I’ve replaced drum brakes plenty of times, but have only recently thought of some things that have me second guessing myself. So I’m redoing the rear brakes on my 1940 Chevy truck. I figured out that the rear axle is from a GM A body, so I went on Amazon and ordered all parts for a 1970 Chevelle for reference assuming that should work. I got new shoes, wheel cylinders, spring kit and drums, I got all AC Delco cause OEM something something (as if anything is made in America anymore anyway). I didn’t remove the backing plate but I sprayed it with brake kleen and hit it with a wire brush. I didn’t prime it, but I painted it with rustoleum Rust Former, which never really fully dried and it ended up more of a flat finish. I probably should have top coated it with a gloss, but like I said it didn’t really ever dry nicely. Like days later it would still come off on your hands. I never used this stuff before so I don’t know if that’s normal? So first question, I’ve never used any kind of grease or lube, but someone was saying that you should put lube on the backing plate where the shoes make contact. This seems weird to me because I’m so paranoid about getting any kind of chemical on the shoes. I went out and bought CRC Silaramic cause it’s all they had at Advance auto. Is that the right stuff to use, and where exactly should I put it? Everything is put back together and I really don’t want to take it all apart, so is it possible to use it while everything it together? I suppose I could just pry the shoes away from the backing plate and squirt some in between? Next question, what do you use to clean the grease and grime off of your new shoes after you get them put on? My grubby hands get the shoes all nasty from fighting with them to get them on. Just spray some brake kleen or do I need to sand them? Next question, it’s been a long time since I’ve gotten brand got new drums, but these have little groves going the length all the way around the drums. Is that normal? Should I sand them down? thanks!
I don’t know if you can see in the pictures, but here is what the grooves look like, I guess this is fine?
Yeah that silaramic stuff should work just fine . I normally use high temp grease or anti-seize . once I’m done installing shoes I scuff them and chamfer the edges with sand paper then brake clean them . I have never had a new drum that did not need to be machined , either warped and pulsating brand new or machined wrong and noises on brake application . your looks like a course cut was taken , but not a finish cut . I would machine them just to be sure , but like I said . I’ve never had luck with new drums . amd yes you can pry the shoe off the backing plate and smear some lube on the contact points .
The shoe can contact the backing plate in a few places, I use regular grease or lithium on those spots. When you're all assembled, spray the shoes and drum surface with brakleen and wipe with cleanish rag. If you haven't put the shoes on yet. Lay them in the drum amd see how far outta round they are. I'm just curious, last set I did had a healthy gap at the center. I assembled them anyway and checked the wear later, expecting more wear at the ends, and it wasn't the case.
Normal…use masking tape on brake shoe until your done handling them…remove just before final assembly
I wear thin rubber gloves disassembling and cleaning the parts then remove the gloves and install the new clean parts with me bare hands. .
Vandenplas has it figured out and everyone else does too. The only thing I would add is scuff the inside of the drum with some 36 or 80 grit sandpaper. After you are all done take it out and run it up to 35 mph and do about a half dozen or so good hard panic stops. Then take back home and let it cool completely. Then after that drive it normal and they should be great. Just remember primary (short shoe) goes to the front of the vehicle secondary (longer shoe) to the back.
I was taught that more years ago than I want to count and taught my students to do the same. There isn't damned thing wrong with stopping to wash your hands a bunch of times either, Greasy hands don't make you a mechanic. It's 11:03 pm so I am not going to run out and check a couple of backing plates to find one that has marks on the pads where the shoes have worn into those pads but if they show a wear pattern from the shoes you can dress them up with a flap wheel or other abrasive disk. As for lubing those pads, I was taught that in the fall of 1962 as a high school sophomore in the first class on brakes we had. just a little smear of lithium or hard grease stick is all you need. I prefer to turn the drums but have done a lot of brake jobs without turning drums including the 12.99 one axle brake jobs we did at the Firestone Tire store that I worked at in the early 70's. They ran 12.99 for one axle brake jobs as bait to get people in a lot and about 40% of the time that was all the customer wanted, a cheap brake job with new shoes that lasted another 10 or 15K. The discount parts house up around the corner sold what were basically bulk relined brake shoes for 3.50 and axle and while they didn't last a lot of miles they were always pretty quiet and stopped straight. Plenty good for a lot of folks who only put 3 or 4 k a year on their cars and seldom if ever got out past the city limits. Still if the drums show wear it is best to turn them.
