Hopefully someone on here can offer some advice.

I've just rebuilt an 8p gearbox with help from elsawin, fitted new synchros, bearings and few new gears. Shimmed the box up as per etka and all went well.

I'm in the process of putting the drive flanges on, and the flange nearest the drivers side has about 2mm of axial play. Tried a different flange but the play seems to be in the diff itself. I've done nothing to the diff apart from replace the worn bearings. Its got the early final drive with no rivets (its pressed together). The play is only on the drivers side flange, the passenger side is good and tight. The flange for the drivers side seems designed to allow for movement, the seal surface is not grooved as per the passenger side which seems to suggest it's meant to move in and out but I don't know, it seems pretty bad.

Have I been dealt a shit sandwich in the form of a bad diff (it was okay before the rebuild) or is there something I've missed?

Anyone out there with an 085 gearbox out of the car that they can check with a wiggle of the drivers side output flange?

Thanks in advance, Vic

Can't help you with this Vic but hope it turns out to be ok mate

Thanks Guy, this has been such a ball-ache of a rebuild.

I believe mines an 085, I'll have a look later on and let you know!

I believe mines an 085, I'll have a look later on and let you know!

That would be awesome, thanks a lot.

I'm not familiar with your particular gearbox, but in general there is a thrust washer between each sun wheel and the diff carrier, just wondered if yours is in place, as 2mm is probably about the thickness of the thrust washer.

Not sure what you mean about a groove in the surface which contacts the oil-seal, surely that should be a plain (cylindrical) surface, could the groove be wear? if it is, then the oil seal won't last too long.

Regards.

I'm not familiar with your particular gearbox, but in general there is a thrust washer between each sun wheel and the diff carrier, just wondered if yours is in place, as 2mm is probably about the thickness of the thrust washer.

Not sure what you mean about a groove in the surface which contacts the oil-seal, surely that should be a plain (cylindrical) surface, could the groove be wear? if it is, then the oil seal won't last too long.

Regards.

Thanks for the reply, I've decided to take to diff out for a look and there's definately no thrust washers between the sun wheel and the diff carrier on either side. The drive flange on the passenger side has a V profile machined in to it where the lip of the oil seal runs, this appears to be holding the flange in one place as opposed to a wear groove. I've assembled the diff and flanges out of the gearbox there is about 2mm play on either flange. It's almost like the flanges are slightly too long where they enter the sun wheels. The play does affect the two sun wheels attached to the flanges, they move in and out with the flanges, affecting the mesh of them with the other two sun wheels.

Is there a 'dirty/rusty' line on the flange outboard of the oil seal? if the is, this might give a clue to the original positioning.

Still not happy about what you describe as a 'v' groove for the oil seal to run in, unless I have got the wrong impression here, this sounds very much like it could be worn in there rather than it being made that way, especially as it is only on one side.

It would be good if anyone has a drawing/exploded view of the correct arrangement.

Regards.

Is there a 'dirty/rusty' line on the flange outboard of the oil seal? if the is, this might give a clue to the original positioning.

Still not happy about what you describe as a 'v' groove for the oil seal to run in, unless I have got the wrong impression here, this sounds very much like it could be worn in there rather than it being made that way, especially as it is only on one side.

It would be good if anyone has a drawing/exploded view of the correct arrangement.

Regards.

Unfortunately, i cleaned everything up including the two flanges when the thing came apart a few months ago. I'll get a pic of the drive flanges. Looking at etka, there are no thrust washers for my type of diff, just a plastic housing.

No thrust washers in a stock 085 diff. The pinion/sun gears do wear though - could that be the cause of the play?

Thanks for the advice Andy, It looks like the pinion gears or the axle flanges are machined too long (or the play is meant to be there!). I've got another 8p in my Derby so i'm going to whip the driveshafts off over the weekend to see if it is the same.

I could get 1.5mm machined off the axle flanges to reduce the play to about 0.5 mm if I have too.

I have just had a look at an 085 box that I have in the garage.

There is definitely no play in the drivers side flange, either in and out or side to side.

The other flange is exactly the same as well.

Hope that helps.

Thanks for checking for me, William - just stripped the diff down and removed the planet gears, etc. Can see nothing wrong with any of it - no wear as such. The splined section of the drive flanges appear to be around 2mm too long allowing the planet gears to move up and down the splines which is causing the slop. Tried a spare set of flanges with the same part number and they are the same.

Turns out that the thrust bearing is a plastic assembly, no copper washers or anything as advanced as that. It looks like my only option is to have the drive flanges machined down - oh joy!

When you bolt the output flanges on to the diff, is there still play in it?

Yes, Andy - I've got the diff assembled and if the flanges are bolted up, there is a good 1.5mm of in/out play on both sides. I think the only cure is to have the flanges machined down by around 1.25mm. Checked my other 8p and there's a little play but nothing like this - the flanges have the same part number too.

shoot me down in a ball of flames here if I'm wrong- is this why some mk3 polo driveshafts are different to others? theres 2mm difference or something in driveshaft length depending on the year of the car-

could it be that you are putting in the wrong parts together which make it a combination of the 2 gearboxes? if the flanges are not the correct ones then you need to change them. might be why you look about 2mm out on the flanges?????????

I've heard the same about the varying driveshaft lengths. Looking at etka, the part no's for the two flanges match the 8p gearbox, but I have no way of knowing if the diff has been changed at some point of course. I'll be using mk1 driveshafts and these flanges have the same part no's as those on my blue Derby (it also has an 8p box). I'm wondering if the diff housing has worn down over the years on the surface that contacts the drive flanges?

I'll have a look on etka for the alternative flange part no's - good suggestion, thanks!

I've a diff flangey thing from an 8p under my workbench if you want it to have a look at?

I've got one i stole the 5th gear from- the casing is now my jig for hydro clutches so i have no need for it.

I've a diff flangey thing from an 8p under my workbench if you want it to have a look at?

I've got one i stole the 5th gear from- the casing is now my jig for hydro clutches so i have no need for it.

Thanks for the offer - really good of you mate, but this morning I've had the flanges machined down a touch and the play is all but gone apart from a deliberate 0.1mm, so happy days.

Glad it's sorted. Good to know the solution too, cheers

yes- glad its done. very useful thread