My 52 chevy has discs all the way around. The joker who owned it before me had the most horrible looking brake pedal and master cylinder set up on the car, but it would put you through the windshield. I decide to get rid of the ugly and go with one of the walton fab kits to run a boosted master on a 49-54 chevy. For the first week of me messing with it I couldnt get a pedal for ****. Mind you I only replaced the master cylinder. After giving up and driving the thing with brakes that needed a half pump to work, I realize I never adjusted the booster to master pushrod. This solved the problem, and made another one. I can feel the back brakes now not wanting to let go when I let off the pedal. They drag after a few stops, and the thing still has a low pedal on the first stop after it has sat for awhile. I have bled it 8 ways from Sunday... and yes it has been bench bled as well. Did I get a ****ty master cylinder from the get go or is there something I missed? My friend got 3 in a row from cpp that were bad from the start...
i have a prop valve in it now. i have adjusted it both ways, and it gets no better or worse. Does anyone know which port is for the front? I lost the paperwork with it and it has been over a year since I did the install
Was the mastercylinder for a four wheel disk rig or a front disk rear drum rig? Also, what pressure residual are you running? Usually having rear disks hang up is due to running a residual valve with too high of a pressure setting.
Ho-ly-****... I thought I pulled them out after I realized I didn't need them. I was working on it so infrequently that I put it on my to-do list and forgot to do it! I think there are wilwood 10 lbs plumbed in cuz i remember them being blue and realizing they were the wrong ones after they were in. First thing in the morning Im climbing under my car to see if I left them in!
false alarm. the blue ones are 2 lbs. Hopefully my memeory is **** and the red ones are in the car and are also the problem.
The rear of the master cyl is for the front brakes and the front is for the rear. But on a 4 wheel disk set up it does not make much diff. It sounds like the rod you have made is toooo long and not letting the piston go past the bleed back hole. There is also a small thing that some times gets over looked. Make sure the wheel bearings are tight. Any wobble in the disk will cause a soft pedal after sitting. You know like when you turn the wheel to put it in the garage well this will push the puck back a bit and when you next push on the brake it will go farther down than normal until you push the puck back out.
"It sounds like the rod you have made is toooo long and not letting the piston go past the bleed back hole." Yup...trim the rod down a LITTLE bit at a time, unless you have an adjustable pushrod. In that case, shorten it a little at a time...
Yup. Disc brakes require only a 2-lb residual pressure valve. Proportioning valve should be manual so you can adjust the front-to-rear brake balance to your particular car. Master cylinder push rod should have about 1/8" free play. If not it can cause the brakes to drag as the system warms up. Edit: You didn't mention what master cylinder you are using. Some Mustang masters have a built-in 10 lb. residual pressure valve in the rear brake circuit. If this might be the problem you can check by gently sticking a paper clip wire into the rear outlet. If you can feel rubber, your master has the built-in valve. If the wire goes all the way in, no valve. Good luck!
its the one that comes with the walton kit. If i remember right its the cpp corvette style master with a 1" bore
i would also make sure that he pushrod isnt too long. the smallest amount of pressure on the pushrod, could make the brakes hang up. i would say to start there first. good luck.
Where is the master mounted ?2 pd valves are usually for when the master is mounted below the calipers so fluid doesn't drain back.
Wilwood two pound residual pressure valves retain a minimum brake line pressure to help eliminate excessive pedal travel in both disc and drum brake systems. The two pound valve is used in disc brake applications where the master cylinder is mounted below the horizontal plane of the calipers and fluid drain back occurs from gravity and vibration. Residual Pressure Valves are made from billet aluminum and color coded for easy identification. Valves with fittings are supplied with two 1/8-27 NPT to 3/-24 inverted flare female fittings that will most domestic 3/16th hard brake line.
I have messed with the pushrod. Its been adjusted, but is there no need for a residual valve at all if the master is above the calipers? I know that they are needed for drain back but if i do have the 2lbs in the back is that really enough to keep the brakes dragging? And the walton kit puts the master on the firewall with a swinging pedal.
You need to double check your pushrod adjustment , at BOTH pushrods . Check you have a little free play at pedal to booster pushrod and also check that the pushrod at the front of the booster to the master is not over adjusted . I have struck exactly this with the CPP kits . You should be able to unbolt the master off the booster and push it hard home on the studs with out feeling any resistance - but you also don't want it overly baggy . Adjust it out a little at a time and keep checking for resitance , when you get resistance back it off a 1/2 turn and lock it up at that . You need this adjustment correct before setting up the adjustment at your pedal pushrod - hope this makes sense ? .
No improvement! do I have a bad master? If any one can help I would appreciate it. When I panic stop the front p*** side wheel locks up hard and pulls with discs. This would lead me to believe there is air in the driver side front but I have bled it every way concievable...
Air in a brake line is an equal opportunity offender. It will affect both brakes regardless of where the bubble is. I'd guess your problem is the brake that is not doing its share of the work. The problem could be anything, stuck piston, different pads or rotor condition, blocked line, you name it. Bill
It's a little confusing with your description but here is a few simple rules. 1. I understand you have a firewall mounted master cylinder? If that is the case, you need to take out the residual pressure valves. There is no functional purpose for them if the master cylinder is above the wheels. 2. Make sure you have the correct type of proportioning valve for your system. If it was already installed, you may have a drum/drum or disc/drum valve which will, at best, not make the brakes apply as designed. 3. It sounds like the pulling situation is related to a frozen wheel cylinder (I know, caliper). One grabs like a mother, the other grabs like a grandmother. You may have to rebuild or replace each caliper to get them to operate smoothly. Either way, you have a lot of work ahead of you. The last time I had this kind of situation, I ended up replacing a lot of hard line (full of crud, didn't trust just flushing them out) replacing calipers and wheel cylinders, and replacing a stuck proportioning valve. Take your time and get it right, you'll get the right results. A good place to start... http://www.cncbrakes.com/maintenance.asp http://autorepair.about.com/od/troubleshooting/ss/ts_brakes.htm
your pulling problem may not be air, it could be that the caliper on the weak side has a stuck slider - this would make it behave as you suggest , I have also struck faulty hoses at the calipers - had one that had collapsed internally, that had me scratchin my a** for a while till we found it! Have pm'd you with a few more suggestions . .
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