Brake Issue

Cdnbuickboy

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1995 RMS
I have to press the break pedal notably harder on my 96 RMW wagon compared to its 94 sibling. And the break pedal seems to travel farther. Does anyone know why?
The breaks are bled, the pedal is firm, the rear shoes are very close, drums were machined, the master cylinder was replaced with a new unit from Rockauto, and I installed the booster from a 120k miles car.
Can the proportioning valve be the reason? I am just really puzzled as to where this pressure and fluid may be going to?
So I should change my hoses if I’m experiencing similar? Or maybe I need to upgrade my front brakes
 

Cdnbuickboy

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1995 RMS
You should start your own thread rather than jump on this one.
Great addition to this thread.

I was just trying to make some conversation or discussion. That’s what forums are for correct? Or are you the resident site arsehole that just likes to be miserable?
 

SKV

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How old are the hoses?
What have you done so far to correct the problem?
The issue is solved! It was the stuck proportioning valve. I had a corroded brake line replaced. A loss of fluid/pressure in the system occurred. The mechanic probably used a vacuum pump to bleed the brakes instead of pressing the brake pedal and opening the bleeder screw so the valve did not reset. Stomping the pedal removed the light on the dash but was not enough to push back the plunger in the proportioning valve.

I did what this fella is showing here and the brake pedal now feels a lot more normal:


The pulsation when braking was caused by warped rotors as they would overheat too often as they were doing all the work and warp.
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BuickGirlFromMars

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1999 Buick Park Avenue Ultra (Supercharged) , 1977 Buick Electra Limited (350 SBB)
It was the stuck proportioning valve.
does your Roadmaster have a rear drum setup or is it a rear disc proportioning valve? From the sounds of it, its a disc/drum proportioning valve and not the "pressure limiting" proportioning valves found in some buicks up to 1999 for sure, maybe lil later on century.
 

SKV

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I have drums in the back but as far as I know the proportioning valve is the same for rear drums and rotors. That’s why impala ss guys modify the valve to get more pressure to their rear rotors.
The brake line went bad while the car was on the road - someone else was driving it - and he kept on using the car with half brakes for some time, and then I ended up driving it home for another hour with literally a hole in the brake line after I got the car from him. The brakes did not fail.
I just bled the front left caliper yesterday and the brake pedal became more responsive. It is still not as good as my other Buick wagon - that one stops like a small car - but much better than before.
 

SKV

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There is only one proportioning valve that sits below the master cylinder. After it the lines go to ABS and calipers/brake cylinders.
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