having trouble with drum brakes on front of 67 el camino. right side grabs hard. have replaced shoes and wheel cylinders and no difference. could it be the master cylinder? it has no proportioning valve just a distribution block for front and rear lines
I've heard sometimes that the steel brakeline can be the problem when this happens. I guess they can collapse a little bit on the inside and increase pressure. Not sure if this is your problem or not, but it might be a possiblity. One of the guys in my car club had this happen to his TA. Grabbed hard on one side, he ended up replacing his original '79 brake line and it stopped.
You did not mention if the drums were machined or not when the linings were replaced, but if not, you can swap drums from side to side and see if pull follows a drum. Also if the front suspension/steering linkage has loose parts, it too will cause a pull.
Most reasons for pulling to one side are usually attributed to contaminated brake shoes. Brake fluid dripping on them from leaks or grease getting on them from greasy hands during assembly. I've done that myself. One other thing, the drums themselves. One drum that has been turned out farther than the other. I had one bad drum that I replaced with a new one, and the car started pulling to the other side. So I replaced the other side and it stopped.
another thing is the flex hoses collapsing or melting from overheating.
Thanks for all your input I will certainly try your suggestions
One more thing , you did not mention the brake hardware . Was it replaced ? The springs and adjusters et al ? If not I have seen these cause a brake to pull on front drums.
Also I am not sure why but lately I have noticed a build up in some steel lines. Its almost like cholesterol and when the fluid is forced through everything is fine but for some reason the buildup does not allow the pressure to release on the brakes. Makes the brake in question hang up. May be some new chemical in the fluid.
I was a mechanic for several years at sears auto center where we done alot of brakes. If I had to guess I would bet it would be the drum. Swaping the drums would be a good idea to try. You should check the flex lines if that doesn't help. Alignment or worn front end parts may also cause a pull. Had a chevy s10 one time that someone else had replaced the flex lines and the pull remained. I had to make camber and caster ajustment to fix the pull.