# 67 gto brake problems



## fiesta62 (Jan 12, 2011)

hi, my brake pedal is low to floor and spongy and really brakes are not stopping car real good, i have factory disc on front , drum on rear, i have replaced the hold off valve, distrubution valve, master cyl, rear drum cylinders, machined rear drums, and bled many times various ways, even bought that phonix brake bleeder, but brakes are still weak, maybe i should remove the distrubution block and hold off valve from the system to simplify things any thoughts on anything ?
the other issue is i get a clunk sound every now and then coming from passenger front side, many times sound is just when applying brakes , everything looks fine, ball joints, bearings are all new, but i noticed the passenger side brake pad moves a bit , i can use a lever wedged between the wheel studs and rock the hub back and forth, i can see the pad move, the pin that holds pad is loose with play but i assume thats normal, possibly the caliper is worn and not holding pad tight, i was thinking maybe upgrade the calipers with some newer designed hopefully better calipers?... mine are the factory 4 piston caliper, which i have read dont move with the disc like newer calipers do, anyone had any expirence in upgradeing factory calipers and if needed the disc rotors, or even if its worth doing ?.....i am not sure how good these factory calipers are as they were the first year design....thanks


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## chuckha62 (Apr 5, 2010)

The 4 piston calipers are essentially the same as the Corvette calipers. Basically a good design, but as you said, not a floating design. The early Corvette experienced the same kinds of issues that you're experiencing and was generally attributed to moisture causing the cylinder bores to rust and bleed off brake pressure. The fix for it is to have the cylinders sleeved with stainless. 

The easier answer is to upgrade to '69 and later discs, which will require brackets and _maybe_ spindles. Others can chime in about the spindles.


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## fiesta62 (Jan 12, 2011)

chuckha62 said:


> The 4 piston calipers are essentially the same as the Corvette calipers. Basically a good design, but as you said, not a floating design. The early Corvette experienced the same kinds of issues that you're experiencing and was generally attributed to moisture causing the cylinder bores to rust and bleed off brake pressure. The fix for it is to have the cylinders sleeved with stainless.
> 
> The easier answer is to upgrade to '69 and later discs, which will require brackets and _maybe_ spindles. Others can chime in about the spindles.


hi, i will get the calipers looked at to see how the pistons are but i am thinking that may not be the problem, if the pistons in calipers were faulty my rear drum brakes still should be working, as its a divided system, so rear should not get any air issues caused by calipers, if i step on brakes real hard its just a soft stop, no where near locking up, also if caliper pistons were rusting i would expect car would pull to one side when braking as calipers would not rust evenly and i would assume one caliper would be rusted more than the other causing car to pull to one side, but car stops straight no issues with pulling to one side , i will take car today to a brake shop to get there ideas, it does seem like a bleed problem, but i have already had 2 mechanics bleed system, and done it myself many ways, something is not right somewhere....thanks


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## chuckha62 (Apr 5, 2010)

fiesta62 said:


> hi, i will get the calipers looked at to see how the pistons are but i am thinking that may not be the problem, if the pistons in calipers were faulty my rear drum brakes still should be working, as its a divided system, so rear should not get any air issues caused by calipers, if i step on brakes real hard its just a soft stop, no where near locking up, also if caliper pistons were rusting i would expect car would pull to one side when braking as calipers would not rust evenly and i would assume one caliper would be rusted more than the other causing car to pull to one side, but car stops straight no issues with pulling to one side , i will take car today to a brake shop to get there ideas, it does seem like a bleed problem, but i have already had 2 mechanics bleed system, and done it myself many ways, something is not right somewhere....thanks


Perhaps, but remember you only have 30-35% braking coming form the rears. You may not feel a "firm" pedal until the fronts are repaired. IF that is what it is. When my hold off valve was tripped, I had no air in the rears, but still had no pedal feel. When I tripped the hold off valve and bled the fronts, the pedal feel was restored. Just a thought.


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## fiesta62 (Jan 12, 2011)

chuckha62 said:


> Perhaps, but remember you only have 30-35% braking coming form the rears. You may not feel a "firm" pedal until the fronts are repaired. IF that is what it is. When my hold off valve was tripped, I had no air in the rears, but still had no pedal feel. When I tripped the hold off valve and bled the fronts, the pedal feel was restored. Just a thought.


took car to brake shop today....they had no ideas except to check my disc pads, they have heaps of meat on them, but i guess could be glazed the brake place said it could be the problem, i kinda doubt it, too easy....but i will post another thread to research the best pads to use....i am taking car to another brake shop on friday these guys seems knowledable so we will see....


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