid,it's not low. It has a hard pedal.

Pump is gone. Replace the pump and put a inline hydraulic filter in the return hose from the cooler or steering box. They sell them for plow hydraulics or for extra transmission filters.

[EndorphinJunky]

Found out what was wrong with the minnie winnie...figured I would report back...It needed calipers and lines up front, that's it. I threw in new heavy duty pads while I was at it...95% better.

Thanks odee and 370. You were both right..

[Machinos]

Just for the record, on some Internationals I've driven you'll get the "pump is working" noise/feel if you try to turn the wheel at a stop with the hydroboost brakes to the floor.