Some of you may remember my post about the damper pulley on my M reg 300tdi Disco going all wobbly and then failing.
I thought I'd put a post up showing some pics of the original damage and how I attempted to fix it.
So for those of you who have a similar problem and remove the damper pulley and find damage to the keyway on the crankshaft ... hopefully this will be of some help.
You'll find the damage to the crankshaft and you'll be told by some that it's a new crankshaft or a new engine. Others will be more positive and tell you to repair the shaft keyway. Some will say to fill it up with liquid metal.
Here's how I did mine ...
( It's not all back together yet and running so it may all fail within a day or so ... we'll see ... hopefully it will last a wee while )
Anyway ... let's get on with it ...
So I got the front bolt off. Mine just undid easily ... no need for dramatics ... but that's probably why the damper failed ( bolt not tight enough ).
So damper pulley off. Here's a pic of what was left of the keyway inside the damper pulley ...
Ok so that's pretty bollocksed but it'll be a new pulley anyway ...
... so what's left of the crankshaft keyway ...
Oh dear ... a bit off a mess. The keyway is now virtually twice the width it should be.
Also note the old style bottom toothed pulley ( no lips ) and the wear to the front 6mm of the belt. The belt is loose because the tensioner/idler pulleys are off at this point. I cleaned out all the shredded belt dust from the casing.
Now those that read the other threads will know that this toothed pulley was just not coming off. I tried it with a puller kit and it just destroyed the pulley kit. I wasn't prepared to throw any more effort at this at that point as it's also due it's MOT and I've only had car a couple of months so wanted to get it tested before spending more money. So paying to have this pulley cut off wasn't happening. So I decided to just fit new tensioner/idler pulleys and a new belt and leave old toothed pulley where it was. Shame, because it would have been nice to get the new mod kit in but never mind.
So I decided to get two new keys. One would be complete and sit in the normal position and the other would be used to fill the worn area and make good.
Here's a pic of the worn keyway with a new key in normal position to show how much area had been worn and needed filling.
It's not easy to see in the photos but the left hand edge ( end of worn area ) is actually worn so that the bottom is actually further to the left than the top. So the bottom of the repair key will be wider than the top. This helped to fix it in as the repair key was wedged in first ( slid in from right to left ) and the new full key tapped in in the normal position at the right. I made it a tight tap in fit to reduce any chance of vibration as much as possible.
So the repair key was carefully made to the right fit with files.
I then fixed in the repair key to the left with JB Weld and used the same to fill the small gap that was left at the very rear of the repair area. The new full normal key was then tapped into place on the right and the repair key to the left then filed down to match the contour of the shaft.
Here's a pic of the repair ...
As I got near to being level with the shaft I kept trying the new damper pulley as I wanted to leave the repair key a few thou proud so that it would be a tight fit with the pulley ... again to hold it tight in place and stop any movement.
Also note the new belt fitted on the toothed pulley. The timing was slightly out so I set that up properly whilst fitting the new belt. I hope she starts when it's all back together.
I vaccuumed out all of the filings.
The new damper pulley now fits on nicely. It's a firm tap fit and once all the way on the key it's pretty solid.
I'll now fit a new seal to the timing case front cover and refit that. The new damper pulley can then be fitted. I'll use Loctite 243 on the shaft and keyway before fitting.
The front bolt can then be refitted and tightened up to the spec of 80Nm and then a further 90 degrees ( or at least I'll try ). Apparently the further 90 degrees takes that up to between 250 and 350Nm. I'll use Loctite 243 on the bolt thread too.
The way I've done it I should be able to get that front damper pulley off in the future to check the repair and replace timing belt as required. Providing that Loctite 243 will come off with a puller ( it says it will undo with 'hand tools' ).
This may all fail within minutes but it seems solid enough at the moment and the key seems to be getting the right torque on that front bolt. If that's done properly then there shouldn't be that much stress on the actually keyway.
Whilst the rad and intercooler are off I'll clean them out.
Hope this has been of some interest / help.
