Brake frustrations
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,962
Likes: 1
From: Topeka-Pothole capital of the universe
Brake frustrations
I have never been satisfied with the brakes on my 78, so
when the front calipers started leaking (again!! :mad )
I decided to do the following:
New (not reman) master cylinder.
Four calipers.
New rubber brake lines.
The brakes have been vacuum bled, gravity bled, and pressure
bled (the last by a local brake and muffler shop). The pedal
is firm for a couple of days, then gets soft. The pads are organic
to keep the squeaking to a minimum.
Any ideas?
when the front calipers started leaking (again!! :mad )
I decided to do the following:
New (not reman) master cylinder.
Four calipers.
New rubber brake lines.
The brakes have been vacuum bled, gravity bled, and pressure
bled (the last by a local brake and muffler shop). The pedal
is firm for a couple of days, then gets soft. The pads are organic
to keep the squeaking to a minimum.
Any ideas?
Burning Brakes
Joined: Dec 1999
Posts: 924
Likes: 1
From: Houston Texas
Re: Brake frustrations (TFeld78)
You didn't mention whether the rotors were turned, or checked. If they're not flat you can loose fluid and introduce air into the system via the calipers.
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Melting Slicks
Joined: Oct 2001
Posts: 2,064
Likes: 1,382
From: Halifax, Nova Scotia, Canada
Re: Brake frustrations (TFeld78)
Have you checked the runout on the rotors.?
A common problem with Corvettes.
If they are out only by a .003 - .005 they will 'wobble' enough to pulse the caliper pistons and introduce air into the system. (30 Min. of driving)
Only two ways to fix this:
1/ True up the rotors, by shim or by turning (machining on the car).
2/ If the runout is not too severe, then "O" ring calipers would help.
(This only masks the problem, but some have had good results)
Do a search on past topics regarding brakes. There are many discussions regarding this topic.
Barry
A common problem with Corvettes.
If they are out only by a .003 - .005 they will 'wobble' enough to pulse the caliper pistons and introduce air into the system. (30 Min. of driving)
Only two ways to fix this:
1/ True up the rotors, by shim or by turning (machining on the car).
2/ If the runout is not too severe, then "O" ring calipers would help.
(This only masks the problem, but some have had good results)
Do a search on past topics regarding brakes. There are many discussions regarding this topic.
Barry
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Re: Brake frustrations (TFeld78)
Buy a Brake Repair Handbook from your State's Bureau of Automotive Repair...it's usually only like $20 and it will explain everything.
Or you could follow my advice:
Jack up the right rear and remove the tire. Place a box end wrench onto the bleeder nut then attach a clear hose to the inside right rear bleeder valve and stick the other end of the hose into a small clear bottle (a one-man bleeder kit is available at Checker/Shucks/Kragen that has the hose and bottle). Loosen the bleeder about a 1/4 turn. Make sure the fluid reservoir is full of fluid then pump the brakes (if power brakes then start car and let idle) about 15 times while watching the fluid flow into the bottle...check for clear fluid with no bubbles...on the last pump hold the pedal down (use either a helper to pump, or use a 2' 2x4 with towels to protect the seat and wedge the pedal down with the 2x4 against the seat) then walk around and tighten the bleeder.
Repeat the process...always make sure the reservoir is full of fluid before pumping...bleed in this order: RightRearInside, RightRearOutside, LeftRearI, LeftRearO, RightFront, LeftFront.
This is the procedure outlined in the California BAR Brake Inspection and Repair Handbook I own, and it works great. I did my brakes last year, and they are still nice and firm.
Or you could follow my advice:
Jack up the right rear and remove the tire. Place a box end wrench onto the bleeder nut then attach a clear hose to the inside right rear bleeder valve and stick the other end of the hose into a small clear bottle (a one-man bleeder kit is available at Checker/Shucks/Kragen that has the hose and bottle). Loosen the bleeder about a 1/4 turn. Make sure the fluid reservoir is full of fluid then pump the brakes (if power brakes then start car and let idle) about 15 times while watching the fluid flow into the bottle...check for clear fluid with no bubbles...on the last pump hold the pedal down (use either a helper to pump, or use a 2' 2x4 with towels to protect the seat and wedge the pedal down with the 2x4 against the seat) then walk around and tighten the bleeder.
Repeat the process...always make sure the reservoir is full of fluid before pumping...bleed in this order: RightRearInside, RightRearOutside, LeftRearI, LeftRearO, RightFront, LeftFront.
This is the procedure outlined in the California BAR Brake Inspection and Repair Handbook I own, and it works great. I did my brakes last year, and they are still nice and firm.
