Shortening Drive shaft

[JackieFan]

Does anyone know off the top of their Swede how much the short side drive shaft needs to be reduced by in order to fit it to a S12/S13 vLSD hybrid diff using BOTH S13 output shafts? Is it just the difference in length between the S12 output shaft and the S13 output shafts+CV joint? Also has anyone got a picture of an S12 driveshaft without the CV joints on the ends?

hope that makes sense

[30psi]

Yeah it will be the difference between the complete S13 shaft bolted to the CV housing compared to the S12 one.

I'd say 2" or thereabouts.

Why do you want to do it this way. Your making it harder for yourself. Getting reliably shortened shafts is very expensive. In fact when i enquired they wanted £100 plus VAT per shaft but actually said they can't predict how strong they'd be after. They then recommended getting custom shafts at £300 plus VAT per side, at which point I hung up.

[JackieFan]

Mainly because I can't see how you modified the S12 shaft to work in the S13 vLSD. When I compared the two output shafts on the bench they are totally different. How long are the splines that the Spider joints fit over on the end of the shaft?

[30psi]

You only need to shorten the passenger side shaft by about 5mm, then deepen the existing groove and it will look just like the passenger side S13 unit.

Then use another passenger shaft because its short but strip the CV joint off of it and fit the S13 one to it. The spider assemblies and splines inside the CV joint exactly match.

Don't go getting custom shafts it will work out too expensive. Might as well buy a proper mech diff for the same money

[JackieFan]

I took photos of the output shafts next to each other so I'll have to dig them out and nose again. I've got all the bit's to do it the way you did it's just that when I looked at the shafts they seemed so different that I didn't even start messing with them.


When the driveshaft is stripped down is there still splines visable after the spider joints?

[30psi]

Shouldn't be splines visible after the spider assembly, maybe only a small amount. What version shafts are you using? ie mk1 or mk2?

[JackieFan]

Shame, I was just trying to think of smart ass ways of shortening the actual drive shaft without chopping it down the middle. Need to get it sorted for JAE!!

[s13eater]

feck me if i can do them, then i'am sure you can mate ,i think i shortend mine by 8mm and same as mart says, just swap the end off of the s13 shaft onto the s12 shaft, its so you have a flanged end on the s12 shaft.

[30psi]

Was it 8mm? I can't remember what I did but just by looking at the passenger S13 shaft shows you exactly what to do.

If it looks like this afterwards then you're on the right track:

[JackieFan]

Originally Posted by s13eater

feck me if i can do them, then I'm sure you can mate ,i think i shortened mine by 8mm and same as mart says, just swap the end off of the s13 shaft onto the s12 shaft, its so you have a flanged end on the s12 shaft.

I'm happy with swapping the CV joint, it's just the modding of the S12 output shaft to fit in the vLSD that I didn't like the look of. I must admit I really took one look at it and thought "sod it I'll just shorten the drive shaft" because at the time it seemed like a better option. I'll pop the S13 output shaft from the diff again at the weekend and have another look at it and see if I can sort it. If it works there'll be a vLSD conversion in the 12 costing the princely sum of £60! Bargain.... If I don't fuck it up!