Brake Problems yet again
Thread Starter
Team Owner
Joined: Sep 2001
Posts: 30,958
Likes: 0
From: Middletown Connecticut
Cruise-In IV Veteran
Brake Problems yet again
so I was driving the vette the past two days and I bled the brake lines on sunday. had a rock hard pedal, then started driving it the past two days and the brake pedal is getting worse over time.. meaning it gets mushy
if I pump the brakes up they get firm again but its still scary to know that they wont be there if I need them quick.
this leads me to think that my master cyl is either toast or needs to be bled, since its not leaking, I dont think its shot. is there a trick to bleeding that?
if I pump the brakes up they get firm again but its still scary to know that they wont be there if I need them quick.
this leads me to think that my master cyl is either toast or needs to be bled, since its not leaking, I dont think its shot. is there a trick to bleeding that?
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Check the rear rotors for runnout. Think about it. If you have a hard pedal after you bleed it, it aint the master cylinder. It is air pumping into the rear rotors.
Last edited by wombvette; Mar 16, 2005 at 02:40 AM.
Pro
Joined: Dec 2003
Posts: 592
Likes: 4
From: Denmark
Originally Posted by wombvette
Check the rear rotors for runnout. Think about it. If you have a hard pedal after you bleed it, it aint the master cylinder. It is air pumping into the rear rotors.
Wipe your calibers and inside of your wheels clean. Take it for a spin, using your brake long enough for the pedal to become soft, and check for leaks. I had a similar situation and could see the brakefluid inside the wheel.
Melting Slicks
Joined: Oct 2001
Posts: 3,025
Likes: 12
From: Pleasant Grove AL
Originally Posted by wombvette
Check the rear rotors for runnout. Think about it. If you have a hard pedal after you bleed it, it aint the master cylinder. It is air pumping into the rear rotors.
You can easily check the rear rotors for runout with a dial indicator, available from Harbor Freight for cheap. If the runout is more than .003", turn or replace.
Safety Car
Joined: Oct 2000
Posts: 3,547
Likes: 12
From: Carbondale Pa.
Originally Posted by StingrayDK
Wipe your calibers and inside of your wheels clean. Take it for a spin, using your brake long enough for the pedal to become soft, and check for leaks. I had a similar situation and could see the brakefluid inside the wheel.
extremely common, and somtimes it is an indication that the dreaded rear wheel bearing job will need to be done soon, almost as common as the rotors not being true. 
peace,,, Moosie 
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Melting Slicks
Joined: Sep 2000
Posts: 2,403
Likes: 416
From: Chester Virginia
Probably not the master cylinder. Sounds like a wheel caliper leaking. Check all four calipers not just the rears. Over Christmas I rebuilt all four calipers, both front and one rear were leaking.
If the car is in the Richmond area I can help with the rebuild and you can borrow my pressure bleeding unit.
Roger
If the car is in the Richmond area I can help with the rebuild and you can borrow my pressure bleeding unit.
Roger
Burning Brakes
Joined: Feb 2004
Posts: 958
Likes: 1
From: In the Beautiful Shenandoah Valley of VA
Originally Posted by Corz
I might as well just replace them, they appear to be original yet turned before
Steve
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
Originally Posted by wombvette
Check the rear rotors for runnout. Think about it. If you have a hard pedal after you bleed it, it aint the master cylinder. It is air pumping into the rear rotors.
Race Director
Joined: Jul 2004
Posts: 12,685
Likes: 329
From: Scottsdale Arizona
If you find fluid on your back wheels, I'd recommend rebuilding the calipers with VBP O-ring pistons. First of all, it's easier to do than the lip seal style and second, it will help if you have some air pumping due to excesive runout. If your rear wheel bearings are going bad, it may not compensate, but it will help.
Thread Starter
Team Owner
Joined: Sep 2001
Posts: 30,958
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From: Middletown Connecticut
Cruise-In IV Veteran
I looked today for the hell of it under the hood and the back of the master cyl was soaked..
And the car is in Connecticut, was HOPING to get it to richmond next week... looks like its staying in New England for a while
And the car is in Connecticut, was HOPING to get it to richmond next week... looks like its staying in New England for a while
Team Owner
Joined: Feb 2002
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From: Sometimes I wonder... why is that frisbee getting bigger? Then it hits me.
Cruise-In X Veteran
St. Jude Donor '06
Cor, loving your IM auto response
" Auto-response from ____: lousy f***g fiberglass pile of s**t"
" Auto-response from ____: lousy f***g fiberglass pile of s**t"
Tech Contributor
Joined: Aug 1999
Posts: 15,135
Likes: 3,939
From: Connecticut, USA
If the back of the M/C is soaked by a NEW not rebuilt M/C. Still check the rotors for runout-replacing them with new rotors will not garantee runoutunder .003" they may, in fact, be worse. If the rotor isn't scored or warped then 100 grit paper on a D/A is all you need for surface finish. Since you have original 36 year old rear bearings you might have to look there. Fix the M/C first then bleed the system. Bench bleed the M/c before installing - go to NAPA and get the metric brake line adapters that fit the M/C and cut the ends off. Screw them in place bend the line up and into each reservoir and you have the best m/c bleeder there is.
Gary
Gary