HELP!! Left tool on crank pulley and it REMOVED the bolt when I turned on the car! - PeachParts Mercedes-Benz Forum

pawoSD · #1 05-04-2008, 11:22 AM

I left my 27mm socket on the front of the engine and forgot about it, started the car, and it undid the bolt and it fell on the floor with my tool!

I took the bolt and put it back in, but I can only get it as tight as the resistance of turning the engine, does it need to be tighter than that or do I have to torque it somehow? And how would I hold the crank steady to do that?

Did I break anything? Its all still in place and I realized it after like 5 seconds of having the engine on when I heard the tool fall on the floor!

Help?!?!

babymog · #2 05-04-2008, 11:33 AM

Now that's funny!

Unlikely the balancer moved on the crank it it was still holding belts when you shut her down.

As far as torque, the old screwdriver in the flywheel teeth always worked for me, or between bolt heads on the flywheel. I'm a lock-tite blue fan also.

pawoSD · #3 05-04-2008, 11:40 AM

What do you mean by screwdriver in the flywheel teeth? Where? Do you mean at the back of the motor?

And you do recommend using loctite to hold it in? It didn't appear to have any on it originally...?

kerry · #4 05-04-2008, 11:50 AM

If I'm not mistaken, that bolt takes 200+ foot pounds. You want to make sure it is tight given the problems that occur with the pins on the crank sometimes. MB does sell a tool for locking the flywheel in place while tightening that bolt I think. Don't know if a screwdriver in the flywheel can hold 200+ foot pounds.

At least you're now familiar with the easiest way to loosen it.

pawoSD · #5 05-04-2008, 11:53 AM

Quote:

Originally Posted by kerry

If I'm not mistaken, that bolt takes 200+ foot pounds. You want to make sure it is tight given the problems that occur with the pins on the crank sometimes. MB does sell a tool for locking the flywheel in place while tightening that bolt I think. Don't know if a screwdriver in the flywheel can hold 200+ foot pounds.

At least you're now familiar with the easiest way to loosen it.

Great.....

Knightrider966 · #6 05-04-2008, 12:10 PM

If you remove the starter, you will find it's easier to hold the engine while tightening the front crank pulley bolt. Sorry, but your going to have to do this now to tighten the bolt back to specs!

Not doing this, you run the risk of losing the bolt completely and stripping the end of the crank in the process, a much more expensive proposition!

spock505 · #7 05-04-2008, 12:14 PM

I wouldnt worry as I have seen it posted before as a way of undoing those bolts, especially if loctite blue is used on the thread -

Easiet way I have found to stop the crank rotating is with a piece of soft wood 2" x 4" about half the width of your car -

Jack it up using a trolly jack against the underside of the crank pully, the wodd needs to positioned across the car (left to right) with the left hand side pushing up against the engine bay or something strong (not the wheel arch)

As you tighten the bolt it may dig in to the wood in which case give another push on the jack handle.

babymog · #8 05-04-2008, 12:14 PM

Quote:

Originally Posted by kerry

If I'm not mistaken, that bolt takes 200+ foot pounds. You want to make sure it is tight given the problems that occur with the pins on the crank sometimes. MB does sell a tool for locking the flywheel in place while tightening that bolt I think. Don't know if a screwdriver in the flywheel can hold 200+ foot pounds.

At least you're now familiar with the easiest way to loosen it.

That's less than 200lb of force at the flywheel teeth, I think it can handle it.

Diesel911 · #9 05-04-2008, 01:20 PM

Quote:

Originally Posted by kerry

If I'm not mistaken, that bolt takes 200+ foot pounds. You want to make sure it is tight given the problems that occur with the pins on the crank sometimes. MB does sell a tool for locking the flywheel in place while tightening that bolt I think. Don't know if a screwdriver in the flywheel can hold 200+ foot pounds.

At least you're now familiar with the easiest way to loosen it.

The special locking tool is expensive and you need to remove the starter to install the tool.

engatwork · #10 05-04-2008, 01:33 PM

Keep in mind what 320Nm is like too. Whenever I have done this job I have borrowed a 1" drive torque wrench that is good for about 600 Nm. I don't think it needs blue locktite at 320Nm

.

I've used the screwdriver against the flywheel teeth to prevent the crank from turning on numerous occasions. The starter does not have to come out if you have the MB "holding tool" but as already mentioned they are quite pricey.

winmutt · #11 05-05-2008, 10:03 AM

Quote:

Originally Posted by kerry

If I'm not mistaken, that bolt takes 200+ foot pounds. You want to make sure it is tight given the problems that occur with the pins on the crank sometimes. MB does sell a tool for locking the flywheel in place while tightening that bolt I think. Don't know if a screwdriver in the flywheel can hold 200+ foot pounds.

At least you're now familiar with the easiest way to loosen it.

I find it hard to believe that the starter can put out 200ft lb.............

tangofox007 · #12 05-05-2008, 10:43 AM

Quote:

Originally Posted by winmutt

I find it hard to believe that the starter can put out 200ft lb.............

Diesel starters typically exceed 200 ft/lbs. But it's not just the starter torque that counts, it's the torque at the crankshaft. The starter/flywheel gear relationship must be considered, also.

Diesel911 · #13 05-04-2008, 01:26 PM

I have done this twice on my Volvo Diesel. As others have mentione I put blue Loctite on the (cleaned and degreased with brake cleaner) threads and after threading the bolt in as fare as it would go by hand used an impact wrench to tighten it down. (On the Volvo you have to do the every time you change the timing belt.)
The other way is if you can get inside the crankcase with a bolck of wood; rotate one of the Crankshaft until you can pin the block of wood against the crankcase and torque to bolt down. I have never had the little oil pan off of my Mercedes to know if there is enough room to do this or not.