Rear diff flanges..

[DJones]

Any BTDT's on changing the flanges on a 7a diff with the larger ones from an ABY diff.

The side ones look straight forward but the front flange is a little more complicated, with regard to the crush sleeve.

The Bentley book talks of a flange turning torque (not nut) of 280Ncm when the center nut is correctly torqued up...

Any advice appreciated...

I guess 280Ncm = 2.8Nm....?

Thanks - Darren.

[Error404]

how come you need to change the front flange?

[LHD_Kid]

I fitted a 7a diff to mine, just changed the side flanges... is the front one different then?

Chris

[DJones]

I may be talking ********.... i have a 4.1 diff in the shed but it has a smaller front flange just guessed it being a 7a. I'm to lazy to rummage through to find the code on it..

So in truth just asking how you change the front flange... the info would be useful the diff in question may be of no use...

Ta...

[LHD_Kid]

I may be talking ********.... i have a 4.1 diff in the shed but it has a smaller front flange just guessed it being a 7a. I'm to lazy to rummage through to find the code on it..

So in truth just asking how you change the front flange... the info would be useful the diff in question may be of no use...

Ta...

My experience is you really need to use a zip gun - the air tools at the garage... This is how I removed mine to fit a new front seal.... but I was not too careful with the tightening torque, just zipped it back up again... seems ok and no leaks...

The diff code should be the same for an S2 and an 7a, just the side flanges are different.... can't remember the code though -someone will tell us soon though...!

Edit: I think the 7a / S2 coupe diff code is AEC

[Error404]

there are different codes for them, but as you say Chris the diffs are the same except the output flanges

My guess removing the front flange would be hammer out the locking tab, couter hold the flange with two bolts and a long pry bar, and crack the nut off

[DJones]

Thanks, i'm just being lazy..... i am accruing the parts for a 6 speed swap and looking to use up some of the shed full of parts (scrap..!)

Thanks - Darren.

[DJones]

there are different codes for them, but as you say Chris the diffs are the same except the output flanges

My guess removing the front flange would be hammer out the locking tab, couter hold the flange with two bolts and a long pry bar, and crack the nut off

Ta, from what i have read, doing it up has to be done with caution as there is a crush sleeve which is measured by a rotating torque to ensure the correct amount of pressure is applied to the bevel bearings. This then ensures the pinion is in the correct place to ensure the mesh is correct with the crown wheel...

Kinda makes sense when you see it in pictures...

[Error404]

Yeah i know what you mean, specialist job really, the rotational torque values change when the bearings are used, plus IIRC there is some weird contraption for measuring it
I think though that you won't need to mess with the front flange, I am assuming you'll need to use a ABY prop on the URq to use a 4.1 gearobx and cq/S2 rear diff? That all bolts up fine

[DJones]

Yeah i know what you mean, specialist job really, the rotational torque values change when the bearings are used, plus IIRC there is some weird contraption for measuring it
I think though that you won't need to mess with the front flange, I am assuming you'll need to use a ABY prop on the URq to use a 4.1 gearobx and cq/S2 rear diff? That all bolts up fine

The Bentley book gives a new and old bearing rotational torque, a light spring weight, similar to a set of scales used for fishing with a hook on it will do.....

The standard prop just needs a 15mm spacer between the prop and box (the 6 speed box is shorter), the rear diff position is identical apart from its currently 3.9...

However the book refers to 280 to 380 Ncm which i think is 2.8 Nm to 3.2 Nm sounds about right....

[Error404]

sounds about right.... but again I'm pretty sure you won't need to touch the front flange