Sierra Rear Sub Frame And Suspention.

[Guest 2b cruising]

Hello. A friend of mine has a complete rear end off a 4x4i.

I can have it for nothing off him, but the question is this.

The diff is a 7.5" type and he thinks it is an open one.

Will my 7" LSD diffs fit it if I use spacers on the mounts.

I am looking at powder coating and disc conversion, getting it ready to put straight on to save time on my busy winter project with engine and gearbox change.

[Longboarder]

I thought all 4x4 sierras had LSD and 7" viscous diffs apart from the cosworths which had 7.5" diffs. Could easily be wrong.

 

Nigel

[Snapperpaul]

All 4x4's had LSD, 3.6 on the V6 and 3.9 on the 4x4 2.0L DOHC

Caveat later Granada's had traction control so no LSD

[Al Milton]

Ken,

Yes, the 7" diff can be fitted to replace the 71/2" diff by using spacer washers to pack out the difference.

 

This is what I did when I fitted my LSD to replace the open diff.

 

The only problem you may experience is with the top mounting bolts. I think the 71/2" diff has threaded holes to take a bolt each side, whereas the 7" diff uses one long bolt across the diff, (well mine did anyway!).

It's a bit of a fiddly bugger getting the spacers in the correct position, but if you have the beam etc off the car to fit as one unit, it should be a darn sight easier.

 

If you need a bit of extra grunt or spare hands, just shout.

 

Cheers

Al

Edited August 12, 2015 by Al Milton

[Bob Tucker]

+1 if you need a hand Ken....

[Guest 2b cruising]

Thanks for the info and offers lads.

I will keep the offers in mind when it comes the time to put it all back together.

The geezer I was getting it from only thought it was an open diff but that is not a problem anyway.

I have one on the car at the mo, and another spare.

Paul, the mind of information your head holds knows no bounds.

If it is the 3:9 I might just be keeping that one to start with to see how I get on with the extra torque I will be getting.

If no good, no problem to fit with shims.

Al, if it is bolted bothe ends, that's no problem, I can fit longer bolts with shims if required.

 

In it marvellous having more than one head at a time.

Even more than two hands when required.

Brill club is this.

[Al Milton]

If memory serves me Ken, the top mounting (to the rear beam) on the 7" diff isn't threaded, there is one 7.5" long bolt.

Which obviously is too short when used with the rear beam from a 7.5" diff.

 

We had a short length of 316 stainless bar at work which I had machined down to size and then threaded it either end.

New nyloc either end, job done (after some effing with getting the ruddy spacers aligned - but nothing some grease on the washers didn't sort out eventually!!

[Guest 2b cruising]

Thanks for the tips Al.

I will even have a look at moving the brackets while they are easy to get to.

No worries about shimming then.

[Guest Ian & Carole]

Another tip when using washers as spacers is the grease like Al said and then wrap them in masking tape.

 

Just pop a bolt in to get them all lined up.

[Guest 2b cruising]

Good tip Ian. Thank you.