Rubbing/grinding noise on new drum brakes

Did you have the shoes arced to the diameter of the drums? If not you're only getting partial contact which may be causing the shoes to chatter against the drums.

Thanks for the response. I did not do that. That could very well be what the problem is. I've never changed the drum brakes before, so I really don't know how to 'arce' the shoes. Does this just mean adjust the spindle adjuster thing so that the drums require a little more effort getting back on?

Thanks!

No, not that simple. What you need to do is take the drums and shoes to a brake shop to have it done. What happens is they measure the inside diameter of the drums with a micrometer type gauge to get an accurate reading for each drum. Depending upon the results, and the condition of the drums, they may need grinding to get rid of score lines or any out-of-roundness. They can only grind them a certain amount before they are too thin for safe use and need replacing. Anyway, after that they place the shoes for each drum on an arc grinder, the grinding arc of which is set to match each drum's exact diameter. When done properly the surface of the shoe will fit completely flush against the inside of the drum.

When placed back on the car, and the brakes are activated, you'll get full braking resistance due to the entire surface of the shoe making contact.

What a pain! Is this a common thing to do when you replace drums and shoes? After you mentioned it, I did google it and it looks like it was a practice from awhile ago. If I just let it go for awhile longer, will it eventually arc itself? They don't tell you that in Chilton's! :)

Thanks for the information!

Same symptoms on a GM Safari after the last brake job. I noticed a lot of brake shoe dust trapped in the rear drums. Cleaned out the dust and no noise for awhile. When I asked the parts house about it, the guy said that it is pretty much normal with the materials used in brake shoe material now days. I have decided to wait until they are worn out and then try OEM parts from the dealer and see how that goes. The brakes work fine-- they just sound like metal to metal when there is plenty of shoe left.

Thanks for the response. I did not do that. That could very well be what the problem is. I've never changed the drum brakes before, so I really don't know how to 'acre's the shoes. Does this just mean adjust the spindle adjuster thing so that the drums require a little more effort getting back on?

Thanks!

If you bought new drums and shoes they should be of the right diameter. When drums are turned the circumference will be slightly larger than than the shoes.

I never had "arcing" done. Never even heard of it. And never had shoes that didn't wear pretty evenly unless they weren't adjusted. Make sure your self-adjusters are working properly. Double-check that you're using the right shoes. If the noise is from one side only see if you can find the difference. You said the shoes "might be" hitting the backing plate. Might take the shoes to a different parts store than where you bought them, or to a GM store, and compare them to what they say are the right shoes. With new drums and shoes, this just shouldn't happen unless a part is wrong or you didn't attach something right.

--Vic

What a pain! Is this a common thing to do when you replace drums and shoes?

I have had it done when I bought shoes at a shop that offered to do it for free, but I have also fitted many sets of shoes that were not fitted.

Unless something is really out of shape with the drums, or the shoes are of poor quality, they will seat in soon enough. There is a procedure for seating a new set of shoes by pulling forward, applying the brakes, backing up and applying the brakes, etc. This also will bring the automatic adjusters to their proper adjustment.. You did pre-adjust those brakes, didnt you?

When you say pre-adjust, do you mean move the spindle out a touch so that the drum fits snugly on? I did, but I'm wondering if I didn't do it enough.

I have some extra time this weekend, so maybe I'll try to go forward, reverse, parking brake, etc and see if it adjusts. Also, I still have the old shoes so maybe I'll try to measure them up and see if they are the same size.

thanks, mike

When you say pre-adjust, do you mean move the spindle out a touch so that the drum fits snugly on? I did, but I'm wondering if I didn't do it enough.

I have some extra time this weekend, so maybe I'll try to go forward, reverse, parking brake, etc and see if it adjusts. Also, I still have the old shoes so maybe I'll try to measure them up and see if they are the same size.

thanks, mike

*********** Rear drums have some provision for preadjustment, which will get the shoes near enough to the drum surface so that the automatic adjusters will take over. You normally put the drum back over the shoes and assembly, and snug it down (by lug nuts or screws or whatever system). Then you go in through the backing plate and adjust the star wheel until the shoes touch, but do not bind the drum. (Your rear drum assembly could vary somewhat).

After this, as you back up and apply the brakes, the starwheels will advance if necessary to keep the rear shoes adjusted properly.

These starwheel adjusters have to be clean and freely movable before you reinstall them.

If you havent done this kind of job very much, let me also caution you that the adjuster mechanisms are side specific. You cannot put a left wheel adjuster on a right wheel and expect it to work.

There are many variants of rear disc brakes, and some variations of rear drums. The drums are usually dead simple; some of the disc systems are not.

Actually and I know this is an old post the problem he is having is poor ma nufacturing processes. Quality Shoes and Drums should fit and his apparentl y don't. This is 2017 and not much has changed in fact it's gotten worse: t he CEO needs another car to complement the 40 he/she already has or another house to add to the 7-10 they already have etc etc etc. The junk that is b eing sold today is much worse than what was sold in 2009 but it all began i n the parts industry back in the late 70's to early 80's as in Sold by Dana or Delco or whatever major brand doesn't mean it was made by them just req uisitioned by them to be made.