brake drum balance

[sqrlnts]

How can I tell if my brake drums are out of balance? Can they be checked similar to a wheel/tire?

Reason I ask is I chose to reuse/turn my original drums instead of replacing with new. They were slightly past the min thickness when turned down. I still have a vibration that I can't pinpoint.

FYI, 1957, 3100, with 4 wheel drums.

Thanks!

[tlorber]

I've never heard of balancing the brake drums. If the vibration occurs when braking, they may be out of round. If the vibration occurs all the time it could just be wheel/tire balance. Unless they have been road force balanced, (a specific balancer that puts a load on the tire while balancing-better simulating real road conditions) you can't be sure they are correct.

You should also check tie rods and ball joints for play. Worn suspension components can cause shimmy.

[Russell Ashley]

They used to balance tires by spinning them while they were still on the vehicle. If you can find a place that can do it that way it might help if the problem is actually an out of balance drum.

[sqrlnts]

Thanks guys. I did find a link that shows balancing drums on a tire machine....

I would be interested in finding a place that balances everything on the truck. Is this how all tires were balanced in the past?

[OrrieG]

In the 60's I worked in a service station, we balanced them on a bubble level machine by placing weights on the rim until it centered. Never had any complaints. In the mid 70's the station I worked at had a machine that spun the tire and wheel and determined where weight was required. I was a tune up guy, I left the tire changing to others. I know most drums have some weight welded on or thickened edges that I have assumed is for or from factory balancing the castings. I have never heard of balancing drums but can see where it might be necessary if they got turned out of round.

I would suspect like the others have said your vibration is in the bearing/spindles or tire/wheel that may have gotten disturbed when you replaced the drums. Usually other steering looseness (tie rod ends, ball joints, drag link ends, steering box adjustment) result is more slop or a shimmey rather than vibration.

[mr48chev]

Spin on the car is the most accurate and if they have the strobe light setup rather than the hub that clips to your rim it is more accurate yet.
At o ne time or another I used the Hunter on the car balancer, as strobe light on the car balancer and bubble and off the car spin balancer and my money is on the strobe that has the sensor that connects to the rocker or frame rail. You don't mark the wheel up with the clip on Hunter style and get a really accurate reading out of it once you figure it out. The dealership I worked at in the mid 70's in Waco had extremely picky customers who we tended to spoil and cater to and I took care of even the most minute vibration. I'd be hunting for a shop that an on the car spin balancer. From what I read a number of big truck shops use them so you might check tire shops that handle big trucks.



I have run into new out of the box drums that were so far out of balance that they couldn't be run on the truck (72C-10)

[sqrlnts]

Thanks for the information, wealth of knowledge here.

[dwcsr]

Originally Posted by mr48chev

Spin on the car is the most accurate and if they have the strobe light setup rather than the hub that clips to your rim it is more accurate yet.
At o ne time or another I used the Hunter on the car balancer, as strobe light on the car balancer and bubble and off the car spin balancer and my money is on the strobe that has the sensor that connects to the rocker or frame rail. You don't mark the wheel up with the clip on Hunter style and get a really accurate reading out of it once you figure it out. The dealership I worked at in the mid 70's in Waco had extremely picky customers who we tended to spoil and cater to and I took care of even the most minute vibration. I'd be hunting for a shop that an on the car spin balancer. From what I read a number of big truck shops use them so you might check tire shops that handle big trucks.



I have run into new out of the box drums that were so far out of balance that they couldn't be run on the truck (72C-10)

I remember using those on cars and big trucks. It was far better than off the car balance and much easier for 1100x22r tires on trucks. They just kinda went out of favor for some reason.

[1project2many]

They use a different design for on the car balancers these days. Digital electronics took the place of strobes and mirrors.

I use an older model Snap-On digital spin balancer that can be used to balance brake drums. I've had to do just that with some of the Chinese made drums these days.

The latest high-tech off car tire balancer can measure differences in force created by the tire as it rolls over the road... IOW the "flat spots" we've all experienced from time to time. They'll correct the tire with a combination of weights and tread grinding. With all the tires coming over in large shipping containers, this method sometimes works wonders.