ok my rear brakes are still locking up....the cylindes are good and the brakes are good...so i am guessing that the proportining valve is shot... the master cylinder is also good.. new pro valve in auto krafters if memory serves me was 200.00 bucks or so... what about the pro valves in summiot racing... for 65.00 bucks...will they work>?? anyone have some ideas...i am going to replace the brake lines at some point since i bet they are rusted... ideas please thanks
I doubt it's the prop valve that's causing the problem, but if it is, I'd never pay $200, or even $100 for a stock one. There's about $2 worth of matierial there, and they don't even work all that great. Get an adjustable unit. Also, make sure that the brakes are adjusted properly, and free of brake fluid or any grease on the shoe linings and drums...
On a stock 71 braking system, the only thing that big hunk of brass does is turn the brake light on if one side should fail. Unless its full of corrosion, it cannot lock up the brakes. Check the rear rubber brake hose, adjustment and and axle seals.
You can get your old prop valve rebuilt. Lots of places advertise in Hemmings that rebuild them. A lot cheaper than the $200.
"On a stock 71 braking system, the only thing that big hunk of brass does is turn the brake light on if one side should fail. Unless its full of corrosion, it cannot lock up the brakes. Check the rear rubber brake hose, adjustment and and axle seals." ok cool....so the adjustable from summit will work fine then? where can i find the rear rubber hose...would checker or autozone have them or is it an auto krafters thing?? i want to rebuild the brake system...new lines... the wheel cylinders have all been replaced except the drivers rear, so i will replace that as well. has anyone purchased an entire brake line kit from anywhere? please give me some info if you have
I didn't even notice that your car is a '71...It doesn't even have a prop valve, just a distribution block with a low pressure switch. Get the adjustable unit from Summit, but first, make sure that the rest of the system is functioning properly. You should not be experiencing a lock-up problem like that...
ok...correct me if i am wrong.....disconnect the lines at the master cylinder....and at the wheel cylinders...and blow air in them and completely remove all fluid....fill master cylinder....bleed.... is that the easiest way to flush the system? also can i upgrade the brake lines.....3/16 line to 1/4 or 1/4 to 5/16.....will it hurt anyhting if i just replace all the brake lines and just go a little bigger...?? thanks for the help guys....
Might have a warped drums, fluid brake or axle, on shoes, or you may simply need an adjustable prop valve. The rear hose would restrict pressure to and from etc.......all good advice thus far from the others.......I would test the rear hose by cracking the line goinmg into it and after it to see if there is a difference in amount of fluid coming out.
i found the culprit......the drivers rear wheel cylinder was rusted...i am waiting for my son to get home to help me bleed the brakes...then test drive...i will let you all know ... while i had it apart i changed the hardware...springs etc... looks nice in there now...lol
well i bled the brakes and it got it all nice and the way it should...but the damned thing is still locking up....so now i know it is not the drivers side wheel cylinder....and the passenger side was replaced back in december... cant be bad already... well the passenger rear wheel is the only side locking up.... Suggestions...please....and it happened all of a sudden....
if the rubber is closing up wouldnt it restrict the entire rear brakes?... the drums are new as well....got them in december.....they have less than 3000 miles on them.....but i will get them checked out
The hose would effect both rear brakes. When you bled the rear cylinders, did it seem to have the same amount of fluid comming out of both ends? Also adjustment is critical. Sounds like maybe the locking side might be tighter than the other. One other thing I thought of is the brake shoes. There is a long pad and a short pad per side. The long pad goes towards the front and the short pad goes towards the rear. You didnt install both long pads on the locking side, did you??
