'96 Yukon rear brake -where is adj. port in drum?

[Jim Spahr]

I have a friend with a 1996 GMC Yukon with 120k and he is trying to adjust the rear brakes. GM cars and trucks have traditionally had a port stamped in the back of the brake housing that you can knock out and put your adjustment tool thru to tighten or loosen the rear brake shoes. This truck has two ports which are covered with black rubber inserts. However, they don't line up with the adjustment wheel. They are apparently to inspect the brake shoes without removing the drum. How do you access the adj. wheel or gear?
The wheek adjuster is just about under the brake cylinder on the top side.. There isn't any port to open up here.

 

[ARCOgraphite]

You typ adjust rear brakes by jabbing the brakes whilst reversing. Ive only used the adjuster wheel when trying to loosen the shoes (pull them IN) to get the drum off past the wear ridge. If the adjuster is "frozen" you will have to remove the drum(s) to service the mechanism.

 

[Jim 5]

My '98 K1500 looked like it had a "knockout" for this purpose but I couldn't get it out because the two spot-welds were too tough.

Backing up and slamming on the brakes is the procedure and you have to go pretty fast. I talking about something like 30 MPH in reverse and then slam on the brakes until they lock up.

It sounds pretty extreme, but if you do this in an empty parking lot at night (or other safe environment) it can work quite well in my experience.

Expect to do this 3 - 7 times to feel a difference.

 

[40Deluxe]

Could you just remove drum and adjust the shoes out to fit the drum tighter little bit extra work but would give you and him a chance to do a good visual inspection in there.

 

[Jim Spahr]

From the original poster: He is going to remove the rear drums and replace the shoes, so that is not a problem. When you pull the drums and the shoes are worn, the drums clear the ridge on the outter edge of the drum. But when you put the drum back on with the new shoes installed, the ridge is a hurtle to get the drum over. So you back off the adj. wheel ( with the drum off , this is easy). Then once the drum is installed, you now have to adjust it tighter. NOw you need the port in the back of the housing.

 

[40Deluxe]

OK, is there any thing on front or face of drum have seen that before

 

[Jim 5]

Originally Posted By: 40Deluxe
OK, is there any thing on front or face of drum have seen that before


The one I had was on the mounting plate for the brake assembly, attached to the axle, closest to the differential. If you had the drum off, you could drill it out, whether or not a knockout exists. You could theoretically drill directly behind the star wheel (with the star wheel removed) on the brake backer attached to the axle. Just in the spot where you'd normally see an adjustment port. Then you need something to plug it up again. This way you could get in there with a heavy flat blade screw driver and adjust the star wheel.

On the other hand, backing up and jamming on the brakes works really well. Especially if you've serviced the drums and you know your star wheel isn't siezed.

 

[WishIhadatruck]

Originally Posted By: Jim Spahr
From the original poster: He is going to remove the rear drums and replace the shoes, so that is not a problem. When you pull the drums and the shoes are worn, the drums clear the ridge on the outter edge of the drum. But when you put the drum back on with the new shoes installed, the ridge is a hurtle to get the drum over. So you back off the adj. wheel ( with the drum off , this is easy). Then once the drum is installed, you now have to adjust it tighter. NOw you need the port in the back of the housing.


It was once suggested to grind off the ridge on the inner edge of the drum. I've tried it and it works well. Every time you have the drums off be sure and file/grind the ridge off. The drums can stay adjusted properly and you can still get the drums off and on. It isn't really that hard. The person I heard the idea from used a dremel tool but I just used a file with a radius.

 

[Jim 5]

Originally Posted By: WishIhadatruck
Originally Posted By: Jim Spahr
From the original poster: He is going to remove the rear drums and replace the shoes, so that is not a problem. When you pull the drums and the shoes are worn, the drums clear the ridge on the outter edge of the drum. But when you put the drum back on with the new shoes installed, the ridge is a hurtle to get the drum over. So you back off the adj. wheel ( with the drum off , this is easy). Then once the drum is installed, you now have to adjust it tighter. NOw you need the port in the back of the housing.


It was once suggested to grind off the ridge on the inner edge of the drum. I've tried it and it works well. Every time you have the drums off be sure and file/grind the ridge off. The drums can stay adjusted properly and you can still get the drums off and on. It isn't really that hard. The person I heard the idea from used a dremel tool but I just used a file with a radius.


Good idea.

