[T3] Axle Beam

Jim Adney jadney at vwtype3.org
Thu Jul 14 20:45:05 PDT 2011


On 14 Jul 2011 at 21:43, Gary Forsmo wrote:

> A technician "rocked" the tire/wheel by grabbing the top and bottom as we
> watched the movement of the ball joint.  Then he "rocked" the tire/wheel by
> grabbing the front and rear as we watched the "play" in the upper ball
> joint, again.  We decided the bolt in the ball joint needed to be
> tightened.  That done; another test drive and the "shimmy" was all but gone.

Would that be the pinch bolt that clamps down on the ball joint stem? 
I've never seen one of those come loose, but I suppose it's possible. 
If so, I'd be concerned that the movement there might have damaged 
the clamping surfaces so that things could never be tight again.

But now I'm wondering if we're looking at the completely wrong thing. 
The upper torsion bar is one continuous bar, actually a sway bar, 
which connects one upper torsion arm to the other. If either arm gets 
loose on that bar, the front end can develop play like what you 
describe, and that play will be worst at some resonant 
frequency/speed. The problem can appear to go away if the tires are 
very well balanced, but the looseness should be fixed quickly or else 
the parts will wear each other out and become junk.  

The test for this is to have someone grab the top of one front tire 
while you get under the front end and watch where the upper torsion 
arm exits the beam. While he yanks the top of the tire hard, side to 
side, you should see little or no movement of the torsion arm in and 
out of the beam. Small amounts of play can be due to wear and can be 
adjusted, but if one side has come loose (usually the left) you 
should pull that torsion bar out and repair the set screw divot on 
the left side.  

This can be done without disassembling much. Just put the front end 
up on jack stands, take both front wheels off, remove the fixing 
screws on both sides, and drive the bar out to the left. Then you can 
inspect the divot, repair it if necessary, and reinstall it.

Beetle front beams are NOT like this, and I don't know about bus 
beams. Your bus mechanic may not have any idea of how the Type 3 beam 
works inside. Most VW mechanics don't.

Checking for this problem takes a few minutes, Fixing would probably 
take you and me a couple hours. If this is your problem, it's VERY 
important to fix it quickly.  

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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