Donuts.

[V8Ian]

No, not the sweet or cinnamon variety, I'm already an expert on those.
The type in the driveline. Mine is showing signs of deterioration, no symptoms or vibrations yet, but an ounce of prevention.....
I've read that BMW ones are more robust, anyone know more, or can offer sound advice, please?

[rick130]

A genuine stock one would be fine Ian, oh, and just remember to replace the centring bush thingy too.

I am running a BMW M3 version which is a higher torque capacity (thicker) Rotoflex, which is also a German made SGF part.
IIRC it was branded as Febi-Bilstein on the box but was a genuine SGF-GKN part out of the box.
Can't recall offhand what series of M3 it was atm and not sure if I could put my hand on the invoice as it might've been one of the bits of paperwork gone ta ta in last years deluge.

[rick130]

From one of my old posts, the Febi-Bilstein part # 26148
This is the thicker BMW version and was cheaper/same price as buying a Land Rover part

The stock bolts are juuuust long enough. I installed new cone nuts and they just grip. I had bought Brighton-Best SHCS's for it but I wasn't happy with the grip (unthreaded) length of the bolts.

Ian, don't forget that it has an arrow, there is a correct way to fit. Arrow points forward.

[discorevy]

From one of my old posts, the Febi-Bilstein part # 26148
This is the thicker BMW version and was cheaper/same price as buying a Land Rover part

Ian, don't forget that it has an arrow, there is a correct way to fit. Arrow points forward.

Hi Rick

The arrows actually point in both directions to denote which way the bolts go through.

This is the correct way to install, with the fat part of the rotoflex being driven by the shaft in a clockwise direction in this pic.

Fitting it the other way will tear it very quickly.

cheers

https://cimg9.ibsrv.net/gimg/landroverforums.com-vbulletin/259x194/rotoflex1_2ea1c2c9209ce70bd130edecdd1d292881bf5471 .jpg

[d2dave]

Ian.
Get rid of it and fit a flange and tail shaft out of a RR Classic.

I have done this with my D1 and D2

[Tombie]

Keep the donut.

My D2 ran a 4” lift and 33.3” rubber for 200,000km on the factory donut without issue. I have the RR flange etc all here for over 20 years and chose not to fit it.

The additional flex helps prevent NVH and driveline shock.

Factory diff centres and axles all lasted that time period, only my son managed to finally kill the rear diff (donut still in good condition, blew the cross pin).

When I finally finish the project a new donut will go in.

[Slunnie]

I agree, I've gone from Donut, to uni and then back to donut. I returned back to the donut for all of the reasons Tombie stated.

In my opinion now, unless you're breaking donuts regularly which will be from shocking them, then stay with the donut.

This is worth a read regarding stronger donuts:
https://www.aulro.com/afvb/technical-chatter/235016-stronger-rotoflex-possibility.html#post2523319

[rick130]

Hi Rick

The arrows actually point in both directions to denote which way the bolts go through.

This is the correct way to install, with the fat part of the rotoflex being driven by the shaft in a clockwise direction in this pic.

Fitting it the other way will tear it very quickly.

cheers

https://cimg9.ibsrv.net/gimg/landroverforums.com-vbulletin/259x194/rotoflex1_2ea1c2c9209ce70bd130edecdd1d292881bf5471 .jpg

Of course!

[d2dave]

If you do a fair bit of offroading and have ACE as I am sure you do Ian, I would suggest that you get a spare "anti roll bar link" if you keep the donut.

I had one of these fail on me out in the middle of nowhere. The ACE hydraulic ram then drops down and sits very close to the rear uni.

I finished the trip with no adverse effects. However, I know someone who had the same link failure as me and the donut took out his hoses on the ram.

I now carry 2 of these links with me.

[V8Ian]

Where is the best place to buy a suitable donut? Repco, dealer?

[Bohica]

Where is the best place to buy a suitable donut? Repco, dealer?

The usual online places. I have had a look at a couple, both the same prices, one has the centralising bush, the other has no mention of it! Both parts made in Germany.

[AK83]

Where is the best place to buy a suitable donut? Repco, dealer?

Look for online services(of your choice).

They're all basically the same pricing give or take a few dollars, but don't just get the donut, get the whole kit(and kaboodle, if you like) .. but if doing it in the luxury of your own shed(or mechanics workshop) .. best to renew the centralising pin(diff side) and the internal bush(internal in the tailshaft).

The internal bush can be a bit of PITA for the home mechanic without an extraction tool, in that using a chisel it'll take about 30mins or so of bashing to remove it. Easy to get new one in tho.
The cetralising pin on the diff just needs a bit of clever use of some bits and pieces to extract, they can be rusted in, but easier to remove than the internal bush.

The donut itself is easy-peasy to replace. Just remember that the bolts for it alternate in the direction of fitment, as in the photo shown.

All up it takes about 1hr to do the complete job .. maybe 10mins to do just the donut.

[V8Ian]

Not keen on online purchasing, I only do it as a last resort.

[Bohica]

Not keen on online purchasing, I only do it as a last resort.

Land rover dealer then

[LRJim]

Not keen on online purchasing, I only do it as a last resort.Land Rover Parts - UNI JOINT - DISCOVERY 1 & 2 (RUBBER COUPLING KIT) (https://www.britishautoparts.com.au/inc/sdetail/7618)

I know your not that keen on online but these guys are great, just make sure you click the GKN (genuine) part box, and make sure you follow the installation instructions lol
Cheers

[AK83]

Not keen on online purchasing, I only do it as a last resort.

Yep, same here on many items.
Too many stories of not getting what you expected to get.
But the link from by LRJim is confirmed to be 100% positive.
I've used these guys too, even tho I live about 40 mins away .. just can't be stuffed to fight Melb roadworks and traffic to get there, and work hasn't sent me out that way in all the time I've been back there.

FWIW: I had mine replaced just after I got the D1. Just the donut. I'd then done well over 100K klms(I think 120K maybe. I now have 130ish on it myself).
They never told me about the pin nor the bush, and the D1 is my first experience with donuts. Prior to that was the RRCs uni system.

I had a worn front uni in my rear prop shaft(just a half mil or so) but as I was checking stuff, I thought fix it. The donut had very light cracks in it, but not broken in any way .. just light cracking. So I thought do the whole thing .. ie. shaft.
I'm sure that I could have left it as is, and just do the front uni.

But contrary to others commenting, the uni really wore out before the donut did, in the 100K or more klms I'd done. I still have the old lightly cracked one in the rear side bins ... just in case(but I doubt I'll ever need it).

I reckon the donut is a far better system than uni. Unis do wear and break, and if you're on a drive of some kind, I can't imagine replacing one out in the field. Could do, but jeez you got to have a lot of heavy tools to do one.
And you HAVE to remove the shaft to do so. If the donut does break, and I get that they can, replacing the donut itself to keep mobile is just having the 17mm or 19mm spanners/sockets to undo the nuts/bolts, slip shaft forward, a mil replace donut, and re-do nuts bolts. maybe 15 mins of work. So donut makes more sense in that field repairs are a couple of orders of magnitude easier.

As I have a few Discos here now, I know it'll come in handy somewhere .. just in case.