[alfavulcan]

my propshaft is rattling badly at idle from the the splined joint in the front. the pinch bolt should tighten it down but even tightened to 65lbs torque i can still lever it in and out using a screwdriver. also is affecting the fitment at the rear coupler, any fixes without pulling the shaft out? i hate to tighten the pinch bolt any further

 

[Gubi]

I don't think there's any in-car fix.

The fix I've seen is to remove the shaft and enlarge the slot via Sawzall. Greg Gordon's site has more info:

Alfa Romeo Guibo, Driveshaft, Clutch Technical Troubleshooting Article

 

[alfavulcan]

i read that but the slot in my pinch bolt area is not closed up tight, maybe 1/16" gap

 

[Milanoguy]

Dear Mr. Vulcan

What I think is going on here is that the splined area of the front guibo holder (the piece that the splined end of the drive-shaft slides into), has worn out.

Meaning that the splines in the guibo holder have wallowed out, over time, and no longer fit snugly onto the splines in the drive-shaft, no matter how hard you tighten down the pinch bolt.

In other words you're going to have to take it out.

I have heard some people say using a file to remove one spline from the guibo holder creates enough clearance to let it fit tightly on the shaft again, but I can't confirm this.

If you don't have another guibo holder I probably have one.

Bye

 

[alfavulcan]

thats what i was afraid of. i guess i'll pull it out next week. or the week after. or...

 

[Scott in MN]

Mine was doing that too. I torqued my pinch bolt to ~85 - 90 lbs and it took care of it. Glad I didn't shear the bolt. That would suck.

 

[alfavulcan]

thats exactly what i'm concerned about. it just feels like its close to its limit

 

[Gubi]

I tried to find a torque spec in the manual but could not. Maybe someone will chime in with one. If you can find out the bolt size and thread pitch there are guidelines for max torque: might let you know how likely it is to handle 90 ft-lbs without failing.

If you read that link I posted, the other suggestion is to pound the splines flatter with a hammer to spread them out. I've never tried that one.

 

[alfavulcan]

i might try that actually, at least i wouldn't have to pull the front guibo. if it doesn't work, a friend has a couple of gtv6 propshafts.

 

[Alfar7]

Pinch Bolt

i read that but the slot in my pinch bolt area is not closed up tight, maybe 1/16" gap

Most likely someone has replaced the bolt or lost the washer under the head, and you are just out of threads to tighten the pinch farther.
Remove it and place a thick washer under the head of it. (Before it comes up, no the washer wont cause any balance issues, the radius of its swing makes it irrevelant)

 

[alfavulcan]

that really does make sense. will try that in the morning. fingers crossed

 

[planetmojo2]

Any chance the problem can be traced to the centering bearing at the front tip of the shaft?

I've had no issues with that myself. But recently, I've heard from a couple of others who's centering bearing had fractured, or was missing its internal guts (perhaps from a PO who put it back together without all the bits?).

 

[alfavulcan]

removed old pinch bolt and could tell threads were deforming. had a new grade 8 bolt same size to try and still cannot tighten down at 75lbs. it feels if i go any more i will strip it out. i can pry the shaft back and forth with a screwdriver so i know it hasn't gripped the splines and did make sure the threads aren't bottoming out. i think one of the trans mounts are bad as i can get some lift on the transaxle when i push it up and i noticed the shifter would move side to side some as i gave it power or let off while driving. so next week i will get it up in the air again, remove the propshaft and trans mounts and inspect closely