Gearbox intershaft bush

[Steve Hainsworth]

I've always been told bushes that are a push fit will close up slightly once pushed in place. This one I definitely had to push into the first motion shaft (using a vice and a socket as a pusher on the face) but it wasn't hard to do. When I checked it on the shaft I might not have made sure it went all the way down. I've been caught out with that before with a spigot bush on an MGB which prevented me from getting the gearbox to mount as the gearbox input shaft wouldn't fit into the bush in the crank. I ended up having to remove the bush with the toilet paper and wooden plug and BFH method!

It definitely doesn't turn as you mention Steve. Turbocharger bushes work that way and have quite a bit of play but then they run lots of oil pressure too. This is definitely a tight fit in the first motion shaft. I will try the Brasso method as it feels only just tight. I suspect the problem is the shaft and where it is worn not the bush.

Never heard of that Timesaver stuff so looked it up. Seems like one of those things that's been around for ever (longer that Austin 7s even!) and does work for certain things very well. If I could get it I would definitely try it but of course not available locally and once you find someone who will send overseas it costs so much not to be worth while.

Even if I have to lap it in it will still be far tighter than the worn bearing that came out so I think it will work fine. The other thing I considered was polishing the gear shaft but only where it isn't worn by the old roller bearing. I would have thought the bush was made to fit based on an unworn size though.

Simon

Hi Simon,
That bush does need to turn inside the first motion shaft . If it is tight it will mean you have less than half the bearing surface you should have, the bearing is obviously not machined to the correct tolerance on the outside- as a previous message states there needs to be room for oil  (.001" ) The tight fit will have shrunk the I.D and made it tight on the 3rd motion  shaft spigot