Posted By: vette1968 3800 Drum - Mon Oct 28 2019 01:05 AM
I have read about this in the manuals but would like to verify if I am understanding correctly.
Are the rear drums on 1949 one ton 3800 trucks the same for single wheel versus dual wheel ? Can the same drum be used for either ?
Posted By: truckernix Re: 3800 Drum - Mon Oct 28 2019 05:20 PM
The online Chev parts manual shows different part numbers for the two models. Parts Book
Posted By: Eureka Jim Re: 3800 Drum - Tue Oct 29 2019 05:08 AM
I don't see 2 different numbers for the rear drum in the parts manual, '46-'52 rear wheel drum # 609808. However, the studs are different lengths for the single rear wheel trucks versus the ones that use duals. There is a difference in the front drums for those trucks that have dual rear wheels.
Posted By: vette1968 Re: 3800 Drum - Tue Oct 29 2019 12:12 PM
Thank you for the replies. I have a chance to buy a rear.drum but it is unclear which set up it s from. As difficult as they are to find I may just go ahead and get it.
Posted By: truckernix Re: 3800 Drum - Tue Oct 29 2019 11:04 PM
My mistake, that is the rear drum for both single and dual wheel application. I guess I was looking at the front drum. So it doesn't matter which one it was used on. Those drums are super rare so I hope that you are able to get it.
Posted By: John Milliman Re: 3800 Drum - Wed Oct 30 2019 12:26 PM
Maybe the guys with the parts books can clear this up .... Considering the HO72 axle was used for so many years ('47.2 through '72, right?), then are the drums the same for all those years or do the part numbers change?

I am scavenging brake parts off an HO72 as we speak that appears to have two different era drums on it -- one is ribbed, the other is smooth, yet they interchange. I'm assuming the smooth one is much newer (after the bean counters told the engineers to figure out a cheaper way to make them ...).

Can someone with the parts books take a look at that to see when/if the parts nos change? Maybe the part number only changes when they went from ribbed to smooth, but otherwise the drum is the same? (Two different part numbers, ribs/no ribs, yet fit/function remain identical?)

I was told by competent authority that everything throughout the run of the HO72 interchanges (i.e., that it should be a simple procedure to retro fit the Bendix brakes from a '68, for example, to a '48 -- from the backing plate out). I have not proved this to myself, though. Nor do I know anything about interchangeability between SRW and DRW axles)

Posted By: truckernix Re: 3800 Drum - Wed Oct 30 2019 07:06 PM
John, I am pretty sure that the drum changed in 53 when the Bendix style came in. It is interesting that you may have a newer drum. A few years ago I bought a set of drums new for a 38 pickup. They were made in Argentina and they are a one piece cast drum, not like the originals. This causes the center section to be thicker so the other dimensions are adjusted to make it work.
Posted By: vette1968 Re: 3800 Drum - Sun Nov 10 2019 03:13 AM
Thanks, Truckernix. I was able to obtain the drum. As you say they are super rare. I got it primarily as a back up and will just throw it on the shelf. Keeping on the lookout for another.

I am keeping my truck entirely stock except I made the change to a 4.10 rear end. There sure is a big difference now and it is nice to be able to go around 50 or a little less and not a max speed of 42 mph.

More out of curiosity than anything I did discover a place in Illinois that resleeves old drums. It is nice to know that is an option too.
Posted By: 1Ton_tommy Re: 3800 Drum - Sun Nov 10 2019 06:11 PM

Would you post the info for the place that resleeves old drums? Or Pm me.
Posted By: vette1968 Re: 3800 Drum - Sun Nov 10 2019 09:07 PM
1 Ton Tommy, I sent you a PM. Not sure about the rules of posting business names here
Posted By: Justhorsenround Re: 3800 Drum - Sun Nov 10 2019 09:22 PM
Vette1968, posting business names and addresses is just fine if they are already published elsewhere. If it’s a small word of mouth type operation, I would ask their permission first.
Posted By: John Milliman Re: 3800 Drum - Sun Nov 10 2019 09:50 PM
Doing a search for "brake drum relining or sleeving" should pull up useable results, as well.
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