Sorry if it's been shown before.
Colin
I thought I'd put a post up showing some pics of the original damage and how I attempted to fix it.
So for those of you who have a similar problem and remove the damper pulley and find damage to the keyway on the crankshaft ... hopefully this will be of some help.
You'll find the damage to the crankshaft and you'll be told by some that it's a new crankshaft or a new engine. Others will be more positive and tell you to repair the shaft keyway. Some will say to fill it up with liquid metal.
Here's how I did mine ...
( It's not all back together yet and running so it may all fail within a day or so ... we'll see ... hopefully it will last a wee while )
Anyway ... let's get on with it ...
So I got the front bolt off. Mine just undid easily ... no need for dramatics ... but that's probably why the damper failed ( bolt not tight enough ).
So damper pulley off. Here's a pic of what was left of the keyway inside the damper pulley ...
Ok so that's pretty bollocksed but it'll be a new pulley anyway ...
... so what's left of the crankshaft keyway ...
Oh dear ... a bit off a mess. The keyway is now virtually twice the width it should be.
Also note the old style bottom toothed pulley ( no lips ) and the wear to the front 6mm of the belt. The belt is loose because the tensioner/idler pulleys are off at this point. I cleaned out all the shredded belt dust from the casing.
Now those that read the other threads will know that this toothed pulley was just not coming off. I tried it with a puller kit and it just destroyed the pulley kit. I wasn't prepared to throw any more effort at this at that point as it's also due it's MOT and I've only had car a couple of months so wanted to get it tested before spending more money. So paying to have this pulley cut off wasn't happening. So I decided to just fit new tensioner/idler pulleys and a new belt and leave old toothed pulley where it was. Shame, because it would have been nice to get the new mod kit in but never mind.
So I decided to get two new keys. One would be complete and sit in the normal position and the other would be used to fill the worn area and make good.
Here's a pic of the worn keyway with a new key in normal position to show how much area had been worn and needed filling.
It's not easy to see in the photos but the left hand edge ( end of worn area ) is actually worn so that the bottom is actually further to the left than the top. So the bottom of the repair key will be wider than the top. This helped to fix it in as the repair key was wedged in first ( slid in from right to left ) and the new full key tapped in in the normal position at the right. I made it a tight tap in fit to reduce any chance of vibration as much as possible.
So the repair key was carefully made to the right fit with files.
I then fixed in the repair key to the left with JB Weld and used the same to fill the small gap that was left at the very rear of the repair area. The new full normal key was then tapped into place on the right and the repair key to the left then filed down to match the contour of the shaft.
Here's a pic of the repair ...
As I got near to being level with the shaft I kept trying the new damper pulley as I wanted to leave the repair key a few thou proud so that it would be a tight fit with the pulley ... again to hold it tight in place and stop any movement.
Also note the new belt fitted on the toothed pulley. The timing was slightly out so I set that up properly whilst fitting the new belt. I hope she starts when it's all back together.
I vaccuumed out all of the filings.
The new damper pulley now fits on nicely. It's a firm tap fit and once all the way on the key it's pretty solid.
I'll now fit a new seal to the timing case front cover and refit that. The new damper pulley can then be fitted. I'll use Loctite 243 on the shaft and keyway before fitting.
The front bolt can then be refitted and tightened up to the spec of 80Nm and then a further 90 degrees ( or at least I'll try ). Apparently the further 90 degrees takes that up to between 250 and 350Nm. I'll use Loctite 243 on the bolt thread too.
The way I've done it I should be able to get that front damper pulley off in the future to check the repair and replace timing belt as required. Providing that Loctite 243 will come off with a puller ( it says it will undo with 'hand tools' ).
This may all fail within minutes but it seems solid enough at the moment and the key seems to be getting the right torque on that front bolt. If that's done properly then there shouldn't be that much stress on the actually keyway.
Whilst the rad and intercooler are off I'll clean them out.
Hope this has been of some interest / help.
Sorry if it's been shown before.
Colin
