Freeing Stuck Rear Brake Adjusters

One of my least favorite jobs on a 2002 is adjusting the rear brake shoes in order to lessen the brake pedal travel. In principle, it's easy—you just pull off the rear wheels, take a 17mm open-end wrench, put it on each of the two adjusting nuts on the backing plate behind each brake drum, rotate the drum, turn the adjuster until you can hear and feel the shoe rubbing against the drum, back the adjuster off a tiny bit, do the other adjuster, then move to the other side and do the same on the other drum. Boom, done.

If you have the dog-leg brake adjuster wrench, in theory you even can do it without taking the wheels off, as the dog-leg shape reaches around the tire.

The problem is that it's very common for the adjusters to be seized, and because there's not enough clearance on the nuts on the back to fit a box-end wrench, you have to use an open-end wrench, and if the adjuster is seized, the open-end wrench will round the corners off the nut right quick, and then you're boned. The dog-legged special brake adjusting wrench doesn't change that one whit. If anything, it may speed up the rounding process, as typically I'll try to tap on the end of the wrench with a hammer to budge the adjusters, and I think that a regular straight open-end wrench is more likely to deliver the torque squarely to the nut than the offset-angle shape of the dog-leg wrench.

So what do you do?

Here's my recipe: Heat, wax, and a stud remover. If you don't know what a stud remover is, they work sort of like the chuck on a drill. Twist the locking ring on the outside counter-clockwise, and the three internal jaws move together and lock around whatever is inside them. You typically can tighten them either with a big crescent wrench, or better yet, a 3/8-inch ratchet or breaker bar stuck into the end. You can buy them on Amazon for about twenty bucks. Just make sure that they'll handle up to a 1/2-inch stud, as the fat part of the adjuster that they need to grab is just a shade under that.

As far as heat and wax, I've written multiple articles about it, and how it's waaaaaaaaay better than any penetrating oil, even SiliKroil. Remember that heat does not mean a propane torch. Propane usually doesn't get things hot enough to un-seize fasteners. If you have an oxy-acetylene setup, great, but if not, Home Depot and Lowe's carry MAPP gas torches. They're the same compact size as propane torches, and they produce a hotter flame. There's a bit of a debate as to exactly how heat works to free stuck fasteners. The "metal expands when it's heated" theory tells you to heat the part around the stuck fastener, not the fastener itself (e.g., if a nut is stuck on a bolt, heat the nut cherry red, not the bolt). The other theory is that expansion is less important than the heat breaking the bond of corrosion. Whichever, using heat, and lots of it, is a proven method of removing fasteners that laugh at your application of PB Blaster or SiliKroil.

As far as wax goes, my friend Lindsey Browne, one of the admins of the Facebook BMW 2002 group and shop foreman at The Little Foreign Car Garage in Waltham MA, wrenches on a whole variety of old metal and turned me on to the use of wax years ago. There used to be a product called Goodson Oil Gallery Wax Sticks. Unfortunately they're no longer made. Goodson now sells beeswax instead. Whatever wax you use, the trick is to heat up the stuck fastener to the point where it begins to glow, let it cool for a minute or two, apply the wax and let it wick into the thread or the crevice you're trying to free up, wait a few minutes, and then give a go at loosening it. If it doesn't work, repeat the process. It may still take several attempts. Patience is a virtue and all that.

Back to the brake adjusters. You can try putting the torch on the nuts on the back of the backing plate and applying the wax there, but it's much more effective if you do it on the front-facing side of the adjusters, and to do that, you have to pull off the brake shoes. I know, it's a little bit of a pain, as you have to deal with that bloody spring at the bottom. But if your adjusters are stuck, it's what you have to do. And it's really not that bad. Pop off the spring on the bottom, spread the bottoms of the shoes apart, and with care, you can spread the tops of the two shoes from around the wheel cylinder and swing them off with the top spring and the little bracket still attached.

Once you have the shoes off, use the MAPP gas torch to heat the protruding part of the adjusters (okay, the areas around the protruding parts of the adjusters) nice and hot. Then apply the wax and let it wick in.

Then put the stud remover on the protruding part of the adjuster and put a ratchet wrench handle on it and tighten it down until it grabs.

Once it's freed, the adjuster should be free to turn in either direction (left or right), but because the stud extractor is meant to remove threaded studs, it tightens around the stud when you turn it left so it can grab a stud and unthread it, so you need to turn the handle to the left. DO NOT PUT SO MUCH LEVERAGE ON IT THAT YOU RISK SNAPPING THE ADJUSTER OFF! If it doesn't begin to give, repeat the heat and wax application.

I have never had this method fail. The beauty of it is twofold. First, it'll free up the adjuster without continuing to round the corners off the nut on the back. Second, once the adjuster frees up, you can keep spinning it around while you spray penetrating oil front and back (or, if necessary, use more heat and wax) until it's so free that you can easily turn the nut on the back, even if a few of the corners have already rounded. 

I recommend positioning the adjusters so the protruding dowel pins are at the top of their arc of travel. That way, once the brake drums are back on and you can't see the adjuster pins, you'll know that you need to turn the adjusters to move the dowels to the outside. That's more intuitive than having to remember that the left rear adjuster needs to be turned clockwise, the left front counter-clockwise, etc.

Reassemble, adjust (perhaps easily for the first time in your life), and enjoy the low travel of the brake pedal.

--Rob