Mainshaft & Driveshaft bushing

AR3040022 · #1 (**permalink**) 04-25-2008, 10:45 PM

Thanks to the guys who gave me a couple of suggestions for my last problem - a leaky head gasket. That was solved by a call to Alfa Parts and a weekend's thrashing.
Since then I have been chasing a vibration problem that didn't exist prior to the engine rebuild.
I changed out the motor mounts and transmission mount. The vibration was not as bad, but the driveshaft was still thumping the body near the handbrake lever, so I decided to rebuild the driveshaft completely.
When I pulled the driveshaft out, this is what I found. When I changed the donut the last time (about 10 years ago), the end of the mainshaft looked pretty normal. Unfortunately, it doesn't any more.
The donut isn't in bad shape, although it does have some superficial cracks in the surface.
I guess it's sort of a rhetorical question to ask: Why is the bushing in the driveshaft steel, and why is the transmission mainshaft a consumable part?
If I can get a replacement mainshaft (or entire transmission) for a reasonable amount of money, I will make a new bushing for the driveshaft out of bronze.

Michael
'72 Spider

seani · #2 (**permalink**) 04-26-2008, 09:55 AM

Now that is some serious wear

I have read that if the exhaust is not hung correctly it will pull the gearbox to one side causing propshaft misalignment, but if this is the case in your situation it does seem excessive.
Was the rubber collar in place when you removed the shaft? I think this may help to prevent fore and aft movement of the prop.

AR3040022 · #3 (**permalink**) 04-26-2008, 10:39 AM

Ummm... Rubber collar?

Michael
'72 Spider

seani · #4 (**permalink**) 04-26-2008, 10:56 AM

There should be a small rubber collar about an inch long that fits over the gearbox output shaft before the propshaft is connected. I think this is mainly intended to keep grease in the bush on the front of the prop but also probably helps prevent the shaft moving fore and aft too much, just an idea

AR3040022 · #5 (**permalink**) 04-27-2008, 10:40 AM

Thanks for the info. I would presume that it would also serve to retain grease in the bushing as well. I'll have to find something to fit in there when I reassemble everything.
There wasn't anything on it the first time I rebuilt the driveshaft, and I've never seen anything like that in the catalogs I receive. I did notice that the most recent IAP catalog shows the driveshaft bushing for $57, but I would guess that it's steel, so I won't buy that.

Michael
'72 Spider

**vf31rhill** · #6 (**permalink**) 04-27-2008, 06:42 PM

If your transmission is OK as is, why dont you remove it and take it to a welding shop to have the worn material mig welded back up and reshape the shaft tip by hand? You know what the tip should look like from the side which is not worn. You should be able to keep the rear seal cool enough not to fail by running water over it during the weld operation.
Robert

AR3040022 · #7 (**permalink**) 04-27-2008, 09:56 PM

My Dad volunteered to weld it up with a tougher stainless steel and turn it back to shape on his lathe. I will just have to pull the gearbox and strip the mainshaft out. It's not a huge deal to strip the box, the hardest part is ripping the whole works out of the car (I dread pulling the console out AGAIN, though).

Michael
'72 Spider

**vf31rhill** · #8 (**permalink**) 04-27-2008, 11:24 PM

That seems sensible. Lot of work, though. When you find out about that Ummm, Robber Collar, let us all know about that. It has been years since I pulled an Alfa transmission and I don't remember that Ummm, Rubber Collar either.
Robert

Rich · #9 (**permalink**) 04-28-2008, 02:11 AM

Hi Micheal,

Yes there must be a rubber ring installed part number 101.12.15.104.00"Rubber Ring".

Thanks

Rich

**vf31rhill** · #10 (**permalink**) 04-28-2008, 06:08 PM

Rich,
Is this rubber ring (101.12.15.104.00) available anywhere that you know of?
Thanks, Robert

Rich · #11 (**permalink**) 04-29-2008, 12:01 AM

Hi Robert,

I purchased mine in locally. What country are you in?

Rich

Rich · #12 (**permalink**) 04-29-2008, 12:10 AM

HI Robert,
Just had a look for you, Highwood in England sell it for 1 pound. I forgot how much i paid here in Oz. If you can't get one locally i can alway measure it for you and you can visit a local rubber supplier or i can buy and post you one.

Rich

AR3040022 · #13 (**permalink**) 04-29-2008, 10:27 PM

Thanks a lot for the info about the rubber collar, Rich.
Can you measure one and let us know the dimensions?
Michael
'72 Spider

Rich · #14 (**permalink**) 05-01-2008, 06:57 PM

Hi Micheal,

No problems, pictures attached.
I removed mine from my gear box to take a picture, so one side is a little bit bigger because it has take the shape of the shaft. I have taken a picture from the outer side ( facing the back of the gearbox) this is the narrow end of the shaft so the rubber is still the same shape and exact measurement.

OD= 30mm
ID = 18mm
Height = 20mm

Thanks
Rich

Joe Papa Sr · #15 (**permalink**) 05-11-2008, 02:02 PM

Where does this "grease" fit into this, as the bushing fits tightly around the shaft tip, leaving no "space" for the grease to sit into?