I'm looking at upgrading my current sierra 7" open diff with push in shafts to an LSD.

I want to keep my rear brake drums, am I right in thinking that all sierra LSD are bolt on? and does that mean they won't work with rear drums?


What options do I have?

Rebuild your current Diff with a Quaife ATB unit inside or a 3J Drivline ATB

That way you keep your entire drive shft and brakes as is.

http://quaife.co.uk/shop/products/qdf15z-0

check blatchat. loads of the caterhams run a sierra 7" LSD with push in shafts

Had 2 LSD's in my Caterham, first was the factory supplied ZF unit which was eventually replaced with a Quaiffe unit. Both have used the same kit supplied push in shafts.

you have 3 options:

1 - aftermarket diff that will accept you current shafts - like Quaife, Gripper, Tran-X or the old ZF..

2 - hybrid shafts with ford LSD - push-in one end and bolt-on the other - these are fairly straight forward and do work, but tend to wear out faster due the mismatched CV joint designs

3 - bolt-on shafts and modify your drum brakes to fit - you'll need the LSD, bolt-on shafts and the bolt-on/ disc brake hubs (bolt-on hubs use different bearing sizes to the push-in so you can't mix and match here) - then offer up your drums and 'adjust' till they fit - this should be technically possible, but I've not seen anyone try it as they normally just upgrade to rear discs....



the best LSD's are the aftermarket ones - you pick the type that suits your style and get it setup to fine tune it for your car (ramp angles etc) - but these aren't cheap

I think its quaife that most caterhams use, and here's flak monkey's old thread about fitting a tranX one:
http://www.locostbuilders.co.uk/viewthread.php?tid=138216


[Edited on 7/2/2014 by mcerd1]

why not just upgrade you're rear brakes to discs?

is there a benefit of keeping drums brakes or do you want to keep them becuase theyre one and work fine?

Cheers guys.

how much better is an aftermarket LSD compared to a standard ford one? I think i'm going down the standard bolt on and modify the shafts / hubs.

I'm not likely to be taking it out every other weekend to adjust ramp and preload etc. I really justy want a basic fit and forget option.


Not wanting rear calipers as I dont see them as an upgrade, if anything they will just upset the balance of the braking and over brake the rear.

I've not had any issues with mine being over braked on the rear, if anything it could do with a bit more as the fronts lock up well before the rears (standard sierra brakes all round)
if you find too much braking on the rear you can fit a bias adjuster in easy enough.

but then if you're not wanting maximum braking, which i assume means you wont be hammering it on roads or track? why bother with the lsd in the first place?

quote:

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Originally posted by BangedupTiger

I'm not likely to be taking it out every other weekend to adjust ramp and preload etc. I really justy want a basic fit and forget option.


Not wanting rear calipers as I dont see them as an upgrade, if anything they will just upset the balance of the braking and over brake the rear.

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I use wilwood powerlite 4 pots with solid discs up front. Brakes are fine.

Diff is needed due to additional power soon going in, z16ler with k04 hybrid.

I went the hybrid shaft route and the Sierra LSD. Works well and has been fit and forget. If you go this route you will need the larger 27mm dia push-in drive shafts as a starting point, then remove the inner CV joint and fit the bolt on type instead. I think these shafts are not the most common as they were fitted to the later diesel and DOHC Sierras only.
The drum set-up gives a lighter unsprung weight than the standard Sierra disc set up due to the heavier CV joints, bigger hubs and bearings , weight of calipers etc.. So in my view the only reason to go disc at the rear is for cosmetic purposes. Even with drums I had to fit a balance valve to prevent an over braked rear when using cheapo motor factor pads at the front.

quote:

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Originally posted by old_timbo
I went the hybrid shaft route and the Sierra LSD. Works well and has been fit and forget. If you go this route you will need the larger 27mm dia push-in drive shafts as a starting point, then remove the inner CV joint and fit the bolt on type instead. I think these shafts are not the most common as they were fitted to the later diesel and DOHC Sierras only.
The drum set-up gives a lighter unsprung weight than the standard Sierra disc set up due to the heavier CV joints, bigger hubs and bearings , weight of calipers etc.. So in my view the only reason to go disc at the rear is for cosmetic purposes. Even with drums I had to fit a balance valve to prevent an over braked rear when using cheapo motor factor pads at the front.

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No probs. LSDs come up quite often on Ebay, so getting hold of the larger shafts will probably be the main issue. What diameter are the ones you have already? The smaller ones are approx 24mm and don't have the right splines on the end for use with the bolt on (Lobro) CV joints.

honestly dont know, I assume 24mm. donor car was a 2.0 sohc sierra.

will the 27mm shafts be compatible with the outer cv's? would using a 7.5 diff and shafts be a problem as i'm currently using 7".

[Edited on 9/2/14 by BangedupTiger]

The outer stub shafts that go through the bearing and drum are the same (the diff. end is as well) for both diameters of drive shaft. Don't know about the 7.5" diffs, I've only used the 7" type.