Drum out of round...

Post by **Cal_Gary** » Mon Mar 16, 2009 5:02 am

One of my front drums is scuffing the brake pad with every revolution. The pad adjustments are correct-I need advice as to who can turn the drum in order to "true" it up. I doubt Midas or the local brake shop has a lathe that can handle this. I'm unable to buy a drum at this time. Suggestions anyone?
Thanks,
Gary

Lifer · Post by **Lifer** » Mon Mar 16, 2009 11:31 am

Since Midas and other small brake shops deal primarily with cars and small pickups, I can understand why they might not be able to handle your M37's drums. A place equipped to service trucks (1-ton aand up) will have all the necessary equipment.

The main problem I see here is that if it's so far out of round that it scuffs with every rotation, it may not be possible to turn it far enough to get rid of the problem. I have no idea what the specs are for turning them, but you may have to find a replacement.

MSeriesRebuild · Post by **MSeriesRebuild** » Mon Mar 16, 2009 1:55 pm

You may not be as bad off as you think. Scuffing like you mentioned isn't out of the ordinary. Do you have new linings? Are you certain they are adjusted correctly at all 4 points? I would drive it a few miles, get on the brakes pretty good & see how they respond. Does the pedal push back out at you during a hard application? I imagine it would be too thin if you turned it back round. I have lots of used drums if you find you do need 1. These drums are thin walled when new, it doesn't take much heat to warp them when they get worn. I don't know where to find any new ones. This factor is a big issue in making the disc system so attractive, does away with the troublesome drum issues for good.

powerwagontim · Post by **powerwagontim** » Mon Mar 16, 2009 2:33 pm

Hi Gary,
You probably already know this but I will mention it just in case. The drums need to be turned while attached to their respective hubs. They are hub-centric, not lug-centric. A lot of good drums have been ruined by turning them to the lugs.
If you have an M101 trailer that has the Budd rims, they will have a pair of basically unused drums. Swap your bad drums with the trailer ones and you are good to go!
Tim

Post by **Cal_Gary** » Tue Mar 17, 2009 6:47 am

Good advice all around, Guys-thanks. I'll do a closer inspection on the clearances-I haven't changed the shoes. Funds are so tight right now I can't buy a drum Charles but I always keep you in mind when I need parts, along with our other Forum mates.
Gary

MSeriesRebuild · Post by **MSeriesRebuild** » Tue Mar 17, 2009 8:41 am

Don't invest in drums from a trailer unless you can inspect them first. We used to do that a lot & they were good, but for a number of years now, I haven't seen a good drum on a trailer, evidently trailers get turned drums. For the last while all the trailer drums I've seen appear to have been turned off center & have a thin side. Not bad if used on a trailer as they only utilize a park brake. Most places who offer turning service won't do it unless you provide a hub, useless anyway unless it's done on the hub as has been brought out already.

Post by **Cal_Gary** » Tue Mar 17, 2009 11:49 am

Fortunately for us gear-heads pulling a hub is next to no extra work at all-thanks again for your expertise!
Gary

MSeriesRebuild · Post by **MSeriesRebuild** » Tue Mar 17, 2009 2:31 pm

There is actually more to the story. When the rim is installed & lug nuts tight, the drum is then & only then forced up against the flange on the hub. We have an adapter plate we can bolt on using the lug nuts to replace the rim against the drum. The drum will always run more true like this, it's the only way to cut one exactly perfect. We have saved many a drum from ruin with this method.

Post by **Cal_Gary** » Mon Mar 30, 2009 4:47 am

I finally got an opportunity on Saturday to dive into this one. I pulled the tire and drum, took a Dremel tool and cleaned up all of the close tolerance surface edges on the hub, drum, and backing plate, then readjusted the shoes. I also noticed a sight bend in the backing plate at roughly 10 o'clock, so I straightened that out, too. I am happy to say that this solved the problem-the wheel now turns freely with no unusual noises and no resistance. (I'd repacked the wheel bearings and replaced all the seals when I went through the diff). I still have good brakes when applying the pedal and I also checked the driver's side just to be sure there wasn't any misalignment or maladjustment-all is ok. Glad to have solved this one-thanks for your guidance!

Next on my "to do" list-that quirky distributor-you might recall my post about inconsistent fire on #1 plug when the timing light is attached-more to follow....
Gary