Date: Sat, 22 Nov 2008 16:29:58 -0500
Reply-To: Mike <mbucchino@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike <mbucchino@CHARTER.NET>
Subject: Re: CV joints...condition?
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The discolored races and balls is a sign of overheating, due to inadequate
grease. This causes a loss of hardness and temper of the steel. As this
situation continues, it eventually causes the steel to become so brittle
that it might shatter like glass, upon a shock or sudden load.
If a CV breaks on you while driving, it usually lets go by the cage
breaking, allowing the balls to fall into the boot. This results in the
inner race spinning freely, but noisily inside the outer race. With a
normal differential, the power then automatically transfers to the wheel
with least resistance; this means that you're going nowhere. I had this
exact thing happen to me in a '73 Porsche 914, and an Audi 5000 turbo. In
both cases, I had to call AAA to tow it back home, where I fixed it myself.
This happens when you let the clutch out as you start out from a stop, or
while turning as you accelerate from a stop.
So, put the discolored, but otherwise un-pitted CV's back in temporary
service until you've got the money to buy rebuilt half-shafts or new
individual CV's. To be safe, don't plan to go on any trips longer than
you're willing to be towed home from, until they've been replaced.
----- Original Message -----
From: "Scott Daniel - Turbovans" <scottdaniel@TURBOVANS.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, November 22, 2008 2:38 PM
Subject: Re: CV joints...condition?
> HI Don,
> Sounds like you're on the right track. Assuming the idea is to stretch out
> the life of the good CV joints and your money .............your idea of
> replacing the two really bad ones and lubing up the remaining 2 'not
> totally
> shot' ones is a fine idea.
>
> Given that they don't fail totally and catastrophically...........re-using
> decent used ones is fine with me. If I have any concern for a big trip, I
> just carry one spare CV joint. They're not that hard to change. I also
> upgrade to the 12 point screws often. They normal 6 mm allen screws strip
> out quite easily. I also use a cold chisel and a hammer to unscrew the
> stripped out ones - not that hard to do at all. Though, I havn't seen
> many
> long cold chisels like the one I use on stripped out outer CV joint
> screws.
> A normal short cold chisel is perfect for the inners, when needed.
>
> I've seen the 'really running thin grease' syncdrom on a few CV joints. I
> believe it's possible that gear oil could find it's way into the CV
> joint -
> that might be an explanation. Or perhaps cheap grease was put in there
> eons
> ago. I use 'black slimey' moly grease on all my CV joints. I put a fair
> amount in there too............
> I don't exactly jam pack the boot, but I put a generous amount of grease
> in
> there, and in the 'cup' of the flange the joint bolts too. When I screw
> them down some extra grease always squeezes out. I've seen quite a few
> dry
> CV joints too, almost like the grease evaoporates, or people just didn't
> put
> enough in.
>
> If you look at the innner part where the balls push, you can see that they
> wear on one side, and not the other. That means if we install it so it's
> being driven the other way ..........we can get the balls to push on a new
> surface, thus extending teh life of that particular joint. I always mark
> my axles for which side they were on and which direction is 'forward
> turning' before removing them- to keep track of which joints were innor or
> outer, and which way they were driving.
>
> Why they're made like they are ?
> - seems like a pretty clever and obvious device to me. A CV joint not
> only
> provides the 'universal joint' affect - transfering drive of a rotating
> shaft through an angle, and one that varies too...........but there is
> also
> length compliance. And of course..............with the rear wheel going
> up
> and down on bumps............there has to be a provision for length change
> in the axle. On earlier designs.......like the rear of a Jaguar, where
> they
> used conventional cross type J-joints........the axle was in two sections
> joined by a sliding coupling arrangement, to account for length change.
> The
> CV joints take care of that by themselves - quite elegant actually.
> Scott
> turbovans
>
> ----- Original Message -----
> From: "Don Hanson" <dhanson@GORGE.NET>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Saturday, November 22, 2008 11:00 AM
> Subject: CV joints...condition?
>
>
>> Finally dove into the task of checking, servicing and possibly replacing
>> the
>> CV joints on my 84 manual 5-sp tranny. Been putting it off because I was
>> just sure I would strip out a couple of the allen head bolts. About 2
>> wks
>> ago, I began 'basting' the bolts with Liquid Wrench and surprise, they
>> all
>> came out without a hitch.
>> The joints were varied as to the condition and since I've not done this
>> task before, what am I looking for/at? I've read the write-ups online.
>> Two CVs on the drivers side axle are obviously shot, for sure. They had
>> chunks out of the bearing races, a couple of the bearings are badly
>> pitted
>> and the one at the wheel end, that one had almost 'liquid' grease, unlike
>> all the others. The others, the grease was really dry..about the
>> consistency of fudge brownies. But that one, the grease actually dripped
>> out..What's up with that? I can't see how anything could be getting in
>> to
>> dilute the grease..
>> The ones on the other axle: One was pretty nice..dry but fine looking.
>> The other has some discoloration of the bearings but no pitting of any of
>> the races...just looks like it's been hot..4 of 6 of the bearings are
>> kinda
>> brown/blue not shiny silver, but they are smooth and undamaged..Should I
>> expect this one to fail soon, or can I just replace it next time..I plan
>> on
>> servicing these yearly now (about 20k miles of driving for me).
>> So, I am doing two of these for sure..the ones with the pitting and
>> galling of the races. One looks as new almost, and one has some evidence
>> of
>> the bearings taking some heat...I'd like to defer replacement on that
>> side,
>> if I can get away with it. Yes? No?
>> Odd critters, the CV joints. I can usually look at a mechanical device
>> and deduce why it is made like it is, etc etc. Not the CV joint...It
>> seems
>> a bit arbitrary, why things are shaped as they are and how it fits
>> together...Not that I 'studied' it or anything..
>> Don Hanson
>>
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