The only vehicle I have left with drums is my early Bronco. I'll file that tidbit away for future use. Everything else is discs, even the front of the Bronco, which I converted from drum brakes. Drums are way harder to work on than discs in my opinion.

 

[mechtech2]

You could take the drum off to adjust it manually, and make sure everything is operating right.
But it will eventually settle back into it's present looser state. It is where those brakes will always return to with the present system, as the brakes wear after your adjustment..

 

[eljefino]

Originally Posted By: WishIhadatruck

It was once suggested to grind off the ridge on the inner edge of the drum. I've tried it and it works well. Every time you have the drums off be sure and file/grind the ridge off. The drums can stay adjusted properly and you can still get the drums off and on. It isn't really that hard. The person I heard the idea from used a dremel tool but I just used a file with a radius.


I get in there with a 4 inch angle grinder. Best angle is about 20 degrees, ie nearly parallel to the edge but not quite. This smooths the crude tool's output and makes it look a little nicer. I overdo it *slightly* for a bevel, so when rust blooms it takes up empty space.

 

[ARCOgraphite]

Originally Posted By: Jim 5

Backing up and slamming on the brakes is the procedure and you have to go pretty fast. I talking about something like 30 MPH in reverse and then slam on the brakes until they lock up.

It sounds pretty extreme, but if you do this in an empty parking lot at night (or other safe environment) it can work quite well in my experience.

Expect to do this 3 - 7 times to feel a difference.
I would say 15mph is more at it - you would nearly redline the engine in reverse at 30MPH most likely. YOu dont have to slam them on - just jab the pedal multiple times. Maybe 2x reversing with 3- 4 jabs each reversal should tuck them up nice. Thats what the Self-Adjuster is there for.

 

[cchase]

Originally Posted By: ARCOgraphite
Originally Posted By: Jim 5

Backing up and slamming on the brakes is the procedure and you have to go pretty fast. I talking about something like 30 MPH in reverse and then slam on the brakes until they lock up.

It sounds pretty extreme, but if you do this in an empty parking lot at night (or other safe environment) it can work quite well in my experience.

Expect to do this 3 - 7 times to feel a difference.
I would say 15mph is more at it - you would nearly redline the engine in reverse at 30MPH most likely. YOu dont have to slam them on - just jab the pedal multiple times. Maybe 2x reversing with 3- 4 jabs each reversal should tuck them up nice. Thats what the Self-Adjuster is there for.


Depends on the gearing. My 93 with 3.42's will do 40 without too much issue in reverse. I've found you have to go pretty quickly to get the adjusters to work as well.

 

[Vikas]

Same for earlier Honda minivans with rear drums. And you have to do this regularly because once they wear out enough, then they will NOT auto adjust anymore and you will have to take the drum off. But Honda does have the port in back.

 

[Jim Spahr]

Here is the answer from my expert Chevy truck man. There is no adjustment port at the back of the brake housing as in the past on GM cars and trucks. You see two ports but they are only for inspection of the brake shoes. Here's the new procedure: Install the new brake shoes and make sure they are seated well. Measure the inside diameter of the brake drum with a large set of brake shoe calipers. Then measure the outside diameter of the new brake shoes with the calipers. Match the brake shoe measurement to fit the drum measurement (minus a fraction) by turning the adustment gear at the top of the brake shoe assembly. This gear was previously a star wheel. Be sure to remove the outside ridge or lip-if any- on the drum so it won't interfer with the caliper measurement or the reinstallation of the drum.

 

[mechtech2]

Put the drum on and hit the brakes to seat the shoes.
THEN make any measurements/adjustments.

 

[FL_Rob]

Don't forget, the parking brake mechanism is responsible for the shoe adjustment on an operational basis.Thats why we set the park brake at least half-way every time .If the adjuster and shoes(at the backing plate)are properly lubed you should be able to pump them up using just the park brake sitting in the drive way.It's possible you may need a new star wheel an/or adjustment arm to get this 'auto-adjust' working again.

 

[Jim Spahr]

My friend with the '96 Yukon has heard of both methods of the 'auto adjust' for the rear brake drums. One is to hit the brakes hard several times while reversing. The other is the application of the parking brake to adjust the rear brakes. Strangely, there is no mention of Either Method in the FSM! He says the reversing and hitting the brakes seems to work.

 

[RH+G]

U could just make ur own hole in the backing plate so that u are assured a proper adjustment.