Tom's '07 Monty

Been a while since I bled brakes on a car, let alone a C3.

Installed four rebuilt (stainless steel sleeved, O ring) calipers. I reviewed bleeding procedures and found several different ways in the articles.

I always took the cap off the M/C, made sure the M/C was full of Dot 3 fluid. (I probably ought to flush it now that I think about it).

I started at the passenger side rear caliper, used a line wrench to loosen the bleeder valve, used clear plastic hose and bottle, bled until no more bubbles and moved to the driver side rear caliper...then the passenger front and finally, the driver side caliper. If pedal was mushy, I repeated the process. Oh, I also relieved vacuum pressure from the brake booster before I started bleeding the brakes.

BTW, I also used new copper washers and caliper mounting bolts. C3 already had flexible S/S brake lines.

Is this the best procedure for C3 brakes? Again, thanks for your advice.

revitup

That procedure is as good as any. Just note there's two bleeders on each of the rear calipers, bleed inner then outer.

resdoggie

That's the way I've always done it and never had any problems.

Tom's '07 Monty

Thanks. The rebuilt calipers from Eckler's had plugs in the lower bleeder holes.

wendellp601

There should be two bleeder screws on the upper part of each rear brake caliper.

One on the inboard half and one on the outboard half of the caliper.

wrwillcox

Here s a picture of a rear caliper. Two bleeders, one on each side, on the top. On the bottom, one brake line inlet on the inside. The bottom outside generally has a plug, I believe you can see it in this picture.

Tom's '07 Monty

Got everything checked out this morning. Bolts torqued 60 ftlbs rear and 130 front. Front wheel bearings installed. Master cylinder installed a few months ago. Everything clean and ready for bleeding. Bleeder screws are all on top of calipers. Rear caliper bleeder screws: one inboard and one outboard.

Will bleed tomorrow afternoon. Method: start with rear passenger side inboard, proceed to outboard. Next rear driver side. Next will be front passenger side and lastly, front driver side. Hopefully all bubbles (air) will be out on first try. If not, do it again. Experience tells me it may take two or three trys. Cross your fingers for me.

revitup

A Motive pressure bleeder is a great asset for doing this job. You'll hear pros and cons but I swear by mine. I change fluid (in effect bleed) every couple of years. Never a problem, good bleed and hard pedal every time.

resdoggie

Open your bleeders and let the brake fluid flow to the calipers by gravity. When they begin to drip, tighten all the bleeders. Now you can begin manual bleeding as previously outlined beginning with the right rear.

drwet

I've been using a pressure bleeder for many years and its the best money I ever spent. Would never try to do it manually again.

Tom's '07 Monty

I just checked O'Reilly's and they don't have it. Any suggestions on where purchase?

What pressure to you use to bleed the C3 brake system?

thanks,

Tom

HeadsU.P.

Actually, if you have the time, watch for a used Motive on EBay. May have to buy new hoses and a MC adaptor plate but its a lot cheaper.
I made my own plate for the MC. Washed out the used tank real well with denatured alcohol. You only need about 12-16 lbs pressure to do all four corners of brakes. See the plate in my profile photo album.

revitup

You want model 0105. They're about $70-$80 at any of the major Corvette suppliers, or Amazon, Jegs, etc.
Get a couple of Irwin woodworking clamps or similar to hold the MC cap on and sealed. The hook and chain setup it comes with doesn't work very well.
I use about 10, maybe 15 PSI or so to bleed.

Tom's '07 Monty

Well we bled the brakes today after replacing all 4 calipers with rebuilt SS sleeved, O Ring style ones. New Wagner Thermoquiet pads, SS flex hoses at the calipers. MC was replaced a few months ago...I cannot verify if the new MC was bench bled before installation.

After three rounds of manual bleeding and testing brakes while on jack stands, we had some pedal.

Put it on the ground and did a slow drive around the neighborhood. Car stops but not quickly. Pedal is fairly firm when about 3/4 way to floor. Brakes not yet ready for traffic or open road.

What is your advice to get a firm brake pedal for quick stops and panic stops? Keep manually bleeding? Take to a shop for pressurized bleeding? Owner says brakes are 200 % better than before - two calipers were leaking badly.

