So I have the 7" frame mounted booster and master cylinder combo for my 50 Chevy truck, and I have finally got all the leaks fixed. The first time I bled it the pedal went to the floor, felt like it wasnt even pushing on the master. But I didnt bench bleed the master, so I pulled it off and had the wife push the pedal and watched as the pushrod came out of the booster a couple inches. Seemed kinda short, but the master recesses in about an inch or so, so I thought it was good. Bench bled it, got out a **** load of air. Put it all back together and pressure bled it again, brake pedal still goes to floor. It has a little resistance as it gets to the floor but has no effect on the brakes as the wheel still turns freely with it down. Questions: Is the pushrod that comes out of the booster adjustable? Is there any adjustment without having to pull the master back off? The front of the booster has a threaded rod that a joint threads onto that hooks up to the brake pedal. It would seem to me that the further out you put that the more travel you would have, but my brake pedal is already very high off the floor, and moves about 8 inches give or take until it gets to the floor with no resistance. Front disc, rear drum. Rears are were properly adjusted when ***embled.Master moved fluid when bench beld and seemed to work properly. When I had the master off it didnt look like the rod was adjustable, but I wasnt really looking for that at the time as I thought it was because I hadnt bench bled it. Any ideas would be appreciated.
1 Hotrod figured this deal out for me.....thought it was good info so here you go... "There are a couple different types of master cylinders one is a shallow bore and the other being a deep bore. Do a search and you will find some info on the two. Shallow is for power brakes and the other is for manual. If you have the wrong one your pushrod may not be going in deep enough. There is such a thing as a bore adapter and you might just need this. http://www.cl***icperform.com/Instru...PDF/Master.pdf" Sure enough, I had that part in my box o goodies. Should be good to go after this. Although I will have to bleed the damn brakes again....arrrr....
You have the exact set up I do, I'm having similar problems. The link you posted didnt work though. So if I'm reading right, my pushrod isnt going in far enough and I can extend it and be fine? Also, does your master have ports on both sides?
Not all power brake master cylinders have shallow counter bores. All of the Ford power masters I have or worked with have deep bores. The booster push rod should have about .040" clearance with the master cylinder counter bore, and this is checked with full (about 20 "HG) vacuum applied to the booster. Curious what a "bore adapter" is
Adapter isnt really the best description, more like extension. It is just about 1.5-2 inch long piece with a point on one end, dished on the other with an oring in the middle to seal it inside the bore. Gave me the travel needed...
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