1972 3/4ton need break down of brakes

[klein1972]

hi
i have looked high and low for a picture of the break down of the rear break assembly. i have a 1972 3/4 ton with leaf springs that seems to take the wheel cylinder from a break assembly with dragbars and coil springs, i need to figure out what is going on so i can order the rest of the parts does any on have the break downs or know where i can find them for a 3/4 ton?

[69GMCLonghorn]

I'm not following you... The brake parts are available at most auto parts stores. What aren't you able to find?

[Stocker]

This thread http://67-72chevytrucks.com/vboard/s...d.php?t=283587 has some pics of rear brake assembly on a '71 3/4T with rear leaf springs...

[cdowns]

factory service manuals are great investments

[Longhorn Man]

you'll have problems getting a lot of the brake parts on that rear. Locate and price it all before investing more than it is worth.

[70gmcjimmy]

You might check www.rockauto.com as they list brake parts I can't find locally for my '72 C2500 such as a self adjuster repair kit and axle flange gaskets. They have several wheel cylinders listed. Most listings have clear pictures to compare your part to theirs.

Later---DAC

[MN Rooky]

Once you have the drum opened, also check the thickness of the drum for wear. This may save you some time and money that I wasted. Drums are not cheap.

[Big-Blue]

I bought everything at LMC for my '71 3/4 ton. Had to buy a new drum from O'Reilly's.

[vectorit]

If they are 11" drums, you can get everything you need to restore them back to 100 percent from just about any Napa store or resto shop.

If they are 12" drum, then you will have a hard time finding the self adjuster arm if yours are gone or worn out.

My 68 K20 has 12" drums, and I have been searching high and low for the left side adjuster arm for over a month now.

In-Line tube carries the E-brake cable that goes into the drum, and after they worked with me they now carry correct 12" cable assembly's for 67/68 K20's. OEM style goes for 65 bucks, and 90 I think for the fancier stainless steel models.

[special-K]

I`m guessing you have a Dana 60 rear.I have a`72 3/4t 4wd with a Dana 60 and napa had trouble getting me the correct shoes,by the listings.Going by the dimensions we discovered the truck was equipped,from factory,with 2wd brakes.You may need to check other applications for the same year.The different set-ups can be swapped from the backing plate-out.The wheel cylinders for coil rears and leaf rears have different brake line angles.I believe the leaf ones angle and the coil ones are straight.Or,it`s the reverse.I`m pretty sure it`s the prior.I think it only matters with leaf.The lines will be bent different.

[klein1972]

thank you guys
i have ordered two 1972 10-30 truck manuals, i think i found a place that has all the break parts, they list leaf spring and dragbar with coil spring .

how would i find out what rear end is in this truck, is there numbers on the rear ? i did some scraping but didn't find any thing but mold marks.

one other thing i found odd the plate that the breaks mount on has two rubber plugs but neither line up with the adjuster?

[69GMCLonghorn]

I had an Eaton rear end with leaf's on mine. I went down to Kragen (O'Reilly in y'all's neck o' the woods) and bought everything... shoes, wheel cylinders, hoses, they even had the axle seals... Luckily my drums were ok.

[vectorit]

Take a picture of the axle assembly for us to see, could either be an Eaton or a Dana.

The rubber plug issue could be a couple things:
1. Someone has the left and right baking plates swaped.
2. Someone did not set up the adjuster mechanism correctly.

Those are off the top off my early morning no coffee yet head right now.

[klein1972]

ok here is some pic of the rear

[vectorit]

Yep, that's an Eaton axle.

Now take a tape measure and measure the drum.

Do this by measuring the inside brake surface at the furthest part apart.

Should read either 11" or 12".

I'm betting they are 11", which means you should have no problem finding drums or 12" specific parts.

Sometimes the drum measurement will be cast on the outer edge of the drum as well.

[vectorit]

I meant if they are 11" you should have no problems getting everything you need. If they are 12" there will be dificulties finding 12" specific parts.

Originally Posted by vectorit

Yep, that's an Eaton axle.

Now take a tape measure and measure the drum.

Do this by measuring the inside brake surface at the furthest part apart.

Should read either 11" or 12".

I'm betting they are 11", which means you should have no problem finding drums or 12" specific parts.

Sometimes the drum measurement will be cast on the outer edge of the drum as well.

[69GMCLonghorn]

Mine were 12" drums believe it or not... Maybe I just got lucky. The parts might have been sitting there for 20 years for all I know...

[klein1972]

hi
i measured the inside of the drums and they are 11" on the outside rim of the drum is stamped MAX.DIA.11.21 i'm guessing that means that is the max they can be turned?

[Stocker]

Yup!

[Longhorn Man]

dont turn the drums unless you HAVE to... they stopped making them 20 years ago... they are hard to come by these days

[klein1972]

ok i found out why finding parts isn't working right, this truck has a 1 ton rear in it, special order from the factory i would guess and the only way we came to that conclusion is bearing #'s matched up with a 1 ton,

as far as the drums, i would think you could have them spray welded, like they do to cranks and returned, might be expensive but could be an option

[Stocker]

Originally Posted by klein1972

ok i found out why finding parts isn't working right, this truck has a 1 ton rear in it, special order from the factory i would guess and the only way we came to that conclusion is bearing #'s matched up with a 1 ton

Eaton diff was used in 3/4 ton (HO52) and 1 ton (HO72) trucks. I don't know exactly which parts are common and which are different, but I bet someone here does...