70 Drive Axles - Trial and Error

[Stephen L.]

not sure why we have to learn from mistakes...why can't we learn from successes? - anyway, i decided to teach myself how to use an arbor press this weekend to press out the trunion bearings on both drive alxles - in the process, i bent almost in half the "flange plate" (?) - the part that attaches to the other end of the drive axle and connects it with the wheel - the other one escaped my buthchery - the living part is "GM30A; 3843018" - I imagine that the dead part is GM30B - does anyone know which is the left and which is the right...i looked in the AIM but could not find this part even called out (was looking at UPC4A2 - it is where part "2" bolts (x4) go through).

As a separate question, from an NCRS judging perspective, is that a part that is judged? - given that I have one original, is it worth trying to find the other? - or are these considered "wear" items? - as for the half shafts (drive axles) themselves, one has a pretty good chunk (not from me!) our of the top portion where the retaining clip for one trunion bearing is - they are generally beat up and a little rough where the trunions are (PICTURES HERE http://s65.photobucket.com/albums/h2...0Half%20Shaft/) - again, are these items that are reproduced - the half shafts that is? - or should I make every effort to rehabilitate them? - thanks in advance for any advice, stephen

[Michael G.]

Re: 70 Drive Axles - Trial and Error

Stephen,
I have read several posts on the ease of destuction to these items. T he archives will have some info on how they should be pressed using some sort of support jig. I opted to purchase a pair of rebuilt half shafts from C Central. The axles are turned to a nice new raw steel finish, (no extrusion markings though) and have new uni-joints installed with the spindle flange installed. I am not qualified to give you any of the points issues. Others will be able to assist you there. I did notice that the spindle flange is a bit beefier than my original, but there is no core charge or need to give them yours so I can swap them when I feel confident enough to avoid the situation you (and others) have experienced. Good luck, Mike

[Chuck S.]

Re: 70 Drive Axles - Trial and Error

Stephen, I can't imagine why you are even thinking about trying to do the real wheel bearings yourself...pretty audacious. I wouldn't even consider doing this task myself. If you think you've screwed up so far, you have not begun to screw up...you must have special tools and knowledge to set up the clearances on those rear wheel bearings just so, or pfffft.

There are people who do nothing but restore rear control arms...I don't have to "learn by doing" by reinventing the control arm restoration wheel. It may be something I want to accomplish in my life at some point like getting a graduate degree, but so far I haven't felt the need to learn rear wheel bearing setup.

As I've told you before...send them out to Bair's Corvettes; it'll be cheaper in the long run, I gah-rahn-tee.

[Joe L.]

Re: 70 Drive Axles - Trial and Error

not sure why we have to learn from mistakes...why can't we learn from successes? - anyway, i decided to teach myself how to use an arbor press this weekend to press out the trunion bearings on both drive alxles - in the process, i bent almost in half the "flange plate" (?) - the part that attaches to the other end of the drive axle and connects it with the wheel - the other one escaped my buthchery - the living part is "GM30A; 3843018" - I imagine that the dead part is GM30B - does anyone know which is the left and which is the right...i looked in the AIM but could not find this part even called out (was looking at UPC4A2 - it is where part "2" bolts (x4) go through).

As a separate question, from an NCRS judging perspective, is that a part that is judged? - given that I have one original, is it worth trying to find the other? - or are these considered "wear" items? - as for the half shafts (drive axles) themselves, one has a pretty good chunk (not from me!) our of the top portion where the retaining clip for one trunion bearing is - they are generally beat up and a little rough where the trunions are (PICTURES HERE http://s65.photobucket.com/albums/h2...0Half%20Shaft/) - again, are these items that are reproduced - the half shafts that is? - or should I make every effort to rehabilitate them? - thanks in advance for any advice, stephen

Stephen-----


I have warned folks time-and-time-again about the folly of trying to replace half shaft u-joints. They are MUCH more difficult than drive shaft u-joints. The exact problem you've encountered, distorting the u-joint flange, is what VERY frequently occurs when the un-initiated try to replace half shaft u-joints. I always recommend taking these to a driveline service shop and having them replace them. The cost is usually not even that high for this service.

