Brakes barely working
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Thread Starter
Pro
Joined: Oct 2007
Posts: 587
Likes: 0
From: Overland Park Kansas
Well I am 23 so you are very right I never drove a 1979 car new. My statement was based on comments made by people I know who did. I apologize if that statement offended you.
And yes, I am worried what it will cost. Saying I shouldn't is simply ignorant. I don't see a cage in your 62, what would happen if it got hit or rolled? You see there are lots of factors which cause people to not make things as safe as they should be, and in my opinion my cost concerns are probably more valid than your appearance or originality ones.
But at any rate, I am going to take it and have it looked at. Thank you for your comments.
And yes, I am worried what it will cost. Saying I shouldn't is simply ignorant. I don't see a cage in your 62, what would happen if it got hit or rolled? You see there are lots of factors which cause people to not make things as safe as they should be, and in my opinion my cost concerns are probably more valid than your appearance or originality ones.
But at any rate, I am going to take it and have it looked at. Thank you for your comments.
Drifting
Joined: Aug 2007
Posts: 1,924
Likes: 6
In my 12 years with mine, I have replaced all the calipers, mc and booster and recently installed russell braided lines
I have found the best method (for me) to bleed the brakes with 2 people is to have the person on the pedal press and hold while I release the bleeder(s)
press hold release
press hold release
right rear
left rear
right front
left front
the pump pump pump hold release thing doesnt seem to work on mine.
engine off
press hold release
I have found the best method (for me) to bleed the brakes with 2 people is to have the person on the pedal press and hold while I release the bleeder(s)
press hold release
press hold release
right rear
left rear
right front
left front
the pump pump pump hold release thing doesnt seem to work on mine.
engine off
press hold release
Advanced
Joined: Jul 2006
Posts: 85
Likes: 0
I bought a pressure bleeder and that solved my problem. I also went with a new MC. My origional issue was the pedal dropping to the floor. I als upgraded to braided stainless flex lines.
If you are sure this thing is bled, then you could have a bad booster ony your hands like mentioned by others. You also might want to pull the MC and bench bleed it, then you will need to bleed the whole system again.
If you are sure this thing is bled, then you could have a bad booster ony your hands like mentioned by others. You also might want to pull the MC and bench bleed it, then you will need to bleed the whole system again.
Burning Brakes
Joined: Oct 2007
Posts: 946
Likes: 0
From: Lake Geneva WI
I took mine to a local mechanic that my wife has used for years. $120 for a new caliper, and $30 in labor and the brakes are perfect now.. Looks like one of the calipers was locked. Source of squeaking and spongy feeling...
Racer
Joined: Apr 2004
Posts: 370
Likes: 0
New England Events Coordinator
3 bleeders on rears??
Hi, I had the same problem last month. I checked around for leaks and there where none at all. I know that over time the rear brakes may get air into them via the seals. I purchased a set of Russell speed bleeders from Summit and installed them on all four calipers. The rear calipers need 3 bleeders each. I had a problem last year bleeding the brakes on my 1970 buick, I needed to take care of the bleeding of the 1980 vette and wasent looking forward to it. Everyone suggested the speed bleeders and I swear by them, once installed I had all 4 calipers bleed in under 15 min and that solved the soft pedal that I had. Start with the speed bleeders and bleed the whole system, that should resolve the problem.
Melting Slicks
Joined: Aug 2004
Posts: 2,063
Likes: 1
From: Beverly Massachusetts
I had the same problem with my 76 when my mom owned the car and we never figured out what the problem was. I bought the car from her a couple years ago and decided to just replace the entire brake system with a complete kit from VB&P and guess what? I had the same problem with the new setup minus the proportioning valve. When I say I replaced everything minus the proportioning valve I mean everything. New lines, rotors, MC, booster, o-ring calipers, braided flex lines, hawk pads……….. I am talking the works here and I still had the same problem. Anyways I got all the new stuff in and even bought the power bleeder and the brakes still felt mushy. It turns out that it was the adjustment rod between the booster and the MC that was not adjusted correctly. I am not sure if you are having the same problem but its worth a shot. Now that I have the brakes working fine I am going to replace my proportioning valve but that isn’t till next spring. 
