Drive shaft bolt finish and balancing

[Steve L.]

This is the set of bolts at the diff and at the tranny. This is for a manual, small block.

Also, the AIM has a note that there is a paint alignement mark at the diff. driveshaft universal, but it doesn't say what to do with this alignment mark.

Also, when taking in the driveshaft for balancing, do you attach the diff yoke to the driveshaft or just tape up the universal bearings and leave the yoke on the diff. Taking off the yoke off the diff. again is a pain.

This is for a 73

[Edward J.]

Re: Drive shaft bolt finish and balancing

Steve, the bolts on my 72 were black phosphate, and if you are taking your driveshaft in for balancing you just take the driveshaft itself. thats all they require. I would add that if you don't have any driveline vibrations I would not bother generally the driveshaft companys like to re-tube and replaced u-joints then re-balance, and then you will more likely end up with problems.my advice would be to replaced the u-joints and call it a day, the alignment marks from the factory maybe long gone so install the driveshaft and road test at highway speeds if all is good then make your own marks on the didd. flange and driveshaft.

[Larry M.]

Re: Drive shaft bolt finish and balancing

Steve:

I agree with Ed. Unless you have KNOWN issues, just replace the u-joints, paint/refinish, and install. Then see how your car drives.

The driveshaft is balanced with the front (transmission) yoke, but not the differential (rear) yoke.

I had my driveshaft balanced by an OLD driveline shop in Slidell, Louisiana. They were simply to CHECK the balance, and only make changes if needed, and after discussing with me. My driver car quit running just as I pulled up to the shop, so I had to concentrate on it and not the Corvette driveshaft.

End result is they removed one of the factory weights and added their own weight(s) which doesn't look anything like factory. Their weight(s) were only VERY SLIGHTLY different in weight than the original, so I don't think they helped/improved the balance very much. The driveshaft balance machine also destroyed a part of my driveshaft finish, and required that I re-do the finish again after balancing. Car drives nicely now, but probably would have driven nicely without all this work and hassle.

FWIW.

Larry

[Richard G.]

Re: Drive shaft bolt finish and balancing

The front yolk is needed because it is use to drive the driveline during the balancing process. Likely the finish damage was from the rear supports used on the other end. Different styles are used but think of something like a lathe steady rest.

Personnel I have had nothing but bad luck with the local balance shop. Kocked off the factory balance weighs and they asked if I wanted it balanced! In another instance (not Corvette) they only wanted the center of differential yolk to the rear seal in the transmission to make a driveline. Then manufactured the driveline with the yolk centered. This was a THM 400 with an "O" ring on the output shaft of the transmission and a special yolk on the driveline. This yolk is smooth for the first three inches or so then the splines start. End result was the driveline was to short and the transmission leaked only sometimes. The "O" ring held when the vehicle was not moving and leaked as the "O" ring pulled from the end of the tube while driving. In reality the driveline was 1.5 inches too short. Then they wanted me to pay for their mistake. (by the inch). One would think they would have known this as they have been in business for years.
If I can't watch them they are not touching anything of mine. BTW they are the only game in town.
Rick

[Steve L.]

Re: Drive shaft bolt finish and balancing

Thanks, I'll try it without balancing. It's not that hard getting it out if I need to balance.