I just recently completed a brake job on my 1941 Ford. During my test drive, the car has a strong vibration at 50mph. The only thing that has changed is that I replaced the front brake drums. I removed the hubs pressed in new studs then had the new drums trued up. I am thinking that the new drums also need to be balanced. Does anyone know where I can get brake drum balancing done?
Have the man with the brake lathe check the outer diameter of the drums for out of round and have the inside re-checked to make sure they got them concentric. Have the shoes arced to fit the drums. Chamfer the lining ends. These things you can do yourself with patience. I have had a few problems with the MT drums that are on the market, i.e. incorrect stud hole size, out of round, hard spots, etc. If everything is concentric with the drum center line they should be in pretty good balance. BTW, you didn't loose a wheel balance weight while you were working on it did you? If you're running stock 16"wheels on your car there are some that take a certain way to install balance weights so they stay on. I was having trouble with continually throwing weights off until I figured out the only way they would stay on these wheels was to install them with only about 5 - 10 lbs of air in the tire. Trying to put them on when aired up to spec I noticed that they would not drive all the way in between the tire bead and the rim. Out of balance drums should not cause a strong vibration at 50 MPH.
I have had the drums done at the machine shop so they have been trued. The new drums were .005 out of round. I will check to see if rims are seated properly. Since most cars these days use disk brakes I think that balancing a brake drum might be a lost art.
One of these would get the job done real well. Find a shop with a strobe and you don't have to attach anything to the wheel. I bought this one from a guy who had close out his service station several years before and was tired of walking around it in his home garage. I've balanced a lot of wheels on the car in the past 60 years on cars that the wheel and tire had been spun balanced off the car and the drum was out of balance. It has to be done each time you change the wheels and tires around though.
A shop that can balance cranks could do it, they probably would not want to though. To use a strobe light balancer and do the drum buy itself it would have to be installed on the rear as there would be no way to spin it on the front. You might put it on a off the car spin balancer and see what the results are.
If you clean the wheel bearings of grease and put light oil on them and don't tighten down the spindle nut most front drums will spin by them self to the heavy spot on the bottom.
I use a old Stewart Warner crank balance machine to do all my drums and rotors. A balanced drum or rotor does make a difference. Kind of like re arching your drum brake shoes to work properly.
Some of the repro drums for Fords coming out of Brazil need help. I have a neighbor with a Snap-On dynamic balancer and he does the drums separately and then the wheel, tire and drums as a unit. He has done my roadster and CCPU and it certainly makes a difference
Whe I replace drums some time back I noticed that the wheel 'rocked back to the same pace when spun. Car was on jack stands. I removed the seal, and with just the drum on the spindle spun the drum a few times to mark the heavy spot. The I secured some washers to the 'light' side with masking tape until the drum stopped in a random position. The washers gave me an idea about hot much metal had to come off the heavy side. On my drums it was lots. Took a bit of messin' around, but made things a whole lot better. If yo can find someone with one of the old 'on car' balancers, this would be the ideal way to finish the job.
Thanks everyone for their posts. I will try this before I take everything apart. I did find an engine rebuild shop said they could balance the drums if they can fit them on their machine. Next week I will take them down and I will post what the results are.
I suppose there is always the possibility of bad parts new, but new drums should be machined much more accurately than they can be on a brake lathe. They will almost certainly have the hub mounting face and lining surface machined in the same setup - meaning they will be "right on". The wheel mounting face could be out of true with the hub surface though, it's machined in a separate operation. Did the new drums have any small steel tabs spot welded on, like originals sometimes do, for balance?
I purchased the new drums at Hershey this past October. The mounting surfaces the brake shoe contact areas were nicely machined. However being cast as I discovered they are not balance. They mounted up to the original hubs perfectly and went onto the car with no issues. I should know this next week if the engine rebuild shop can balance them.
An update on my drums today. I brought them down to my local engine shop and they were able to fit the drums with the hubs on their balance machine they use to balance cranks and flywheels. One drum was 20 grams out of balance and they were able to take some material out to balance it within one gram. Unfortunately the second drum had some issues. This drum was 200 grams out of balance and when the drum was manufactured the center was machined several thousands off center. Mounted on the car there was no indication that anything was wrong until the car car was up to speed. They were not able to balance this drum. Next steps; I called Boling Brothers and ordered a couple drums from them. They assured me that there should not be any issues with balance of their drums and will warranty any issues. In hind site, I should have done a little more research and these drums would have come to the top of the list, instead of going for a cheaper swap meet drums that in the end cost me more that if I bought these in the first place. Not the first time I’ve made a mistake like this!
