The Ford Barn

Fredb_ · 09-28-2015, 01:25 PM

I got real lucky and found these four drums in a batch of parts I bought recently. I believe they are correct for my stock 38 sedan. Do I need to have them machined "true" before installing on my car? Also, the rears have some small pieces broken off of the edge in one spot. Will this be a problem with balance that I need to be concerned about?

Mart · 09-28-2015, 01:49 PM

If they are nos, my hunch is that they would not need to be machined. In my opinion, the chunks out of the rim, while unfortunate ought not to cause a problem with wheel balancing.

I will put my hand up, though, and say I am only guessing, but I am using the best of my judgement.

Mart.

Fredb_ · 09-28-2015, 01:51 PM

I think your judgment to be pretty good....thanks Mart

ford38v8 · 09-28-2015, 02:10 PM

The wheel/tire is balanced, so there is no reason the drum should not be balanced. The chips out of one side should be matched with drilled spots on the other. Note also, a good installer will note the heavy spot on a wheel before mounting the tire, then rotate the heavy spot of the tire opposite that mark. For your '38, the wide five adapter needs to be balanced first.

deucemac · 09-28-2015, 10:28 PM

Having worked in Ford service for far too many years, I would not trust a rand new drum for being true. Often, some parts person not paying attention would drop a drum and put it back on the shelf. I can drop a drum from waist high and get a .015 out of round condition. It has been my choice to chuck a drum in a brake lathe and check it for true. Even if yo only take .010 out, there will still be enough meat o last a long time. The other method is to install the drums as is and then try to figure out which one(s) are causing the brake pedal pulsation. There were far too many clumsy handlers at the factory, dealerships, and parts houses for me to trust them. That also goes for more modern drums too. Rotors are much stronger and very seldom need to be trued.

JWL · 09-29-2015, 05:50 AM

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The simple answer is---if the lining face is not concentric with the bearing bore they need to be machined. So, check them before installing.

It has been my experience that most tire/wheel balancing shops do not have equipment which is sensitive to the point of accurately recognizing a quarter ounce. If you think your shop does, ask them to balance your wheel/tire to zero-zero, then loosen the cone and rotate the wheel 180 degrees on their spindle and take another reading.

tiger.1000 · 09-29-2015, 12:03 PM

Fred, regarding the rears with the chips on the circumference.....isn't it worth have them repaired by cast iron welding? Not a big job. When done , clean them up on a lathe then check them with a dial gauge. If they need trueing up, that's the time to do them.

09-28-2015, 01:49 PM	#2
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,755	Re: Question about NOS Drums If they are nos, my hunch is that they would not need to be machined. In my opinion, the chunks out of the rim, while unfortunate ought not to cause a problem with wheel balancing. I will put my hand up, though, and say I am only guessing, but I am using the best of my judgement. Mart.

09-28-2015, 01:51 PM	#3
Fredb_ Senior Member Join Date: May 2013 Location: Coos Bay, OR Posts: 640	Re: Question about NOS Drums I think your judgment to be pretty good....thanks Mart

09-28-2015, 02:10 PM	#4
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 6,646	Re: Question about NOS Drums The wheel/tire is balanced, so there is no reason the drum should not be balanced. The chips out of one side should be matched with drilled spots on the other. Note also, a good installer will note the heavy spot on a wheel before mounting the tire, then rotate the heavy spot of the tire opposite that mark. For your '38, the wide five adapter needs to be balanced first. __________________ Alan

09-28-2015, 10:28 PM	#5
deucemac Senior Member Join Date: May 2010 Location: Tehachapi, Ca. Posts: 208	Re: Question about NOS Drums Having worked in Ford service for far too many years, I would not trust a rand new drum for being true. Often, some parts person not paying attention would drop a drum and put it back on the shelf. I can drop a drum from waist high and get a .015 out of round condition. It has been my choice to chuck a drum in a brake lathe and check it for true. Even if yo only take .010 out, there will still be enough meat o last a long time. The other method is to install the drums as is and then try to figure out which one(s) are causing the brake pedal pulsation. There were far too many clumsy handlers at the factory, dealerships, and parts houses for me to trust them. That also goes for more modern drums too. Rotors are much stronger and very seldom need to be trued.

09-29-2015, 05:50 AM	#6
JWL Member Emeritus Join Date: May 2010 Location: Fitzgerald, Georgia Posts: 2,204	Re: Question about NOS Drums Sponsored Links (Register now to hide all advertisements) The simple answer is---if the lining face is not concentric with the bearing bore they need to be machined. So, check them before installing. It has been my experience that most tire/wheel balancing shops do not have equipment which is sensitive to the point of accurately recognizing a quarter ounce. If you think your shop does, ask them to balance your wheel/tire to zero-zero, then loosen the cone and rotate the wheel 180 degrees on their spindle and take another reading.

09-29-2015, 12:03 PM	#7
tiger.1000 Senior Member Join Date: Apr 2011 Location: Hertford (UK) Posts: 905	Re: Question about NOS Drums Fred, regarding the rears with the chips on the circumference.....isn't it worth have them repaired by cast iron welding? Not a big job. When done , clean them up on a lathe then check them with a dial gauge. If they need trueing up, that's the time to do them.