CV swapping

[Billy Mitchell]

A friend of mine suggested that, since the CV half-shafts on most Subarus
are of equal length, that you can swap them over, left for right,
effectively doubling their life.

Anyone heard of this? I'd like to do it to my '98 Forester as it's just
started making that clunking sound when the steering wheel's cranked all the
way.

thanks
billy

 

[Jim Stewart]

A friend of mine suggested that, since the CV half-shafts on most Subarus
are of equal length, that you can swap them over, left for right,
effectively doubling their life.

Anyone heard of this? I'd like to do it to my '98 Forester as it's just
started making that clunking sound when the steering wheel's cranked all the
way.

You've lost me. I would assume that if you take
out a worn-out left half-shaft and put it on the
right, it would still be worn out. Where am I wrong?

 

[ed]

CVs on shafts usually wear out due to torn boots, allowing grit getting
inside. Although there is more force in the drive direction than in the
coast direction, meaning in theory axle shaft life would be longer if
swapped at regular intervals, (although I doubt double), unless you do it
yourself, the labour cost would far oupace any saving on a rebuilt shaft. In
your case, if it's already noisy, it's too late to switch it over, the wear
is already there.
Ed B.

 

[John]

Agreed on all points:

1. You need to do this before there is a problem
2. If you're not doing yourself, you've wasted money on the 2nd
installation.
3. If you're doing yourself, you've wasted your own time on the 2nd
install.

 

[Billy Mitchell]

99% of the wear is on the front side (how long do you spend in reverse?) of
the joint. When you invert them, you basically present fresh, unworn faces
(the worn sides now being on the backside). It took me a minute to visualize
it as well.

Unfortunately, the fellow who presented this idea passed away earlier this
year..

billy

 

[Billy Mitchell]

Good points.

I admit I haven't been checking the boots personally, but the extended
warrantee just ran out and we had been pretty careful about regular dealer
maintenance. It's got 170,000 Km on it now and the clutch has just gone. I
figured, while they're in there maybe swap the shafts, but maybe I'll just
get them replaced.

Thanks for your input!
billy
www.blixner.com

 

[Jim Stewart]

99% of the wear is on the front side (how long do you spend in reverse?) of
the joint. When you invert them, you basically present fresh, unworn faces
(the worn sides now being on the backside). It took me a minute to visualize
it as well.

I understand that. The problem is that you now have
a loose joint and that has to have it's own set of
problems. If I had to guess, turning it around would
probably make things worse because at least the two
old surfaces have "worn in" so to speak.

I guess if you want to risk a day with the car up
on jackstands getting your hands really dirty, it's
a free country. As for me, I'd buy new ones.

BTW, I've driven 250k-300k miles on cars with CV
joints and I've never had to change one. Replaced
a couple boots though.

 

[Ian Firth]

99% of the wear is on the front side (how long do you spend in reverse?) of
the joint. When you invert them, you basically present fresh, unworn faces
(the worn sides now being on the backside). It took me a minute to visualize
it as well.

Basing this on experience with CV joints on 4WD SUV's that I have
replaced, the wear is even on all surfaces of the joints.

Half the time you are accelerating, half the time you are decelerating,
it wears everything pretty evenly.

 

[ed]

Yes, except coasting does not present the same pressure on the joint as does
the force of the motor on acceleration (unless you drive very gingerly)
Ed B.

 

[Ian Firth]

Yes, except coasting does not present the same pressure on the joint as does
the force of the motor on acceleration (unless you drive very gingerly)
Ed B.

Good point. The CV's in my Xterra are worn very evenly at the Rzeppa
joint and at the tripod joint, but it rarely sees the brakes in 4WD
since it's in low range and engine braking is all I need with a 4:1
transfer case.