Drum Brake Adjustment Procedure

by Tommy, Volkswagen Restorations USA

I have been reading with interest lately a lot of discussion about brake problems of one type or another. The topics have been the usual, "pulling" brakes, low or no pedal, "locked up" wheels, etc. The suggested fixes have been right on for the most part.

One thing happened that bothered me though. I asked someone the procedure he used to adjust his brakes. He didn't answer. This wasn't done to insult anyone, I just thought it may have been contributing to the problem.

Maybe some people don't understand the relationship between having all the slack out of the wheel cylinders and brake shoes, and having air in the system. As you apply the brakes there is only so much travel in the master cylinder's piston stroke, thus moving the fluid through the lines, wheel cylinder, etc. If the slack isn't taken up by proper adjustment, you waste all or part of that movement. So you can bleed brakes until the chickens come home and still think you have air in the lines. The pedal won't firm up as you "pump" the brakes. Although, if you pump fast enough, you take up that slack by "piling" the fluid in the system before the pistons can return it, but the next time you apply the brakes, you have no pedal, or "slack". When in reality by neglecting the importance of proper adjustment of the brake shoes and hand brake cables, you have caused your dilemma.

So I thought I would suggest one sure way anyone can get a good start to a good stop! I have adjusted brakes this way so long I don't remember from who or where I learned to do it this way.

After all necessary repairs have been made, including making sure nothing is leaking, flex hoses replaced, drums true, wheel bearings adjusted properly -- in general, the system is mechanically sound -- the next step is adjustment, right?

I am using a Type One, four wheel drum brakes car as an example. These rules will apply to all Volkswagens, and drum brakes in general. Early Type Two's with separate front wheel cylinders work and adjust the same, just two wheel cylinders per, but they are much more sensitive to adjustment and hose problems. On cars and Buses with disk front brakes, service the rear the same way.

All parts CLEAN ENOUGH TO EAT OFF OF! Never blow compressed air on dry brake parts. Even though Asbestos has been outlawed long ago, there may be some still around. Buy a $2.00 can of "spray brake cleaner", use a stiff brush and wash everything down, wetting all the dry dust before any compressed air is used!
Make sure the adjuster screws are free enough to turn by hand all the way in and out, and the hub is free in the mounting holes, and that none of locking spring clips are broken! Take your "freed up" adjusters and apply a light coat of anti-seize on the threads, and in the mounting holes. Make sure the angled "slot" in the adjustment screw head is oriented to the angle on the end of the brake shoe. Different years have different angles -- if they don't match you have the wrong shoes or adjustment screws.
Closely inspect your brake hardware, checking for things like return springs close to breaking on the hook ends. Check the "C" clip that holds the hand brake lever to the shoe for cracks and fit. Check the shoe retaining pins and cups for wear -- the slots in the cups have a habit of pulling through 20 miles after the job is finished, and wiping out everything in that wheel including the drum. $100.00 plus repair for a $0.10 part.
Make sure the contour of the shoe matches the drums fairly well. At one time you could have your shoes ground to fit the drums. Because of asbestosis I don't think anyone should do this any more. Your machinist should have checked the drums for wear, but you never know. The idea is that if your drums have been turned (machined) too much, or are worn past their limit, the contours won't match and only part of the shoe friction surface will hit the drum.
Front brakes: Take a rasp or heavy file and cut a 45 degree bevel, 1/4 inch (6 mm) wide across both end edges of each brake shoe friction surface front and rear (this will help to keep the shoes from grabbing). Install the shoes using a very small dab of brake lube on the ends of the shoes where they fit in the wheel cylinders, and in the adjustment screws. Also lube the backing plate where the shoes make contact. Install the heavier of the return springs closest to the wheel cylinder, the lighter one goes to the adjustment end. Make sure the brake shoe retaining springs (the ones that the pins fit through) haven't lost their tension. Clean any hand prints from all friction surfaces with your spray can of brake clean. Repack wheel bearings, replace the seal, install the drum, and adjust wheel bearings as per Bentley Manuel, depending on if you have ball or taper bearings.
Rear brakes: Now is when you should replace the axle seal, so it doesn't ruin your new brakes. Look closely at the shoes, check contour, and bevel as above, make sure they are the same width as the old shoes and that the width is right for the drums. Compare the length of the friction surface (the actual contact surface) of the two shoes. If one is longer it is the primary shoe, and will go to the rear of the car. Using a new (if possible) clip, install the hand brake actuator lever on the front shoe, making sure you place it on the proper side depending on which side of the car you're working on. Lube the shoes and all other moving parts at the contact points, as with the front shoes. Clean all hand prints as before. Install the drum, torque axle nut to specifications (318 ft lb's although some manuals say 336 ft lb's, if you get that close it will work, better than a crescent wrench and cheater pipe, don't laugh, you have done it!), install a new cotter pin.
Hand brake: Inside the car, loosen both hand brake cables until there is plenty of slack.

Now! Let's adjust the brakes!
Start at any wheel, any adjuster. Turn the adjustment "star", spreading its shoe, all the while turning the wheel back and forth to seat the shoes, until the wheel locks up tight! Back off the star one "click" at a time until the wheel will turn slightly. Then back off the adjuster THREE more clicks. At this point your wheel should be free, it may make a slight rubbing noise, but don't be concerned. Now move to the other adjustment star on this wheel, and adjust the same way. Follow this procedure on the remaining wheels. Move inside the car, and adjust the hand brake cables one side at a time, until the handle will only come up THREE clicks, and tighten the lock nuts.
Time for the road test. Before getting on the road, check the brakes: do you have a full, firm, pedal? Do they release when you take your foot off? If all seems well, at a very slow speed, in the driveway, check the brakes' stopping function, including the hand brake! All still seem OK? Then, pick a road with no traffic, and while driving slowly about twenty MPH or so, gently apply the brakes until stopped several times, going forward and in reverse. Not hard, not going fast, just enough to wear them in, and let them get hot a few times. DO NOT OVER HEAT THEM!
Now take the car back to the shop, lift it up and look everything over very closely for leaks, anything loose, any missing bolts, parts, etc. While you did all of your quality control work the brakes have had a chance to cool down, so... It's time to readjust them all, including the hand brake if necessary! Finally, don't do any high speed, long duration stops for a first few hundred miles. Apply on and off as much as you can, let them seat in, and go through several heat/cool cycles before any real hard braking. Keep them adjusted every 3000 miles and you won't have to do this very often!

Well, again, this wasn't meant to insult anyone, just my long winded opinion. Does this all sound like over kill? I don't know, but seems like the "key" word there was KILL! I know it sounds like a lot of extra work, but after you do a few like this it will become much faster, almost like second nature. Your brakes will last longer, stop straighter. And most of all, I may be on the highway, and meet you at a high speed cross road, and YOU will be able to stop! Thus saving my bacon!!!! :-) :-)

Last updated Thu May 10 21:56:25 CDT 2001