Ok I had thought about upgrading to the larger calipers but was not able to find the brackets available. I went ahead and put the rebuilt metric calipers on. Now the next problem I am running into is getting a master. I looked up a 1970 Chevelle 1 1/8 in caliper for disc/drum. It looks like the old one but there are a couple differences. The new one has a bolt spacing about 1/8 in wider that the old. Also the center hole where the pushrod goes in is 1 5/8" deep. The pushrod barely comes out to the mating surface of the master. It comes up about 1 " to short. Also the round portion that slides into the booster is 5/8 " long and the depth into the booster is about 1/2". The booster is 7". I will try and attach a couple pictures. 57booster2.jpg57booster.jpg57booster3.jpg57booster4.jpg
You have a master cylinder built for either manual brakes or a 60s booster. Get one for a 70s and later power booster. I think a 72 Chevelle one with power brakes would work for you.
I have never seen a booster quite like that one. A good parts man could match up your old master i he still has his old books.
Last edited by markm; 02-27-2022 at 07:11 AM.
Thanks guys. It did turn out to be a 72 chevelle power brake master. I am still having issues. I do not have rear brakes. I am not getting hardly any fluid come out of the bleeder when trying to bleed the brakes. Yes the master is bled. There is a proportioning valve installed on the car. It looks just like the one on Jegs. The nob looks to be screwed all the way down. I cannot move the nob at all. I think that screwed all the way down should give the most pressure to the rear brakes. Is this correct? I am hoping it is the other way around. Then I can try to get it to break loose. So that is my first question. Is screwing the knob down cutting pressure to the rear brakes? I am kind of wondering why it has the proportioning valve on it in the first place. With a disc drum master and it has the oem looking distribution block on it as well. Also does a proportioning valve restrict flow even at its lightest setting? I am thinking this may be the issue and also think one of the wheel cylinders may be frozen. Ideas are certainly appreciated.
If it's like the Wilwood proportioning valve I use, it is like an air-pressure regulator. Clockwise increases the pressure. You will need to dig a little deeper to troubleshoot, and maybe bypass it. Usually, you want to decrease the rear brake pressure to lock-up just after the fronts. Knowing brake pressure is critical, which is why I have F/R brake pressure gauges easily adjusted with just a knob in 2 of my cars, and stupid easy to see an issue.
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Last edited by 55 Rescue Dog; 03-02-2022 at 05:26 PM.
Hey All,
I've been wondering about this caliper stuff, my calipers are 5.5 inches between the mounting bolts so I'm guessing metric? what cars/trucks would use these ones. I was thinking '70ish Chevelle but now that I know it's 7 inches between bolt I'm guessing not. They both have M10 threads for the hose connection, but one has M10 threads for the bleeder and the other has either M8 or 5/16 threads I have to run a tap in it to figure it out. I don't want this so I'll have to use two wrenches to bleed it!!! Thanks for the info in this thread!!!
You definitely have "metric". Metric was used on early 80s Malibu and similar cars, as well as many years of S10 pickups and similar vehicles.
It doesn't surprise that some had SAE threads on the bleeders and others had metric.
You almost certainly have Chevelle rotors.
To convert to Chevelle calipers will require different caliper brackets.
Thanks for the input Rick, I don't know if the rotors are Chevelle or not but I can't change the brackets as they are cast into the new 2" drop spindles. I've never liked the bolt on cad plated brackets so I looked for cast ones. Have a good one!!
No dropped spindles use Chevelle rotors Many do use metric calipers.