I've just got my Haynes Roadster on the road and I'm looking to upgrade my standard sierra diff and rear drum setup.

I have noticed that sierra 4x4 LSD is an option which have bolted flanges on the diff and discs.

Has anyone done this conversion? What parts will I need to do the conversion?

Will my prop bolt straight to the LSD diff and what's involved with changing my drums to discs i.e. bolt hole alignment, handbrake fitment.

What are the different ratios available in the sierra LSD ?


Any advise what to look for / avoid will be much appreciated.
Then I can start looking for some parts.

Thanks Paul

The hub carriers are different for disc brakes with bolt on shafts
It would be best/easier to buy bolt on hubs and shafts then find a LSD diff
The LED diffs are usually 7" 3.62 from 2.8 Sierra and Cosworth Saphire
The standard Cosworth had 7 ½ LSD
The 2.0L DOHC 4x4 had a 3.9 LSD
All bolt on

The more complicated option is to modify shafts with bolt on inner lobro so you can fit LSD and keep drum brakes

do you need rear discs?

if converting to LSD and discs requires a diff, shafts, hubs, calipers and discs, I'd say that it was much simpler to convert your shafts to bolted flange (about an hours work and dirt cheap last time I bought a pair of bolted CVs) and simply fit the LSD?

Thanks for that.....

I will look for an LSD diff.

Converting my existing driveshafts keeping the drums sounds the easiest option.

Paul

OK previouse thread answer simplifies the shaft problem
The bolt on shafts (disc brake) are bigger diameter than push in (drum brake) therefore the spline ends won't fit.
There are a few different drive shaft diameters and I would suggest you look at Seventh heaven web site as all possible dimensions are there
As stated in my post, it's not simple unless you have all the right bits

How to in pics

Cut outer tin cowl of push in shaft




Slide the trilobe out





Remove the circlip on the end of the shaft and slide the trilobe off. You will then need to remove the inner circlip on the shaft as well to leave just the splined shaft





If you use std sierra or 4wd bolt on 100mm CVs then they will push straight on as shafts and splines are the same. Yiu dont need the inner circlip as the CV butts up to the end of the splines. 2wd cosworth and 108mm CVs use a thicker shaft

One last thing, is that the trilobe style have a spring in each cup to keep the shaft itself central as it plunges in and out as the suspension moves thru bump to droop. Personally i refit this spring between the CV and the diff flange to keep the shaft central but most people dont bother and dont seem to have an issue, so uour call.


You can see the spring in the end of the trilobe cup