10 replies to this topic

[new_van_man]

Hi,

I am rebuilding my diff. I have replaced the planet wheels and copper bits behind as well as the main shaft, but the diff seems very tight, in fact so tight i cant even turn it before the crownwheel has been fitted and torqued up. It is literally rock solid.

I have tried not fitting the new fibre washers and swopping in the old ones, but makes no difference.

It does not seem right in my semi mechanical mind that it should be that tight.

Any help would be much appreciated.

Cheers,

Ed

[dklawson]

If you have fit new cupped washers under the spider gears, consider taking the diff back apart. Take the cupped washers and spider gears to your bench vise along with a block of soft wood.

Place the cupped washer on the block of wood, then put the spider gear on the curved surface of the cupped washer. Place these assembled bits in the bench vise and tighten it slowly. The spider gear will be driven into the cupped washer which will sink into the block of wood. This will force the cupped washer to better take on the shape of the spider gear.

Take those re-shaped bits and reassemble the differential. This may help give you a few thousandths of an inch more clearance. If it doesn't resolve the problem, at least it will have done no harm.

[new_van_man]

If you have fit new cupped washers under the spider gears, consider taking the diff back apart. Take the cupped washers and spider gears to your bench vise along with a block of soft wood.

Place the cupped washer on the block of wood, then put the spider gear on the curved surface of the cupped washer. Place these assembled bits in the bench vise and tighten it slowly. The spider gear will be driven into the cupped washer which will sink into the block of wood. This will force the cupped washer to better take on the shape of the spider gear.

Take those re-shaped bits and reassemble the differential. This may help give you a few thousandths of an inch more clearance. If it doesn't resolve the problem, at least it will have done no harm.

Ok will give that a try, my old cupped washers have abit of a lip on them and look a little worn and the planet gears are very shiny where they have been rubbing so i think best to replace these.

Will give it a go now. Thanks for the quick response , will let you know how i get on.

Cheers,

Ed

[new_van_man]

Well it kind of helped but resulted in a very lumpy movement.

I have refitted the old components with new pin and fibre washers and the play is reduced and diff rotates very freely. There is still abit of wobble at the ends and small gap opens up between the fibre washer and casing, so th current planet gears are worn a bit.

But when i tried fitting with new planet gears and old curved washers the result was very lumpy and would lock up half way round on rotation.

How tight should the diff be when rebuilt? should be toufgh to turn but assum eit should turn smoothly and no lumpily. The diff is unlubricated?

I also tried fitting new curved washers with the old planet wheels and the result was lumpy rotation.

Only combination which seems to work is teh old parts....... I dont get it am i being really simple and missing something very obvious?

Cheers,

Ed

[new_van_man]

I have measured the new planet gears and they seem tobe 0.06mm thicker than the old ones. Would this be enough to cause the diff to lock up?

[v21ash]

Have you fitted Genuine fibre washers? as they are apparently 48 thou thick which with new gears can lock up the diff, original ones were 35 thou thick.
I fitted genuine ones in my X Pin diff which made it very tight so i then bought Mini Spares BTA101 standard size washers and it was ok after that.

[new_van_man]

Have you fitted Genuine fibre washers? as they are apparently 48 thou thick which with new gears can lock up the diff, original ones were 35 thou thick.
I fitted genuine ones in my X Pin diff which made it very tight so i then bought Mini Spares BTA101 standard size washers and it was ok after that.

Yup tried fitting the old washers and still locks it up

[Guess-Works.com]

When and where did you get the pinions from ?

[new_van_man]

When and where did you get the pinions from ?

The pinions and domed washers were part of rebuild kit
From minisport bought about 3-6 months ago when they had full kit reduced

[dklawson]

I remember the same comment about fiber washer thickness that V21Ash made. I seem to remember that a common fix was to gently lap the washers against a piece of sandpaper resting on a piece of plate glass until the desired thickness was reached.

John, am I remembering that right?

[new_van_man]

I remember the same comment about fiber washer thickness that V21Ash made. I seem to remember that a common fix was to gently lap the washers against a piece of sandpaper resting on a piece of plate glass until the desired thickness was reached.

John, am I remembering that right?

I tried using the old washers which are very thin, and still totally locked, this is before crownwheel has been placed so no weight on it so should turn freely? No?

Spoke with minisport and they have agreed to take a look and sort out for free which i was quite surprised by.