Technical Pilot bushing in end of crankshaft removal

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Technical Pilot bushing in end of crankshaft removal

jjacob

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There are numerous posts on the web about how to remove the pilot bushing in the end of the crankshaft at the flywheel end. This is the bushing that the transmission input shaft runs in.
I tried soaking in penetrating oil and using vice grips. Did not work.
Then I tried the grease and drift method! WORKS BEAUTIFULLY!
You pack the bushing with grease and then use a drift or rod that is almost exactly the same diameter as the internal diameter of the bushing. Hit the drift with a hammer and the bushing will magically work its way out. Unbelievable how well it works.
Some guidelines from my mistakes:
-Make sure to pack the grease in tight, making sure there are no air pockets left.
-The drift or rod you use has to be a close fit.
MOST IMPORTANT! Only hit the drift a couple of times. Then withdraw and repack. Repeat. I kept hitting and the drift bottomed out and struck the circular metal disc/plug that seals the end of the crankshaft off. This loosened the disc just enough that it was no longer tight. I was able to fish it out and will replace it. Had I not allowed the drift to bottom out, I would not have damaged it.

I wonder if this is something that causes complaints of low oil pressure when hot for some folks after they do an engine rebuild.
John
 
I must try harder next time John.
The bush was worn so badly in mine that even using an old input shaft was useless. So I resorted to a perfectly fitting shaft from the recently scrapped gearbox from my modern Citroen. The bush would not budge and the videos I saw of it being done always involved a proper roller bearing rather than a blind bush.
Congratulations on that and thanks for the useful tips where you contributed to Chris' thread:
https://www.fiatforum.com/500-classic/445157-65-500f-engine-rebuild.html
 
Peter, you could not get the bush out using the grease and drift method?

Nothing else worked for me. The secret was to really pack the grease in there and use a snug fitting rod to hit. You have to hit it pretty hard, like an impact hammer would, sharp blows. Once it moves the first time it will move a few millimeters with each packing/hitting until you can just wiggle it out.
John
 
is it possible to post a picture to see what are you talking about?
 
Here are two pictures. Item 8 is the bushing and it is pressed into the end of the crankshaft. The end of the transmission input shaft runs in this bushing. Both the end of the input shaft and the bushing need to be measured to make sure they are still within spec when you rebuild the engine.
John
 

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When I replaced my modern car clutch recently (I don't recommend that job to anyone!), the kit came with a very small pack of high-temperature grease which was to be smeared along the input shaft. The bushes as above may be sintered steel capable of absorbing oil, but there appears to be a liner of stainless steel. So I think that a tiny bit of lubricant should be applied. Although the bush was well worn on mine, the shaft was fine.
 
Hi Peter,
There is no SS liner in the pictured bushing or in the one on my car. That is just a machining mark that makes it look that way.
When using the grease packing method you really need to hit the drift hard to create an impact wrench kind of force. This breaks the bond and subsequent blows will slowly work the bushing out. Maybe you could try on a spare crank you might have. I clamped the crank in my bench vise, clamping onto the counter weight.
You are correct that some grease needs to be put into the bushing.
John
 
Last edited:
Here are two pictures. Item 8 is the bushing and it is pressed into the end of the crankshaft. The end of the transmission input shaft runs in this bushing. Both the end of the input shaft and the bushing need to be measured to make sure they are still within spec when you rebuild the engine.
John[/QUOTE

Thanks for the picture.
 
Good info John.
I'm going to wait until the next engine rebuild, which is maybe not so far away, before I try that again[emoji1] But it always helps to know that something that seems tricky has actually been done. I haven't had any engine problems in over 13,000 miles that could be blamed on poor rebuilding techniques. But when I see how precise and thorough people like you have been it makes me wonder if I've been lucky[emoji3]
 
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