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Melting Slicks
Joined: Jan 2007
Posts: 2,589
Likes: 5
From: Salisbury Maryland
Has the car been sitting?
I went through the same thing last year. Turned out one of the rear calipers was letting air into the system when pumping the brakes. All the bleeding in the world wouldn't fix it. As a result, I bought new O-Ring calipers, rubber lines, new MC. Bled 3x around and...wella! Brakes that work!. Finding the source of the air is the issue. If you have thoroughly bled and still don't have a good pedal, then air is coming back into the system, you've got to find the source. It may not even be leaking fluid, mine wasn't, makes it even harder to find!
Good Luck!
I went through the same thing last year. Turned out one of the rear calipers was letting air into the system when pumping the brakes. All the bleeding in the world wouldn't fix it. As a result, I bought new O-Ring calipers, rubber lines, new MC. Bled 3x around and...wella! Brakes that work!. Finding the source of the air is the issue. If you have thoroughly bled and still don't have a good pedal, then air is coming back into the system, you've got to find the source. It may not even be leaking fluid, mine wasn't, makes it even harder to find!
Good Luck!
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
You shouldn't be driving it if the brakes are not 100%.
Melting Slicks
Joined: Jan 2007
Posts: 2,589
Likes: 5
From: Salisbury Maryland
You must systematically look into each part of the system and find what the issue is. If you can't do it yourself, or don't have the time or money, you probably bought the wrong car. If you're loosing your patience, then walk away from it for a few days and come back to it with a fresh mind, that always works for me. These cars are 35+/- years old, they have problems, it's that simple. Fixing it is part of the fun, and when your through, the feeling of accomplishment is second to none. Not to mention what you learned.
Good Luck!
Burning Brakes
Joined: Dec 2002
Posts: 1,179
Likes: 3
From: STANTON CA
I had the same problem with my 76 when my mom owned the car and we never figured out what the problem was. I bought the car from her a couple years ago and decided to just replace the entire brake system with a complete kit from VB&P and guess what? I had the same problem with the new setup minus the proportioning valve. When I say I replaced everything minus the proportioning valve I mean everything. New lines, rotors, MC, booster, o-ring calipers, braided flex lines, hawk pads……….. I am talking the works here and I still had the same problem. Anyways I got all the new stuff in and even bought the power bleeder and the brakes still felt mushy. It turns out that it was the adjustment rod between the booster and the MC that was not adjusted correctly. I am not sure if you are having the same problem but its worth a shot. Now that I have the brakes working fine I am going to replace my proportioning valve but that isn’t till next spring.
Former Vendor
Joined: Nov 2005
Posts: 683
Likes: 1
From: Mounds View Minnesota
If the pedal is mushy you have air in the system.
Remember power brakes ALWAYS feel mushy.
If you can pump it up and it stays up with your foot light ly on the pedal, you have air in the system
if you pump it up and the pedal slowly sinks, you have a leak or a bad MC
If you can't pump it up you have a bad MC
If you pump it up and pedal still goes to the floor, check the push rod as stated above. It should have just a tiny bit of play, like the thickness of a piece of paper.
(lie on your back and look up under the dash. it's that rod you can hardly get to that moves when you move the brake pedal)
Remember power brakes ALWAYS feel mushy.
If you can pump it up and it stays up with your foot light ly on the pedal, you have air in the system
if you pump it up and the pedal slowly sinks, you have a leak or a bad MC
If you can't pump it up you have a bad MC
If you pump it up and pedal still goes to the floor, check the push rod as stated above. It should have just a tiny bit of play, like the thickness of a piece of paper.
(lie on your back and look up under the dash. it's that rod you can hardly get to that moves when you move the brake pedal)
Burning Brakes
Joined: Dec 2002
Posts: 1,179
Likes: 3
From: STANTON CA
If the pedal is mushy you have air in the system.
Remember power brakes ALWAYS feel mushy.
If you can pump it up and it stays up with your foot light ly on the pedal, you have air in the system
if you pump it up and the pedal slowly sinks, you have a leak or a bad MC
If you can't pump it up you have a bad MC
If you pump it up and pedal still goes to the floor, check the push rod as stated above. It should have just a tiny bit of play, like the thickness of a piece of paper.
