Pictures of a Uni joint conversion

**langy** · 21st April 2007, 06:57 PM

As you would be aware, it's possible to go back to a uni joint at the rear diff on vehicles fitted with a rotoflex joint. There have been several threads about this, and credit to Messrs Ace and Slunnie and the site Discoweb.

(http://discoweb.org/rotoconversion/index.htm )

Last weekend I found that the rubber couplings don't like rocks. And since I happen to enjoy climbing rocks on the odd occasion ( Ta to Discowhite for inviting me) I went and bought a new diff flange and a 2nd hand prop shaft from a 91 RRC.

Although the DW site has some good pics, the Karcraft adaptor flange on the right is slightly different from the one shown in the later model DW pics. The kit from Karcraft ( STC4858) costs $140, and comes with a new seal, cotter pin, bolt and nylock nut - so every model diff is covered. The object on the left is the dreaded centre pin for the rotoflex - it protrudes sufficiently so you have to undo the propshaft on the TC end as well to get the shaft off. You'll notice the mudslingers on the two flanges are different, and that's why I've posted this thread, because the finished product looks different than the Discoweb one.

This is how I got it out - others will have other methods, and this is by far the hardest part of the conversion. Figure out a secure way to pull the centre pin out before you start, as once you conquer it, the rest is easy.

This is where there are some differences - note how deep the mudslinger sits. Which means that unilke the DW version you have to drive the seal down about 4mm from the edge - theres a step machined in my diff housing so you drift it down gently until it bottoms. The pinion will move about whilst you do this, so remember to seat it properly before tightening. The seal is prelubricated, but a smear of grease on the shaft of the flange is always a good thing.

Getting 130 nm of torque on the pinion nut can be difficult. Making a copy of the LR tool out of a piece of steel bar is necessary to hold the flange whilst you turn the nut.

And, apart from personal preferences with silicon and threadlocker, that is basically it.

Rovernaut · 22nd April 2007, 09:51 AM

thanks for the pics.
In the DW tutorial he had to put a spacer ring on the pinion
Quote from article"Here's a pic with the flange removed. You can see my original pinion oil seal and the pinion itself. I've put the spacer ring on the pinion in this photo"

Did you have to do that.
Does the mudslinger on yours rub after fitting, as you say it does look different.
I'm interested in doing this conversion myself.

**Utemad** · 22nd April 2007, 10:10 AM

Thanks for the pics. I've been contemplating this since I replaced my last rubber donut a month ago. The last one only last about 7 months

**p38arover** · 22nd April 2007, 10:20 AM

In general, how long do the doughnuts last on a road car? Do I need to replace it before going to Derby next week?

Ron

**Utemad** · 22nd April 2007, 10:28 AM

Originally Posted by p38arover

In general, how long do the doughnuts last on a road car? Do I need to replace it before going to Derby next week?

Ron

Mine has a 2in lift and you can see the flex in the coupling as it is just sitting there. So it must be really flexing at full wheel travel.
Mine is a V8 manual with a rear air locker so it probably gets a decent amount of shock load.

If your 300Tdi has no lift and is road only I'm sure it would last a lot longer than 7 months. Is yours auto or manual? I think auto ones would last longer again.

**p38arover** · 22nd April 2007, 10:45 AM

Auto with no lift (I think).

Ron

lokka · 22nd April 2007, 12:27 PM

For peace of mind id change the rotor flex or at the least carry a spare ...
Its not hard to replace the rotor flex to uni best way is how slunnie shows it on his web page cut with 5 in grinder down through the sides as far as the wheel will go before touching the housing then spread with chisel and hammer and i use a bolt that fits in the spigot a foot or so of chain and a heavy obgect bolt chain to spigot with bolt then attach chain to heavy object then use like slide hammer and out the bugger will come to easy tho ive had a bit of practice now and can do em easy

**cal415** · 22nd April 2007, 02:29 PM

Originally Posted by Rovernaut

thanks for the pics.
In the DW tutorial he had to put a spacer ring on the pinion
Quote from article"Here's a pic with the flange removed. You can see my original pinion oil seal and the pinion itself. I've put the spacer ring on the pinion in this photo"

Did you have to do that.
Does the mudslinger on yours rub after fitting, as you say it does look different.
I'm interested in doing this conversion myself.

if i remember right the Kar Kraft kit doesnt need a spacer ring, i think that spacer ring only applies if you pull the flange off an old rangie diff.

**Ace** · 22nd April 2007, 02:44 PM

Ron, my rotoflex was fine until i started using the muddies. Even with the lift and the smaller tyres it was fine. For general off road use and on road use it will be fine. Have a look at it, if it looks in good condition i cant see it being a problem. If you are worries do as lokka said and carry a spare, i think CAL415 has one in his shed he doesnt need anymore.

Langy- mate you got it easy, i couldnt get me centre pin out i have to cut the flange and splay the wings out to losen it enough to get it out. Matt

**Disco300Tdi** · 22nd April 2007, 02:57 PM

Originally Posted by p38arover

Auto with no lift (I think).

Ron

With all the sites you post on Ron,, and the knowledge you have

this is quote of the month..

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