CV Experts, why not flip a CV joint?

Gunter · Gunter's Garage

Upon inspection, I found slight wear marks to one side. Without changing anything else, why can the CV joint be flipped in place so that the other side of the grooves get a fresh seat for the balls? I cleaned the old joint completely, removed the circlip, reversed the joint, re-attached the circlip and checked movement. It feels good and I cannot see any reason why this can't be done. Any comments, please?

350HP930 · 06-22-2003, 04:36 PM

I have never heard of a reason why you can't do so when possible.

Al S · 06-22-2003, 07:03 PM

Gunter, I've done this on a Saab I used to own, never had a problem.

Geary · 06-23-2003, 07:24 AM

Flipping the CV does absolutely nothing. You must switch it to the other side of the car.

Gunter · Gunter's Garage

Geary, think a little harder, flipping the joint in place will change the direction of rotation. You now have the balls seated against a new side in the groves. Because the half shafts receive torque in one direction, the intent is to leave them in place and only either flip each joint in situ, or exchange the inside/outside joint with the grove still facing the respective flanges. By not reversing the shafts, they will still get the torque from the same direction and not risk a snap. Thanks Al, more thinkers please. BTW, my 8mm Allen bolts had no washers or plates. I will install Schnorr washers.

Rot 911 · 06-23-2003, 08:06 AM

If you did it and aren't hearing any rumbling I don't see why it wouldn't work although I'm not sure that the bearings are completely true and that you can expect significant life out of them.

RoninLB · 06-23-2003, 08:10 AM

I flip my CV direction when I'm under there.. I try to do it every 15k miles............Ron

island911 · 06-23-2003, 08:34 AM

When you say "flip" what do you mean?

You can flip the inner "race" (clock it ~60°) and the re-assembled CV will have the balls riding on some new surface.

If you're just flipping the whole unit, your not buying much.
(think: accel - deccel forces. . . wearing on the same spots)

Gunter · Gunter's Garage

Ron: Please, explain exactly what you mean by "flipping CV direction"? Exchanging axels from left to right? Or turning the axel in place so that the outer CV now becomes the inner? (Which means that the torque on that shaft is reversed)
Island: The acceleration force is much bigger then deceleration. If you only flip the inner part, the outer "race" will still have the old wear spots. Please, think again. One way: I believe that changing the outer joint to the inside, and vice versa, will give the balls a fresh seat. Another way: Flip the whole joint in place. Both ways will not change the axel rotation and avoid torque issues. By looking at the half shaft now in a vice, I can see that the wear pattern is off center on each joint which means that by flipping, or exchanging, a new position for the balls is obtained. BTW, I did not find any roll pins in the joints. Where are they supposed to be? And what is their function? Thanks.

RoninLB · 06-23-2003, 09:59 AM

Quote:

Originally posted by Gunter

Ron: Please, explain exactly what you mean by "flipping CV direction"? Exchanging axels from left to right? Or turning the axel in place so that the outer CV now becomes the inner? (Which means that the torque on that shaft is reversed)

my understanding is that the right side CVs gets the most torque load on acceleration.. the right tire should wear quicker than the left [all variables equal].. so I do the right to left flip and reverse CV rotation..........Ron

jmohn · jmohn's Garage

"Flip" it any direction you want; it won't hurt anything, but it also won't repair a damaged joint; once the material is gone ... it's gone. Will the joint last longer if reversed? Maybe, I've never seen any documented test, just lots of anecdotes and opinions. The ones I've disassembled that were worn or scuffed I replaced, I had no wish to remove them again until necessary (50K maintenance).

Good luck,

Jerry M
'78 SC

Geary · 06-23-2003, 12:30 PM

Quote:

Originally posted by Gunter
Geary, think a little harder, flipping the joint in place will change the direction of rotation. You now have the balls seated against a new side in the groves.

No it won't. You have to move the CV to the other side.

Geary · 06-23-2003, 01:32 PM

OK, OK --- I out-thunk myself. You're absolutely correct.

RoninLB · 06-24-2003, 09:19 PM

Quote:

Originally posted by island911

When you say "flip" what do you mean?

I looked for some hard info on the left/right act. didn't find it.. but I do remember reading it somewhere..

and I recently changed a new torn boot.. the CV grease I used, on new CVs, felt and smelled like brand new.. that's after 20k of constant average 70mph/ no street... mountains and desert heat included... so if your not happy with the routine good stuff.. I got a wild option....................Ron

Porsche_monkey · 06-25-2003, 03:36 AM

Just be prepared for clicking when your in reverse. Standard 'worn out car' practice where I live.

Gunter · Gunter's Garage

I have to make it clear that this is no fix for worn out CV's. The intent is to extend the life of a joint with minimal wear. After some close inspection, and serious thinking, I believe that exchanging the outer CV to the inside, and the inside CV to the outside, without flipping, is the way to go. The half shaft will still have the same direction of rotation to avoid reversing torque. The CV on the transmission, which is the "driver", is now on the wheel side to become the "driven". The balls on both CV's will have a fresh area in the grooves. I'll proceed on the above and will post a follow-up. In time, If I need new ones, PP has them. I have standard 8mm 6-point Allen bolts without plates. How do these "half moon" plates function?

1980SC · 06-25-2003, 07:27 AM

Quote:

I have standard 8mm 6-point Allen bolts without plates. How do these "half moon" plates function?

My '80 is the same way. Just 8mm 6-point allen bolts. Nothing else. I too would like to hear about those "half moon" plates. I assume mine were lost at some point.

Rob
1980sc

Porsche_monkey · 06-25-2003, 07:32 AM

Aren't they just a washer under the bolt head? (It's six months since I did mine, but that's what I recall).

cmelecci · 06-25-2003, 09:21 AM

I believe you're correct in finding a new surface for the balls to contact but this is only under load. Backlash will remain during shifting and stopping. Also check the balls for signs of wear, pits, cracks, from heat. As you mentioned this would be performed to place even wear on a existing good joint, extending it's life.
Thanx, just my thoughts
Carl

throttlemaster · 01-14-2022, 05:08 AM

Quote:

Originally Posted by 1980SC

My '80 is the same way. Just 8mm 6-point allen bolts. Nothing else. I too would like to hear about those "half moon" plates. I assume mine were lost at some point.

Rob
1980sc

Hi,
The 1980 911sc uses original Cv boots that have much thicker flanges than the cheaper aftermarket boots so they don’t need washers or the half moon plates like a VW beetle has.
I recommend using original boots as the thick lockdown plate may add some rigidity to the cv
Joint casing. They are $110 each compared to the aftermarket $28, but by going cheap you
Need to either get 5mm shorter bolts or rhube Goldberg spacer washers or gypsy lockdown half moons , and still offer less bracing strength to the joint housing- I saved you shipping- had to see the parts and send them back, but I needed to see before the lightbulb lit in my head…(I have a 1980 911sc)