Brake Drum Backspacing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ZEPPELIN · 04-02-2015, 09:26 PM

I'm rebuilding the rear brakes on my '68 GMC C1500 and I picked up a new set of drums at the local auto parts store. Got them home and noticed they weren't a match. The originals have an additional 3/8" of backspacing over the new replacements. Searching for the correct part online, it appears that the new drums I got technically are the correct drums for my truck, but obviously not for the axle that I have. Any idea what year/make/model I need to be searching for to get the correct drums? The only identifier I can find anywhere on the rear end is the Dana 44 marker. Nothing stamped in the axle itself.

Thanks

ZEPPELIN · 04-03-2015, 08:15 AM

Alright, I did some deeper digging and I think I answered my own question. Here's what I found for any others that might run into this problem. The deeper drum is unique to GMC's with the Dana 44 and leaf springs on the rear, which is apparently at the more rare end of the spectrum. That said, a direct replacement is not available. I did find a few posts that claim the Raybestos 2067 drum will work, but the lug holes have to be drilled out from 1/2" to 9/16". If anybody else has more input, please feel free to share.

04-02-2015, 09:26 PM	#1
ZEPPELIN Registered User Join Date: Aug 2014 Location: Isle of Palms, SC Posts: 4	Brake Drum Backspacing I'm rebuilding the rear brakes on my '68 GMC C1500 and I picked up a new set of drums at the local auto parts store. Got them home and noticed they weren't a match. The originals have an additional 3/8" of backspacing over the new replacements. Searching for the correct part online, it appears that the new drums I got technically are the correct drums for my truck, but obviously not for the axle that I have. Any idea what year/make/model I need to be searching for to get the correct drums? The only identifier I can find anywhere on the rear end is the Dana 44 marker. Nothing stamped in the axle itself. Thanks Attached Images

04-03-2015, 08:15 AM	#2
ZEPPELIN Registered User Join Date: Aug 2014 Location: Isle of Palms, SC Posts: 4	Re: Brake Drum Backspacing Alright, I did some deeper digging and I think I answered my own question. Here's what I found for any others that might run into this problem. The deeper drum is unique to GMC's with the Dana 44 and leaf springs on the rear, which is apparently at the more rare end of the spectrum. That said, a direct replacement is not available. I did find a few posts that claim the Raybestos 2067 drum will work, but the lug holes have to be drilled out from 1/2" to 9/16". If anybody else has more input, please feel free to share.



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