63(may be '62) Build
 

Subject of the day, Brakes. The goal here is to restore the original brakes to new status. This includes the hydraulic system. Before anyone says how dangerous single hydraulic systems are, I understand. Considering my intended use (occasional driver) this system will be fine. Not really wanting debate the merits of disc/drum or dual master cylinder conversions.
I will however, for those interested, discuss the process of rebuilding these "duo-servo self actuating" drum brakes.
The hydraulics are all new parts, including fabrication of lines. I've always hated my double flare tool, so for this job a new Lisle flare tool (cool design I had never seen) appeared in an Amazon box. Awesome, perfect flares every time!
Since brake fluid is hydroscopic, Silicon Dot 5 is the fluid of choice. Not sure if everyone is aware, but those combo brake/clutch master cylinders vent atmospheric pressure to the fluid. Any wonder why they are rusty?
So... guess this means we'll do the slave cylinder as well. Rusty beyond rebuildable, just 1 more cyl. replacement.
I'll insert some photos, and add more later.

Re: 63(may be '62) Build
 

Great, I'm along for the ride

Re: 63(may be '62) Build
 

So, today’s challenge:
The brake drums are the same, front & rear... well, not really. The fronts have 7/16 stud holes, but the rears have a larger hole to accommodate the shoulder on the studs. So I can drill them out, but think a trip to the parts store may be in order, since a longer thread reach would be better to accommodate mag wheels. Not sure the shoulder would be the same on a longer stud. And btw, the front studs are smaller in the knurled area. The Dorman web site has a wealth of info on wheel studs, so here we go...

Re: 63(may be '62) Build
 

What the heck is going on with your rear end? It seems like you have a coil spring not connected to anything and a panhard/anti sway bar running across behind the diff.? You seem to not know if you have a 62 or 63? 62 has torsion bar front, 63 has coil in front. Rears are leaf. Maybe I am not looking at the pic correctly.

This is the Coupe de Grass flaring tool, the Pierre de France, cats meow,

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Re: 63(may be '62) Build
 

Rears are leaf starting in '63, but coils for '60 to '62.

Re: 63(may be '62) Build
 

That's what I said?...................63 has coil in front. Rears are leaf.

Re: 63(may be '62) Build
 

Ed & Ken,
Thanks for the help! Like I said, I'm here to learn and share! 1962 it is... Coils in the rear and torsion bars in the front. I suspected as much when I saw the generator, since I remember Chevy switching to alternators in '63.(wasnt sure about GMC). Not sure how it got 63 paperwork, but no big deal I guess.
Just ran the Vin decoder, J=1962.
Bob

Re: 63(may be '62) Build
 

Probably the reason your 1962 has 1963 paperwork could be the fact in was sold in the 1963 calendar year. Have had a few Model T Fords as well as Model A Fords that was titled as the year they they was sold. A word from the wise - DO NOT go to the State DOT office and ask them to change the year - you will end up floating in a sea full of hurt with no paddle.:censored:

Re: 63(may be '62) Build
 

Ok, side note: Dad had GMC Wreckers when I was a kid. One for sure a '60. I recall how he liked the torsion bar suspension, and was disappointed in the ride of his new GMC. (would have been a '63! This discussion is reviving old memories. I started driving them when I was 17...1967.

Re: 63(may be '62) Build
 

Ok, back to brakes. The front and rear are most definitely not the same! Contrary to all the suppliers I have researched, the rears are ofset about 3/16 - 1/4". As I said before, the stud holes are larger too.
So, careful inspection shows the shoes will be flush with the drum edge. I see no option except drill the holes and press on (unless someone has a source for the correct drums) . No reduction in braking surface.
Hopefully the pictures make sense... the white paper was added to highlight the gap.
Bob

Re: 63(may be '62) Build
 

GMC drums are NOT the same as Chevrolet. Way to many suppliers group these together as one of the same - which there are lots of difference from the turn- signal switch to the radiator support and more.

