72 rear drum brake question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Robert8096 · 03-17-2009, 10:20 AM

A friend gave me a 72 coil spring rear with 3.08 gears. I planning to put it in my 69, I know it is a little wider that my original but my real question is about the opening for adjusting the star wheels. Is the opening suppose to be in the brake backing plate or in the front of the drum? It has a set of drums on it and there is no opening to adjust the star wheels. That is a real pain in the A** when trying to back the shoes off so you can remove the drums.

Thanks
Robert

Bus Ted Knuckle · 03-17-2009, 10:25 AM

there is supposed to be one in the front of the drum, but new drums do not have it. I actually cut a slot in the backing plate so I can adjust (like most rear drums) . I drilled two or three holes, then used a file to clean it up. It looks just like a factory adjusting slot.

When correctly set up, the rear brakes are supposed to be self adjusting.

Robert8096 · 03-17-2009, 10:51 AM

Thanks. I think I am going to do that also so I can get the drums off that are on it now and if I need to replace them in the future I will not have to worry if the new drums have slots or not.

68gmsee · 03-17-2009, 10:58 AM

Look very carefully at the drums to see if it has a "knockout." If it's stock and has never had this done, you will have to use a hammer and chisel (what I did) to open it.

I had a pic but can't find it. I'll post it if I locate it.

Disregard the info... I reread your post and your access hole should be in the backing plate.

Robert8096 · 03-17-2009, 11:55 AM

Quote:

Originally Posted by 68gmsee

Look very carefully at the drums to see if it has a "knockout." If it's stock and has never had this done, you will have to use a hammer and chisel (what I did) to open it. Disregard the info... I reread your post and your access hole should be in the backing plate

I had a pic but can't find it. I'll post it if I locate it..

I see there is an indention on the drums for the hole and I know that my 69 has the holes in the drums and not the backing plate. I have the backing plates off the 72 rear end, going to powdercoat them so I may just cut the hole there before I coat them and then I don't have to worry whether the hole is in the drums or not.

**mr48chev** · 03-17-2009, 12:30 PM

Get a pair of the rubber plugs that normally go in the holes and use them to figure the size of the hole you need and then you can use them to plug the holes.

If everything is working right you shouldn't have to adjust the brakes after you do it the first time but we all know that these often don't seem to work right all the time.

03-17-2009, 10:20 AM	#1
Robert8096 Registered User Join Date: Nov 2007 Location: Goose Creek SC Posts: 161	72 rear drum brake question A friend gave me a 72 coil spring rear with 3.08 gears. I planning to put it in my 69, I know it is a little wider that my original but my real question is about the opening for adjusting the star wheels. Is the opening suppose to be in the brake backing plate or in the front of the drum? It has a set of drums on it and there is no opening to adjust the star wheels. That is a real pain in the A** when trying to back the shoes off so you can remove the drums. Thanks Robert

03-17-2009, 10:25 AM	#2
Bus Ted Knuckle Son of a gun Join Date: Jan 2007 Location: Hot Springs, Arkansas Posts: 1,636	Re: 72 rear drum brake question there is supposed to be one in the front of the drum, but new drums do not have it. I actually cut a slot in the backing plate so I can adjust (like most rear drums) . I drilled two or three holes, then used a file to clean it up. It looks just like a factory adjusting slot. When correctly set up, the rear brakes are supposed to be self adjusting. __________________ Bill BEATERS ARE NEATER

03-17-2009, 10:51 AM	#3
Robert8096 Registered User Join Date: Nov 2007 Location: Goose Creek SC Posts: 161	Re: 72 rear drum brake question Thanks. I think I am going to do that also so I can get the drums off that are on it now and if I need to replace them in the future I will not have to worry if the new drums have slots or not.

03-17-2009, 10:58 AM	#4
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: 72 rear drum brake question Look very carefully at the drums to see if it has a "knockout." If it's stock and has never had this done, you will have to use a hammer and chisel (what I did) to open it. I had a pic but can't find it. I'll post it if I locate it. Disregard the info... I reread your post and your access hole should be in the backing plate. Last edited by 68gmsee; 03-17-2009 at 11:21 AM.

03-17-2009, 12:30 PM	#6
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,705	Re: 72 rear drum brake question Get a pair of the rubber plugs that normally go in the holes and use them to figure the size of the hole you need and then you can use them to plug the holes. If everything is working right you shouldn't have to adjust the brakes after you do it the first time but we all know that these often don't seem to work right all the time.



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