Around here it can be rather hard to to find a shop that will turn drums and rotors. The O'Reilly's does it if one of the guys on duty at the time knows how. The tire store that I deal with hits you with a pretty stiff charge and the Sears Automotive center that turned them exactly as I liked for a fair price is closed. Years ago I had said if I changed jobs again I'd put in a little hole in the wall shop in town where I just turned drums and rotors and did valve jobs and had cleaning tanks to hot tank or otherwise clean engine parts The farm mechanics in the area would keep you busy enough with just that.
The suggestions made are all good. Somethings I handle different. When I'm ready to handle the shoes I'll make my hands 'kitchen' clean. They just work better that way. Click the little box to see the whole message. ABOVE HERE Back then I worked for a big box chain auto department. They would advertise 4 wheels for $28 bucks. The backing plates do need a dab of lube. This gets put only on the high spot contact area. Usually 2 per shoe, and less than a square inch. In my day it was lithium. Today we have Permatex anti-seize compound. A much better choice. The reason for this is to protect the metal from moisture and corrosion. Moisture can occur in several ways. If not dressed the backing plate can, in time, become notched at these points. New drums don't need to be turned. They must!!, however, have the anti-rust protectant coating removed from the contact surface, before putting them into service. Today there is 'brake clean' we used to get it done with carb cleaner. Otherwise the shoes will be grabby, when the pedal is pushed. Those machine grooves in your drums are fine. I must call a caution about cutting drums. One cut too many can lead to drum failure. The outer part of the drum separates from the flat side part where the lug holes are. I have seen this twice, the second time the left side front separated, while the owners little sister was driving. This stove her into a parked car. The laws are in place to prevent this. The drum should have the limit measurement cast into it, The machinist should check the wear with a caliper before cutting. Myself, when a drum is not terrible but not perfect I'll run it no prob. But as I already said, the new drum just needs to be cleaned. Have Fun OH yeah, If the shoes wont come clean with brake clean try acetone.
I use a high-temperature white grease on any metal-to-metal contact points. When in doubt, less is more. Front drums need a coarser cut than rear drums which helped them break in faster and not glaze up. I was taught to keep front drums within .010" of each other when cutting them, too thin drums were a comeback waiting to happen. I never had an issue with greasy shoes, just make your hands are reasonably clean when you put them on. I used to get everything ready to assemble, I always cleaned everything and lubed the parts too. Then check my hands, we had a GoJo dispenser handy in one place I worked. Anywhere I worked, we cut drums for either $3 or $5 each. Big truck drums were more and I was generally the only one that could do them. The shop that fixes my new cars, he has nice turning equipment but rarely uses them. Almost always he uses new rotors. I know a couple of places that still cut drums and rotors. Back in the day, some parts places had a guy turning drums and rotors all day. They would be lined up with the customer's name on a tag.
Thanks for the responses! I’m gonna go ahead and put a tiny dab of grease on the high points of the backing plate where it contacts the shoes. Before I do that I’ll spray the new shoes with brake kleen and wipe them down to get all the grim off them. As for the drums, I sprayed them real good to get all the oily film off of them and I’ll just scuff them with the finest sandpaper I have, and call it a day. One more question- is there any benefit to painting the drums, other than preventing rust? I might paint them gloss black, if I do, does it need to be high temp engine paint or does that matter?
I don’t turn drums unless there is a problem, a big part of the brake drums job is to store the heat it can’t get rid of while braking until we aren’t braking anymore. The reason there is a machine to limit is to maintain enough heat mass to do that. If the drum had no damage there is no gain in turning it.
We turn alot of brakes and drums, alot of people act surprised when they ask "what's that machine do?" You tell them and some look totally dumb founded, others ask "do you really need to do that when you put on new brakes?" And then those " I've always done my own brakes and never needed to do that in 30 yrs". I always just cut enough to clean and clear the glaze off every car I've owned and put brakes on.... .
No, don’t use fine sandpaper use coarse 36 or 80 grit. Yes, you do have to use hi temp paint! In a long stop them suckers get hot! Colors I have used black, red, orange and my favorite white. All depended on color of car and windows in wheels.
The Jalopy Journal
