brakes
Thread Starter
Pro
Joined: Oct 2011
Posts: 703
Likes: 76
From: leesburg fl
St. Jude Donor '12
brakes
On my 87 c4 I believe that my master cylinder went bad, Because all of a suddon you have to apply a lot more pressure on the pedal to stop.
If it is the master cylinder should I replace it with a stock 87, or can I change it to an 88 model? my thinking is the the 88 with 2 reservoirs, may be a little bigger.
I dont know
Jim
If it is the master cylinder should I replace it with a stock 87, or can I change it to an 88 model? my thinking is the the 88 with 2 reservoirs, may be a little bigger.
I dont know
Jim
Race Director
Joined: Oct 2005
Posts: 11,770
Likes: 175
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
Your description of needing more pressure on the pedal to stop is a symptom of a bad brake booster.
The power brake booster is operated by engine vacuum. If you lose that vacuum (bad hose, connection, or crack) you won't have "power brakes".
It will feel like the old manual brakes or worse.
A symptom of a bad master cylinder would be your brake pedal going almost to the floor when stepping on the brakes.
The power brake booster is operated by engine vacuum. If you lose that vacuum (bad hose, connection, or crack) you won't have "power brakes".
It will feel like the old manual brakes or worse.
A symptom of a bad master cylinder would be your brake pedal going almost to the floor when stepping on the brakes.
Team Owner
Joined: Feb 2003
Posts: 54,073
Likes: 9,398
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Your description of needing more pressure on the pedal to stop is a symptom of a bad brake booster.
The power brake booster is operated by engine vacuum. If you lose that vacuum (bad hose, connection, or crack) you won't have "power brakes".
It will feel like the old manual brakes or worse.
A symptom of a bad master cylinder would be your brake pedal going almost to the floor when stepping on the brakes.
The power brake booster is operated by engine vacuum. If you lose that vacuum (bad hose, connection, or crack) you won't have "power brakes".
It will feel like the old manual brakes or worse.
A symptom of a bad master cylinder would be your brake pedal going almost to the floor when stepping on the brakes.
Racer
Joined: Aug 2009
Posts: 342
Likes: 0
From: Dallas Texas
Your description of needing more pressure on the pedal to stop is a symptom of a bad brake booster.
The power brake booster is operated by engine vacuum. If you lose that vacuum (bad hose, connection, or crack) you won't have "power brakes".
It will feel like the old manual brakes or worse.
A symptom of a bad master cylinder would be your brake pedal going almost to the floor when stepping on the brakes.
The power brake booster is operated by engine vacuum. If you lose that vacuum (bad hose, connection, or crack) you won't have "power brakes".
It will feel like the old manual brakes or worse.
A symptom of a bad master cylinder would be your brake pedal going almost to the floor when stepping on the brakes.
Burning Brakes
Joined: May 2008
Posts: 1,008
Likes: 5
From: Greensburg PA
I agree, while you are reworking your brakes, don't neglect your 24 year old rubber brake lines. ANY system is only as strong as it's weakest link. The lines that go from the body/frame to the wheels, there are 4 of the of course, each about a foot long. These are 24 YEARS OLD and made from rubber and consitantly moving and exposed to all kinds of weather and road trash. As they get old and beat up they can expand under pressure (makes the brakes feel squishy) and eventually leak or brust, bad news. There is a guy on this forum, I can find his tagname, but he sold me a full set of 4 stainless steel lines for $100 delivered, brand new. Search the parts section for SS Brake Lines. Not a bad deal for some much needed brake insurance on a 24 year old car....cheers!
One of the best mods I did to my 88 was SS lines(Goodridge), new Synthetic fluid, and new rotors/pads from brakemotive. I didn't realize how bad my stock brakes were until I changed them.
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
If it has just happened and was fine the other day i agree the power brake booster may be leaking.
If you have replaced the brake pads well there are some really bad brake pads that don't have any friction material, they will show the same symptoms where you can stand on the brake pedal and barely slow the vette.
There are aftermarket all metal power boosters, i say go for one of those as the plastic goes brittle. and when the time comes to recondition it will be a bin job.
Note the 88 to 96 master cylinders wont work on the 84-87 vettes.
They had twin piston calipers and the bias will be wrong.
Best get the correct master cylinder for your year vette that was designed for it.
If you have replaced the brake pads well there are some really bad brake pads that don't have any friction material, they will show the same symptoms where you can stand on the brake pedal and barely slow the vette.
There are aftermarket all metal power boosters, i say go for one of those as the plastic goes brittle. and when the time comes to recondition it will be a bin job.
Note the 88 to 96 master cylinders wont work on the 84-87 vettes.
They had twin piston calipers and the bias will be wrong.
Best get the correct master cylinder for your year vette that was designed for it.
Last edited by gerardvg; Dec 12, 2011 at 01:19 AM. Reason: More info
Thread Starter
Pro
Joined: Oct 2011
Posts: 703
Likes: 76
From: leesburg fl
St. Jude Donor '12
brakes
I changed out the brake booster, checked the vacuum I have plenty of vacuum. But the brakes still are the same. Maybe change the pads, check the rotors, and change the rubber lines. Because the brakes still are not like they were before, The car would stop on a dime.
Thanks a lot for all the help and advice
Jim
Thanks a lot for all the help and advice
Jim
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