Rear Brake Drum Dilemma

[Ozzy2013]

Originally Posted by kieth

You could have the center of the axle machined down in diameter to match the brake drums, that was what we did to my 66 gmc when converting it to 5 lug.

Kieth

http://kieth.smugmug.com/Trucks/66-GMC/i-8bbRfcq/A


with the brake drum installed:

http://kieth.smugmug.com/Trucks/66-GMC/i-4G39bfw/A


One other thing you will have to do is to drill a oblong hole out in the backing plate to allow one to adjust the brake shoes before bleeding the brakes the final time. (my brakes were adjustable from the outside of the brake drum wheras the later model drums were adjustable from the bottom backside of the backing plate......Keith

Keith i have a 68 with a 6 lug dana 44 rear i am going to weld and redrill my axles to 5 lug .It looks like this is what you did where did you get youre 5 lug drums?Thanks for any help you can provide.Oz

[Critter]

I also have one of these axles under a customers GMC. Does anybody know the minimum thickness that drums can be machined to? I don't see it on the drum anywhere and can't find the data in any book.

[roger55]

I think it's 11.06"

[Critter]

So the inner drum diameter can be 11.06"? I'm not a brake guy, I just need to tell the guys that are how much we can open them up while turning. Thanks!

[Nasty N8]

I just redid the brakes on my 66 GMC and got both the 2067DGS and the wagoneer drums yes with machine work they would have worked perfectly. But the 2067DGS is a perfect fit. I measured and rechecked the shoes hit the drum completely. Thanks for this thread made it easier. LMC had sent me the wrong 3" Chevy drums told me sorry nothing we can do.

[roger55]

Originally Posted by Nasty N8

I just redid the brakes on my 66 GMC and got both the 2067DGS and the wagoneer drums yes with machine work they would have worked perfectly. But the 2067DGS is a perfect fit. I measured and rechecked the shoes hit the drum completely. Thanks for this thread made it easier. LMC had sent me the wrong 3" Chevy drums told me sorry nothing we can do.

Take a look at post #53.
What is the measurement on your 2067DGS drums?

The O'Reilly ones I measured were 2 7/16" and would not fit my '65 GMC leaf-version rear.

[scottofksu]

Rockauto has the drums to which you refer in stock... (Centric - 12266037) They are $100.89...

[roger55]

Originally Posted by scottofksu

Rockauto has the drums to which you refer in stock... (Centric - 12266037) They are $100.89...

Nope. Put them in your cart and they come up out of stock. I would suspect that this part is now permanently discontinued from Centric.

In any case, it was significantly cheaper for me to buy the Wagoneer drums even after the machine shop charge.

[scottofksu]

Rats! Sorry...

[Nasty N8]

Not sure on the exact measurements but I did it against my my rear end with shoes in place. It's close but they sit all the way on the drum. They are from oriellys

[roger55]

Originally Posted by Nasty N8

Not sure on the exact measurements but I did it against my my rear end with shoes in place. It's close but they sit all the way on the drum. They are from oriellys

If those drums with the same number from the same store were the same as the ones I looked at with the 2 7/16" measurement, then your rear axle (and thus the original drums) are not the same as mine.

[VonDog]

Originally Posted by roger55

I have a '57 Chevy pickup and the rear housing it has came out of a '65 GMC pickup (with leaf springs).

I cannot find new brake drums for this. I've got the originals but they are worn out.

I just paid $900 to have this rear all rebuilt (with new gears, bearings and posi unit) so I need to somehow solve this issue.

Evidently, these drums are a fairly rare bird and only came on '65-'67 GMC rears with leaf springs and '66-'67 Chevy P10 step vans with leaf springs.

The only present part# that comes up for those is a Centric 122.66037 but the Centric warehouse has been out of stock on those for quite some time with no expected date. I've been searching for about 6 weeks now and only found one supplier with 1 in stock (for $194) but just 1 doesn't do me any good.

Btw, here's the specs on the Centric 122.66037:




This may be an option though. There is a brake drum available for a '74 Jeep Wagoneer that is similar. It's a Centric 122.63028

The height is very close and the bolt circle is the same but the hub circle and bolt holes are both too small. I would have to take them to a machine shop to have the hub hole opened up to 3.56" and the bolt holes enlarged to .58". It appears that they would probably work if I had that done. Probably cheaper even after the machine work since these drums cost $28.79 on Rock Auto. It appears if the 122.66037 ever do come back in stock, they will be over $100 a piece.

Here's the 122.66028:



Any advice or ideas would be appreciated.

I got mine from rock auto a month or so ago. It showed it was out of stock but I closed down the web site and reopened it and it allowed me to order. I went through the whole crap you're going through - be patient and if the web site says out of stock - close and reopen it. Took several weeks and several tries but finally got front and rear for my 60 k20. **** another place I found is autoatlanta. They have the ones you're looking for.

[VonDog]

Here's another search in autoatlanta for gmc.

[roger55]

Thanks. Good information. I'm surprised they became available. Possible somebody found some old stock somewhere though.

But, take a look at post #70 in this thread.

The Wagoneer drums only cost me $69 a piece after paying for the machine work.

