Front caliper wows
Thread Starter
Pro
Joined: Jul 2009
Posts: 503
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From: Gambrills Maryland
Front caliper wows
I have a new to me 1968 with stock brakes. When I got the car, the calipers were all rusted up so I got 4 rebuilds from the local Autozone. The are stainless sleaved with lip seals and are marked with the stock GM numbers on the castings. I have been having trouble getting them to work correctly. I have followed the various threads on bleeding in this forum. I just realized that the front calipers only have a bleed fitting on the top of the "inside" half of the caliper....is this correct? The backs have a fitting at the top of both halves. How can the fronts be bleed with only one fitting.
I already returned my original caliper cores. Could someone look at there C3 fronts with OEM calipers and tell me what you have?
I already returned my original caliper cores. Could someone look at there C3 fronts with OEM calipers and tell me what you have?
Thread Starter
Pro
Joined: Jul 2009
Posts: 503
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From: Gambrills Maryland
Mushy pedal and no stopping power. I forgot to say that it has manual brakes. The previous owner had installed a "line lock" and I just removed that andit improved stopping power greatly. I have replaced the master cylinder twice, put a gallon of fluid though the lines, bench bled the master, used evey possible method of bleeding, etc.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Mushy pedal and no stopping power. I forgot to say that it has manual brakes. The previous owner had installed a "line lock" and I just removed that andit improved stopping power greatly. I have replaced the master cylinder twice, put a gallon of fluid though the lines, bench bled the master, used evey possible method of bleeding, etc.
Thread Starter
Pro
Joined: Jul 2009
Posts: 503
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From: Gambrills Maryland
I believe that its the correct master because it has the deeper pocket for the pedal rod. Does a manual master have bigger "metering holes" than the powe master. Could Cardone not know what they are doing and are building manual masters with power metering holes?
Interesting thing is that I bled it after removig the line lock and the peddle felt nice and hard but it was too late to take it for a drive. the next day when I took it out the pedal was softer than the day before. No puddles on the floor or anything Does that make many sense?
Interesting thing is that I bled it after removig the line lock and the peddle felt nice and hard but it was too late to take it for a drive. the next day when I took it out the pedal was softer than the day before. No puddles on the floor or anything Does that make many sense?
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
On some of my vettes I had to push the pads back with a screwdriver or prybar. Forcing the brake fluid back into the MC. Start with the rear first and take care not too chip up the pads or rotor. I used some wood shims for home construction to hold the pistons back while I do the others.
Then when you take them out, make sure the MC is full and only pump the pedal 1/2 way slowly until hard.
Also on most cars there are 2 holes on the brake pedal. Make sure your rod is on the upper hole
Good Luck
Then when you take them out, make sure the MC is full and only pump the pedal 1/2 way slowly until hard.
Also on most cars there are 2 holes on the brake pedal. Make sure your rod is on the upper hole
Good Luck
Race Director
Joined: Jul 2004
Posts: 12,703
Likes: 329
From: Scottsdale Arizona
I don't know if the metering holes are different but the diameter of the piston is. If I recall correctly, the manual one is 1 inch ID OD and the power one is 1 and 1/8 inch. Not sure if this is your problem though.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Forgive me if this is what you are already doing, but this is an issue with folks who haven't bled brakes since "back when"....or ever.
You must depress the brake pedal and then let up on the pedal S-L-O-W-L-Y to prevent any turbulence which could put air back into the brake fluid. Always work from the farthest bleed screw [from the master cylinder] to the nearest one. So, R-R-outside screw, then R-R-inside screw, and so on. There is also a little known process recommended by GM to depress and hold a 'centering pin' on the proportional valve using a small bracket. This is detailed in the Chevrolet Chassis Service Manual. But, working the pedal down and up very slowly negates the need to do that.
