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Drum brakes and bolt on drive shafts
flak monkey - 21/5/09 at 10:23 AM

I am sure that there was a way of keeping sierra drum brakes and changing the inner or outer CV joints on the half shafts so that you can use bolt on shafts and retain the drums, but I cannot for the life of me remember which parts you need to do it.

Anyone done it?

Cheers,
David

matt_claydon - 21/5/09 at 10:51 AM

Yep, I have.

You need to find a set of 'push-in' driveshafts but with ~27-28mm dia shafts rather than the usual ~23-24mm. You can then remove the inner tripode joint and replace with a Lobro joint from a disc-brake shaft.

It's a matter of scouring ebay and asking sellers to measure the shafts I'm afraid!

flak monkey - 21/5/09 at 11:06 AM

quote:
Originally posted by matt_claydon
Yep, I have.

You need to find a set of 'push-in' driveshafts but with ~27-28mm dia shafts rather than the usual ~23-24mm. You can then remove the inner tripode joint and replace with a Lobro joint from a disc-brake shaft.

It's a matter of scouring ebay and asking sellers to measure the shafts I'm afraid!


I think my push in diff has the larger shafts, but I am not sure, will have to check. But I seem to remember have as set of the smaller ones which wouldnt fit in the diff and i had to get some larger ones....

Just a case of dismantling the joints and swapping them then?

David

matt_claydon - 21/5/09 at 12:38 PM

Yep, it's very straightforward. You have to destroy the casing of the tripode to get at the innards, remove the circlip on the end of the shaft and pull off the joint with a puller (or a hammer!). The Lobro joint will also have a circlip to remove but should slide easily off the splines. The Lobro joint will have a circlip either side whereas the tripode is a push-fit and only has a circlip on the outer end. Press/hammer the Lobro joint onto the Tripode shaft and refit the original circlip (not having the inner clip won't be a problem as the joint will not go past the end of the splines).

Note, you can't do this the other way around (outer tripode joint onto lobro shaft) as the tripode joints need a special domed end on the shaft to work properly. The Lobro shafts do not have this domed end.

flak monkey - 21/5/09 at 01:40 PM

Thanks Matt very helpful

flak monkey - 23/5/09 at 07:17 PM

Quick question regarding this method...

The tripode (push in) shafts change length by the spring in the joint. The lobro ones change by the whole joint sliding on the splines on the shaft.

If you have to press fit the lobro onto the end of the shaft dont you effectively halve the amount of adjustment too?

matt_claydon - 27/5/09 at 09:01 PM

quote:
Originally posted by flak monkey

The tripode (push in) shafts change length by the spring in the joint. The lobro ones change by the whole joint sliding on the splines on the shaft.


I'd check that - the Lobros I have are retaiend on the shaft on both sides by circlips and do not slide on the splines. The outer race of the joint is free to move in and out relative to the inner race to take up variations in length though.

NS Dev - 28/5/09 at 06:34 AM

Matt is right, as std the normal lobro joints are retained by circlips each side and are fairly tight on the spline.

The autograss ones we use have extra long splines and circlips only on the outsides, and allow the whole shaft to slide through the joints to allow much more articulation

flak monkey - 28/5/09 at 07:03 AM

Thanks for clearing that up guys, most of the ones I had seen allowed the joints to slide on the shaft. I had just assumed the sierra ones were the same, having not had one apart.