Removing hexagonal bolt on bottom crankshaft wheel

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vertford

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There are engineers and mechanics.... and then there is me.

I am trying to get the bottom crankshaft wheel (Is is that called a flywheel?) off on my 1GM10. How do you that? Very big socket set nut? Flywheel puller?

I have YouTubed and Googled and get lots of stuff about cars but cann't seem to find any inboard engine stuff. Flywheel pullers just confuse me.

I need to take the wheel off so I can access some bolts to take the water pump out to change the seals.

Thanks
 
No its not the flywheel! All you are looking at is the crankshaft pulley.

There is a workshop and other manuals at http://www.motoren.ath.cx/menus/yanmar.php

The pulley appears to be keyed onto the shaft. Not sure if its on a taper or not.

If I read the manual correctly the nut is pretty tight so yuo'll need a good 1/2" drive socket set and the correct size socket ( measure across opposite flats in mm)

If it is on a taper you will need a puller as well.
 
vertford said:
There are engineers and mechanics.... and then there is me.

I am trying to get the bottom crankshaft wheel (Is is that called a flywheel?) off on my 1GM10. How do you that? Very big socket set nut? Flywheel puller?

I have YouTubed and Googled and get lots of stuff about cars but cann't seem to find any inboard engine stuff. Flywheel pullers just confuse me.

I need to take the wheel off so I can access some bolts to take the water pump out to change the seals.

Thanks
Click to expand...
Hi,I have removed the water pump on a raw water cooled 1gm10 Yanmar without removing the pulley.A bit fiddly to get the bolts out-you may need to modify a 10mm spanner,but not impossible.If you do need to get the pulley off you will find it benificial to "shock"the retaining bolt by thumping the spanner or socket bar with a heavy mallet or hammer.If you are lucky you wont need to lock the engine to stop it rotating.Hope this helps.
 
The nut is 27mm a/f and is tight. Although it isn't on a taper it is keyed, and I used a puller to shift mine. In fact I used this puller:
http://www.machinemart.co.uk/shop/product/details/cht248-13-pce-harmonic-balance-puller to shift mine.
To stop the engine turning I fastened the puller to the pulley with two of the supplied bolts, and then wedged a large screwdriver across the bolts and against the edge of the engine bay - it's easier than it sounds.
However as has already been mentioned unless the innermost bolt is damaged you don't need to remove the pulley to get the water pump off.
 
Innermost bolt..

Thanks Pete for the puller info.

I have a feeling that the innermost bolt head is failing as Elton's link talks about
I took my spanner off it yesterday as the bolt head started to take a rounded off look to it.
 
A cracking good way to undo such things is to use an air impact driver, like the ones the gorillas at Kwikfit use to attach your wheels irremovably to your car. You don't even need to chock the crankshaft - the blows are so brief that the nut will invariable undo after the crankshaft has barely turned.

FACNS1010F.jpg


If you are not in a position to get a compressor airline to the engine, it might be worth trying an electric impact driver. There are some cheap ones available and though I haven't - yet - tried one on a crankshaft bolt I have seen them used to good effect.

DC12V_Impact_Wrench.jpg
 
1GM10 water pump continued. Covering the hole...

I have bumped this back up as I have managed to get all the bolts off and the pump off/loose.

My next query is this. Once I take the pump out to reseal and repaint it, what do I cover the hole into the engine block with? I assume something to keep dirt and moisture out. Masking tape? Make a little cover up and stick it over? A sock...
 
vertford said:
I have bumped this back up as I have managed to get all the bolts off and the pump off/loose.

My next query is this. Once I take the pump out to reseal and repaint it, what do I cover the hole into the engine block with? I assume something to keep dirt and moisture out. Masking tape? Make a little cover up and stick it over? A sock...
Click to expand...


masking tape, gaffer tape. duct tape all good
 
If you are going to work on the crankshaft nut and you are going to use a spanner on the end of the crankshaft remember that all a diesel needs is is a bit of compression to fire.

Even a small 'kickback' could ruin your day, not to mention break an arm, foot, fingers or anything else in the way!
 
Undoing crankshaft pulley nut

You could try an old trick but you do need a good fitting socket and a sturdy bar with which to stop the socket turning.

Jam the bar so that it cannot turn. Hold the socket/bar in position and get some body to briefly hit the starter button. The crank will turn in its normal direction of rotation. The socket will not be able to move because the bar is jammed. The nut will be loosened. You may need to do this a few times but usually it comes loose first time. Be carefull to make sure that your fingers cannot become trapped.

This is the way that I have undone many crank pulley nuts/bolts. Sounds crude but it does work. A bit of care is needed.
 
On the basis that you won't be doing anything boaty until the pump is back on there isn't much need to block off the hole. There is almost as much condensation inside the motor as outside. Put a sock in it is not as daft as it sounds. It's what rags are made for.
 
Crankshaft nut

Perhaps amusing but a word of warning. My memory still smarts of my attempts to remove the front crankshaft pulley on a petrol Mitsubishi van. It was difficult to reach and see but there was a big hex nut on the pulley. I tried very hard to remove that nut. Eventually destroyed a socket. Finally found the pulley attached by 3 bolts around the hex. The hex was there to enable the engine to be turned over. it was cast into the pulley. Beware... olewill
 
If you really struggle getting the pully off ring up a Mobile Mechanic thats what I did. Perhaps £20 an hour when I wanted a camshaft belt changing which involves removing the bottom pully which I neither have the large socket for or a torque wrench to put it back on correctly.
 
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