I am trying to remove the head off a diesel engine. I got them all off except the center row. They are a size 12mm allen.

I can't get them off and afraid I am going to strip the bolt head. (I have a 3 foot pipe on 1/2' drive breaker bar).

Someone said try heating the bolt. Any other suggestions?

 

Hi,

Thanks for the post. I looked up the "triplesquare". I already removed all of those bolts (with a star type socket).

Then I removed the cam shaft. Under the cam shaft is a row of apr. 5 bolts. A 12 mm allen just about fits right. (just a hair loose). Note: the top of these bolt heads are just about flush with the head so there is no way, in the event of striping the allen socket, that I can cut these bolt heads.

I put a 3' pipe over the 1/2"breaker bar to help get some turning leverage and with all my might, I tried unscrewing the bolt. No luck.
(PS: To help push down on the socket, I ended up straping a wide tie down strap around the engine and over the breaker bar and pulled the socket super tight into the bolt.) I have tried turning but now the allen is turning in the bolt headand is coming close now to striping.


Any other hints?

Scott

 

As per FI 's instructions : "It is not an Allen"

"Almost Fits" or "It's a tad Loose" will create a nightmare scenario which you are enjoying now!

Proper tools use on Mercedes is almost paramount to a successful repair.

To answer your question: You are ****** on this repair...pray and hope that a machinist
can drill and remove the offended bolt (If you cannot with an "Easy-Out")

Chances are you've "boogered" the other bolts also with this treatment...No worry,replace with
new bolts WITH the proper tool.