The Stovebolt Site Forums The Shop Area Driveline Big brake drum problem

Hello folks.
I have a 1952 GMC 3/4 ton pickup truck with the 8 lug wheels. I need brake drums because mine are totally worn out and unusable.

I can find 6 lug drums all day long. No one makes an 8 lug drum that I can locate. Centric SAYS they have one, but when I ordered it, it's an inch too big. It's supposed to measure 11 inches and what they sent was 12 inches.

I desperately need brakes. Am I going to be force to switch to a different bolt pattern just because of a lack of parts? Or is there a company someone knows about out there that sells the PROPER size 8 lug drums?

I think turning used ones have been the only option for a long time. Occasionally NOS ones appear on eBay. A 52 Would still have Huck Brakes. Getting a backing plate from a 53 to 59 will give you Bendix brakes and parts for them are much more available. You would still use your 8 hole wheels.

My original brake drums are about shot. One is shot. It is actually cut in half.

There was a guy I remember, if I could find his number...
He was in Denver and had a huge store of used truck parts for the AD series. I used to buy stuff from him all the time.
That might be my only chance.

Maybe I could either buy the '53-'59 backing plate, or I could buy the '52 8-lug drums if he has either.
And Ebay is a good idea, I'll check there too.

This is actually a pretty good idea...but it's a lot more than the standard brake job I was thinking of. A couple of hundred...maybe. But a grand is steep for my budget right now.

http://www.brotherstrucks.com/prodinfo.asp?number=DBC8L20

Hmmm...that last disc brake conversion kit is not for my year of truck.

I did find the part number of the drums that I need.
The original part number is 3847128.

It is out of production, so my only chance to find one is if I get very lucky, or I find a used drum that can be cleaned up.
So the search is on.

Those early AD 3/4-ton front drums are the holy grail. Next
to impossible to find Dad. I got lucky a few years back and
found a pair of NOS 3847128 drums, Hope they'll last me
another 27 years.
http://www.pbase.com/dennygraham/image/160723376

Like to hear more about this Bendix conversion for the 3600
Ken. Will those backing plates just bolt up to the early
steering knuckles? The original reason for doing this was
because the drums were shot. How bout the drums for the
Bendix brakes, is the bearing spacing, diameter, seals and
all that the same as the Huck brake??? If it were, why
couldn't you simply use the later drums with the Huck
brakes??? They should both be 11".
Seems to me like there are a few of those tiny details
missing for a Huck to Bendix conversion.
dg

Wow Denny those drums were quite a find. I had one good turn left in mine. After that it's replacement time.

Yes they were, din't come cheap and had to get them shipped up
from South America, took almost a month and wasn't sure they
would make it right up till UPS dropped them off.

I've been in the process of restoring a large 16" Lodge &
Shipley engine lathe for some years now. If I ever get it
finished it's big enough that I can do some experimenting
with welding original centers into later drum rims. It's one
of those projects that I'd like to do some experimenting with
since the supply of early 3600 drums are pretty much run it's
course.
DG

I think it would be a whole lot easier to convert fronts to disc, others here have done conversion.

Denny you hit the thought I had. Why couldn't someone, not me I don't have the resources to do it, weld a round steel band inside a drum and then turn it? Breath new life into the drums no longer available.

...sleeve and engine, why not sleeve a brake drum, eh. Makes sense to me.

Not on my watch Alvin. with the heat generated in a drum brake
and the different coefficients of expansion of steel and
Meehanite cast iron, welding a liner in a drum would be a
disaster waiting to happen.

Appears to be some confusion as to what I was talking about. I
did not mean weld a steel lining in the cast drum. This whole
idea was just a passing thought, something like gas, you know.
What I meant was to swap centers with a later model drum and
it was just a thought. I really haven't delved into this very
deep, got enough projects going on right now and I'm not in
need of brake drums at this time.
With out having an early Huck drum and a later Bendix drum on
the table in front of me to compare, it's hard to visualize
just where the problems lie. If it's just a width problem then
it may be possible to face the drum down to the narrower
width if there were enough thickness. If it's an offset
problem then the only solution would be to cut out the center
from both and weld the old center into the new drum. This
would have to be done on the steel center, not on the cast
drum rim.
I've never been able to find any information on how two piece
drums, that is, cast/steel are made but I think the steel
centers may be cast or potted into the drum at the time they
are poured rather than welded together.
When you look at the joint of a cast drum/sheet steel center
it appears by the step that there was a lot of material
machined away before the finish diameter was reached.

