Technical drive shafts

[berkeleyman]

Hi, I am sure this must have been covered many times before but I am still not sure of the following;- I understand that when fitting a 650 engine and gearbox into a fiat 500, 25mm diameter shafts should be used, are the shafts 25mm diameter along the whole length of the shafts? My recently purchased 1971 500L (fitted with 650 engine and synchro box) has just started leaking oil from a split oil boot and when I checked the drive shafts they are only around 18mm diameter. If I am going to change the boots I may as well change the shafts also if they are wrong. That said, can anyone suggest a source for the shafts? I am in north east england. Thanks

 

[Toshi 975]

Looks like someone has done a sneaky one there. The 500L should have the thicker shafts, same as the 126 but shorter. Earlier drive shafts have been fitted to that gearbox. Thing is you can change the boots with the gearbox in situ but to change the drive shafts it is a gearbox out job.

 

[Paolo66]

Mine are 24mm around the main central bit. The originals were 19mm. Dead easy to change. I found a link on the forum to Ricambi 500 pictures on flickr which show a step by step. Make sure you get some gasket sealant for when you split the box. When you buy them get the kit so you get the boots and spline ends etc. I got mine from leo van der laan in holland, cant remember exact web address but just google it. A top bloke, really cheap, has stock and really fast delivery

 

[berkeleyman]

Thanks a lot for the replies guys, if its a gearbox out job I might just change the boot for now (got 2 decent spares) and take it easy till I change the shafts. The car is to be fitted up for an a-frame to tow behind the motorhome to microcar rallies so wont be actually driven hard or far, it will give me time to get the replacement shafts ready to fit after the rally season. Eric

 

[Bambino]

The measurement taken is the diameter at the level of the bearing cone.

And yes, it's a gearbox out and diff strip down job. It's quite easy to do, though takes some time.

The procedure is here - http://www.flickr.com/photos/ricambifiat500/sets/72157615692546231/

Chris

 

[JakeF]

Yep. And make sure you order the correct size oil boots

 

[berkeleyman]

OK, so do I take it from what you say BAMBINO that the middle diameter of the shafts could well be smaller than 25mm, in which case I will find the true shaft diameter when I remove the oil boot? Thanks again for your interest

 

[Bambino]

Yep - I just crawled under my car and my shafts are about 21.5mm across the centre section.

If you don't drive like a maniac, the narrower shafts should be OK with the standard 650cc engine. I replaced mine when I rebuilt and upgraded my standard 126 engine to 695cc and ~33bhp.

Chris

 

[berkeleyman]

Hi, Thanks for all your trouble BAMBINO, just taken the split boot off and shaft is 20mm! took a good boot off a spare gearbox I was given with the car, its 25mm,BUT the shafts (25mm dia),on the spare gearbox are longer, I suppose they are 126 shafts (about 20mm longer). As I posted earlier I will just replace the boots on my present shafts for now (other side weeping slightly) and take it easy for this summer ( if we get one), then fit 25mm shafts later in the year. Thanks again, Eric

 

[Bambino]

Eric,
The 126s had a wider rear track hence the longer halfshafts. The shorter length 25mm shafts are still easily available as they were fitted to the later model 500s (the Ls & Rs).
Chris

 

[berkeleyman]

OK thanks Chris