Rear drum brake self-adjuster screw

[jonnycat]

Hi all. I changed my rear shoes last year, including new springs, but I kept the same adjustment screws (98 XJ, 160k). I recently took off the rubber boot on the back of the backing plate, and was able to turn the adjusting screw quite a bit before the brakes started to rub on the drum, and they work a lot better now. I was also able to turn the self-adjusting screw both ways without moving the adjusting plate out of the way.

I did make sure everything is routed correctly on both sides, and everything was installed properly.

Obviously the self-adjusting mechanism isn't functioning properly, and I am wondering if anyone has found that over time, the self-adjusting screw teeth wear down and the screw needs to be replaced.

Thanks!

 

[scoobyxj]

I have basically found the whole design is worthless, and never stays adjusted correctly..... I got to do mine about every two months, and when I did the brakes almost two years ago I replace everything including the adjuster wheels....

 

[cruiser54]

Just adjust them yourself.

 

[8Mud]

Most times it is the lever (lever parking brake adjuster left and right) that wears first or rusts before the star wheels wear out. If you can turn the star wheels by hand ( and they aren't frozen on the threads), the (adjuster) lever isn't worn, rusted or just plan rotting apart, it should self adjust if it is put together correctly.

Where a lot of people go wrong putting them together is the cable guide, about the middle of the adjuster cable. It has to sit flat against the shoe and is sometimes hard to get together and held in place while you are installing the spring (one of those jobs that takes three hands or a little luck to get right the first time). The bevel on the bottom of the cable guide pops out of the hole while you are trying to install the spring end that holds it in place. It can be hard to see, but the end effect is it leaves about 3/16" of play in the cable. If the cable guide isn't sitting perfectly flat on the shoe it is not put together correctly.

If your star adjuster isn't frozen, your lever isn't worn out and the cable guide is installed correctly, your brakes will likely self adjust.

You can apply your parking brake just until you feel a little resistance while backing up. Then back up at a moderate speed, say 3-5 MPH, then apply the brakes sharply, but don't lock them up. Repeat a few times, then notice how your brakes just feel tighter.

The self adjusters adjust in reverse, if you don't back up often, or are really light on the brakes when you do back up, they may not self adjust.

I use motorcycle chain lube on my star wheel (adjuster) threads, a lite coat of lithium grease or copper paste also works. A tiny dab of Lithium grease (or copper paste) behind the adjuster cable guide, some lubrication on the star wheel adjuster threads and have few if any issues with my self adjusters. I swap out the adjuster levers every 5-7 years, a few bucks appeace. I've never had to swap out a star wheel (or adjuster assembly).

The only other issue I can think of is, if you disassembled both brakes at once and got the star wheels mixed up. They are left and rights, one has reverse threads (I forget which is which). I never do both sides at once anymore, I only made that mistake once.

The self adjuster setup has been around forever and is proven technology that works. Especially when you consider that the brakes get, hot, dirty and are constantly exposed to the elements, the system holds up reasonably well. It just needs a little cleaning, lubrication and service every now and then.

 

[four_shot]

You can't really add to that. ^

I've found that many aftermarket adjuster cables aren't the correct length to be effective (too long). If you have replaced your adjuster cables it's something to check into.

 

[Dragonslayer]

I did mine last week. The self-adjuster cables were too long and so the adjuster plate
was not making contact with the spur wheel at all. I unhooked the cable from the adjuster
plate and twisted the cable by one revolution and then put it back on. Be sure to twist the
cable in the direction so that you do not unravel the cable braids. That fixed everything
and it all tested OK.

 

[jonnycat]

Thanks for all of the responses guys, I appreciate it. I'll have a crack at it next weekend (today was front brakes and bleeding) now that I have some things to watch out for.

You know one thing that concerned me when I was putting it all together last time was the lack of a shoulder for the adjusting cable eye to ride on; I can't help but wonder if this was a design issue or if they really did intend for it to fit this way.

This isn't my picture, but mine ended up looking just like this:

 

[Matthew Currie]

REgarding cables that seem to be too long: they may not actually be, but the upper pivot which inserts into a hole in the upper shoe, held down by the spring, tends to come out of its hole. You may not see this, and the spring continues to function properly, but it makes the cable too slack to work. Aftermarket pivots must be very carefully held in place when you put the spring in to prevent this. Once they're in right, they seem to stay, but they can be a nuisance to install.

This is not saying you can't also get cables that are too long. Make sure you don't get the cables for 10 inch drums if you have 9's.

 

[Dragonslayer]

Jonnycat - the eye for the self-adjuster cable(s) look just like the one in the photo.
I, too, thought that it was odd that there was no shoulder for the eye to better center on.
The cable guides were installed correctly - flat against the shoe. I used a screwdriver
to hold the cable guide(s) in place while working the shoe return spring in place. I checked, and checked again, to be sure nothing was wonky before deciding to twist the cable in order to shorten it a bit.

 

[jonnycat]

Thanks Dragon, glad to know that's the way the eye is supposed to be. I'll try your twist technique and see how that runs.

Matthew, interesting point about the cables; I got this jeep used, so it is indeed possible that someone along the line put the wrong cables in there.

 

[8Mud]

If I remember correctly the adjusting lever should be horizontal and just touching the star wheel teeth (maybe 3 teeth) below the horizontal center line.
Just some vague mental picture I have in my head that may or or may not be fact.

I also got one of those too long adjuster cables, I found a good used one (in my parts stash) and just tossed the new one. But they seem to be in the system. I thought it was just a number screw up in the database. I guess it could be a whole batch of out of spec adjuster cables.. I've found more than few data base screwups over the years. That is one reason I most always look up the Jeep numbers in my Jeep parts data and have them cross reference at the parts store before I buy something. Jeep makes fewer mistakes than aftermarket does (though I've found a few Jeep screwups also)..