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**Dave The Hat** · #1 26 Sep 2010

Hi guys,

Anybody here have any experience of lengthening or shortening a propshaft?

Im planning to lengthen a chassis to increase the wheelbase, which of course will involve lengthening the prop too.

Anybody hady good or bad experiences with this? If anybody has link to a site where I can see the process in more detail Id sure appreciate it. The prop in question is for a mercedes 16 tonne truck.

Many thanks,

Dave The Hat

**palace15** · #2 27 Sep 2010

Try ...propshaft services in Feltham Middx, I used them years ago for a UJ. good service. Propshaft Services - Propshaft Manufacturing Specialists

**Dave The Hat** · #3 27 Sep 2010

Many thanks Dave, they might just be the boys to do the job. Absolutely critical to get the lengthening done properly and then balanced or my whole project could be buggered later down the line.

Thanks for the link!

**Big Yellow Tractor** · #4 27 Sep 2010

Another recommendation for Prop-saft services. In the past I have had them shorten, lengthen and make hybrid shafts for me (half escort, half LJ80) They did one for an SJ410 while I waited.

**Dave The Hat** · #5 27 Sep 2010

Hi BYT,

If lengthening, I understand the shaft is cut and a new piece of tube is welded in.

My concern is the strength of the weld.....if for instance seriously bogged and trying to power out of the mud, all that torque and twisting going through the shaft may start to open up the weld over time.

How have your shafts performed over the years (sorry if that sounds a bit kinky!)

Cheers.

**Griffdowg** · #6 27 Sep 2010

Quote:

Originally Posted by Dave The Hat

Hi BYT,

If lengthening, I understand the shaft is cut and a new piece of tube is welded in.

My concern is the strength of the weld.....if for instance seriously bogged and trying to power out of the mud, all that torque and twisting going through the shaft may start to open up the weld over time.

How have your shafts performed over the years (sorry if that sounds a bit kinky!)

Cheers.

worth dropping the propshaft clinic a mail to, they may be able to help. They could probably knock you up 1 from scratch, saves you worrying to

G

**Big Yellow Tractor** · #7 27 Sep 2010

Quote:

Originally Posted by Dave The Hat

Hi BYT,

If lengthening, I understand the shaft is cut and a new piece of tube is welded in.

My concern is the strength of the weld.....if for instance seriously bogged and trying to power out of the mud, all that torque and twisting going through the shaft may start to open up the weld over time.

How have your shafts performed over the years (sorry if that sounds a bit kinky!)

Cheers.

I wouldn't worry about the weld strength, it will be at least as good as the original. There are issues with very long shafts twisting/bending due to torque. If you look at very long drive-trains (on HGVs for instance) there will be a bearing carrier and another set of UJs midway.

What vehicle are we talking about ??

**Dave The Hat** · #8 15 Nov 2010

Just lengthened the chassis, now just about to get the prop sorted.

I have a Mercedes booklet which goes through the process of extending or shorthening a wheel base. They touch on the subject of the prop shaft. They say that you can go upto certain lengths without a carrier bearing (ie unsupported), and these lengths vary according to the thickness of the tube on the shaft.

I have a 90mm thick shaft, and they say you can go upto 1700mm long without a carrier bearing.

If you have a 140mm shaft, they say you can go upto 2300mm long without a carrier bearing.

Question that I have is the following:

Can you have a 90mm thick shaft from the gearbox to the carrier bearing, and then have a 140mm thick shaft from the other side of the carrier bearing to the diff? Or do you have to have both parts of the shaft at the same thickness?

Might sound a bit far fetched, but several mechancis I know said this is possible.

If so, then I may be okay, as I can keep my front section of prop as it is, then swap my rear section for a bigger shaft and pay some extra for it.

**Big Yellow Tractor** · #9 15 Nov 2010

I don't see any problem with what you suggest.

**RogerM** · #10 15 Nov 2010

Quote:

Originally Posted by Dave The Hat

Just lengthened the chassis, now just about to get the prop sorted.

I have a Mercedes booklet which goes through the process of extending or shorthening a wheel base. They touch on the subject of the prop shaft. They say that you can go upto certain lengths without a carrier bearing (ie unsupported), and these lengths vary according to the thickness of the tube on the shaft.

I have a 90mm thick shaft, and they say you can go upto 1700mm long without a carrier bearing.

If you have a 140mm shaft, they say you can go upto 2300mm long without a carrier bearing.

Question that I have is the following:

Can you have a 90mm thick shaft from the gearbox to the carrier bearing, and then have a 140mm thick shaft from the other side of the carrier bearing to the diff? Or do you have to have both parts of the shaft at the same thickness?

Might sound a bit far fetched, but several mechancis I know said this is possible.

If so, then I may be okay, as I can keep my front section of prop as it is, then swap my rear section for a bigger shaft and pay some extra for it.

Will depend on the availability of UJs that can match 90mm prop shaft off the back of the gearbox to a 140mm prop shaft connected to the diff, thats a big size hop - I dont know what Merc have available - its generally not a good idea to have mismatched or custom made parts when you might need spare parts support that will rely upon your VIN to get the correct part to you.

**Dave The Hat** · #11 15 Nov 2010

Thanks guys that's reassuring.

I looked at a Mercedes Atego today that has been altered, and this had a different thickness shaft at front compared to the back so I guess it is possible, providing balancing is done correctly.

Spare UJs wont be a problem they're readily available for both sizes of prop shaft, and I intend to take spares with me on the journey Im planning.

Am going to speak to the prop specialists this week, so appreciate the heads up regarding what is and is not possible.

Cheers.

**Neil H** · #12 7 Dec 2010

Hello Dave the Hat

Can you tell me if you done your chassis extension, did you do it or get someone to do it for you.

We are also looking at a 70cm extension or and the least 50cm.

We will also need to get the propshaft done, so any information would be greatly received.

Our vehicle were hopeing to use is a Mercedes 1017a army truck.

Neil

**Dave The Hat** · #13 15 May 2011

In the end this company did it for us

Bailey Morris Limited - Propshaft Manufacturing Specialists

Basically, without fitting a second carrier bearing, we had to go from a 90mm guage tube upto 140mm. That way we could have a the rear part of the prop (carrier bearing to diff) as long a 2.15 meters.

Basically it was a question of reusing part of the old prop where the sliding joint goes in, then a brand new tube all the way (so quite a bit of new tube, and thick tube at that). They also replaced both UJs as both were starting to wear. Was a little pricey but they did a great job. It was about 450gbp in the end (without VAT). Suspect quite a bit cheaper without replacing the UJs.