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Hi.

I got your attention!

I added a new Guibo, new drive shaft support bracket and a new bracket bearing on a '73 GTV.

When I install the front shaft and secure the bracket to the chassis bolts the Guibo (front shaft) comes up about 3/8" short of the transmission yolk.

I can squeeze the Guibo to transmission yolk and secure it, but I am not sure this is the right thing to do.

Any suggestions?

Will the shaft “seat” after usage?

Did I press the bracket on too far, thereby “shortening” it when it is installed?

Jim
 

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I can squeeze the Guibo to transmission yolk and secure it, but I am not sure this is the right thing to do
I am quite sure that is NOT the right thing to do. Giubo's are pretty delicate and I don't think you want to stress one that way.

Did I press the bracket on too far, thereby “shortening” it when it is installed?
Seems there was a similar thread in the past six months: the the front driveshaft bearing/support had been replaced and the giubo no longer fit. My memory (never reliable) was that someone advised that the bearing and/or support had been installed backward.
 

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Seems there was a similar thread in the past six months: the the front driveshaft bearing/support had been replaced and the giubo no longer fit. My memory (never reliable) was that someone advised that the bearing and/or support had been installed backward.
I remember that some people have had trouble with aftermarket center supports, specifically the "heavy duty" type.

The center support should go onto the studs naturally. Elongating the holes is one option, but you are likely to run into driveshaft alignment issues. The U-joints should operate through the same angle. That means that the front section of the driveshaft should be parallel to the differential input shaft when the car is normally loaded. You can get vibrations if this alignment is not correct. Bolting the center support into an "unnatural" position is more likely to give you vibrations.

If you need to move the center support to the rear you could space the Giubo from the yoke with thick washers.
 

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My guess is the donut is thinner than the original. There are repro donuts around now, I've heard mixed things about, haven't used one myself. One suppliers slightly alters a Mercedes donut, cuts some tangs off, I didn't have a great experience with that either.

I just replaced the donut on a friend's Duetto with a new Alfa donut, aligned perfectly on the center mounts when I reinstalled. 3/8" is a big change in this realm, something's not right.

Andrew
 

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I'd be comparing the new parts with the old parts and working out which new part is wrong or has been installed wrong.

Good luck
Pete
 

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Jim,
I'll be very interested to hear if you solve this as I have the exact same problem with my GTV driveshaft. Like you I replaced the donut, bearing and support. The parts were sourced from IAP and the bearing was pressed on to the shaft at Glynn's Motorsport, who generally get these kind of things right.
Upon reassembly I had the same 3/8" space at the transmission end, so after some head scratching, ended up milling 3 spacers to fill the gap. All the new parts, including the donut, matched the old ones, so no apparent problem there. The only clue I have is that the holes in the bearing support needed to be elongated to fit, so it seems something is wrong there. I'd like to get it right at some point, but after running it like this for 5yrs/5k miles, I've noticed no problems.
 
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