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2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Hi and Welcome.
You did a good job of servicing your brake system.
Measure the rotors and if in spec just leave them as they are.
The free travel for the power brake pedal is 1.8 inches, that is almost 2 inches of travel before the brakes work, that seems excessive but that is the way they were made. As said before, it takes a little time to get used to that much free play and is way more that most daily drivers.
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Master cylinders are 1" bore for manual brakes and
1 &1/8" bore for power brakes, but you can fine deep hole or shallow hole so compare to what is being replaced.
The gap between the booster rod and the master cylinder must be between 1/32" to 1/16"
Last edited by Peterbuilt; Feb 8, 2022 at 12:07 AM.
Reason: 1/32" to 1/16" not 1/6
I know I look/sound like one of those guys on TwitBook that "likes" or thanks everyone for each comment, but I think it's well-deserved here.
Thank you all, again, for your responses - this has been beyond instructional, informative, and just plain fun. I'll report back on the progress... once more unto the breach.
. The fairly long pedal travel is still present, but it's within spec (thanks, Peterbuilt) and I'll be tilting at windmills at this point if I try to eliminate the "long" travel.
Consumption of bourbon.
Thanks again, gents, for all of the info - y'all are top shelf.
Last edited by Aeredan; Feb 26, 2022 at 09:32 PM.
Reason: Grammar...
After taking a long drive, the pedal travel became progressively worse, stopping was far more difficult, and a hissing sound was heard within the cockpit. Long story short, the power brake booster decided to shuffle off it's mortal diaphragm - it will no longer hold vacuum. It stands to reason that this could have been the friggin' problem all along...
I'll update once I replace the power brake booster.
Replacement of the power brake booster and the investment of a Motive Products 105 Brake System Power Bleeder cured my issues entirely. I can lock 'em up without standing on the pedal, and it simply "feels right". I cannot thank everyone here enough for their input and guidance.
For anyone that ventures into replacing the power brake booster, this video aided in preparation:
Replacement of the power brake booster and the investment of a Motive Products 105 Brake System Power Bleeder cured my issues entirely. I can lock 'em up without standing on the pedal, and it simply "feels right". I cannot thank everyone here enough for their input and guidance.
Replacement of the power brake booster and the investment of a Motive Products 105 Brake System Power Bleeder cured my issues entirely. I can lock 'em up without standing on the pedal, and it simply "feels right". I cannot thank everyone here enough for their input and guidance.
Another good and very inexpensive way to bleed brake calipers is the gravity method. I've done it for years w/o ever having a problem. Let a cup of brake fluid drain from every bleeder one at a time in proper sequence; Only draw back is it's time consuming. Just my 2 cents.
Last edited by Jud Chapin; Mar 11, 2022 at 08:59 AM.
With the vehicle up on jack-stands, all tires off, you can bleed all four rear bleeders at once.
Four bleeders, four clear hoses, four catch bottles.
Pull up a chair at the drivers fender. In one hand is your favorite car magazine, one hand a cup of Jo, third hand has a bottle of DOT3.
Just sit back, relax, read, and watch the masters fluid level.
Getting the air "out" is the main reason we bleed our brakes. Air wants to go UP and it doesn't get pushed down very well without enormous pressure. I tried Gravity bleeding when I first bought my C3 and was not able to remove all the air completely. I tried the Motive system next and it did a better job than the gravity bleeding did on my C3. The pedal was still a bit softer than I am used too so I moved on.
Finally I tried a Phoenix Reverse Bleeder after having used the Motive system bled the lines and when we first pushed fluid up towards the master cylinder I saw the air bubbles coming out that had been trapped in the caliper. After that air was gone the brakes felt their very best and worked very well. I think it was the caliper that was the guilty culprit in holding air.
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
I too have used the gravity method but also followed up with the brake pedal method. More air bubbles came out. For my stock brake system, gravity bleed didn't remove all the trapped air. I've also never had any problem at all bleeding with the brake pedal. It's the method in the GM repair manual and it works.
A "problem" with the reverse pressure bleeding is that you're forcing the worst brake fluid in the entire system back towards the mc.
I prefer to force it the other way.
Reverse bleeding does in fact push the old fluid back into the master cylinder.
That has never been a problem with a large turkey baster and a bowl below the MC just in case. I love seeing the fresh new clean fluid push it's way up and into the MC along with any tough to get out air bubbles. I bought a large kit from Phoenix and it has all the adapters to help control the fluid from making a mess. I also use lots of disposable rags to keep the area sanitary and free from brake fluid.
I would think it would be a bigger problem when you have ABS Pumps and controllers in the way. Then I let the shop pressure bleed them for me. I do however flush the fluid every five years as it is easy enough to do. It hasn't hurt the 1988 C4 with its very early attempt at ABS in the several times I have flushed the brakes. It also helps with my 1987 VW Vanagon Syncro and it's long stretches of brake lines. I draw the line at the modern ABS equipped cars
I need to make the job as easy as possible so I will do it as needed. Otherwise I have to pay someone else to do it for me.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
Hi and Welcome.