Any way you look at it, this would be a major project that
would involve a LOT more engineering and tooling than I'm
capable of or would feel safe with.

DG

Old Buick drums are sleeved frequently. There is a local guy that does this. They insert a new steel band into the aluminium drum. They were never meant for this to be a repairable part. Used on hot rods all the time. It is a high heat process. Just FYI.

Never heard of that Bruce, thanks. Thought Jerry, with his
vast exposure, would jump in on this discussion to fill in
the blanks.
Seems kind of odd that they would use a steel sleeve in an
aluminum drum with the large spread in the expansion coefficients of each.
That becomes especially problematic when you're talking about
a ring that is 10", 11", 12" or what ever their drum diameter
is.

Think I'd feel more secure with old school two piece or single
piece ferrous drums. But....you know me, I'm not a hot
rodder. And obviously I'm not up on the latest automotive
repair procedures.
However, I am always willing to learn something new. After
googling "Aluminum Brake Drums" I see now that they are not
at all that unusual.

Enough of this silliness.....I'm gonna go out to the barn
and do some real work.

DG

The only thing that really concerns me is how to prevent the welded two-piece drum that you end up with, from being out of round. I mean, it's going to have to be gnat's-ars perfect or it won't work.

I thought about trying to see if Centric or one of these other drum manufacturers would consider drilling one of their 11" drum blanks with 8 lug holes instead of 5 or 6. That right there would solve the problem nicely. However, considering that they now get their drums from China, I don't know if I'd put my money on a Chinese custom-job. I just don't have that much confidence in the Chinese.

My best chance at solving this problem is to find another 8-lug drum at a salvage yard, and hope I can get the darn things apart.

I did, however, find a '60's GMC 3/4 ton 2WD truck in the salvage yard here locally, and it has...(drum roll please)...a bolt-on crossmember on a narrowed front frame with DISC BRAKES on 8 lug wheels!!!

I might have to drive on three brakes instead of four, and do a lot of downshifting, but if I buy that front clip and spend the winter restoring it, that might be my best bet.
Unfortunately, returning my '52 GMC back to stock front brakes is kind of impossible if you can't even get restoration parts.
There's all kinds of stuff for half-tons, but almost nothing for 3/4 tons.

Later drums with huck brakes.
I actually considered that.
I found a drum, 11 1/8" diameter, on 8 lugs on Ebay.
Problem was it was a half inch too deep, and the guy wanted almost $200 for it.
It might have worked, but $200 with a no-return policy, still needing machine work to cut 1/2" off around the rim to reduce the depth?
I thought I'd keep looking.

I bought an extra set of front drums off a fellow here awhile back. They do not match mine so I'd be willing to let them go. If you want to private message me the measurements on yours I can check these and send you pictures.

As much as I hate to say this, the Chinese actually do a very good job of casting iron. The trick is that you have to specify exactly what you want, because that will be the spec they make it to. With the experience I've had dealing with late models, and using rotors cast here, Brazil, Mexico, Canada, and China, the Chinese drums and rotors seemed to be at least as good of quality as the US, Canadian, and Brazilian made parts, and in some cases, surpassed them, and far surpassed the Mexican made parts. I've actually had to machine a new rotor made in Mexico because it was so far out of spec for runout, never had to do that with a Chinese version of the same part.
Also, consider the fact that the Chinese were casting iron when the Europeans were still trying to figure out Bronze.

I have converted Huck to Bendix but its been years. It wasn't that complicated and it was before I had all the shop equipment I now have. I think it was a simple matter of drilling 5/16 holes to accommodate 3/8 bolts. Lots of 3/4 tons get scrapped. It is worth looking at old 3/4 tons. A few years ago a friend of mine discovered almost new drums on a 3/4 ton cut off and made into a trailer. Making trailers out of 3/4 ton used to be popular because of the full floating axles and the possibility of either 15" or Ford 16" wheels.

I bought some Raybestos drums for a 54 GMC and a 56 Ford Passenger car. They are all made in China.

I will not install any more Chinese drums on my semis. I bought a pallet of them from International with International part numbers. About 25% of them broke to pieces which is not only a dangerous situation, but also a DOT out of service. I don't need points on my CSA 2010, nor do I need to pay tow charges for red flagged vehicles. Fleetpride made me a deal on 6 pallets of Centrifuse drums. They cost 3 times as much as the Chinese junk, but we haven't had a single failure. And we are hard on brakes. Grossing 84,000 on 5 axles and a lot of stopping in the metropolitan San Antonio area traffic.

