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Posted By: Packard Joe 13 x 2.5 Rear Drums - Mon Sep 20 2021 03:41 PM
I have a 66 K20 and can't to find a part number for the rear drum. It's an HO72 with 13 x 2.5 inch brakes, 8 lug. This Eaton housing is the wider version to accommodate single rear wheels. I do have a set of 13 inch drums on my dually Eaton but that housing is an inch or two more narrow and the drums are different. I have piled through the parts books, this website and I have looked and asked on the the other site too where there were several answers but none that led me to the right drum. I have also paid an online visit to suppliers. All drums listed are 11, 12 or 14 inch, no 13's. I wish to keep the original brakes on the truck. Drum brakes work well for me, especially in the rear, so no disc conversion. The old drums I have are not salvageable and any markings that were on them have disappeared with time and weathering. Has anyone had this same issue and resolved it? Appreciate!
Posted By: Justhorsenround Re: 13 x 2.5 Rear Drums - Mon Sep 20 2021 04:01 PM
Rockauto shows they have drums to fit your application but do not list dimensions.
Posted By: Packard Joe Re: 13 x 2.5 Rear Drums - Mon Sep 20 2021 06:54 PM
Originally Posted by Justhorsenround
Rockauto shows they have drums to fit your application but do not list dimensions.

Yes, you are correct. I have researched them all, none are 13 x 2.5 inch except for the dually drums. Several years back I bought a new set from Rock Auto for my dually rear. Centric brand name. They fit perfectly on the dually but will not work on the single wheel version. The dually drums are quite deep compared to the single wheel version, even though the braking surface is the same. Recently the dually drums are out of stock too...
Posted By: 3B Re: 13 x 2.5 Rear Drums - Tue Oct 12 2021 03:54 PM
Hy Packard Joe, my research this morning shows the first mention of 13" X 2.5" rear brake drums on K20 models as appearing in 1972, Bendix p/n 140363 there is no mention of single rear wheel or dual rear wheel, only one p/n. The first mention of single rear wheel/dual rear wheel I find is the 77-79 K30 w/13" X 2.5" rear brakes SRW p/n Bendix 140387 DRW p/n Bendix 140388. Are you sure this rear axle is original to your truck? If you could give us more dimensions, such as the overall height of the brake drum we may be able to find a drum by dimensions, hope that helps.
Posted By: DoubleDingo Re: 13 x 2.5 Rear Drums - Tue Oct 12 2021 04:27 PM
Are you the original owner? If not, did someone swap over the 14 bolt axle brakes to the HO72?
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