So in the end, I'm glad I couldn't get the Centric ones. They are overpriced.

[VonDog]

Originally Posted by roger55

Thanks. Good information. I'm surprised they became available. Possible somebody found some old stock somewhere though.

But, take a look at post #70 in this thread.

The Wagoneer drums only cost me $69 a piece after paying for the machine work.

So in the end, I'm glad I couldn't get the Centric ones. They are overpriced.

I got my fronts for $94.00 from rockauto when the other places wanted $150 +. Glad you found some!

[old cool]

Hey Roger. Hope you're still out there and willing to communicate. If so..great!
Hopefully my questions are simple and straight to the point.
1. Is your braking still in perfect working order with the 74 wagoneer drums from Orielly?
2. I have a 66 GMC with rear leafs and a dana 44. The build date was 1965. Yes, the drums are bigger than the front (depth about 3.5 inches). Sounds just like yours. If I have the center bored out to specs and the lug openings, will I need to do anything else? Your additional info on the emergency cable sounded like it has nothing to do with the drum working. That is, it was a mod you needed to make because the plate was incorrect.

Buy drums, have them machined, and put em on. Sound to good to be true.lol

[roger55]

Originally Posted by old cool

Hey Roger. Hope you're still out there and willing to communicate. If so..great!
Hopefully my questions are simple and straight to the point.
1. Is your braking still in perfect working order with the 74 wagoneer drums from Orielly?
2. I have a 66 GMC with rear leafs and a dana 44. The build date was 1965. Yes, the drums are bigger than the front (depth about 3.5 inches). Sounds just like yours. If I have the center bored out to specs and the lug openings, will I need to do anything else? Your additional info on the emergency cable sounded like it has nothing to do with the drum working. That is, it was a mod you needed to make because the plate was incorrect.

Buy drums, have them machined, and put em on. Sound to good to be true.lol

Still here.

Yes, the Wagoneer drums work perfectly with the center hole machining and lug holes drilled out larger.
Go for it.

Right the e-brake cable issue doesn't have an effect on the drum working. But if you use the stock e-brake setup, you either have to have custom rear cables made (I suggest Inline Tube for that) or find as set of donor back plates and do what I did. Donor plates would be simple to come by at a wrecking yard. That style was use extensively over the years.

[Ozzy2013]

I have a whole dana 44 6 lug rear differential for sale for 100.00 its from a 68 gmc.
the drums are in great shape.

[roger55]

Makes a great rear for a 55-59.
Perfect width, very wide assortment of ratios available. All parts for it are available too including the trac-loc posi units.
Unlike the situation for the original rears for our trucks.

I solved the situation for replacement drums.

[old cool]

Man o man Roger. Im still unclear about backing plate dilemma. I am 100% 65 gmc dana 44, 3:54 gears as original. Why do I need to make a mod at all for e brake. Does it not work with wagoneer drum? Or, is my stock backing plate too large or small??
All I need are the drums.
Why I'm getting confused is I'm thinking you have a 57 backing plate. Mine is a 65.
One more clarification would be greatly appreciated.
BTW, excellent thread. Thank you a million. I'll bet every guy with a 65 or 66 will find this extremely helpful!

[roger55]

Originally Posted by old cool

Man o man Roger. Im still unclear about backing plate dilemma. I am 100% 65 gmc dana 44, 3:54 gears as original. Why do I need to make a mod at all for e brake. Does it not work with wagoneer drum? Or, is my stock backing plate too large or small??
All I need are the drums.
Why I'm getting confused is I'm thinking you have a 57 backing plate. Mine is a 65.
One more clarification would be greatly appreciated.
BTW, excellent thread. Thank you a million. I'll bet every guy with a 65 or 66 will find this extremely helpful!

Sorry, I guess I wasn't clear.
My backing plates came with the '65 GMC rear assembly so they are the same as yours.

The e-brake issue has absolutely nothing to do with the usage of Wagoneer drums.

The issue is the rear e-brake cables that are used with this generation of truck use this style of connection to the backing plate:



While the '65 GMC pickup e-brake cable mounts to the backing plates like this:



So, if you have stock rear e-brake cables in your truck or if you order new ones, they won't mount to the 65 GMC backing plate unless you do one of two things.
Get custom rear e-brake cables or modifiy the backing plates using donor plates like I did.

Here's a photo of the donor plates I used along with my 65 GMC plates:



Here's a photo of my 65 GMC plates after doing the modification and my Chevy truck original e-brake cable and the 65 GMC e-brake cable.



I hope this clears it all up for you.

[Ken O.]

Thanks guys, I just had to do the exact same thing on my 67 GMC. It had the same drums you mentioned. Can't find them anywhere. I did the same Jeep Wagoneer drum modifications and it fits like a glove. I would have gone and bought a whole new rear end if I hadn't seen this thread.

[roger55]

Glad I posted everything.
Aren't forums a great thing for our hobby!

[Ken O.]

Originally Posted by roger55

Glad I posted everything.
Aren't forums a great thing for our hobby!

YES! Same thing with my model boat stuff.

[donthekawguy]

I took mine to the scrapper when I swapped to 5 lug. Guess I should have kept them.