B44.2 slipper issue.

Hog · #1 22-01-2016

After yet another rear diff failure a week ago, time came to do something about it.

I've rebuilt the diffs with new balls and thrust races and shimmed them correctly (even a little on the tight side at 7 & 2 rather than kit suggestion of 6 & 3).

Racing on Wednesday evening another issue came to light which could be the cause of the failures though - and that's the slipper adjustment, or lack of it.

Even with the adjustment nut backed off as far as it will go so it's touching the forward drive cup, there is no slip from the slipper. If I take the assembly out of the car I can make it slip reasonably easily, but back in the car - nothing. Even when out of the car there is perhaps only 1/2 to 1 turn of the adjustment nut from some to no slip. Nothing is binding in the car, and I've taken the whole assembly apart, cleaned it and rebuilt as per the manual.

I even took the slipper assembly out of my other (used once since new) B44.2 and that's the same. The B44.2 manual says there should be a 2mm gap between adjustment nut and forward cup, but that just locks everything up solid.

Surely this can't be right can it? Do I need a shorter softer spring to give me a better range of adjustment? Or do I have something fundamentally wrong?

At this stage I'm even considering going the route of B44.3 diffs once I've exhausted my stock of B44.2 diff parts!

Thanks in advance for any advice!

stuey · #2 22-01-2016

On my B44 I noticed that the slipper adjustment nut was backed right off, but it still didnt allow any slip. I took the spring out, and fully compressed it a couple of times with some big pliers. Now the adjustment nut is about half way along the thread, and it slips ok now.

Darren Boyle · #3 22-01-2016

You need to file down (remove some material) from the thin end of the top hat which is closest to the centre bulkhead bearing. Simply put the combined width of all the components in between the two bulkheads is too wide, so when put in place the bulkheads squeeze it all together locking up the slipper. It is a known issue on B44.2 and .3 and something we realised really quick on the X6-S which uses the same parts.

Take the small part of the top hat to almost two thirds of its original thickness and it will be fine.

You can also confirm this by taking the slipper out of the car and trying it. It will slip in your hand but as soon as re-installed lock up again...

HTH

Hog · #4 22-01-2016

Stuey - tried that - had no effect on my spring.

Darren - thank you Sir - exactly what I needed to know. And yes it slips in my hand but not installed in the car. Weird though as it fits in the chassis braces easily enough and doesn't feel like it's being squeezed.

stuey · #5 22-01-2016

Darren knows his onions!

Darren Boyle · #6 22-01-2016

Quote:

Originally Posted by Hog

Stuey - tried that - had no effect on my spring.

Darren - thank you Sir - exactly what I needed to know. And yes it slips in my hand but not installed in the car. Weird though as it fits in the chassis braces easily enough and doesn't feel like it's being squeezed.

It will pinch when you fit the top cover and tighten top decks. The amount is small, but enough... I can't take credit for that one since Rich Lowe showed me.

Hog · #7 26-01-2016

Your diagnosis was spot on Darren. I removed some material from the thin end of the "top hat" spacer and took it from 2.6mm to 2mm and now the slipper is fully functional.

Many thanks for your help.

Hopefully my rear diffs will last a bit longer now!

Darren Boyle · #8 26-01-2016

Also regards diffs. Assuming you mean ball diffs, don't be afraid to shim them tight when first built. I put ALL the shims behind the diff gear side when building. On the bench it feels really tight and notchy but after just one run they bed in and free up massively and then last ages too...

Hog · #9 26-01-2016

As tight as that?

Kit shim setting is 6 & 3, but I run mine 7 & 2.

I'll see how I get on now with the slipper doing its job but I shall bear that in mind for the next rebuild if I don't go the 44.3 gear diff route. Have only just rebuilt both 44.2's with Avid ceramic thrust races and Schelle tungsten carbide diff balls so I'd like to get my money's worth from those first before considering changing!