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converting Sierra 7.5" to 7" diff
laptoprob - 18/10/14 at 12:31 PM

Is it pretty straight forward or anything nasty i need to know before it gets stripped out?

jacko - 18/10/14 at 04:05 PM

It should be stright forward you will need a 12mm spacer , the 7.5 diff prop nose is about 10mm closer to the gear box then a 7 diff
jacko

[Edited on 18/10/14 by jacko]

laptoprob - 18/10/14 at 08:28 PM

quote:
Originally posted by jacko
It should be stright forward you will need a 12mm spacer , the 7.5 diff prop nose is about 10mm closer to the gear box then a 7 diff
jacko

[Edited on 18/10/14 by jacko]


Phew looks like Jackos the only one thats ever done it lol

Thanks mate.

[Edited on 19/10/14 by laptoprob]

CosKev3 - 19/10/14 at 09:20 AM

Pretty sure lobros are diff size on shafts?
Or have you got them anyway?
108mm rings a bell, and 7 inch ones are 100mm iirc

fha772 - 19/10/14 at 09:55 AM

Why are you swapping Rob?

laptoprob - 19/10/14 at 09:56 AM

quote:
Originally posted by CosKev3
Pretty sure lobros are diff size on shafts?
Or have you got them anyway?
108mm rings a bell, and 7 inch ones are 100mm iirc


Hadnt even thought of those to be honest but thanks i'll check those

laptoprob - 19/10/14 at 09:57 AM

quote:
Originally posted by fha772
Why are you swapping Rob?


New car Frank...

Bought a Westy and taking the drivetrain out of the Tiger and dropping it in the new one

jacko - 19/10/14 at 03:49 PM

hi i had a 7ins and a 7.5 along each other all measurments for fitting where the same apart for the one 12mm spacer and the 10mm nose difference
the drive shaft fitment where the same 100mm 6 bolts 8mm thick
the diffs where
7ins sierra
7.5 granada
jacko

loggyboy - 19/10/14 at 04:09 PM

Depends on the source cars, some 7.5 inch and 108mm driveshaft flanges.

[Edited on 19-10-14 by loggyboy]

Non custom - 19/10/14 at 04:33 PM

All cosworth 2wd diffs are 7.5" and have 108mm lobro bolt on style flange which also need the bigger 2wd shafts and stubs to suit
All 4x4 rear diffs are 7" with the smaller lobro 100mm

If fitting 7" diff in 7.5" beam you need to space the top left mount with the prop flange facing you
Likewise a 7.5" diff will fit a 7" rear beam by grinding the 1/2" difference from top leftt mount as above

Worth noting the exception to the rule is the granada or Scorpio diff as these are 7.5" some of them but with the smaller lobro flange as per 4x4 100mm

[Edited on 19/10/14 by Non custom]

Non custom - 19/10/14 at 04:37 PM

Forgot to add the bolts on 7" diffs are usually 8mm
As opposed to 10 on the 7.5"

I have pics of both shafts if anyone needs to see a pic for future reference ?

[Edited on 19/10/14 by Non custom]

Non custom - 19/10/14 at 05:14 PM

2wd left and 4x4 on the right
Can clearly see the bolt size difference



Same again 2wd left and 4x4 right


2wd on left slightly thicker



Hope it helps anyone using search

mcerd1 - 19/10/14 at 07:12 PM

as above going from the larger diff to the smaller one is just a mater of spacers and longer bolts
(7" diffs are mounted with 2 long through bolts at the top / bottom)


but the driveshaft size / type needs to match or you'll end up needing to swap the whole axle

quote:
Originally posted by jacko
the diffs where
7ins sierra
7.5 granada
not necessarily - it depends on the engine and what ford had in stock that day...

both the 89 2.0 pinto Granada's I stripped had 7"
but the 2.0 DOHC sierra had a 7.5"

my xr4x4 had a 7" as all the 4x4's are meant to - but that didn't stop ford sticking 7.5" into some of the last of them (I assume they ran out of 7" ones)

apart from the cossie ones (which do seem to be consistent) all you can say is that 7.5" diffs are more common on the later cars

[Edited on 19/10/2014 by mcerd1]

[Edited on 19/10/2014 by mcerd1]

laptoprob - 19/10/14 at 08:13 PM

Many thanks gents for the imfo and Non Custom for the pics. More than enough info here to follow.