I've searched the posts on this topic but don't have an answer as to what to try next. So, as usual, I turn to Team Camaro.

Brake setup - 1968 Camaro - 1988 S10 master cylinder (front outlet to rear brakes, rear outlet - closest to the firewall - to the front brakes); stock distribution block; Summit proportioning valve between front outlet on master cylinder and distribution block; 2000 Camaro dual piston PBR calipers on the front; 1980 Cadilac Seville calipers on the rear; braided steel brake lines all around; new pads all around; no leaks; teflon tape on all joints.

Bench bled MC; bled passenger rear, driver rear; passenger front; driver front allowing 45 seconds between each pump of the brake pedal. Adjusted the integral parking brakes on the rear calipers and rebled. No resistance on the pedal at any time.

Without putting on the brakes the front rotors can be turned but are tight and the rear rotors turn with a little resistance. With the brake fully depressed, there is an increase in resisitance at the rear, but they are still turnable. (I haven't checked the fronts with the brakes applied.)

Any ideas?

How much fluid should I pass through the system to the passenger rear wheel to get all the air out since everything was open?

Can I use a vacuum bleeder with the S10 MC?

Mike

I don't know the MC and I wouldn't wait 45 seconds between pumps. Is there a reason for waiting 45 seconds? I'm thinking it would give any bubble more of a chance to rise back towards the high side being the engine compartment sectons of the brake lines. Most systems will gravity bleed to a certain degree. I kinda liked the speed bleeders last time around with my brakes. One funny thing I never thought of until reading it was how for some brake arangements for mods a guy could accidently install the calipers so that the bleed nipple is on the bottom and no matter how much you bleed them you aint ever going to get the air off the reversed around chamber filled with air on top.
All I can think of is don't wait 45 seconds between single pump bleedings, calipers upside down / reversed on which side they go on which puts them upside down, the rod off the brake pedal assembly that pushs the MC piston is too short, or the bench bleeding of the MC didn't take good. While bench bleeding mine I had to vigurously and fast pump the MC while it was in a vise. I think you really need to have it flat and level. I used the butt end of a screw driver to pump like all get out to get the air out. If it ends up having to be the MC didn't bench bleed good try tilting the the MC a little bit to see if you find a sweet spot for air to come out of the pin holes that feed fluid into the pistons. Being flat should do it.
Oh yah. I always thought the rear line to rear and front to front brakes.

isn't that master the "quick take up" design that is a pain to bleed? i think David Pozzi has mentioned that a few times. perhaps head over to his site and do some reading.

The S10 is the "quick take up" design and it IS a pain to bleed. David Pozzi has at various times recommended waiting anywhere from 30 to 60 seconds between pumps to allow fluid to bleed into the larger cylinder. I used 45 seconds as the negotiator's preferred solution.

As for the rest, all calipers are installed with the bleeders up and no signs of leakage anwhere. I made the push rod and it has (I'd guess) maybe 1/16 inch freeplay at the pedal before it engages the master cylinder.

I'm now getting a firm, but low, pedal. I'm going to take another crack at bleeding. If I don't get a higher pedal, I'll look at the master as being defective as David Pozzi has suggested that a defective check valve in the S10 master can result in a low pedal.

Thanks for the replies. Because my last post of a question drew no responses, I was wondering if I was snake bit or something. smile.gif

Why not take it to a shop and have it vaccum bled for $30?

Still need to r/r engine & trans; fire up engine and break in cam; reinstall front end sheetmetal -the list is endless before I can drive it anywhere.

Believe me, if I could pay $30 to have someone else bleed these ^%($*$*^&) brakes, I'm there!

If all that work needs to be done first, than why worry about the brakes now?

Not bustin' your nuts, just curious why the brakes are that important at this point in time.

I know how to do everything else that needs to be done. I'd hate to get it all finished and then still be trying to figure out my brakes.

Your plumbing sounds correct for that master cyl.
It sounds like either air in the rear line or bad adjuster on the rear calipers. They are known for sticking adjusters.
Also you need to reduce the end play on any C clip rear axle by shimming behind the C clips. Valve spring shims work well.

The axle end play won't cause trouble until you drive the car, then it can knock back the caliper pistons.
If the MC is rebuilt, the special valve in the rear reservoir may not be working right.
If you can, elevate the driver's side of the car and bleed by loosening the brake line at the outlet port.
If you don't wait long enough for the fluid to refill the rear MC piston, you won't get any fluid out of the rear caliper, that is how you can tell if you have waited long enough between pumps. The GM manual says to wait 30 seconds, I think...
David
David

I understand the 30 second wait to refill the rear pistons area now. When I kept seeing the air down the in the little hole not wanting to break surface tension to come out I pulled the MC out of the vice and started tilting and tapping it to try to get it started coming out. That air not wanting to let the fluid reload is why I ended up doing the rapid pumps to try to dislodge the air and get it moving. I think the hole from casting is too small but I'm sure there is some engineering reason for it being so small. The thing that gets me is I pretty much remember after not seeing air coming out the rear line bench bleeding one time I went for broke pumping fast again and got more air.
Before I bench bleed my new one a couple months ago I read some of your stuff and noted it being a pain at times. So when I bench bleed mine I thought of the writings and went right back at it like a maniac pumping. I gotta wonder if warming up the brake fluid would help it get in better and not be so prone to having heavy surface tension not wantng to let go of dry areas.
Good luck to anyone doing the job. Mine went great but now I have a MC lid gasket that likes to let fluid by it in the rear.
PS Mkelsy I guess the saying you have to pay for what you get is true. That brake system once finished is a real nice set up. Everyone is probably going to be saying ask you later on for observations while others attempt to do the job.
Nice brakes. graemlins/thumbsup.gif

Snatchin Gears: Thanks for the compliment on the brakes.

I've really learned a lot doing this car. I've played with shoulder belts, the Guldstrand mod, big disk brakes w/o a kit, C5 wheels and the backspacing issues, a T56 and the hydraulic and physical adaptation issues, new Autometer gauges, the list goes on - I feel like I've bitten off more than anyone should, but it's always "as long as I've got it apart I might as well do [insert next difficult mod here]."

I chased my tail on my Chevelle for months trying to get some pedal. Turns out the push rod was 1/8" to long and wouldn't let the master cylinder return to get another swallow of brake fuild.