Date: Thu, 13 Jan 2000 10:29:08 EST
Reply-To: JKrevnov@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rico Sapolich <JKrevnov@AOL.COM>
Subject: Re: Syncro U-joints/More than You Want to Know
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In a message dated 1/13/00 4:24:31 AM, vw4x4@FYI.NET writes:
<< Most are unsucsessful with these. >>
Eric:
I have been reluctant to enter the fray regarding Syncro u-joint replacement
because I replaced mine only about 1Kmi ago. Pour a cup of coffee because
this is going to be long.
I started to get a drivetrain vibration which got progressively worse. I, of
course, checked the u-joints and cv's first. Everything appeared OK.
Although it has never happened to me, I was hoping it was just a thrown wheel
weight. In an attempt to isolate the problem, I decided to remove the
driveshaft. By this time the u-joint had worn so much that its condition was
obvious without removing the driveshaft. So much for checking the u-joints
in situ.
Looking at the u-joints, I could not understand all the fuss on the list
about replacing them. I started to realize that something was hinky here
when I could not find replacements at the usual sources. I did an archive
search and turned up some aftermarket P/N's and dimensions. I also turned up
a posting describing the trails and tribulations of replacing them. This
fellow said that after a few thousand miles his vibration was returning.
I called Sendell VW in Greensburg, PA and they said they have the u-joints in
stock. Unfortunately, the parts guy had not heard the "center" when I asked
for driveshaft u--joints so, he assumed I wanted CV joints. After several
calls, they were unable to turn up u-joints or a remanufactured drive shaft.
I did locate a used shaft but, I decided not to deal with that unknown
quantity and just install new u-joints.
Armed with the dimensions (27mmX70mm) from the P/N I had found, I crawled
under the van with a mike and a vernier caliper. The cup bore proved to be
correct @ 27mm. The cross trunnion, cup-to-cup dimension was .006" shy of
70mm, measuring @ 2.750" right on the nuts. I figured that's close enough
for a guy wearing bifocals and working in fading light.
I ordered Neapco, P/N 1-0321 u-joints from a local driveshaft fabricator. He
said they would be of USA manufacture. He was wrong; they are made in Italy
and branded by Neapco. I asked him about installing the u-joints and
balancing the driveshaft and he said that balancing would not be needed if I
was just replacing u-joints. Anyway, he did not have the right flanges to
balance the Syncro driveshaft.
When I compared the Neapco's to the original part, I found the Neapco cross
trunnion measurment to be about .008" greater. Also, the new retaining
rings supplied were much thinner than the originals. Summing the differences
in the make up dimension showed that the fit would be about .016" loose. I
returned to the driveshaft specialist seeking thicker circlips. When I told
him that the fit was about .016 loose, he said not to worry about it because
the bottom of the cup has to have some room for grease. That didn't sound
right to me, still, I seated the first 2 cups. That is when it really did
not seem right with that 1/64th inch of side-to-side play.
I then called Neapco. They did not have an application listing for the
Syncro either. They did tell me that the fit for that u-joint should be
.002" tight to .0035" loose with a mean of .0015" loose. Now, that was more
like it. I tried to find thicker retaining rings so that I could dress them
to the required dimension. Since none of my regular vendors had them on hand
and I did not want to wait any longer ( this was taking too long as it was),
I decided to use shims.
One curious thing, one trunnion required .016" of shims while the other, on
the same joint took .020". I wish I had saved the old circlips so that I
could see if they were selected to provide for the variations in fit up. I
did not have any shimstock in .0005 increments so, I left one trunnion .001"
loose.
And finally! All I can say is so far so good. I have one question for all
who have bothered to read this: WHY THE HELL DOES VW NOT SELL THE RIGHT
U-JOINT??
Richard