Thanks again for your advice.

revitup

Buy the Motive bleeder. This won't be the last time you'll bleed the brakes. You'll use it again and again.

HeadsU.P.

You likely still have air in the system. But you have to go to the root of the cause or the begining: Master Cylinder. I doubt the MC was bench bled properly. There is always a couple bubbles lodged in there.
Its not that big of deal to remove MC, two nuts, two brakeline fittings. While you are in there glance at the distance from the booster pushrod to the MC piston. Some are way short. Should be around 0.020 clearance, can be checked with clay (Playdough).

Put the MC in a vise on your bench. You will need a MC bleeder kit ($8). Check out my profile photo album for bench bleeding. Re-install MC on car, re-bleed entire system, should be good to go, (I mean stop).
ps: is the "dash brakelight" on?

jb78L-82

I use the manual procedure as well. Have had VBP SS GM Lip seal calipers (Not O rings, did not exist in 1985) on the car since 1985 with no issues.

If you have not bench bled the MC, you need to. Also, you did not mention if you have all new brake pads? Brake pads should be bedded in or driven gently for the first 50-100 miles to become fully effective with the rotors.....New pads will feel lethargic if not bedded in correctly for first 50-100 miles.

Lastly, C3 brakes do not have a tremendous amount of power assist like many newer cars or even other GM power assist cars of the era, on purpose. Power assist dulls the feel of the brakes for the driver. Make no mistake, though, with adequate pedal pressure, if working correctly, they will STOP the car very effectively, with 4 piston fixed calipers at each wheel, front AND rear, on 12 inch VENTED rotors both Front AND Rear. For a firmer, more linear brake pedal, replace the rubber caliper hoses with SS braided brake hoses.

Once you get the brakes working effectively, a maintenance tip is to make sure you bleed and change the brake fluid every 4-5 years for proper brakes actuation moving forward.......I am 2 years overdue on the brake fluid change for my 78 and will be doing the same this Spring

HeadsU.P.

I disagree with gently breaking in new pads. Most manufacturers recommend taking the vehicle out to a remote area. Starting at 25 mph, hit the brakes firmly. Allow to cool. Then again at 30 mph. Then 40 and so on. This hard braking must be done five times to inbed the pads without glazing-over the rotors or the pads. Then you are good to go (stop).

jb78L-82

It depends on the brake pad manufacturer.....Some say immediate bedding as you described, some say 50-100 miles avoiding severe stops, some say either one..............

I use Performance Friction pads on my 78 C3/01 Grand Prix/08 Chrysler 300 and have used MANY sets over the last 15 years and never bed them. PFC has no special bed in procedure for their carbon metallic street pads (their race pads are different) and I usually get 60-100,000 miles per set with tremendous braking ability throughout their life with no degradation over that time.

I also have Stop Tech High performance street pads on a couple of other cars and here is what their website says about bedding..it is an either or:

FAQ #2: What happens if I can't do the bed-in right away?

"Often times, weather or other conditions can prevent one from fully bedding-in the brakes before having to drive the car. Fortunately, this is not a dire situation. If you are running new street/performance pads and rotors, remember that they are designed for the street and will slowly bed-in by themselves over time. Typically just a few stops from moderate speeds will start the bed-in process for normal driving.

In general, as long as the brakes are not overheated, you can drive them at normal street limits indefinitely without worrying about a formal bed-in. It's only when you get them good and hot that a fully bedded-in system becomes so important. This is why we recommend a slightly more aggressive bed-in procedure than most…we know performance brake customers are not “normal” and typically can't wait to try their new brakes at speed."

I almost never bed my pads and have never had an issue. I prefer the gradual bed in procedure, my choice......follow the manufacturers recommendation is the best answer.........

I really don't make this stuff up.........personal experience and documentation is what I use as a guide^^^^^^^^^^^^^^^^

resdoggie

This has been my experience with brake pedal application. The power assist system works but not like my 2017 Ram Rebel where you just touch the pedal and your feel braking immediately. But my wife's 2013 CTS-V with PB, 6-piston Brembo's, ABS and huge rotors feels less effective at braking especially when wet. But they will stop real quick when put to use.
My advice to the OP is go out and see if all wheels will lock up repeatedly after 3 or 4 panic stops. If so, you probably bled them correctly.