getting out the *&?**! spigot bearing bush

Post by **wibble_puppy** » Sat Nov 03, 2007 4:13 pm

ello chaps,

well it's a bit of a poor show this afternoon.

Have been trying to get the old spigot bearing bronze bush out of the flywheel hole, in order to replace it (it's the bush visible in the centre of the crankshaft hole, centre of flywheel after removal of the clutch). It's the part which the workshop manual calls a "drive gear bush".

I've been using a method recommended to me, of packing the hole with grease and then inserting an input shaft and tapping it with a mallet. This is supposed to create a hydraulic force which shifts the bush.

Can't make it budge.

I've tried gripping the end of a long nail with pliers and hooking its head behind the inner edge of the bush and heaving - no good.

Any ideas?

wibble

Post by **kennatt** » Sat Nov 03, 2007 4:32 pm

had the same problem once on an mgb used a broken hacksaw blade and carefuly cut through the brass bush then drove thin screwdriver down the side and freed it up then it fell out

Post by **bmcecosse** » Sat Nov 03, 2007 4:39 pm

The bush is in the crankshaft end stub - not in the flywheel. If it's present - just leave well alone! If you MUST change it then either continue with the grease - it does work, but you have to be brave and really mash the stick going down the middle - or, drill it out until it falls to bits. These bushes rarely wear - so as earlier - seriously consider just leaving it be !

Post by **Alec** » Sat Nov 03, 2007 4:48 pm

Hello Wibble,

I agree with BMCE, it's not that critical.
However, for the grease method to work needs very little clearance for it to work and I suspect an input shaft and a worn bush will be too sloppy.

Alec

Post by **bmcecosse** » Sat Nov 03, 2007 4:54 pm

Indeed - I hadn't noticed 'input shaft' - a wood dowel rod works much better - but does need to be tight in the bush. And 'tapping with a mallet' will never do it!

Post by **Willie** » Sat Nov 03, 2007 5:15 pm

Easy, it is made of phosphor bronze which is quite brittle and it is housed in a much harder lump of steel so just tap a sharpish thin screwdriver between the bush wall and the housing and it should shatter and fall out
without damaging the flywheel.

Post by **alex_holden** » Sat Nov 03, 2007 5:18 pm

bmcecosse wrote:Indeed - I hadn't noticed 'input shaft' - a wood dowel rod works much better - but does need to be tight in the bush. And 'tapping with a mallet' will never do it!

Input shaft, grease, and a big copper-faced mallet worked for me without too much difficulty. What I didn't expect was for the bush to split into several pieces as it came out. beware using an input shaft to drift the new bush in - it's chamfered at the end of the small diameter which distorts it rather than pushing it cleanly in.

Post by **wibble_puppy** » Sat Nov 03, 2007 5:28 pm

Thanks very much for your posts, everyone.

The bush is worn and needs replacing.

Sounds like I'm not going to get it out with this input shaft - there is indeed a bit of "wiggle room" between it and the bush. My use of the word "tapping" was perhaps a little understated

So tomorrow it sounds like I should be getting in there with something designed to cut the wall of the bush. Hmmm.

Willie wrote:tap a sharpish thin screwdriver between the bush wall and the housing and it should shatter and fall out

Thanks v much for that, Willie. The bush is a pretty snug fit, though, and of course cylindrical, how do I get a flat-bladed screwdriver between it and the wall of its hole? Do I need to grind the blade to angle it to a point?

alex_holden wrote:beware using an input shaft to drift the new bush in - it's chamfered at the end of the small diameter which distorts it rather than pushing it cleanly in.

Thanks for that, Alex - my next question was indeed going to be, how to drift the new bush in (as the actress said to the... never mind)

Suggestions?

Post by **les** » Sat Nov 03, 2007 10:04 pm

If you screw an M12 second tap into the bush it should 'extract' itself out, or use any tap that will start to cut a thread. Good luck.

Post by **Alec** » Sun Nov 04, 2007 8:28 am

Hello Wibble,

"how to drift the new bush in"

Ideally, a stepped diameter drift would be used, but anything you have to hand that is softer than the bush will do, e.g. a piece of timber end on of a suitable size. Just take care to start the bush square and keep it there. If it goes off true stop and start at the beginning.

Alec

Post by **wibble_puppy** » Sun Nov 04, 2007 8:33 am

les wrote:If you screw an M12 second tap into the bush it should 'extract' itself out, or use any tap that will start to cut a thread. Good luck.

mmm I don't have any taps large enough I don't think - but that's an exceedingly cunning idea, les - I will go and look - thank you!

Thanks Alec for the very useful tips on sticking in the new bush - this is a wonderful adventure isn't it - I'm learning a lot! Will whittle myself a nice dowel of the right diameter - cheers

Post by **Willie** » Sun Nov 04, 2007 10:27 am

You are missing the point, the bush is so soft compared to the flywheel
that the screwdriver or whatever will normally shatter it with no damage to the housing. Witness the remark above from Alex that it fell to pieces when extracted.

Post by **ndevans** » Sun Nov 04, 2007 10:53 am

Not having done this myself I'm probably not in a position to give advice, but here goes....from what Willie says it sounds like a couple of swift blows with a cold chisel would bring matters to a conclusion????

Post by **wibble_puppy** » Sun Nov 04, 2007 12:37 pm

that's the curreent plan

will have to search deepest depths of old toolboxes to see if I have a cold chisel which is small enough though

and then make one out of a screwdriver if I don't

Post by **MoggyTech** » Sun Nov 04, 2007 3:46 pm

While you are attempting to extract the old bush, make sure the new one is soaking in engine oil for at least 24 hours prior to fitting.

FWIW I got the old bush out using the M12 tap method, it took all of about 2 minutes.

Post by **wibble_puppy** » Sun Nov 04, 2007 7:41 pm

cheers for that, MoggyTech

Well, after a fair amount of time with a cold chisel I did manage to get the blighter to turn up its toes. A few bits went inwards, and I scooped them out, along with the copious quantities of grease still in there from yesterday's efforts

The rest of the cylinder then came out easily.

It's interesting to see what the hole looks like without the bush in.

Will soak new one as suggested, and bung it in asap. Then it's on with the new clutch!

Thanks for all your help, everyone, it's much appreciated

It's interesting that NONE of the books I have mention replacement of this bush - and yet so many of you have replaced yours. Doh.

Post by **bmcecosse** » Sun Nov 04, 2007 7:50 pm

They never really NEED replacing unless they get damaged when changing gearboxes. There is only relative movement (and therefore possibility for wear) between shaft and bush when you are sitting in gear with your foot on the clutch - which of course you (we) never do!

Post by **wibble_puppy** » Sun Nov 04, 2007 7:52 pm

bmcecosse wrote:sitting in gear with your foot on the clutch - which of course you (we) never do!

Nope, I have good driving habits, by and large (and always interested to learn new ones

)

On the other hand, I've only driven this van for a few months, between buying it and starting the restoration, and you don't always know how the vehicle was treated before you got it, I guess.

Post by **bmcecosse** » Sun Nov 04, 2007 9:06 pm

Indeed - POs - bless them! Anyway as above - take great care fitting it to make sure you don't damage the new one !

Post by **wibble_puppy** » Sun Nov 04, 2007 10:01 pm

Incidentally, the mighty struggle left a couple of small scratches to the hole in the crankshaft. I'm surprised, as my cold chisel doesn't seem to have a particularly good temper (it's an old one and has been much abused by Griff

) I'm hoping (I mean, I'm really hoping, a lot) that these scratches aren't a problem?