New brake shoe and adjustment question

[cattlerepairman]

New brake shoe adjustment difficulty - yes, I read the TM

Disclaimer: I have, use and read the pertinent TM and also searched.

I replaced, a little while ago, full brakes, all around; cylinders, flex lines, shoes, hardware.

I adjusted the brakes exactly as per TM - at least, tried to - and I am not happy with it.

Can I get the brakes to work? Sure. They work, quite well, I can get lockup.

What irks me is that I cannot get the adjustment to be precise. When I try to get the lower gap to 0.01, the top drags. When I get the top to 0.02, the bottom is way more then 0.01.

It almost seems as if the "curve" of the new brake shoes does not quite match the curve of the drums.

I managed to adjust all brakes so they work. Probably work well. I tested them hard on a gravel road and made sure I can lock up all six.

I do not know for how long, I do not know if the shoes flex - with brake pressure applied - and make full contact with the drum or if I am just braking with a certain segment of the shoe making contact with the drum.

I guess I could test it...load the truck full with gravel and get the brakes hot on a downhill slope and see how long it takes for them to fade.

Any pointers? Am I missing something? Is this normal or common? Did I put hardware in incorrectly? Do I get to rip it all off again and need to put each shoe into a vise to squeeze it into shape?

I have read, in other threads, that other people resort to adjusting their brakes similar to drum brakes on a car; tighten until drag, then back off. Maybe for similar reasons?

Shoes, btw, are from a reputable vendor off this site, so I assume they are being used by many SS members.

 

[Wildchild467]

I hear ya on the adjustment. I adjusted my brakes just because i thought they "should be better" and the brakes were great! the only problem i had was my brakes were getting hot and it was lugging the truck down....

i bought my truck in mid april and when i adjusted the brakes, the wheel cylinders looked new (nice green paint) and the shoes had great meat left on them. Also the booster looked new along with the master cylinder. I adjusted the bottom and tried to get the .010" at the bottom but some of them it was at the max adjustment for the bottom piviot. Im not sure about this or why it is, but i knew it was better than before. I adjusted the top to the .020" like the TM said, so everything was very close. Also when i adjusted the brakes, i put a VERY VERY VERY light little bit of teflon spray libe for the piviots. even if the brakes get hot, it will not run or anything, but i felt it will help things move a little better and may help the brakes move smoother. Ok, so after that i had a lot better pedal and the brakes were absolutely great!...except they were noisy like the pads vibrated when i went slow speed and they still seemed to drag. I then loosened up the top piviot a little by guessing to let them pads release more and may help. All the brake springs seemed good when i adjusted them through the inspection hole. What else would make the brakes drag? It also seems like the brakes release slow which makes me think a clogged vent line? I should unhook the vents from the booster and master cylinder and then try the brakes. could the new style booster i have need some lube incase the pistol is sticking? thats the only other thing i could think it could be.

Anyway back to your post. i wouldnt bend the shoes or anything. If there are no other warning signs or anything and they operate better, i would say you are ok. one thing you could do which would be a pain to do, is put a light coat of heat paint on the shoes and then drive it and pull the drums off again and see where the wear spots are. personally i wouldnt worry about it much if you got the brakes adjusted a lot better and all. still take hills in low gear and all, who knows what could happen with the single system on these trucks.

 

[Kohburn]

sounds to me like they just need a little time to wear in then get re-adjusted.

 

[Barrman]

I have done it by the numbers and had mixed results before. Now, I adjust the bottom excentric to the book number. Then, turn the drum while adjusting the top adjuster until I hear it rub. Then do the same on the other side. Very high pedal, no drag or heat going down the road.

 

[JOAT 0311]

Gentleman, great post! I will be putting brakes on this winter. I too, tend to be meticulous. Looking to see what comes out of this post.

 

[cattlerepairman]

I have done it by the numbers and had mixed results before. Now, I adjust the bottom excentric to the book number. Then, turn the drum while adjusting the top adjuster until I hear it rub. Then do the same on the other side. Very high pedal, no drag or heat going down the road.

When you say you adjust the bottom excentric to the book number, you mean that you set the bottom part of the brake lining at the TM's 0.1 gap and then adjust the top until you hear the shoe rub?

 

[gimpyrobb]

I do the same as Tim(Barrman).

 

[Barrman]

Yes, I adjust the bottom to spec on both sides, put the cover back on, put on the tire and spin the tire while adjusting the top with a box end wrench. When I hear noise, I move to the other adjuster and repeat. Then I put the axle shaft or hub back on along with the outter tire if needed once the tire on there has been torqued to the called for 300 ftlb.

Moving the bottom excentric is called a "major" adjustment. Just moving the top is called a "minor" adjustment in the manual. Unless I have to pull the shoes off again, I normally only do a minor adjustment as the pedal starts to feel low or I have the tire off the ground for something else.