Re: 63(may be '62) Build
 

THIS IS TRUE, NOT THE Same i used jeep wagoneer drums drilled out the 6 holes to 1/2 and had to open up the center hole bigger with a hole saw, if your interested i can go into more detail how to do it, i did 2 trucks like this worked great

Re: 63(may be '62) Build
 

Yes, I'd be interested in the details. My studs are close to 9/16 (at the base - knurl)
Thanks,
Bob

Re: 63(may be '62) Build
 

For the rear brake drums I used Centric Part 123.66003 they have fins and fit over the backing plate and still fit the stock rims. Just drill out the stud holes to 9/16. No need to open up the center hole.

Re: 63(may be '62) Build
 

Thanks for the information! I'm currently using the drums I bought, and will inspect them after a few miles. If the shoes don't contact completely now I have the solution!
Bob

Re: 63(may be '62) Build
 

With the brakes just about done, I moved on to a simple project, replacing the fuel sender assembly. New part arrived, and here we go again... GMC is different, using a 3/8 line while the new sender was 5/16". Found a suitable fitting to modify (drilled it to the 5/16 line OD) and sweated it on to the pickup tube. The mod didn't take long, just frustrating that it had to be done.

Re: 63(may be '62) Build
 

I found the correct sender with the 3/8 line from tanks inc worked great

Re: 63(may be '62) Build
 

I would like to see these measurements as compared to the original drums, that centric part number crosses yo an71 k10 I have a 71 and I tried this drum and it still was different

Re: 63(may be '62) Build
 

Today, finally closed the book on Title... Had to use the Vermont process, got her registered and plated in Vermont. Then transferred it to Arkansas where she was issued a title. If you are without title and at a dead end with your DMV, the Vermont (dubbed America's DMV by Jaloplink) process works!

Re: 63(may be '62) Build
 

jolly's old site has several part numbers for rear brake drums for the spicer 44 rear axles on our gmc's. another alternative is the rear drums for a mid 70's j-10 jeep pick up. i found on another site the same discussion and found a 71-2 k5 blazer 4x4 rear drum 440-1200 napa that looks like it will fit as well. i hope this helps.

Re: 63(may be '62) Build
 

Wrapping up the Brake job, finally, after ordering the wrong parking brake cables, returning…then backordered, here’s the solution. Real original cables aren’t available, so I modified the new version. The backing plates don’t have an attachment point like Chevrolet. The cables have 2 brackets that bolt to the backing plate and secure the cable end. I had to remove the spring clip and grind the cable housing. One of the two brackets had to be removed from the old cable, and slotted to be used on the new cable.
Here’s the pictures.

Re: 63(may be '62) Build
 

So I figured it was time for a quick oil change... Wait, did I say quick? Researched the filter, and decided the wix 51123 was the ticket. (plenty of good input elsewhere in this forum). I should have been wary when I discovered rtv on the canister, but the real tipoff was the home made (milk jug) gasket. So the gasket from the 51123 was too small, and apparently the last owner used a Chevy filter... Too short! (not much filtering going on) And it didn't leak!
Solution was to rummage through old transmission kits and find the correct size square cut seal. (FYI Ford c4 and Chrysler 904 both had one) so much for quick oil changes.

Re: 63(may be '62) Build
 

This was taken from another page

here is some part link info and alternative drum info from the archives in 6066 GMC site. Hope this helps.



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Amazon.com: Centric Parts 122.66037 Brake Drum: Automotive

The front drums are easy. They are the same as a Chivy and should be easily found and are relatively cheap. They have a 3" height or depth. Here's Rockauto.com's listing.
RAYBESTOS Part # 2005R $33.79

The rear drums are a bit harder, but I have three part numbers you can try for rear 6 lug brake drums. These have a 3.5" height or depth. The first is CENTRIc Part # 12266037 . The second is Allsafe 2067 DGS or Raybestos 2067R.
Rockauto.com shows the Raybestos 2067R for $58.79. Rockauto.com also has the Centric Part #12266037's for $119.79.

I used the Allsafe 2067 DGS from Autozone. The 2067's are for a later model (i think 67-72) truck with 4 wheel drive. It has fins on the outside unlike the original that is smooth. The only modification that I had to make was to drill the 6 lug holes from 1/2" to 9/16" so that the drum would fit on the shoulders on the rear lugs like the original. This drum had the right offset unlike the Chivy drums.

On the Centric, I haven't used that one, but was told it was a direct match to the original (a bit pricier though).

I hope this helps with those looking for rear 6 lug drums.