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Discussion Starter #1
:hang: I'm in the process of trying to finish my ground up restoration on my '88 Spider, and I had a mechanic pull the engine and transmission out, do the body work and then put everything back in once it was painted. But after reading a few posts about removing the transmission, I came across a comment about a fact that the drive shaft needed to be balanced and remember something about that on an old '76 spider I once owned when I installed a new donut.

Can anyone tell me how I would go about knowing whether or not it is balanced once I reinstall the transmission BEFORE I cut the band on the rubber donut? I want to have my transmission rebuilt by someone with expertise and knowledge, NOT your run of the mill transmission shop.:hammer:
 

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Richard Jemison
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Driveshaft

If you keep it assembled as originally done you should not need rebalancing.

If you change U-joints you should have marked the shaft before disasembling.
Good luck finding replacement U-joints. Absolutely no US supplier has the correct ones to fit 2 L shafts.
 

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If you keep it assembles as originally done you should not need rebalancing.

If you change U-joints you should have marked the shaft before disasembling.
Good luck finding replacement U-joints. Absolutely no US supplier has the correct ones to fit 2 L shafts.
Does that explain, why the ones I got from VIckAuto, went on kinda easy and the clips never really fit properly and had to sand them down a bit?
 

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I tried to have the driveshaft balanced on my 750 . I brought it to a well known driveline shop I was told they would try but didn't think they could get it set-up in the machine properly . The operator didn't have the proper ends to hold it in place . The shaft wasn't giving me problems but I figured as long as its out of the car.....I did mark everything before I pulled it
 

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Richard Jemison
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Balancing

he flanges on the rear "U-joint" section of the shaft are standard Euro/*** size flanges. The issue is wirth the "Guibo" end and commonly that is centered in a common pointed "live center".

Transaxle shafts are more problemsome.
 

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Back in the day - 1995 - when I had a Spider, the U-joint I purchased was #413 at $21.50. Today, Moog and PartsGeek both show listings for it, designate it as Alfa Romeo 2L fitment and offer it at about the same price.
 

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How did I miss that?

I went through this a few months ago, every place that said they had them actually had the slightly smaller joints for the earlier cars. Got them from Spruell, just had to wait a few days for them. I sent them out with the driveshaft to be balanced. I haven't heard if they were needed or not yet

I will file that away for next time

Thanks
 

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A few years ago I bought incorrect U-joints from four different vendors. Two were obviously from the same manufacturer, they were sold by well known Alfa parts vendors and they were too long. The cups were the correct diameter but it was impossible to install the second snap ring. A third had a similar problem but it was only a little too long and it installed after grinding the snap rings. The fourth type came from Advanced Auto parts. The cup diameter was too small and they were also too short. They had a grease nipple that the others did not have. I finally bought good ones from Highwood Alfa in the UK. These came in white boxes. The ones that were much too long were packed in plastic bags with no boxes. I don't remember how the other two were packaged.
 

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About 2 years ago, I bought u-joints for my 71 from Centerline and took them and the driveshaft to a driveshaft balancing shop here in Dallas. They specifically commented that the u-joints were good quality and they were pleased to see that. They were concerned about having 'chucks' (?) to hold the shaft for balancing but they did, and they installed the u-joints and balanced the shaft for around $100 or so as I remember. The visit to the shop was really interesting as they had some huge driveshafts, and some spectacularly failed shafts that still give me bad dreams every now and then.
 

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I need a couple of later model u-joints and found two NOS boxes way back in my cabinet from the mid-70's. The look like Alfa logoed parts boxes; the box on one says 1300-1600. But the trunions have no zerks as earlier models would. The caps are ~23.90mm diameter. What are the cap diameter of early vs later 105/115?? Thanks.

FWIW, as pertains to this thread, I have been told by an expert Alfa mechanic that Alfa main shafts never need rebalancing unless the original factory balancing weights were mucked with or the short end (of the slide yoke) was changed out. If the slip joint is disassembled for any reason, it needs to go back in the same orientation (flanges in phase). I have bought two cars where the shafts were out of phase by 2 or more splines leading to vibrations. And FWIU, it is virtually impossible for shops to re-balance the half-shafts (giubo end).
 

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I spent quite a lot of time and money to get rid of a driveline vibration.

1- If there is a little bit of side play in the splines, you will feel it at highway speed.
2- It is possible to get the front shaft balanced by most shops if you supply them a gearbox output shaft and a good giubo.
3- If you cut the band and need to remove/reinstall a giubo use a large hose clamp.
4- U-joints. The cap diameter is not the only critical dimension: the width of the cross with the caps is also citical. Too wide (the first set), the snap rings won't fit. Not quite wide enough (the second set - by .010'') they will move sideways and will be impossible to balance. You can always shim them, but see #4. The local driveshaft shop didn't like that and they came up with perfect fitting joints. They came from a u-joint catalog, but they did not communicate the brand/part number.
4- Original Spica joints were supplied with a pair of springs. It took a while to understand why. One spring was mounted behind the cap on each axis to take up the sideplay. When I replaced my first Alfa u-joint ages ago, the Alfa guys told me I would need to get the driveshaft rebalanced. As stated before this does not make sense if you don't move things around. But the springs actually leave the shaft slightly off-center. If you move the springs around, you've moved the center. New, narrow joints won't work with springs because you'll be too far off-center. The same thing is true of shimming a loose joint: on which side do you need the shims?

It took two shafts, three sets of u-joints and 5 visits to the driveshaft shop to learn this.
 

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Arrghh, wrote a long note and it disappeared. Summary. Jorma - thanks for the info. They mic'd at 23.83-87 so that is in the ballpark for the smaller early ones, but they did not have grease zerks, so that is curious. I bought a pair of #413's for the 75 Super shaft. Will mic before fitting. FYI - the rear shaft is the same as a Berlina (~36.4"); the front shaft on a Berlina is longer.

Yves, I chased vibrations all around Europe on a 3500 mi trip at three shops. Inconvenient and $$$. Seems like the craft of driveshafts and u-joints is a lost art with FWD cars. That problem was solved by Mkie Keith in Houston when the car got home.
I may report on this new one in a new thread just for member learning. Seems like two basic problems on it.

PS: if one does re-balance a shaft, what RPM is appropriate. I was told there is a thread here that advises 4500 rpm minimum and Alfaholics site says they balance their new shafts at 8000 rpm.
 
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