GTV6 Wheel bearing mods.

by Michael Harris

Parts Needed:

  • Mercedes Axle Nut
  • Extra axle spacer washer

 

John Pituch told me a while ago about a possible fix to resolve the GTV6 wheel bearing failure problem.
I have found that there is too much slack in the bearings, and this cannot be removed by tightening the nut one more 'notch' (at the next 'notch' the bearings are way too tight)
He suggested replacing the Alfa axle nut with one from a Mercedes 240D which is the same thread, and has a small hex pinch bolt to lock the axle nut in position (instead of the split pin method). Many P-cars also use this method.
In this picture, you can see the components needed to replace the Alfa nut (pictured in the center).

The Mercedes nut system seems to be better than the GTV6 system because the tightness of the axle nut can be set very accurately, and then locked by tightening the pinch bolt. (more resolution in the nut setting possibilities).
I found a Mercedes 230 (circa 1978 or so) at a junk yard and bought the axle nuts for $2. I found that they fit almost perfectly - with the only slight hiccup being that the nut needs to be turned in so far that the hex pinch bolt can no longer be tightened (the lip of the hub is in the way so the hex wrench cannot be inserted). This is easily solved by using 2 spacers instead of 1 behind the Mercedes axle nut. I found that my local VW dealer had a washer that was almost identical to the Alfa washer (see above photograph) - make sure it is the correct thickness.

Here you can see the installed nut, tightened, and ready to install the grease cap.I found the clearance between the Mercedes nut and the grease cap to be marginal, so it would be wise to verify that there is no interference on your particular car. Make sure the pinch bolt is tightened properly! Replace the grease as well.

You will need to decide on just how tight to make the axle nut. One method I used was to remove the plastic Alfa crest from the center of the wheel, then mount the wheel on the hub & tighten the wheel nuts a bit (grease cap off). Now grasp the wheel at the top and bottom and rock it back and forth. Tighten the axle nut as needed. When adjusted properly, there should be only slight play in the bearings. Note that it should not be necessary to use a wrench to tighten the axle nut (of course, you will need a hex wrench (Allen key) to secure the pinch bolt.)

  


August, 1997.

New Information - Apparently, late model (approx 1991) 75's were fitted with a similar pinch-nut (as a factory upgrade). You'll need two each of the following parts (instead of the Mercedes bits):

60701300 - nut
60501548 - washer

These would have been only available in Europe, but some Alfa Parts sources in the US are accustomed to ordering parts from Europe.

 I hope you find this helpful - I would appreciate hearing your findings if you perform this upgrade.

Mike Harris

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