(lie on your back and look up under the dash. it's that rod you can hardly get to that moves when you move the brake pedal)
Remember power brakes ALWAYS feel mushy.
If you can pump it up and it stays up with your foot light ly on the pedal, you have air in the system
if you pump it up and the pedal slowly sinks, you have a leak or a bad MC
If you can't pump it up you have a bad MC
If you pump it up and pedal still goes to the floor, check the push rod as stated above. It should have just a tiny bit of play, like the thickness of a piece of paper.
(lie on your back and look up under the dash. it's that rod you can hardly get to that moves when you move the brake pedal)
the master cylinder and ajust it that way
Former Vendor
Joined: Nov 2005
Posts: 683
Likes: 1
From: Mounds View Minnesota
The MC needs to be in place and fully tightened to adjust the pushrod ( for a manual brake car )
For a power brake car there is an adjustment sometimes on the rod from the booster to the MC. If that is out of ajdustment.
Advanced
Joined: May 2006
Posts: 69
Likes: 1
From: West Linn Oregon
I'm not positive how the Corvette brakes operate since mine are working fine and I haven't had reason to get into them yet. But I just had a similar problem bleeding my '67 Chevelle with a Master Power 4-wheel disc set-up (80-85 Cadillac Seville), and it ended up being the emergency brake adjustment. Until the e-brake adjusters for the rear pads are properly set-up against the rotor, there is no way to get them to bleed properly. But like I said, I'm not sure it's the same on the Corvette, so take it with a grain of salt. I'm only suggesting it because I haven't seen it mentioned...and I know (first hand) how frustrating brake issues can be, especially when you think you've already tried everything else. Good Luck!
Former Vendor
Joined: Nov 2005
Posts: 683
Likes: 1
From: Mounds View Minnesota
Unfortunately Corvette Emergency brakes are a different universe ( an alternate evil parallel universe)
One more trick I just remembered.
This only works on Rubber flex lines and only as a last resort.
DO NOT do this with stainless Braided!
Clamp off all four flex lines with vice grips. You have to squeeze the line pretty good. All 4...
press on the brake pedal. It should be rock hard (power brake people have the engine running)
If it's not you have a bad MC or a leak or air in the lines.
unclamp one line at a time. See what happens. Re clamp the line, try another wheel.
Keith
One more trick I just remembered.
This only works on Rubber flex lines and only as a last resort.
DO NOT do this with stainless Braided!
Clamp off all four flex lines with vice grips. You have to squeeze the line pretty good. All 4...
press on the brake pedal. It should be rock hard (power brake people have the engine running)
If it's not you have a bad MC or a leak or air in the lines.
unclamp one line at a time. See what happens. Re clamp the line, try another wheel.
Keith
Advanced
Joined: May 2007
Posts: 83
Likes: 4
From: Leander Texas
I'm not positive how the Corvette brakes operate since mine are working fine and I haven't had reason to get into them yet. But I just had a similar problem bleeding my '67 Chevelle with a Master Power 4-wheel disc set-up (80-85 Cadillac Seville), and it ended up being the emergency brake adjustment. Until the e-brake adjusters for the rear pads are properly set-up against the rotor, there is no way to get them to bleed properly. But like I said, I'm not sure it's the same on the Corvette, so take it with a grain of salt. I'm only suggesting it because I haven't seen it mentioned...and I know (first hand) how frustrating brake issues can be, especially when you think you've already tried everything else. Good Luck!
Thread Starter
Pro
Joined: Oct 2007
Posts: 587
Likes: 0
From: Overland Park Kansas
Sorry for not posting back. I got the system sorted out and it's working well now. 3 of the calipers were leaking, so I replaced all 4. One of the front lines was bulbed so I replaced the front 2. That didn't fix it, so I replaced the MC and now it's great. Had a friend help me bleed them (pump pump turn etc), and she is as good as I can expect. I guess it was a combo of the calipers being screwed and the MC, but now with a mostly new brake system she stops fine.
Thanks for all the advice!
-Josh
Thanks for all the advice!
-Josh