If one does try to replace the half shaft u-joints, then the u-joint flange MUST be supported while pressing is being done. This means you have to use a special fixture or an old spindle flange.

If you've bent the flange, I recommend replacing it. The flanges are still available. However, they are configured slightly different than the 64-74 flanges. They are 100% functional, though. Otherwise, you can purchase used originals from sources like Ikerds or Bairs. Are they judged? I don't know.

Your half shaft is ok. The "irregular" INNER edge of the yokes is pretty common; I think many were made this way. The small "chunk" in the outer surface should cause no problems as long as it's not associated with a crack.

[Stephen L.]

Re: 70 Drive Axles - Trial and Error

thanks guys - chuck, i should 'a listened - anyway, it seems that i escaped with just the flange plate going to the graveyard - i'll give bair's or c central - thanks again! - sl

[Stephen L.]

Re: 70 Drive Axles - Trial and Error

p.s. is the one i trashed...GM30B...the left or the right? - thanks again!

[Joe L.]

Re: 70 Drive Axles - Trial and Error

p.s. is the one i trashed...GM30B...the left or the right? - thanks again!

Stephen-----


There is no left or right for these u-joint flanges; the same part is used for both sides. The "GM30B" is a forging die number; it has no real significance.

[Stephen L.]

Re: 70 Drive Axles - Trial and Error

thx Joe!......

[Alan S.]

Re: 70 Drive Axles - Trial and Error

Hi Stephen,
I understand your tale sooo well. My best lessons involve either $$$ or blood, or BOTH. Carry On!!!
Regards,
Alan

PS: When you have the body on a high dolly so you can work under it sitting on a 'seat creeper', the clips for the trans tunnel insulation put the most unbelievable gashes in your scalp. TWICE!!!!

[Stephen L.]

Re: 70 Drive Axles - Trial and Error

thanks alan...feeling like a chump at the moment...appreciate the encouragement!

[Chuck S.]

Re: 70 Drive Axles - Trial and Error

thanks alan...feeling like a chump at the moment...appreciate the encouragement!

Aw, don't be too hard on yourself...we'll be hard on you. Only kidding you...all of us have a tale like yours.

I misread your post...you were doing u-joints. Not quite as many wrenches difficulty as the wheel bearings but still tricky. There may be local shops that can do the u-joints for you, but I'm not sure how available original GM flanges are. I assume you are talking about the spindle flange. Local shops may have a generic replacement that looks exactly the same, or it may be different. No judge is going to be looking for GM part numbers on that flange...I'm pretty sure of that.

If you can't find the flange anywhere else, Bairs also has had a pretty good stock of used original parts.

[Stephen L.]

Re: 70 Drive Axles - Trial and Error

i think it is called the spindle flange...i'll track one down...perhaps this is a common syndrome, that you don't mind replacing something that already is missing or came broken...but you absolutely hate killing a part of the car yourself!

[Joe L.]

Re: 70 Drive Axles - Trial and Error

i think it is called the spindle flange...i'll track one down...perhaps this is a common syndrome, that you don't mind replacing something that already is missing or came broken...but you absolutely hate killing a part of the car yourself!

Stephen-----


It's called the U-JOINT FLANGE. The SPINDLE FLANGE is the part that has splines and fits on the end of the spindle and is retained by a slotted nut. On the car, the u-joint flange and the spindle flange are bolted together with four 7/16-20 bolts.

The original U-JOINT FLANGE used for 1964-74 Corvettes was GM PART #3843018. The 75-79 flange is GM #360913. The latter part also services 63-74. It's still available from GM (for about 150 bucks, GM list). However, as I mentioned previously, it's configured a bit differently than the 64-74 piece.

[Wayne W.]

Re: 70 Drive Axles - Trial and Error

Wait till he trys to press them back on. Probably mess the others up. Hint: Take the flange off of the spindle. Bolt it to the axle flange and then do it.

[Stephen L.]

Re: 70 Drive Axles - Trial and Error

Joe/Wayne - thanks!