I would strongly consider used drums. These guys cut a lot of old 3/4 ton pickups. http://rpmclassicparts.com/

I would give them a call. I have bought quite a bit of stuff from them.

The brake drums you need are super RARE to find in GM NOS .

This photo shows the last two that I've seen on ebay.

photo@photobucket

http://i669.photobucket.com/albums/...k_Front_Brake_Drums_NOS__zps4nsu0f08.jpg



The Rear drums are also super RARE .

My friend who has a 1950 3600 bought these two GM NOS rear brake drums.

One on ebay back in 2006 for $50.00
&
another from W.D. Foster down in Texas for $150.00.

photo@photobucket

http://i669.photobucket.com/albums/...Rear_Brake_Drums_GM_NOS__zpshjtlekvp.jpg


Once in a blue moon someone will re-finish a used brake drum that still
has not reached the " NO GO " limit and offer it up for sale.
These rear brake drums were on ebay a few years ago.

photo@photobucket

http://i669.photobucket.com/albums/..._Brake_Drums_GM__609807__zpstofxzn0k.jpg

I've swapped my rear end for a Ford Dana 60 a few years ago, so that should be a little easier to find parts for.

About the only chance I've got on my front brakes is to either scour the salvage yards for 8-lug drums and hope I can get them apart, or convert to newer brakes.
(Or both).

I don't understand why the aftermarket concentrates on the half tons but almost nothing is available for the 3/4 ton.

PM sent. Thank you.

I did apparently find an old 3/4 ton brake drum at RPM Classic Parts. They want $45 for the drum, plus whatever shipping it is. A reasonable deal, provided the drum is still in good condition. Hopefully once I get it, it will fit.

I have bought quite a bit of hard to find stuff from RPM and it was always better than what I expected. I hope you have the same kind of luck with them that I have.

I just can't believe how hard it is to find restoration parts for a 3/4 ton. I'll bet most people convert to 5 or 6 lug wheels just because you can find plenty of stuff for that. But in all these years, no one can step up and produce 3/4 ton parts...unless it is shared with the half tons?

...Why?

There simply aren't that many 3/4 ton trucks that are being
restored, everyone wants 3100 five window trucks. Isn't worth
tooling up for a small market such as the 3600.
I've been trying for a decade to get someone interested in
making a run of 3.90 gears for the HO52/72 rear axle but
there again, not enough to justify making a batch of them.

There certainly is a market for 3600 hard to find parts, all
we need is someone with the manufacturing skills to pick up on
it.

dg

I ran into that problem when I needed a rear main bearing set for a Chevy big block with the thicker thrust flanges, like you used to always be able to get. The part number is still active, but unless they get at least 100 orders, they won't send it in to have a batch made.

Might be something like that.

This is why I finally broke down and replaced my original rear end with a Ford Dana 60. Other than the lack of a posi, it is nice to have a 3.50 gear set back there! I actually have highway legs now.

I think if you have a 3600, you're almost forced to restofy instead of restore.

Not so "ke-mo sah-bee"! I've been driving a bone stock '50, 3600
since 2005 and put several thousand miles on it each year.
Been able to fix, repair, replace, rebuild everything on it so far.
Just takes a little extra effort.

dg

The only reason I bought my Howard Knapp truck because it was cheaper than any other AD style truck but it was 1 ton...so it sorta looked like a 1/2 ton....the very first thing I had to do was literally cut two of the four stock 8 lug drums off with a cut off wheel due to broken brake springs...that started the swap that I did not want to do...I pulled the 8 lug rear end out and put a 6 lug K5 Blazer rear end in and then I went up front and yanked the whole front end out...springs....hangers...axle...spindles everything and mounted a 1/2 ton 6 lug front end under it...I did a disc brake upgrade for less than $1000.00. The rear end swap I think was less than $250.00 with used 1999 Chevy rear truck springs and new (Speedway Motors) spring perches....in end now I have now is like a heavy 3/4 ton truck...and I can get over the counter NAPA type parts for the truck...

I have not run this rig yet so I am really praying that all this work will work in the end...

My 2 cents...

MikeC

Oh, modifying the 3/4 ton to make it safer and easier to get parts for does not bother me. It's just sometimes what you have to do. I did actually find a drum for it, and I paid for it...but have not even received confirmation that they got my payment or are sending the part.

This is RPM Classic Parts.
So I need to check on it and make sure I didn't just pay for "air".