Hello all,

Hope someone can help.

On my '28 101 I have the clutch casing parts ready to assemble.

If I fit the intermediate gear shaft into the "Driver Case" S2433 (the end of the shaft with the "woodruff" key), then fit the outer cover S2437, the shaft has quite a lot of end float between the cases.

Measuring all the parts with a digital caliper I got end float of around 2.65mm (0.104").

I attach a PDF drawing which I have created showing the section through the cases, with the shaft moved sideways to illustrate the problem, and also a picture of the actual cases, where the gap between the thrust washer and end of the shaft can be seen.

The thrust washer that is fitted to the inner (driver) case S2433 is missing as I found it to be cracked and needs replacing - however I assume it is similar to the outer thrust washer with a central hole large enough to allow the shaft to pass through. (Outer thrust washer has bore diameter 20.75mm (0.817") while the shaft is diameter 20.6mm (0.811")

The shaft carries 2 sets of caged rollers, which if left like this will allow the rollers to run off the end of the shaft.

The selection of thrust washers available are to set the intermediate pinion end float, but I'm wondering about centralising the inner shaft.

The solution that comes to mind is to machine a disc to be fitted behind the ends of the shaft to centralise it.

Has anyone else noticed this? Or am I missing something?

Help appreciated.

it is called the idle gear and idle gear shaft. The idle gear connects between the driver gear on the crankshaft, and the gear on the clutch basket.

You have something wrong there, the sideplay should not be that large. Making thicker thrust washers for that large gap, or shim the shaft in the center bore is not a good idea for several reasons.

Both thrust washers needs to be properly installed, they are and should be same thickness. If you do have both washers installed and still have that sideplay, then I think the thrust washer have spun and the seats are worn deep, modified or wrong thrust washers installed.

Or shaft is wrong, worn or modified or perhaps the shaft have been installed without the woodruff key and spun grooves in the thrust washers. I don't have the shafts that I have, at hand, so I can't measure it for you right now today. 

Mick, sorry I misunderstood!  Here's a couple of pictures to start, let me know if you'd like more or have me take some measurements!

Hi,

Thanks for the input.

I'm coming to the conclusion that the keyed bush on the inner casing has been pushed in when the shaft plus woodruff key was fitted with misaligned key. If you refer back to my earlier posting with 5 images, one clearly shows the keyed bush way down below the surface for the thrust washer.

Looking at the damage to the key, some considerable force must have been used to press the shaft into the bush.

I don't have any idea what the original machining of the bare casting is like in terms of bore depth to take the bush (as bush is still in there), so it is possible that factory assembly was to press the bush in flush to the face of the casting with room spare behind the bush to allow for tolerances - or course this is my conjecture - Feel free to correct me!

The only problem with verifying where the top of the bush should be - is that without removing the keyed end of the shaft from the casing, it's not easy to check dimensions.

Now I have 2 options:

Option 1 is to try to make or  modify a blind bush puller that can grip the tiny amount of gap behind the bush, heat the whole case up in the oven, and try to pull the bush back to the desired position.

Option 2 is to machine up a disc (thick washer), with a cut-out to clear the woodruff key to take out the end float. The disc would be trapped behind the new thrust washer when everything is assembled. Downside is that woodruff key engagement will be reduced.

Unfortunately due to the keyway, I cannot use the sized bar/grease and hydraulic force method to push the bush out.

I'm going to put that part to one side for now and ponder, while I do something else on the list!

I'm sure someone else must have found this problem??

Regards Mick