You must depress the brake pedal and then let up on the pedal S-L-O-W-L-Y to prevent any turbulence which could put air back into the brake fluid. Always work from the farthest bleed screw [from the master cylinder] to the nearest one. So, R-R-outside screw, then R-R-inside screw, and so on. There is also a little known process recommended by GM to depress and hold a 'centering pin' on the proportional valve using a small bracket. This is detailed in the Chevrolet Chassis Service Manual. But, working the pedal down and up very slowly negates the need to do that.
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Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
I use the gravitiy bleed method on all my C2/3 Vette brake jobs. You need to have the MC cap off, and slightly depress the brake pedal to unseat the pistons in the MC. Then go to the passenger side caliper, open the bleeder screw and using a clear hose on the bleeder nipple, watch the fluid flow until there are no air pockets in the fluid flow. You can also tap the caliper with a piece of wood or rubber mallet to vibrate it and cause any air pockets to flow outward from the casting. Repeat on driver's side after checking MC fluid level and your done. Same method for the rear but start on outer passenger side bleeder then inner, check fluid, do same on driver's side. This method has worked for me for many years without fail.
If you trying to use the brake lines butchered for a line lock, I would order new ones and hoses from a vendor, cheap insurance and you may be fighting a leak in your brake line.
If you trying to use the brake lines butchered for a line lock, I would order new ones and hoses from a vendor, cheap insurance and you may be fighting a leak in your brake line.
Thread Starter
Pro
Joined: Jul 2009
Posts: 503
Likes: 0
From: Gambrills Maryland
I did replace the piece of hard line that had the line lock in it. Is there a way by looking at the MC to see if it is the 1 " diameter piston?
Also,the pads are probably about 12 yeas old but only have 2K miles on them. I have not replaced them because they have almost 1/4" pad on them. Could they be bad somehow?
Also,the pads are probably about 12 yeas old but only have 2K miles on them. I have not replaced them because they have almost 1/4" pad on them. Could they be bad somehow?
Melting Slicks
Joined: Jan 2003
Posts: 3,029
Likes: 94
From: meraux LA
Go to harbor freight and buy one of the brake bleeding vac pumps, and use it. Keep going until no bubbles come out. It will take a while. Make sure you keep the master full or you will have to start over if you let it go dry.
Burning Brakes
Joined: Feb 2003
Posts: 1,128
Likes: 4
From: Upland Ca
This story will come out OK if omegac1 has the correct MC and follows the correct bleeding instructions as 7T1vette outlined. Also goes beter when rear calipers are raised up higher that the front. Sounds as if there is still air in the system if mushy. You should be able to lock up those binders with no problem at all. Older pads should not be a problem unless they and the rotors are glazed over.
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
OK, the bleeding the furthest caliper first rule is BS. that is for production shops trying to optimize their time. For us, start anywhere and go around the car a few times.
second, new calipers are a B$%^ to bleed, you DO need to bleed both sides.
But not the bottom.
Bang the caliper with a rubber mallet, move the pistons around and keep trying.
Manual MC have a 1 inch bore and a deep well. I'm sure you're OK
Buy or build a pressure bleeder. it turns a painful 2 man job into a well, painful 1 man job.
You can make a pressure bleeder with a piece of 1/4" plate steel, an old MC gasket, a schrader fitting and a bicycle pump, just don't run the MC dry or you will be starting over!
If you put on new calipers I hope you replace your rubber lines. the newest original lines are what 28 years old? well past their life expectancy. If you didn't replace them they are original
second, new calipers are a B$%^ to bleed, you DO need to bleed both sides.
But not the bottom.
Bang the caliper with a rubber mallet, move the pistons around and keep trying.
Manual MC have a 1 inch bore and a deep well. I'm sure you're OK
Buy or build a pressure bleeder. it turns a painful 2 man job into a well, painful 1 man job.
You can make a pressure bleeder with a piece of 1/4" plate steel, an old MC gasket, a schrader fitting and a bicycle pump, just don't run the MC dry or you will be starting over!
If you put on new calipers I hope you replace your rubber lines. the newest original lines are what 28 years old? well past their life expectancy. If you didn't replace them they are original