I stripped out the allen head starter bolt - PeachParts Mercedes-Benz Forum

Dlduchon · #1 09-09-2002, 10:22 AM

I was changing out my starter on my 1983 240D. Everything was going smoothly until the last, top 10mm allen-head bolt. It would not budge. I used a 10 mm allen head socket with a cheater bar and it would not budge and began to strip out. It actually felt like the socket would snap if I tried any harder. I soaked the area with penetrating oil and was working with a cool enginge. Would it be better with a hot engine? Would hitting the bolt with a torch help or cause more damage? I saw the idea of valve lapping compound but I think I am beyond that stage. There is some room between the fire wall and the bolt, but the room is limited. HELP?

Darryn

joe p · #2 09-09-2002, 10:28 AM

find a 12 point short socket and pound it over the bolt head, the pounding should loosen it too.

Joe

brianc320 · #3 09-09-2002, 12:49 PM

Not knowing exactly what the configuration is makes me hesitant to reply. Proceed at your own risk, YMMV, etc

Having worked in aerospace for the first career (15 years), I came upon a lot of frozen allen head bolts. I found that some heat applied to the surrounding area would tend to expand the I.D. of the threaded hole slightly, frequently freeing the bolt. The trick is to work fast because once the bolt heats up you lose, since the O.D. of the bolt expands as well, negating the advantage. I would soak thoroughly, tap the head to set up some vibration (may free rust or oxidation) and then try the heat trick.

If the problem is that it's over torqued, the opposite could work. Heating the bolt could expand the length and give you the needed release.

In either case, don't apply too much heat as taking the temper out of the bolt or surrounding metal could be bad.

Brian

#4 09-11-2002, 11:19 PM

one trick that works when you come across a frozen nut or bolt is to never keep pushing the limit until the head breaks. playing chicken with frozen bolts is a real headache. if you encounter a frozen bolt hit it with lots of liquid wrench then apply a torque in both the positive and negative direction this works more effectively than just applying a 'loosening' force. this also works if you have a screw somewhere at home that has been painted over.

car54 · #5 09-12-2002, 06:52 AM

Follow the previous members advice of pounding a 8- or 12- point socket firmly over the head of the bolt, I often do this and then use an impact wrench to break it loose. I feel sorry for you, its pretty hard to pound a socket onto that starter bolt, but it can be done. If you cant seem to get it done the first time, dont feel stupid, just cuss more the next time and it should work better. remember, the right tool wont get the job done any faster than lots of four letter words.

Dlduchon · #6 09-15-2002, 07:59 PM

I got the bolt out. It was fairly stripped, but if inserted all the way it had some decent grip. Pounding a socket over the top was going to be nearly impossible. I tried heating the starter with an acetylyne torch, since it is the only part that the bolt screws in to. I thought it would expand and release the bolt. I tried it about five times with a friend on the torch and me on the bolt. It did nothing, would not budge. I tried pounding it. Nothing. I tried liquid wrench, no movement. We heater the bolt head with the torch for about a minute, my friend advised against it thinking it would expand the bolt and make it worse. However it popped right out with minimal effort on the first try. Amazing.

haasman · #7 09-16-2002, 12:01 AM

That reminds me years ago of helping someone with a very similar situation...but our last effort was to pour iced water over the allen bolt head after heating (which didn't do anything) It steamed and hissed etc but came right out!

I recently used the cryo-solution on a bad hard drive for a computer. It was almost gone, a high heat situation. I took the drive out, put it in a ziplock bag, sucked the air out, and put it into the freezer for 24 hours. I was skeptical but willing to try anything to get the data. It worked! Long enough to retrieve the information.