CV Drive Shafts

Rod Dittmar

Supporter
Probable dumb question, but which way do the CV Drive Shafts go? Splined/Slip Joint end toward the transaxle or the wheel?
TIA, Rod
 

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Rod Dittmar

Supporter
Bill, thanks for the tip. Much appreciate all the help I get from you guys. Hoping to get some some adapters from RCR this week to attach these things to my ZF. So much to learn.....Rod
 
Bill, thanks for the tip. Much appreciate all the help I get from you guys. Hoping to get some some adapters from RCR this week to attach these things to my ZF. So much to learn.....Rod
My Driveshaft Shop axles didn't need any adapters to attach to the RBT. Yours might be different. Or my RBT may have come with the adapters you speak of.

axles.jpg
 

Phil G

Supporter
I thought the same thing. Rods axles look the same as mine..I don't see a need for adapters unless as you say Rods ZF is different.
Bryan, Glad to see your still checkin in.
 

Larry L.

Lifetime Supporter
Oops, sorry guys. I just found the answer after realizing BOTH ends have slip joints. I originally said it was probably a dumb question....Rod

If I had a nickel for every "dumb question" I've asked over the last 78 years, I'd be a multi-millionaire.
However, along the way I've learned that the only truly "dumb questions" were the ones I know I should have asked but didn't.
Those are the ones that can really cost ya. ;-)
 

Terry Oxandale

Skinny Man
Bill, how much end play should you look for? I’m getting ready to install the axles and this info would be helpful.

As with anything automotive, it's not that simple? If heim joints are utilized throughout the entire rear suspension, you can get pretty close because nothing is going to change outside of the suspension movement (and really small thermal expansions on the aluminum case/bearing retainer, axle?). Rubber or poly bushings would obviously require more clearance. I kept mine simple. I used axles with 3" long splines (common offroad aftermarket axle), and just allow the CVs to float. Have never had an issue with this, and clearance is about 1/2" (from the end of the axle, to the CV cup on the axle or trans). Also, remember that if you get them pretty close on clearance for street use, and then you want to track the car, and you increase the camber at the rear, and you do that with the upper lateral arm, it will decrease the CV clearance a little....depending on the geometry of the upright, and the amount of change between settings.
 

Rod Dittmar

Supporter
My problem is that the 'bump out' on the axle end is deeper than the recess in the ZF's output shaft. See pics attached. I think the 'adapter' I need is shown in the picture of Bryan's RBT. Waiting to hear back from RCR. Learning soooo much and still having fun!
Rod
 

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Markus

SPRF40
Lifetime Supporter
Hello Rod,

There are different drive flanges for the ZF.

- four bolt flange (what you have) > for matching cardan u-joint (standard on Panteras?)
https://precisionproformance.com/sc1010.php

- Three arm flange > flexible coupling > classic GT40
https://gelscoemotorsport.com/?page_id=123

- round CV-joint flange like on Bryan's picture > to take CV-Joints > most common on replica's

This are all I know of, there might be others and this only on transaxle side.... outside on upright is different story

Not sure if there are adapter's available!? If yes, then you need to check the length of drive shift again (staking up adapters would also be not ideal due to adding up potential imbalance of components and "shortening" length of drive shaft and with this increasing joint angle's)
Easiest, I think, is to replace the flanges to matching CV-Joint flanges....

Others?

Markus
 

Rod Dittmar

Supporter
Marcus,
Easiest? The only easy thing on this build so far is how easy it is to empty my wallet on it. Replace the flanges? How the heck do I do that? The only thing I know about a transaxle is that there are some gears, shafts, bearings and seals in there. This sounds complicated.
Rod
 

Bill Kearley

Supporter
I used a tape measure and wood dowel the same diameter as the axle.. Measure from the inside center of each end, ( trans to spindle drive flange ) The wood is easy to hold while moving the suspension up and down. I allowed about 1/4 inch float
 

Chris Kouba

Supporter
I am pretty sure that Dennis Quella at Pantera Performance makes the adapters you seek.

He also would be able to re-flange your trans, but that involves sending it to him and back. I got mine from him and spec'd the CV output flanges from the get-go.
 

Howard Jones

Supporter
Rod,

When your half shafts are new then it doesn't matter which side you install them on. But once you have used the car, the driveshafts are now "handed". If they are removed they should be re-installed back on the side they came from and in the same orientation. That is, the outboard end should remain on the outboard end as well as re-installing the cv joints back on the ends they came from if you disassemble the driveshaft completely. More to the point, the shafts themselves will take a twist in them and if they are reversed then they have a greater risk of failure due to metal fatigue.

I mark mine with red stripes at the outboard end around the shafts one on the left and two on the right, but any method will work.

Gary,

Porsche does not schedule the grease replacement up to 200000 miles as far as I can determine. This is as long as the boots are not torn or leaking grease. This would be on a road car. If I have my axles off the car for other work then will inspect the cv joints, clean out old grease and add new grease on the SLC track car. So far it never looked like it was overheated or worn out but then this would be at best about 400-600 miles of total track time. I have done the street gt40 once at about 15000 miles and it still looked good to go. I use Redline grease.

 
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