Can someone help identify the 12 bolt in my 63?

[lotus]

Here is a picture of the 12 bolt that is in my 63. It appears something was cut off the left side and by the center section top right something was cut off. Does this appear to be a 70's truck rear? it is a 6 lug.

[protrash64]

To me, the rear looks like it's from a newer year of truck, maybe 1967 thru 1970. The mounting area was for the original panhard bar (upper right). It appears as though an aftermarket panhard has been installed bolted to the original pivot location and attached to the passenger side trailing arm.

IMO, this is an improvement as the rear axle will not move as far left/right as the axle travels up and down. Hope this helps somewhat.

[Captainfab]

I agree with protrash64. That is definitely not a '63 12 bolt. That appears to be a '65-'70 12 bolt. I'm not sure what may have been cut off of the left side, but the upper right center is where the '65-'72 panhard bars were attached. The panhard bar that you have now is better.

[aerotruk63]

63 12 bolt would have a splined backing plate to mount the brakes too.

[lotus]

i scrubbed on it and i can't find any stamped numbers. I lifted the rear off the ground and it acts like a open diff but i hear that is misleading with clutch packs.

Guess I just need to lite them up and see what spins

[lotus]

I ordered what i thought were the right 5 lug axles for this rear. I pressed in the new studs before confirming the axles were the same. I removed the old axle and sure enough the old ones are slightly shorter than the new ones 1/4 inch give or take a little from eye balling.

What are my options? get a wider drum so the pads/braking surface line up 100%?

Shim the backing plate out?

I also have a ten bolt from a early 90s disc brake camaro. I wonder if that setup is slightly wider and would make up the difference?

or...is the only option push out the studs and try to return the axles which they may or may not take back since i pressed studs in.

thanks....

[bubba327]

Any idea what the panhard bar is from? Does it appear to be commercially made or a one off fabrication?
I kinda like the style-It certainly has less side to side movement
The 60-69 years were 6 lug and narrower by 1 1/2" than the later 70 and later 5 lug

[Captainfab]

It sounds like you may have one of the late 1970 rear ends, They were still 6 lug but were 1 1/2" wider like the '71-'87 rear ends. Just to be sure, measure your rear end WMS to WMS (wheel mounting surface) with the original axles installed. If it is the '63-early '70 width, it will measure 62". If it is the late '70-'87 width it wil;l be 63.5"

[protrash64]

Originally Posted by bubba327

Any idea what the panhard bar is from? Does it appear to be commercially made or a one off fabrication?
I kinda like the style-It certainly has less side to side movement
The 60-69 years were 6 lug and narrower by 1 1/2" than the later 70 and later 5 lug

bubba...CPP sells that panhard set-up. Maybe some other places, too.

[mrlush]

I have a 12 bolt in my 63.

It seems that the drums are pressed on as there is no backing plate attaching the drums.

Question... since this 12 bolt does not have backing plates, is it going to be impossible to upgrade to disc brakes?

Thanks

[raycow]

You got me scratching my head here. The 63 12 bolt definitely has backing plates. Those are what the wheel cylinders, shoes, parking brake lever, etc are attached to. The drums are held in place by the wheel studs and have nothing to do with the backing plates. Could you please post a pic showing what you are talking about?

Ray

[mrlush]

Originally Posted by raycow

You got me scratching my head here. The 63 12 bolt definitely has backing plates. Those are what the wheel cylinders, shoes, parking brake lever, etc are attached to. The drums are held in place by the wheel studs and have nothing to do with the backing plates. Could you please post a pic showing what you are talking about?
Ray

I mis-spoke. It's not the drums I'm referring to, but the backing plate is usually attached by 4 bolts to a flange. That flange is used for calipers in disc upgrade kits. It looks like my backing plate is pressed on instead on bolted on. Any ideas?

[lotus]

my six lug axles are shorter than the summit 5 lug axles that I bought.
The summit ones i bought are for 70-81 and are 31.312 inches in length.

sounds like the axles are for late 70 and my 12 bolt is early 70. Is it possible to get late 70 axles to work with early 70 rear?

[raycow]

Originally Posted by lotus

Is it possible to get late 70 axles to work with early 70 rear?

It's possible, but risky. Lay one old and one new shaft side by side with the inner ends lined up. Now look at the bearing wear mark on the old shaft. Will it fall completely onto the machined area of the new shaft? If not, don't use the shafts. If it does, make spacers to move the backing plates out to meet the drums.

Ray

[bubba327]

You can always have your favorite machine shop re-drill the old axles for 5 lug. I think they have to weld one hole up if I recall.

[Captainfab]

I wouldn't try and 'make them work'

I would suggest contacting Summit and see if they will exchange them for you. If not you should be able to sell them to someone in need of a set of new axles. You could try listing them in the classifieds on the forum here if you were a supporting member.

[aerotruk63]

There's been a guy on ebay trying to sell NOS splined backing plates for the 63 differential. He has a kit which included the master cylinder.