1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Soft pedal after big brake upgrade

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Old 05-24-10, 05:06 PM
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Soft pedal after big brake upgrade

84gs. Got a new master cylinder when I changed to gsl-se rear end and brakes.

Recently changed to big brakes up front and now my petal i pretty soft with it working close to the floor. Petal is solid with no vacuum. No leaks. Pumping them up driving is effective.
Do I need a bigger master ,proportioning valve or?

Thanks
Old 05-24-10, 05:18 PM
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Did you bleed it correctly?
Old 05-24-10, 06:16 PM
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you need the se proportioning valve.
Old 05-24-10, 06:18 PM
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Originally Posted by Jeezus
Did you bleed it correctly?

Well, ive put a lot amount of fluid through it thinking its bleeding problem. Gravity, pump, pressure, you name it. But motor off the petal is solid, with vacuum is where the petal goes away
Old 05-24-10, 08:31 PM
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If your pedal goes soft with vacuum, Try swapping out your booster. My brother had a similar problem. New master and he'd have to pump the pedal twice while driving for the brakes to kick in. And he had a new master and all new calipers.
Old 05-25-10, 11:23 AM
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I did not change my proportioning valve when I swapped in the GSL rear end. No issues.

Get your self a full set of Speed Bleeders (cost about 30.00). Then install them and re-bleed your brakes. For the cost of these things, they are well worth it in reduced headaches. It can be very tricky to bleed the brakes without them, even if you do everything correctly.




.
Old 05-25-10, 07:25 PM
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Ya through searching and reading it seemed to me that noone seems to need a bigger bore master or upgraded proportioning valve, and this seems true from your responses...

I will continue bleeding and see if that helps, i guess I can try to adjust the 'fork' too?

I guess i def can't rule out a brake booster either, but I guess I would just get a Gen2 booster and master combo and mod it in there if I go that direction.

I also have speed bleeders on the rear but not on the fronts, they are a wierd US small fitting, ill have to look at a speed shop...
Old 05-25-10, 07:37 PM
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Press and hold pedal, bleed, tighten, release brake pedal and press and hold brake pedal, bleed, tighten, repeat. Do not do the "pump 3 times" thing as this will cause any bubbles in the line to break up into smaller bubbles that will cause headaches.
Old 05-27-10, 03:01 AM
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i have the same problem changed to T11 calipers front and rear with a gsl-se shell, stock booster etc i bleed the brake through three times i had a lot of travel in the pedal but it was solid once it got there, my car is a second car and after only driving it in the last couple of weeks the pedal has got better although i would like to bleed them again (i rebuilt all the calipers and sometimes the rubbers swell)
Old 05-27-10, 11:18 PM
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Hey, make sure you are bleeding in order... Start with the farthest wheel and work your way to the closest one...


For the front speed bleeders go to Charleston Carquest on Main St. & Owens and ask for Jerome.
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