Re: Rear driveshaft joint

[Eddi Jew <jew@rysa.dtc.hp.com>]

 > I recently had to replace the front CV joint in my 87 CSTQ.  The mechanic 
 > said that the CV joint should be lubed every 50-60k miles, but the dealers 
 > and most shops never do.

If the boot's sealing has not been compromised, it shouldn't be (practically)
necessary. Does the grease thin out that badly? My boots rip (and junk got
in) before I get a chance to see.

 > If properly lubed, the CV joints should last almost inndefinitely, or so 
 > he claimed.  

Trade off the cost of normal wear (finite life) over the cost of the labor
for a few "re-lubes", which, to do right (i.e, make them last "almost 
inndefinitely"), means to remove joint, degrease, repack, reseal boot. 
Another tradeoff is the small risk in weakening the boot, causing it to 
not seal when you least expect. The labor on that would be high.

 > Note that the CV joints are not available as a replacement part--Audi 
 > only sells the whole shaft as a unit.  

Maybe not the dealer, but Lobro joints can be bought at most parts places
(see the vendor list in the archives).

 > My "new" one came from another car.

Rebuilders of complete half-shaft assemblies are also common. Reason is the 
cost of labor (at the mechanic) of replacing a joint, versus the (lower) cost 
of a centralized rebuilding factory doing complete units. Then the mechanic 
can offer a total lower cost (parts plus labor) to you at (a percieved) better
value. BTW, The factory (or was it Lobro) does not endorse rebuilding CVs.
And I'm sure there's differences in quality between rebuilders.

I think a better way to go is check the boots regularly, inspect/repack when 
it tears and replace boots with *good* (original) ones. When the joints 
finally die, get the best parts *and* labor guarantee on a rebuilt one, 
or do it yourself and choose your own price/reliability/time tradeoff of 
parts and approach.

As far as the economics of planned obsolecence (or design lifetime), it's
not as good as the old 'merican rear axles, but I think the net tradeoff
of having CVs is a positive one. But I do miss the tight turning circle 
of my previous Volvo 142 :) . But I don't have to fight for parking space
in Chinatown (S.F.) anymore, either.

-- Eddi

 > John Winkelman