Do drum brakes self-adjust when braking in forward?
#41
Right out of drum brakes 101...."When the brake pedal is depressed while the vehicle is moving backward, the brake shoes expand and contact the drum. The shoes are forced by the drum to begin rotating; however, the upper end of no 1 shoe is wedged against the anchor pin. Since no 2 shoe is moving away from the anchor pin, it causes the adjusting lever to pivot and turn the shoe adjusting screw and reduce the clearance. If clearance is proper, the adjusting lever will not engage the tooth of the adjusting screw. Since each adjusting screw is in contact with a brake shoe the brake shoe clearance decreases as the screw turns."
Shoe no 1 and no 2 refers to the primary and secondary shoes. When you take off the drum you can replicate this movement by hand. Again, drum brake shoes should NEVER adjust in forward EVER! Reason is as the drum heats up like going down hill it expands. If the brakes adjusted at this time they would work ok but as soon as the drum cools it would contract and the wheels would be locked up.
Shoe no 1 and no 2 refers to the primary and secondary shoes. When you take off the drum you can replicate this movement by hand. Again, drum brake shoes should NEVER adjust in forward EVER! Reason is as the drum heats up like going down hill it expands. If the brakes adjusted at this time they would work ok but as soon as the drum cools it would contract and the wheels would be locked up.
#42
But, I´m having problem with front left. Proportioning valve is for balancing rear and front?
I quess I´m gonna go along the line going back to distribution block and the master cylinder and just crack open the connections and look for where I do not not have brake fluid spray out under pressure.
I wonder: could a bad distribution block or a bad master cylinder cause just one side drag? Should not both front brakes drag equally?
I quess I´m gonna go along the line going back to distribution block and the master cylinder and just crack open the connections and look for where I do not not have brake fluid spray out under pressure.
I wonder: could a bad distribution block or a bad master cylinder cause just one side drag? Should not both front brakes drag equally?
#43
Right out of drum brakes 101...."When the brake pedal is depressed while the vehicle is moving backward, the brake shoes expand and contact the drum. The shoes are forced by the drum to begin rotating; however, the upper end of no 1 shoe is wedged against the anchor pin. Since no 2 shoe is moving away from the anchor pin, it causes the adjusting lever to pivot and turn the shoe adjusting screw and reduce the clearance. If clearance is proper, the adjusting lever will not engage the tooth of the adjusting screw. Since each adjusting screw is in contact with a brake shoe the brake shoe clearance decreases as the screw turns."
Shoe no 1 and no 2 refers to the primary and secondary shoes. When you take off the drum you can replicate this movement by hand. Again, drum brake shoes should NEVER adjust in forward EVER! Reason is as the drum heats up like going down hill it expands. If the brakes adjusted at this time they would work ok but as soon as the drum cools it would contract and the wheels would be locked up.
Shoe no 1 and no 2 refers to the primary and secondary shoes. When you take off the drum you can replicate this movement by hand. Again, drum brake shoes should NEVER adjust in forward EVER! Reason is as the drum heats up like going down hill it expands. If the brakes adjusted at this time they would work ok but as soon as the drum cools it would contract and the wheels would be locked up.
http://techno-fandom.org/~hobbit/cars/brkjob/adj.html
#44
As I mentioned I had a v-6 cylinder on one side and a v-8 on the other. You ruled that out so are you 100% sure the suspension is in good shape ie, tie rod ends, ball joints, spring perches, and shocks? In addition, as I think about this even after I did my brakes they did pull to one side for a few miles. Once I redid all of my front suspension and put a few miles on it it stops as straight as an arrow.
But, I do want to know if it could be a faulty master cylinder och distribution block since it is only one side dragging?
#45
Foghorn Leghorn
Join Date: Dec 2006
Location: I reside in a near constant state of amazment.
Posts: 2,923
I have seen weird brake drag caused by having a simple twist/loop in the soft brake lines. It drove me crazy trying to figure that out on my Mark VIII. Luckily I have a friend who is much wiser than I am who spotted the problem and bet me 10.00 that was the issue. I doubted him and lost 10.00.
Go ahead and check for blockage. Hook up your one man bleeder setup and crack the bleeder valves one at a time to see if you get good flow and pedal return when you pump the pedal. As long as you get good flow then blockage isn't your problem and I doubt it is the master cylinder or distribution block either.
Go ahead and check for blockage. Hook up your one man bleeder setup and crack the bleeder valves one at a time to see if you get good flow and pedal return when you pump the pedal. As long as you get good flow then blockage isn't your problem and I doubt it is the master cylinder or distribution block either.
#46
Perhaps this link will help to explain my position
http://techno-fandom.org/~hobbit/cars/brkjob/adj.html
http://techno-fandom.org/~hobbit/cars/brkjob/adj.html
#48
I am gonna try to disconnect both ends of the steel pipe and try blow out the lines with compressed air. I am positive a faulty master cylinder cannot affect just one side.
#49
Someone else has already said it but maybe you should try putting some miles on it to see if it wears out, or is too unsafe to drive as is?
#50
I have put some miles on it and it does not wear out.
I will disconnect the distribution block this weekend and start from there. I have also ordered a new brake hose if the last one was bad out of the box.
My friend is 100% certain that it is sediment in the master cylinder or a faulty push rod in the mastercylinder that does not fully retract, but I am thinking that this would affect both sides.
I will disconnect the distribution block this weekend and start from there. I have also ordered a new brake hose if the last one was bad out of the box.
My friend is 100% certain that it is sediment in the master cylinder or a faulty push rod in the mastercylinder that does not fully retract, but I am thinking that this would affect both sides.