C-3 Axle Half-Shafts

[David W.]

I am completely rebuilding the rear suspension on my C-3 (1980) and have all removed except the differential.
The half-shafts are out and I know which one was on the right and which was on the left but did not mark them as to which end was attached to the differential or which to the wheel.
Is there a difference? I am replacing all u-joints and possibly the differential side yokes and having the wheel bearing assemblies rebuilt along with the trailing arms.

Thanks, David

[Michael W.]

Re: C-3 Axle Half-Shafts

Makes no difference which goes where.

[David W.]

Re: C-3 Axle Half-Shafts

Thanks Michael. Is there any difference between right and left? And do you have any idea the bolt head size for the u-joint flanges? I have tried everything to get the drive shaft (propeller shaft) bolts out of the flanges and nothing fits.

Regards, David

[Jack H.]

Re: C-3 Axle Half-Shafts

Only one PN for half shafts (different PN's depending on year and configuration of car), meaning there was no distinction between RH and LH side...

[Michael W.]

Re: C-3 Axle Half-Shafts

Thanks Michael. Is there any difference between right and left? And do you have any idea the bolt head size for the u-joint flanges? I have tried everything to get the drive shaft (propeller shaft) bolts out of the flanges and nothing fits.

Regards, David

No difference left, right- same same. I believe the bolts might be a metric size.

[David W.]

Re: C-3 Axle Half-Shafts

Thanks for the replies. I have tried both metric and standard on the propellor u-joint straps. Nothing works. They appear to be rounded off some. I am just going to leave them in place and drop the rear end.

Regards, David

[Joe L.]

Re: C-3 Axle Half-Shafts

Thanks for the replies. I have tried both metric and standard on the propellor u-joint straps. Nothing works. They appear to be rounded off some. I am just going to leave them in place and drop the rear end.

Regards, David

David-----

First of all, as far as I know, no u-joint FLANGES, per se, either inner or outer, were used for 1980-82. Both inner and outer half-shaft u-joints used STRAPS with bolts for retention. Also, you don't mention if the car is an automatic or manual transmission and it makes a difference in this case.

If the car is an automatic transmission, the u-joint strap bolts were originally GM #14023500. These are a special bolt but of standard SAE thread size of 1/4-20 X 5/8". I don't know what the across-the-flats (i.e wrench) size was for these bolts but I'm almost certain it was a standard US size. The standard size would have been 7/16", but these may have been a size or two larger (i.e. 1/2" or 9/16"). These bolts are no longer available but a replacement is available under GM #12338087.

If the car is a manual transmission, then different straps and bolts were used. The bolts were GM #458300 and were of size 5/16-24 X 3/4". They remain available from GM to this very day.

By the way, although the half shafts are the same for either side, for 1980 they are different for manual and automatic transmission-equipped cars.

[David W.]

Re: C-3 Axle Half-Shafts

Joe,

Thanks for the reply. Sorry about using the wrong terminology. They are straps and this is for the prop shaft. The car is a 4-speed. I assumed they were the 5/16th but they are not...smaller. No metric fits them. Everything is too small or too big. I guess they began life as the 5/16th bolts but have had the heads rounded off.

Regards, David

[Joe L.]

Re: C-3 Axle Half-Shafts

Joe,

Thanks for the reply. Sorry about using the wrong terminology. They are straps and this is for the prop shaft. The car is a 4-speed. I assumed they were the 5/16th but they are not...smaller. No metric fits them. Everything is too small or too big. I guess they began life as the 5/16th bolts but have had the heads rounded off.

Regards, David

David----


Are you talking about the u-bolt straps and bolts for the DRIVESHAFT or for the HALF-SHAFTS? You use the term "Half-Shafts" in your thread title, but in the post you refer to "prop shaft". The later usually refers to "propeller shaft" which is another term used for the drive shaft and not half-shafts.

In any event, depending upon whether automatic or manual, the same bolts are used for the driveshaft u-joint straps as are used for the half shaft u-joint straps. So, you require the 458300 for all u-joint strap bolts, both half shaft or driveshaft.

I think your problem is bolts with damaged heads and not an "oddball" head size.