So I have front discs, rear drums, all stock with new brake hardware. The booster is a 7" aftermarket item which I have used on several different cars including my last maverick, the master is from a 89 Ranger, new. And am running a prop valve from a 76 maverick. All the lines are good, with new lines to the differential and to the front calipers, My problem is the pedal goes almost to the floor before any resistance is felt, pumpimg them up doesnt help, have replaced the new M/C with another, same results. Bled the sysyem many times. I am super frustrated at this point and ANY help would be gratefull. Have restored several cars and added P/B to them all, and have never experienced this before. About the only thing I can think to do is replace the 89 Ranger M/C with one from a 76 Maverick. Havent done that yet, as I really like the look of this late model style M/C over the stock unit, BUT, if that fixes the problem then who cares about looks right? I have checked online and the bore is about the same between both M/C's, but havent found any measurements for the stroke on either M/C....Help!!!!
If the rod from booster into MC is too short there will be excessive travel in pedal, too long and brakes will drag... Possibly the cup is deeper on the Ranger MC??
I feel your pain I have been fighting a brake issue with my Falcon but I am going disc-disc, I have researched every website about brakes and master cylinders and associated problems. Here is something to think about, try the process of elimination start at the master cylinder and take the brake lines off and plug the ports then when you pump the brakes you should have pressure from the start if not no need to go farther until that is resolved, next thing to try is clamping your brake lines closed two front disc brake lines and one rear brake line (after you have bled them again) if you have pressure then unclamp them one at a time until your pressure problem comes back that should at least give you the general area to look for problem. I know the master cylinder should have a 10 pound residual valve in it for the rear brakes since you using drum brakes Some of the things I have read are rear brakes not being adjusted good enough and the proportioning valve being bad something to do with it not being centered, I have never dealt with a proportioning valve so I dont know enough to say anything about it but I have read that that solved other peoples problems like you are having, and the brake push rod not being the correct length or geometry of the push rod not correct Good luck
it think tom is on to the most likely cause. if thats not it then follow mikes diagnostic suggestion. i would try clamping the lines before i take off the lines from the master cylinder first. that way may save you a bleeding secession.
Just a thought. Are your front calipers on with the bleeder screws on the bottom. If they are they should be on the top. You can never bleed the brakes if they are wrong.
I have manual brakes but I have disk all the way around and we used a ranger master cylinder and a calipers from a 97 explorer have you bled the master cylinder? with power brakes its a bit more complicated because youre adding two more things to possibly give you trouble the booster itself leaking air or not getting enough vacuum or the rod not being long enough
I agree with Krazy Comet, and Junrai, the brake linkage rod. Watch as you bolt up the master cylinder ,and check for enguagement of the brake piston,and when. Some rods are adjustable. I have never had to do this on my many 69 mustangs until recently. I would guess its the length of the piston in the master cylinder!
Yep, I rechecked the rod between the MC and booster, and it was 1/8" too short, thought I had it adjuster correctly, but no, so now the pedal feel is better, but not what I want yet. Am going to try and adjust the rears again tomorrow, hoping that will take up some more slack.
