The Stovebolt Site Forums The Shop Area Driveline Another brake adjustment question

I have a 54' 3/4 ton chevy with drums all the way around, but I did upgrade the master cylinder with a dual chamber with power boost. I also have 2 10# residual vales on it, one for the front and one for the back. They came with the kit. Ok so here is my question: what is a heavy drag on the brakes when you adjust them? I keep seeing that you adjust them until you get a heavy drag and then back them of 7-10 clicks, but I'm not sure if that means right before you cant turn the wheel by hand anymore or not. So just how tight is a heavy drag lol??!! Thanks for the help

yes, tight enough they're hard to turn by hand, but it can still be done a good way is as you're turning the wheel, adjust them just until they get too tight to turn, which insures the shoes are squarely seated, then back off until there's still just enough drag to feel/hear, number of clicks is just a generalization, will vary on different trucks at different times, just try to have all wheels close to the same

Bill

Okay so tighten them up to the point of too tight and then back them off so they are hard to turn but can still be turned?

If you are referring to being able to rotate the drums/wheels "so they are hard to turn but can still be turned", that is too tight. When that braking system gets hot, the heat-expansion will most likely cause significant drag.

Heavy drag is when you can turn the wheel but it has a heavy resistance. Then back it up about 5 notches. It may have some drag in it yet but won't hurt anything. New shoes will drag more then old ones till they get seated.

1954 Shop Manual - Steps 3 & 4 - 1/2, 3/4, and 1 ton

The problem for most people is "what is a notch"

I back off until the drag can almost not be heard - it is almost never what I would consider to be 7 notches. My brakes are strong/firm (1954 1/2 ton).

Ok thanks guys. I put new star adjusters in the front because I kept having one tighten up on me after about 20 miles worth of driving. I have old shoes but in good shape. So I adjusted them last night and still had some drag all the way around but there is no way they are adjusted right. I took it out and the pedal had resistance but it was to the floor, the pedal is no where near hard enough for me. Before I would barely touch the pedal and I would start stopping. But I kept having issues with the front brakes tightening up so I figured the adjuster were just worn out. The brakes have been bleed and the master cylinder and wheel cylinders are all new. I'm just having a hard time determining when the brake are to tight.

if the brakes are adjusted up and the pedal goes to the floor [or near], you're very low on fluid or didn't bleed them well

the adjusters shouldn't be able to tighten themselves, they drag on the springs so there's force need to turn them ["click"] - it may be what was causing apparent 'tightening up' is pressure not releasing, might be internally bad hose[s] .... it's also a good idea to adjust up the shoes until you can't turn the wheel by hand to insure the shoes are seated properly and don't end up shifting with use, then back off for the proper drag

Bill

The brakes were fine until I pulled them apart and started backing the adjusters off. I just think I don't have them adjusted right because before I did this I had plenty of pedal. I'll keep messing with it and see what happens. I do have the 10LB residual valves in line because you are suppose to but I dont think that 10LB would be enough pressure to keep the shoes against the wheel because how tight the springs are.

So I went out to my shop tonight to try to adjust the brakes again. I got them all to were I thought was good and the pedal felt great. Took it out for a drive and went about five miles. By the time I got home I could tell they were to tight. I pulled in the shop and jacked the truck up, the front brakes were pretty much locked up and the rears I could still move a little. So after they cool over night I will give it a shot again tomorrow. I have come to the conclusion that I hate drum brakes LOL!! After this ordeal I should be a pro!!

You should check and adjust the pushrod that goes into the master cylinder. You may also want to check the drums to make sure they have not been turned oversize, also check to make sure that they are round.

I have a 52 with Bendix brakes and there is an adjustment called for in the Factory manual to 'set' the pivot pin. I don't know if 54s have the same procedure. This procedure centers everything up prior to adjusting the wheel brake cylinders. Do you have new brake fluid? Do you have new soft brake lines? A clog will prevent fluid from returning to the master cylinder, leaving the wheel cylinders in the partially engaged position.
Carl

I'd suggest the problem may be in the "upgrades" done, the modern MC and power booster and the residual valves

Bill

Probably just too tight, back off a few more clicks. A very light drag is how I adjust mine and it stops very well.

After adjusting a wheel I pump the pedal a couple of times and spin the wheel again. This helps make sure every thing is centered.

Everything is new. I'm guessing I still have them a little too tight. I checked them the next morning and I still have a pretty heavy drag all the way around. I guess I will keep backing them off until I get it right

thinking the same thing... Residual valves.
I'm in the middle of the same upgrade- all new everything, and switching over to dual pot MC (manual, no booster)

I did all the reading on the valves, and can't figure out why they are required... For drum brakes.

I understand that for DISK brake conversions with the MC down low, you need them- however for Drum brakes, it seems you need them for a different reason- keeping the shoes against the drum... which they would need regardless of the placement of the MC-
So by that rationale- if the MC donor vehicle used drum brakes, unless it had external residual valves, it should be part of the MC... At least thats my thought process. S

I have a dual pot manual MC for a 67+ chevy truck. Anyway, hopefully my setup will work without adding extra valves.

I should have it bled and working in a week- i'll let you know if it turns out i needed the extra valves or not!

residual valves aren't needed to 'keep the shoes against the drums', the adjusters do that, the shoes can't move any further away from the drums than the cylinder pistons allow, but some drum brake systems do incorporate a type of residual valve in the MC to maintain enough pressure to keep the cylinder cups sealed, keep a firm pedal feel, and prevent drawing air in if there's a leak .... yes, the residual valves could be naks problem

Bill

My problem is just about fixed. I made an adjustment to the push rod for the MC, I had to turn it in 5-6 turns. So I think that could have been part of my problem. Second I back the shoes off a little more and drove 10 miles, the rear brakes are perfect now. I still might need to back off the front shoes just a few clicks, not much though. No overheating brake issues this trip, so I think I about got this thing licked! The residual valves I never really suspected because 10LBS is no where near enough pressure to keep the springs out, those springs are tight. My MC did not have valves in stalled in it so that is why I had to put them in each brake line. Like Red58 said, they keep a firm pedal, especially in a truck that isn't driven every day. Thanks for all the advise guys!!

Okay here is my update. Drove the truck right after the last post and the brakes were still heating up a bit. So after thinking about all the things everyone said to check, I decided to start at the residual valves. I thought for sure it wouldn't be those but they are easy to check. So I cracked the bleed valves on a front wheel cylinder and sure enough they were holding WAY to much pressure. I took the residual valve for the front brakes and pulled the spring and check ball out of it. I was able to adjust the brakes with a little drag and great pedal. Funny thing was only the front brakes did it, the back brakes are fine. I'm starting to wonder if the front side of my MC did in fact have built in residual vales, which doubled the psi when I added the inline valves. Anyway I took it to a car cruse tonight and it went pretty good. When I got home I jacked up the front end and decided I still have too much drag, so I waited for the brakes to cool and backed them off some more. Now I have next to no drag, with a hard pedal. The pedal only travels 2-21/2 inches before it wont go any farther and I still have 6-7 inches of pedal left!! Now were getting somewhere LOL!! So the moral of this story: Screw the residual valves, the truck never had them in the first place!!!!!!

Could the residual valve have been in backwards?