Vibration problem solved! The new Boling Brothers drums arrived and they looked beautiful! Nicely machined. I checked the runout and they were both at 12.005 and needed no turning. The tolerances on the hub center was perfect, however the stud holes are drilled to .060 and original style studs are .057 so there is .003 movement in rotation with the drum. I did call Boling brothers and after some discussion we agreed that as long as the drum was tight at the hub center and the wheels were torqued down properly there should not be an issue. After re-arcing the brake shoes to match the new drums they went on the car with no issues. I went for a test drive and the car was smooth up to 60mph. The vibration at speed was much better but still present. I did confirm with Boling Brother that they do not balance there drums. So I sent the drums out the the engine shop to have them balanced and they found that each drum was 20 grams out of balance. Because the drums were machined so well on the outside they were able to add the weights to the outside, rather than drill the drums. Back on the car they went and out for a test drive. Wow what a difference. Smooth as glass! I drove the car up to 80 mph, finally! It’s like a new car. On a side note I ordered a brake adjusting tool from Lime Works and it came with these instructions. I had always followed the Ford service manual and could never get a good firm peddle until after putting some miles on the car. I thought I would try this method and the results were impressive. I must say that the car now stops better than I can ever remember! The instructions with the tool was well worth the investment. I hope that this post will help someone in the future. The driving season has ended here in New England but I know that the car is ready to go once the season opens again next spring!
I would be concerned that "tape weight" may not stick so well to the brake drum OD after a stop from highway speeds.
I was too, but after some checking , I have a friend that runs 200mph at Bonnieville and uses the same weights with no issues. They are also used on many race cars running much higher speeds than highway speeds without issue. I did check with my local tire shop and was told that they normally have to cut the weights off when replacing them and very rarely ever have them come off. I will run them for now and see what happens.
The factories typically welded steel weights to drums to bring them into balance, I'm surprised no one suggested that. I don't recall ever seeing a drum with material removed. I'd be worried about stress cracks from heat cycling developing at the lightening holes. Vented rotors are balanced with what amounts to giant 'roll pins' inserted into a vent or two.
I was thinking the same thing. LOL ^^^ One of the things I have noticed when it comes to drums is that people using aluminum drums commonly remove the weights and loose them. I have zero understanding of that. Anyway the way I have gotten around that is to take the velicle in question to a shop that spin balances the wheels on the vehicle. Easy cure. There has been a ton of good info on this thread so this is just another option for those reading this at a later date.
A bubble balancer works well for checking and/or correcting balance. An old tire store probably has one.
I made up my own disc brake kit for my 54 Stude wagon. While fitting the caliper brackets on the spindles on my work bench, I installed the aftermarket, Avanti replacement rotors onto the spindle. While fitting the calipers, I noticed that the rotor kept spinning to it's "heavy side". I thought wow, something with as little mass, and as machined as this is (machined on most all surfaces), it's outta balance. So, I started drilling into the edge of the rotor (no cooling fins) with a center drill. I used Vaseline as a grease to both protect the bearings and to provide some lube. One rotor took a fare amount of holes, the other took about half that much. Now with a light spin, they never stop at the same location. Mike
One more thing to be aware of, I’m running buick drums on original ford hubs, I balanced the drums on wheel balancer where I work, it worked surprisingly well. I fitted the drums to the hubs, they are indexed, so only fit in one way, then with a bit of oil on the bearings and lightly adjusted. I still had one that always stopped in the same place, turned out it was the hub, hopefully you can see in the photos, the machining was offset slightly, you can just see it, one side is thicker than the other, I still have the stick on wheel weights I used to get it to balance. Another hub, and all is good
I'd make note of where the tape weights are located. I'm thinkin' that tape weights used the normal way on the inner diameter of a wheel rim get spun tighter against the relatively cool rim, so the adhesive isn't really required to retain the weight by resisting "centrifugal" force.. A tape weight on the outer diameter of a hot brake drum tests the tape adhesive strength and even the thin backing foam in a more direct way, under tougher (hotter) circumstances. The weight relies 100% on the tape adhesive and foam to keep it in place. Just sayin' .
After some thought considering some of the things you had mentioned. I plan to fasten the weights differently. I think I can drill and tap the side of the drum so the weights will be attached by screws.
Couldn’t moving the weight inboard slightly change the balance? That is even if you find fasteners with the same weight as that removed by drilling/tapping? D
Bursonaw, Wasn't trying to be inflammatory but you have already gone deep into perfecting the balance. I'm sure you can do what you are thinking just fine but I would think rebalancing would then be in order. Then a vicious cycle ensues! If they could add sticky weight to your drilled weight, you could then remove and weigh to know what final single weight after drilling you would need. You could buy a larger weight and trim it to that single needed weight. Kudos to you on chasing this down without a "good enough" attitude. D
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