Drum Brake Adjustment

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Revision as of 18:42, 20 March 2011

Whether you have a 1200 with front disc brakes, or drums all around, keeping the drum adjusted is key. All-drum 1200s stop amazingly well if they are adjusted correctly -- nearly as well as disc brakes. If you keep them adjusted once a month the pedal will be high and tight and stop hard and fast with a minimum of pedal travel.

Overview

With drum brakes, the pedal will go down a bit but then should be firm -- not spongy. Sponginess indicates air in the line. If you do a panic stop (press very hard) all four wheels should lock up at the same time. If only one wheel locks up, something is wrong or not adjusted evenly.

1. Bleed the Brake master cylinder, if that was never done, bleeding at the wheels will never fix your brakes
2. Bleed the wheel cylinder at each wheel. Start at the rears, then do the fronts
3. Check and adjust the brake pedal play
4. Adjust the play at each wheel. Turn the adjuster as tight as you can get it (with moderate wrench effort). When you back off the flat of the adjuster the brakes won't drag, but the play will be gone.

Adjust at the Wheels

From mklotz:

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It's all in the adjustment of the shoes. If the pedal feels rock solid when you push down hard, you've bled it correctly. If it feels spongy when you hold it down, there's air in the line. If it slowly drops while you're pressing hard, there's a leak. So...going by what you said....it sounds like it's rock solid, doesn't drop and is not spongy.....it's simply the shoe adjustment. The shoes are requiring too much travel before engaging.

With the car on stands and the wheels still on, adjust each wheel until they drag constantly....then back off a couple of clicks. Press the brake pedal to recenter the shoes and see if they drag. You'll want a bit of scuffing...probably no more than about 25% of the rotation. This should go away in a couple of days of driving and the shoes seat into the drums. When I say 25%...drums typically scuff in one spot when turning as opposed to dragging all the way around. If it drags really hard in one or two spots and not in the others, I'd take them off and have them turned....yes, even if they're brand new. Most parts stores will true up new drums or rotors for you when you buy them if you ask....but if you take them and bring them back, you'll have to pay. If the drums are "true" and perfectly round, the shoes should scuff fairly evenly all the way around. I would leave them with a slight drag...something you hear more than feel in the rotation. Don't forget to keep pushing the brake pedal down hard each time. Each time to turn the star adjuster, you can move the shoes back and forth....offsetting how they are centered....so, do a few clicks and spin the wheel, but push the pedal down hard before you trust what you hear or feel.

You want to leave the tire/rim on because if you do this with just the drum, the tiniest rub will feel like it's rubbing really hard. The diameter/weight of the tire will give a much better feel of how hard it's rubbing. Also, it's good to have the drum held on with the torqued down lugnuts so that it's all nice and even.

You want some scuff or rub so that you know your shoes are really close. If you jack it back up after a couple of days, I'll bet they don't rub anymore. You can readjust them again....this time you'll be looking for very little to no scuffing. Reason being that you "bed" the shoes into the drums. This can take a couple of days to a week or so, depending on how much and how hard you drive it. With the initial "softness" of the shoes gone, you should be able to get them really close without needing to rub. You may notice that in the first week your pedal drops a slight bit because of the shoes seating.

Anyway....you've adjusted all four and have what feels/sounds like even amounts of scuffing on the new shoes......your pedal should be close to only being half way down or less if your drums are pretty true.....time to drive. I prefer to test them in dirt or gravel to save on my tires....or I do it in the rain. You're looking to see which one locks up first. This is probably much more noticeable on the front brakes. One wheel locking up on the rear is easy to tell, but it won't throw off the direction of your vehicle like one front wheel locking up. If your pedal feels good and you have one constantly locking up first, back that one off a click and try again. If you have one that doesn't lock up like the rest, tighten that one a click and try again.

Yes.....this is a pain in the rear....that's why everyone goes to disc brakes!!!

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Improvements

• Performance linings. Order perfromance oriented shoes from brake shop, such as "Ott's Friction Supply" in Portland, Oregon

• Stock disc brakes won't stop any faster than a well-adjust drum setup. However, discs are less subject to fading from repeated brake use -- such as descending a mountain road

• Fitting larger brakes will improve both stopping power and pedal effort

• If the pedal takes too much effort for your tastes, fitting a Brake Booster will make a difference