c3 brake bleeding

is there a certain order to bleeding the brakes on a c3 (1980) we have one in the shop here I am pretty sure that we have got a bad master cylinder, we have bled the brakes with a pressure bleeder starting
with the farthest from the master cylinder first, working our way back to the to the closest, my shop info only goes back to 83 so I do not have any info on this year model. we have replaced the rear trailing arms, all the rubber lines, some of the steel lines, new SS calipers, new rotors, new booster and master cylinder plus a bunch of other things on this car but we seem to be having problems getting a good pedal, all of the brake parts came from Ecklers. about the only thing that has not been replaced is the proportioning valve and some of the steel lines. it is giving symptoms of a classic case of a bad master cylinder in that the brake pedal goes slowly almost all the way to the floor when the engine is running. I am just wondering if this has got some weird bleeding sequence like a 240 Volvo. my guess is a bad master cylinder but it does not hurt to ask. also has any one had any experience with Ecklers tech department? I called and left them a message last week and have not heard back from them yet, and I have a commercial account set up with them and have been using them for a few years, but this is the first time I have ever called them with a tech question, and to tell you the truth after six days I am not real impressed. thanks Greg
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Pass/rear - Driver/rear - Pass/front - Driver/front. I'm sure you know better than I do, but doesn't a slow pedal to the floor indicate perhaps a leaking booster? Or the need to bench bleed the master? Both of those were things I discovered about my C3 when the bleeding didn't seem to work. You may have said you had already checked that stuff, though.
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we did bench bleed it before we put it on, and we even tried doing it the old way with one guy on the wheel and one guy pumping the pedal, just using the pressure bleeder to keep the master full. the reason i ask is because of the two bleeder screws on the calipers on this car, on a early 240 Volvo with Girling (i think they are girling brakes on the one i am thinking of, but Volvo used about 4 manufactures for brakes) they had multiple bleeder screws on each caliper that had to be bled in a certain order or you would not get a good pedal.
but it sure would not be the first time that i thought i had a bad component when in reality it was just me not doing something right. sometime i really do love working on other peoples cars for a living, this was not one of those days, if you know what i mean ;<{) thanks for your help, greg On Wed, 17 Aug 2005 19:01:56 -0700, "BDragon"

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My mechanic has had to bleed my system. He used the gravity method. It takes a long time, but it works best.

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thanks we got them, turned out they just need to seated in, i just do not like even taking one on a test drive unless it is perfect. thanks for your help On Thu, 18 Aug 2005 15:09:54 GMT, "Paul J. Veres"

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I have the same problem for my 78 no pressure to the back brakes. What do you mean it was seated? I have power bled new master cylander new caliper on left rear side fluid comes through the line when I open the valves yet the back braked refuse to engage. I am totaly baffeled. Couled the proportioning valve be stuck closed in the back half of the system. Thanks for any help given.

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Hi Vetteman, by seated I mean the parts had to wear into each other to take up space that was caused by (more than likely) a uneven surface on the pads.
when you say you have power bleed the left rear, you should start with the one that is the farthest away from the master cylinder, then move onto the next farthest one, until you get to the closest one.
when you say left and right side of the car, that reference is always from the drivers position, so it would be right rear first, left rear, front right, left right. it also sometimes helps when you are bleeding the brakes with a power bleeder to have a hose running from the bleeder screw into a container, we just use a coke bottle with a hole in the screw on top with some stiff wire to hang it up with. that way once you start to bleed them no air can get back into the system, then have a helper swiftly apply the brakes with the bleeder screw open to try and force any air out. in turn do this at each wheel.
as far as the proportioning valve is concerned, it is possible that is your problem, but unlikely.

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Thanks so much I will try this weekend and report my progress..........Thanks again for your help

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I had the same problem with a 68 corvette. I replaced the master cylinder, but still had a soft pedal. I took it in to have it power bled, but still a soft pedal. Improved, but soft. I drove it (probably not wise) for about 100 miles and the pedal improved drastically. I'm not sure what it was.....master, metering block etc, but they have worked great ever since. Probably not much help, but maybe its something you can work with.
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