bad brakes

[MADLT1]

hi guys I ihave really bad brakes on my 71 at the moment and they used to be unreal,i have replaced the pads,bled the brakes a couple of times now and they are still spungy and not very responsive,do I need to resleeve the calipers ?how do I evan know if they need resleeving,i was quoted $390 per caliper,so I want to be sure first,cheers

[MY081]

Im an ex Bricky but for what it's worth I have heard of the rubber brake hoses near to the caliper sucking in when you apply the brakes ,If they are old this could be your problem . Ray

[MADLT1]

no I replaced them years ago with the braided metal lines

[sabre]

Re sleeved calipers would only be required if you have fluid leaking around the calipers. $390 per caliper is a bit expensive. You should be able to get an exchange set of 4 with pads for around $1200. I recently got SS sleeved set for $1000 on ebay.
I would be suspicious of the master cylinder. Reconditioning by a reputable brake place should set you back around $200.

[bfit]

With out seeing how you bleed the brakes I  first would  research the method of bleeding the  brakes  correctly.
First you need to bleed the master cylinder. Before anything down stream
Do we have a booster
Bfit

[sirfixalot]

Were they spongy before replacing pads? Have  you tried clamping off all the flexible hoses to see if pedal improves, release individually to  locate  a  bad caliper,have you tried bleeding brakes & taping caliper with a rubber mallet to dislodge air in caliper galleries. Perhaps a bent pad pushing back pistons. Do the new pads sit up to disc. IE have discs got a lip on outer & inner edges of braking surface holding pads off

[77CVT]

 

[MADLT1]

good feedback guys,yes it has a booster and yes I will get back under the car this weekend and try to solve this problem cheers

[Ausrs]

found a vacuum bleeder to be one of the best tools available to bleed the brakes on a C3 corvette,it makes life so much easier and takes about 10 minutes all up

http://www.ebay.com.au/itm/FPK-TOOLS-Brake-Bleeder-Kit-Vacuum-Pressure-Tester-Pump-Hand-Held-/291152875341?hash=item43ca104f4d:g:lKkAAOSw8-tWZgYw

[sirfixalot]

So what was the problem?

[MADLT1]

I have not touched it yet been to hot lol

[bfit]

The vacuum pump idea works well, as long as there are no leaking calliper seals .
you can spend a lot of time pulling air out of the system only to find it coming through a seal.
A pressure feed system is far the better system
bfit

[Vettech]

If they are the orginal seals and disks out of square, and as they sit off the disk by only a thou or two, then they will be wobled by the disk causing them to suck in air.
The replacement style are I think "O ring" type, and seal better than the square setion seals, used in conjuction with S/S sleeves, once bled are great. I had continual issues like you on a 78, once overhauled (s/s sleeves o/ring braided line) I never touched them again AND it now stopped on a dime.

[Chris Jurgeit]

I had heaps of trouble with my '68's brakes.  I'd bleed them, drive for a day or so, and the peddle got longer.  I did the usual - braided lines, new master cylinder, new front calipers (they were replaced because of seal failure and fluid leakage).  Back calipers 'seemed' ok.  No leaks in system, but still the long pedal issue persisted.  In the end I bit the bullet and bought new stainless piston-seal rear calipers and pressure bled the system again.  To date (six months) my pedal is good.  When I inspected the old rear calipers I found a hairline crack in the cast iron of one of them.  This was on the inside of the caliper and couldn't be seen unless the caliper was damp, then dry.  The moisture identified the crack, much like magnafluxing I'm guessing.  While I'm not 100% certain, I think the crack was letting air into the system, but not letting fluid out.  For what it's worth....