Quick question about rear brake adjustments

[tgwright]

I'm in the middle of a rear brake job on my '99, 4DR, 2WD Tahoe. This is the first rear brake replacement in it's 137,000 miles. It's very straightforward, but in the GM manual it says to adjust the brake until it drags, then back it off 20 clicks. Back WHAT off 20 clicks? There is no access hole to the self adjusting screw which is the only adjusting screw. What am I missing here....this is usually a simple job. I can see no way to access the adjuster once the drum is in place. Should I be going DUH? Thanks.

[j cAT]

Originally Posted by tgwright

I'm in the middle of a rear brake job on my '99, 4DR, 2WD Tahoe. This is the first rear brake replacement in it's 137,000 miles. It's very straightforward, but in the GM manual it says to adjust the brake until it drags, then back it off 20 clicks. Back WHAT off 20 clicks? There is no access hole to the self adjusting screw which is the only adjusting screw. What am I missing here....this is usually a simple job. I can see no way to access the adjuster once the drum is in place. Should I be going DUH? Thanks.

I put vehicle in neutral so wheels will rotate drum off adj shoes drum on rotate,, repeat until drags then drum off reverse adj wheel 10 tits..repeat other side...I don't miss this style...also are you sure those drums are still good???? lock drum in place with a couple of lug nuts when drum rotating to centre the drum for shoe dragging...

[tgwright]

I was afraid someone was going to suggest doing it that way, but then I can't figure out any other way. What a pain, eh? I'll try that in the morning after I get the drums back from the shop.....IF they're good. It just seemed to me that if they're self adjusting all I may have to do is back them way off, reassemble, and then start backing up and hitting the brakes. I'll try you suggestion, though. Thanks.

[j cAT]

Originally Posted by tgwright

I was afraid someone was going to suggest doing it that way, but then I can't figure out any other way. What a pain, eh? I'll try that in the morning after I get the drums back from the shop.....IF they're good. It just seemed to me that if they're self adjusting all I may have to do is back them way off, reassemble, and then start backing up and hitting the brakes. I'll try you suggestion, though. Thanks.

this is my opinon "a cut drum is a BAD drum".....the radius of the shoes now no longer match the radius of the drum....what this means is the shoes will only wear at the top of the shoe not over the full shoe surface...poor rear brake effort is the result...

[Scrapper]

yah i do the same taking drum off and ajust your self.but there is a place to ajust them with out taking wheel off. behind rear drum you should see a stot although theres no hole you usually punch them out then stick your spoon in there there is one you'll have to buy 2 rubber seals you put in hole.but like he said just ajust them with drums off and ajust them to you feel a little drag on them..

[tgwright]

Thanks for the info, gentlemen. That adjustment technique worked much better than I expected. One last requrest for advice....I was also flushing the hydraulic system while doing this job, and I found that one of the bleeder valves on the front calipers is absolutely frozen in place. I have wrung off enough bolts to know that I have applied just about the maximum torque I should before this thing is going to break off. I've tried the penetrating oil thing, but my guess is that the repeated heating and cooling of the caliper has this thing seized very well. All I can think to do is add some heat myself, with a torch, and then see if I can break it loose. Any suggestions?

[j cAT]

Originally Posted by tgwright

Thanks for the info, gentlemen. That adjustment technique worked much better than I expected. One last requrest for advice....I was also flushing the hydraulic system while doing this job, and I found that one of the bleeder valves on the front calipers is absolutely frozen in place. I have wrung off enough bolts to know that I have applied just about the maximum torque I should before this thing is going to break off. I've tried the penetrating oil thing, but my guess is that the repeated heating and cooling of the caliper has this thing seized very well. All I can think to do is add some heat myself, with a torch, and then see if I can break it loose. Any suggestions?

I've done this before and it works put C clamp on caliper piston,, position caliper so that brake line to caliper is at the highest point unsrcew brake line so that it is loose and start cranking on the C clamp to push cal piston fully back... this does work rather that going thru the bleed screw replace or cal replace...with helper you can do a very good job at getting that old fluid out....

[ChadClancy]

Originally Posted by j cAT

this is my opinon "a cut drum is a BAD drum".....the radius of the shoes now no longer match the radius of the drum....what this means is the shoes will only wear at the top of the shoe not over the full shoe surface...poor rear brake effort is the result...

If this were the case, just putting a new shoe on a worn drum would cause problems. The shoes have to put some amount of wear on the drum increasing the radius and for the first shoe, it wears in the same shape as the drum so it isn't a problem. I would think that the difference in the radius of the new shoe and the cut drum (as long as it is still in spec) would be so slight that the shoes quickly conform to the actual drum radius. That being said, sometimes buying a brand new drum or disc isn't that much more than the surfacing cost so you might as well replace them but this depends on the vehicle.

I did have a problem once with some resurfaced discs. The shop left a pretty rough surface on the disc and the pads would grab them hard, then release such that I got a noisy pulsating effect. They gave it another shot and everything was fine.

[tgwright]

I think I agree with you. In my case they removed about .018" of drum surface (which left another .0021 available before hitting the max diameter allowed), and I can't even imagine that the new shoes are made to tolerances that would mate that closely to the arc of the uncut drums.

[j cAT]

If you have had drums as I have had drums over many years like the 1967 olds that had front/ rear drums it is even more apparent that when the drum is cut braking effort drops off... especially at highway speeds...


with front disk and drum rear it is less apparent as with this set up most never use park brake and the rear shoes most always never do any heavy braking as the vehicle that started this post had 100,ooo plus on rear shoes ....do you really think those shoes did any braking????


on the resurfacing of the rotors/disks this is OK as the cutting does not interfer with the braking effort,,,,the problem arises when the thinner disk gets warped and then the pulsating brake pedal....


use of the proper braking pads and a high quailty pad will have a less damaging effect on the disk surface....I still have the same un cut disks on 2000 silverado....oem pads....surface does not have grooving but rust at edges of coarse damm rust belt....

[odrazorbac1]

on some cars you can adjust the rear brakes by pulling on the emergency brake slightly & drive in reverse, which will adjust the brakes automatically.
Could be worth a try.

[Scrapper]

only way they can ajust rear brakes they have to have disc. if you have drum you can ajust by putting in reverce and hit the pedal if wont ajust take drum off and see if star ajuster is frozen.