Rear brake drums 1960

[Thomas H.]

I have a bit of a confusing situation going on. Today I put the rear tires on for the first time since I rebuilt the rear end. When I tightened down the rim, the wheel would no longer spin. I traced the problem to the drum interfering with the backing plate. Once I loosened up the lug nuts, the wheel would rotate.

As part of the rear overhaul, I replaced the axle bearings. They are the newer sealed type with two o-rings. When I first installed the axle, I used the spacer and found that with the spacer, I could not get the axle end cap to seat to the backing plate properly so I removed the spacer and everything went together fine. I had read somewhere that the spacer was not necessary when using the newer style bearings as they are thicker then the original ones.

With what I experienced today, it looks like I need some sort of spacer. As an experiment, I put a 7/16 washer over each lug and then installed the drum and installed the tire. Everything rotated easily so I need to move the axle out a smidge.....

Any ideas?

Thanks,

Tom

PS the drums are new.

[Erich C.]

Re: Rear brake drums 1960

I don't remember the size of the original shim but would a differential carrier side bearing shim work. I have a shim left over when I did the 12 bolt in my Chevelle. It measures 2.990 O.D. x 2.215 I.D x .066 th. IIRC they come from .066 to .090 thick. If that is too big maybe a 10 bolt rear has a smaller dia. shim.
Erich

[John F.]

Re: Rear brake drums 1960

Search for Tom Parson's article on rear bearings.

[Thomas H.]

Re: Rear brake drums 1960

Search for Tom Parson's article on rear bearings.

John,

I did read Toms article which is where I learned about the different thickness bearings and the spacer not being required when using the newer bearings.

I think I'll go re-read it just in case I missed something.

Thanks,

Tom

[Erich C.]

Re: Rear brake drums 1960

I read Tom's article and I don't think the axle would have moved much if at all from it's original position. I measured the distance from the axle face to the backing plate and got 2.269". I measured it at the 8:30 position where there is a raised flat area on the backing plate. Another possibility is the brake drums are new but are not machined to the right dimensions. I would check the drums to see if they are right. I posted a diagram with the dimensions of the drums on my '62.
Erich

[Thomas H.]

Re: Rear brake drums 1960

I read Tom's article and I don't think the axle would have moved much if at all from it's original position. I measured the distance from the axle face to the backing plate and got 2.269". I measured it at the 8:30 position where there is a raised flat area on the backing plate. Another possibility is the brake drums are new but are not machined to the right dimensions. I would check the drums to see if they are right. I posted a diagram with the dimensions of the drums on my '62.
Erich

Erich,

This is great information, thank you. I was wondering if the drums may be different and was planning on comparing them to the originals tonight. Your drawing helps take some of the guess work out.

Tom

[Keith R.]

Re: Rear brake drums 1960

Hi Tom. I've been experiencing the same problem. I put on all new drums from Paragon Corvette some years ago and found that the rolling chassis was very hard to move. I never investigated further as I thought it was the new brake shoes rubbing against the drums. I filled the system with brake fluid recently to make the brakes operable and tried to adjust the rear drums and found that it took a great deal of effort to turn the rear wheels. They were nearly impossible to rotate them. This has been puzzling me for quite a while and today when I tried to move the car (which is now mated to the chassis), I found that I could not move it. The rear wheels were actually making skid marks on the garage floor. (See the attached photo) I disconnected the drive shaft with no improvement. I reconnected the drive shaft then mounted the tires without the drums and could turn the wheels fairly easily so this pointed to a drum issue. I pulled all the drums and compared them to the originals and found that the inner rim (which is the shoe surface) is about .317" lower than the outside rim which fits over the backing flange. On the reproductions, the inner shoe surface is even with the outer rim and found that it rubs against the brake backing plate flange. You can see the rub marks on the flange in the attached photos. The right rear drum got damaged when I tried to get it off the hub so I had Paragon send me a replacement and the configuration is completely different from the first set that they sent me a number of years ago - on the new drum, the outer rim does not fit over the backing plate as did the originals. I plan on giving them a call on Monday because I am NOT pleased.

[Keith R.]

Re: Rear brake drums 1960

For all those who are interested - I took the reproduction drum to a local NAPA machine shop and they milled down the inner rim about 3/8". I'll be installing it on the car tomorrow and am pretty sure that it will no longer rub against the backing plate.

[Frank D.]

Re: Rear brake drums 1960

If that fixes it then I would notify the vendor of the problem....that's unacceptable...
Makes me glad I bought pristine original drums for the 61 from Fuelie Dave....

[Keith R.]

Re: Rear brake drums 1960

That did fix the issue Frank. I installed the re-machined drum today and the wheel and tire rotate easily now. I'll be talking with Paragon Reproductions for sure about this incorrect configuration. There's really no excuse for it and it causes guys like us more problems than are necessary.

[Frank D.]

Re: Rear brake drums 1960

Paragon has always been responsive to the very few issues I've had with their stuff; they are one of the "good ones"..

[Keith R.]

Re: Rear brake drums 1960

I spoke with Ken Bond in Paragon's technical department and he unfortunately did not seem interested in what I was telling him as the drums are not made in house. Of course, I am the first to complain about this. He hurried me off the phone before I was done with the conversation and sent me over to customer service who gave me a return authorization. If Ken had listened, I would have had the chance to tell him that my call was in the interest of improving his product to the benefit of the hobby.

Paragon has always been responsive to the very few issues I've had with their stuff; they are one of the "good ones"..