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MG MGF Technical - impact wrench on Crankshaft Pulley

Does anyone know if I use an impact wrench on the Crackshaft Pulley to undo the central bolt or will it damage the bearings?

One of the difficult bits about changing the Cam belt is undoing the pulley bolt - if it can be undone with a impact wrench the only difficult bit is then to to tighten it up to the correct torque !!

Chris

C Bowes

I used one on mine...

The crank will barely turn as you apply force to the bolt. As for doing it up again I found a long enough extension to go through the wheel, and someone standing on the brak pedal with the car in gear worked OK.

Alan Brooke

Why not just get a good breaker bar - thats what I used (with becky holding the engine upright as it was lying on the floor).

Torqueing back up is the tricky job at 210Nm
Will Munns

Mark the centre bolt's position in relation to the pulley before undoing it with the impact wrench.
When fitting (with the same tool) tighten until the marks align. Then it should be equally tight to what it was before dismantling.

Using an impact wrench on timing gear is OK as long as it is a belt one. A timing chain is not flexible and may be harmed by the shocks from an impact wrench.
Jon

If your gonna do it then please do it properly. What is the point of using a stupid solution to get it off if you haven't got the material to do it back up again to its correct torque.
If you've got the tools to torque it back up then these tools will undo it no problem.

Don't risk killing your crankshaft thrust bearings with an impact driver.

Pete
Pete

Chris

I'd borrow Becky to hold it up right if I were you.
JohnP

>If you've got the tools to torque it back up then these tools will undo it no problem.

Not so for the standard 'click' type wrenches - these should not be used as breaker bars. I have a deflection type which is good for undoing as well as doing up. But a breaker bar is the _correct_ solution.
Will Munns

Pete

''Don't risk killing your crankshaft thrust bearings with an impact driver. ''

I was considering using an impact wrench not a impact driver!

This was to allow the bolt to be undone without taking the starter motor off to lock flywheel. I can then torque it back up by using 5th gear and the brakes on

Chris

C Bowes

Excuse my ignorance. Following this hints with utmost interest :)

What's the difference between impact wrench and a impact driver?

**joke mode on ***
_an_ impact driver ?? ;-)
**joke mode end ***

Dieter
Dieter K.


Impact wrench or impact driver, you are still hitting the sh*t out of it with a huge hammer.

What is a breaker bar ??

Pete
pete

>Impact wrench or impact driver, you are still hitting the sh*t out of it with a huge hammer.

Not so, an impact wrench is the airgun type arangement used by tyre fitters, where it uses a number of knocks to free the bolt (I made this mistake as well - but thought I better look it up!)

A breaker bar is a iron bar with a 1/4,3/8,1/2 etc. drive at the end. They come in various lengths - I have a foot long, a 2 foot long and a 3 foot long bar. This alows you to get a lot of torque thru your nuts.
Will Munns


"This alows you to get a lot of torque thru your nuts"

good one that.

sorry for being wrong but i thought an impact wrench would need to be hit by a hammer.

pete
pete

"This alows you to get a lot of torque thru your nuts"

If nothing else, that sounds painful Will! 8oO
Rob Bell

After doing various cambelts on a variety of cars including a Lancia HPE which gives you about as much space as an MGF to work with I thought long and hard about doing the cambelt myself.

and I decided against doing it simply because of the crank pulley issue. you just cant afford to get this bit wrong! so I left it to a Rover Mechanic who had a air spanner and the appropriate wrenches and locking devices


Neil

This thread was discussed between 06/09/2004 and 08/09/2004

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