Hitchcocks Forum

Hi All, I'm just starting to rebuild my 1990 500 bullet gearbox with the Hosts sealed bearing kit, I've found that when putting the new bearing on the mainshaft (there is a small amount of float one the gear) was like this with old bearing. When placing the shaft and bearing into the case the gear will rub slightly on the case ? I've only gone this far at the moment as i'm questioning it (NOT the kit , just if it's right) not sure if once it's all assembled and tightened that it might pull away?? Ant ideas??

You have bigger issues that you are aware of.


The bearing is NOT supposed to be a push fit into the case; it requires heat on the case for the bearing to fit. So, the bearing you have (C3 clearance?) is not suitable.


IF the fit is only a slight 'push' fit, degrease all and fit a Std clearance bearing with retaining compound.


If the brg is a loose sloppy fit into the case, you will have to remove the gear box case for repair...


That the main shaft gear is making contact with the case is cause for serious concern. I would advise you to seek a second professional opinion; something is very badly worn: the Case itself, the Gear or the Sleeve?

Hi Tim , thanks for your reply, I have seen your replies to a few other GB problems.
The bearing to case fit is very tight ( I am only "dummy" building) that this stage to confirm everything.
When I do final assembly,, I will use bearing fit loctite.
My main points are one the main shaft gear has end float between shaft and bearing ?
This was noticed on strip down ?? Not a lot but noticeable .
Then as stated the gear rubbing the case, this now appears to be the gear is kissing the layshaft bush.
It's only slight, and only when the gear " floats" towards the bearing???
Do you know if this float is normal ?
I was toying with the idea of shimming The between the gear and bearing,
This would bring the gear away from the case ?
Any thoughts???
Just to confirm I'm familiar with gearboxes as I worked for ZF for over 10 years.
Thanks again

Excess end float on the sleeve gears implies the gear box sprocket nut has not been fully tightened...


But in that situation the Lay shaft 1st gear teeth will also be making contact with the outer race of the ball bearing; check the old bearing for ANY sign of damage/wear to the corners of the outer race.


With a correctly supported main shaft and sleeve gear, it should not be possible for the for gear to make contact with the layshaft bush. Even if the bush was not seated deep enough into the case...

Excess end float on the sleeve gears implies the gear box sprocket nut has not been fully tightened or the bearing seated fully...


But in that situation the Lay shaft 1st gear teeth will also be making contact with the outer race of the ball bearing; check the old bearing for ANY sign of damage/wear to the corners of the outer race.


With a correctly supported main shaft and sleeve gear, it should not be possible for the for gear to make contact with the layshaft bush. Even if the bush was not seated deep enough into the case...