Mr. Hundered & 1 questions here. I got the 61 (swb Apache10 Chevy) on the road yesterday and among a few other bugs the main one is the brakes. My stepson came over and we bled them and ended up with good rear brakes but the fronts are still an issue. The pedal goes almost to floor and then it only feels like the rears are operating. When we bled them the fronts were engaging fine along with the rears. We did bleed them with the motor off and the bleed bottle had what looked like very fine bubbles in it almost milky. The whole brake set up is new. McGaughey disc conversion in front, booster is junk yard Astro Van, M/C is a new 74 chevy C-10, wildwood risidual checks, no proportioning valve, and all new hoses & lines. The fronts are plumbed to the front reservoir and back to back. The motor is a 30 over 400 with a mild cam, automatic tranny, 12 bolt rear. Do I need to keep bleeding the fronts? Install a proportioning valve (even though I have not much pedal)? I am out of ideas and patience is dwindling. This truck will stand up and go but I am affraid to go too much without brakes. Thanks so much for the help here.
To cut down on the goose chases, pinch off all three of the brake hoses with vise grips. You should have a hard pedal. open one hose at a time untill the pedal goes to the floor. bingo that is where the problem is. If the problem is in the front, check to make sure that the caliper bleeder screw is at the very top of the piston. It's very easy to get the calipers on the wrong side trapping air in the caliper. You'll never get a pedal with them on the wrong side.
Did you bench bleed the MC before installing it? I've never worked on a dual MC that didn't have a lot of trapped air that took a lot of bench bleeding to remove. This will not come out in any amount of wheel bleeding. Also, do you have any low-mounted stuff in there? I used to have a GM A-body that had the proportioning valve way below the MC on the frame rail, and I could not sucessfully bleed that car's front without parking it uphill on a very steep driveway.
This sounds just like the problems I had when I first tried to get my car on the road. Took many hours of frustration, dollars and a lot of so-called experts and still could not figure out the problem until the HAMB's ElPolacko turned me on to the solution: A lot of these front brake conversion kits come with GM's "metric" caliper. These calipers draw the pucks back away from the rotor in order to lessen drag and squeeze out a few more MPG. These calipers require a special "quick uptake" MC which has a progressive plunger that quickly throws the pads back against the rotor. Nedless to say without the proper MC all the pedal travel just goes to getting the pucks back against the rotor. It's too hard to find the correct master cylinder to make it work, so instead, be sure to use front calipers from before 1982 (I think that was the year the metric caliper came out) I used 1978 Monte Carlo front calipers and as soon as I swapped those in - problem solved! Note - The 1978 caliper looks absolutely identical to the metric caliper in every way, but apparently the internals are different. I even relayed this story to a local aftermarket place that sells the front disk conversion kits, and their response was: "That would explain why we are never very happy with the way they work" ?!?!? go figure.
Bruce - yep bench bled that sucker until all the air was out and made a nice mess on the work bench I dont have a proportioning valve installed and the rear circuit is bled pretty good. Cleatus - "quick uptake" calipers, I never heard of those before, but the calipers use a 10mm wrench on the bleeder, and I think the outfit uses caprice calipers and that would explain why the pedal is almost on the floor before I get brakes. I did notice a lot of movement in the caliper when I was bleeding them. Is there any casting numbers on the calipers that would tell me what to see? Thanks again for the help.
"Quick uptake" was the term for the compatible MC not the caliper. The only numbers I can see are a "1" and a "5" But I do remember comparing the "metric" calipers to the other "78 Monte" calipers and they looked identical in every way, so I was sceptical that I had found the fix - until I bolted them on. Instant fix! and the've been working great ever since At one point I did find a note about all of this on the "trouble shooting" page of Master Power Brakes website, so that may also shed some light for you. Hope this helps
Cleatus, did you have to change your brake hoses when switching from the metric calipers? I don't remember if I had to get a metric hose for them. I have never been able to get a good pedal on my dodge and after reading your post and the MP brakes site, I think I know why. Why the brake guys never told me that is beyond me, or maybe they didn't know. I think I have a weekend project now. Here's the link to the info on the MP brakes site: http://www.mpbrakes.com/trouble13.htm
Hello all. Newbie to the HAMB, here. I was referred to this thread by someone over at Webrodder.com. Wayfarer, Did you make this change also? Did it solve your problems? I've got the calipers in front of me (metric) but I have no idea if they're the ones that require the "quick take-up" M/C or not. Did any of you ever find a part number or anything? Thanks, Richard Gautier Gautier, MS Turbo Buick powered '36 Chevy
Cleatus told me that the non-metric calipers are a direct replacement and will bolt right up. I plan on doing it tomorrow, at least if my local parts store has them in stock. You can look up part numbers on NAPA's website, www.napaonline.com. I'll let you know how it goes.
These are the GM part #s for the '78 Monte Carlo caliper. As you can see, they changed several times. caliper LH: 18005262 repl by 18016155 repl by 18060134 caliper RH: 18005263 repl by 18016156 repl by 18060135 HTH,
Something you said here made me think,,,, [ QUOTE ] We did bleed them with the motor off and the bleed bottle had what looked like very fine bubbles in it almost milky. [/ QUOTE ] Fine air bubbles means you are somehow introducing air into the system. I have seen this done a couple of ways. By rapidly pushing the brake pedal you can airate the fluid and what air is trapped in the system causing this. You will have to settle down and slowly bleed the system. Do not use excessive pressure on the pedal when the bleeder screw is cracked open. Moisture in the system also looks like this. DOT 3 and 4 brake fluid will absorb moisture over time. If any part of this system has been sitting open for a period of time it may have enough condensation in it to cause this also. So be sure and use NEW brake fluid from an unopened bottle. My next thought is a cracked line or fitting somewhere in the system. If it seems you get more air out of one bleeder more than any other on the system, that is the place to start. I had a similar situation on a 32 Ford roadster. It turned out one of the adapter fittings in the rear wheel cylinder was cracked. It would not leak fluid but when the master cylinder was released air would get sucked into the system and the more you pumped it the worse it got. This particular car had a unique problem with pulling to the right also. It turned out that the calipers were mismatched and had a larger bore caliper on the right side, which would have a higher clamping force and thus would pull.
The Jalopy Journal
