Thanks for checking my post. I've been running hot and determined that I needed a new radiator, fan clutch and thermostat. I figured while at it, go ahead and do the water pump. Ordered all the parts from Phil and a local indy set up to do the replacement. He's not a MB expert, but has many years experience.

Last night he call while I was at the baseball game to tell me he can't get the old water pump off. Has stripped at least one of the allen bolts. Suggested that since it's not leaking, just leave it. True, I don't think the pump was shot, but it was getting long in the teeth.

Any ideas of how to free this strippeed allen? I don't know which one, haven't seen the extent of the damage. Thanks for any suggestions!

Dave

The last time I couldn't get an allen bolt off I ground off the head with a dremel, removed the unit, and dealt with the remaining stud. Make sure antiseize compound is used on the threads when it goes back together.

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95 E320 Cabriolet, 169K

there are 12 point and 6 point allen head like sockets that can be driven with a hammer into the stripped bolt and this will get it out.i do this every day.in fact i have just this morning used that method to remove two motor mount bolts from under a 1986 190e.they were in so tight that a cheater bar was necessary on a half inch breaker bar and this 12 point allen held even with the force required to remove those.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

Thanks guys. The mechanic gave up and reassembled the car with all the new parts, sans the water pump. Guess I'll have to deal with that one when it actually goes out. He'd never heard of a dremel tool.

I'll let you know the eventual resolution.

A mechanic that has never heard of a Dremel tool? Sheesh!

You need a new mechanic. Preferably a MB specialist.

Steve

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He probably never heard of a metric allen either...use the wrong allen/hex on these and they will strip every time...

It never occured to me that he would not have metric allen wrenches. That is really unconscionable. I'd have loaned him mine if he just asked.

He most likely does , but it is easy for a guy in a hurry to use the incorrect hex ..I always keep my set in seperate boxes just for that reason. If the correct one is used [ and it is not a POS one] , they are pretty hard to strip out.
Another preventive trick is to clean out the hex of dirt/grime before inserting the allen so it gets full depth seating........ then they are very strong and seldom fail. The deeper it seats , the stronger they are.
Another is they have ones with a ball end for offset angle usage , but these should not be used on bolts that are really fastened...bests to break them loose with a straight , short, well seated, correct allen bit on a socket.

..and a trick for removal of a stripped one when all else fails is to place a nut on top and weld up the hole, then use a socket the size of the nut..that is a last resort, but comes in handy sometimes..[ good trick for sheared off studs , too...]

Bingo, Poole was right.

All you need to do is put a spline drive socket into the inside of the stripped hole.
I think either a #10 or #12 spline socket.

Just put it at the end of a wobble type extension and pound the end of the extension with a hammer and you should have no problem turning the bolt out.

For added non slip assurance, I always put a little valve grinding compound on the spline socket so it bites in even better.

Sounds like Poole knows his stuff.

he does.

dalton does too.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The ones that get me mad are the ones that are already stripped when I start the job from the last guy stripping it on the way in or putting the stripped bolt back in that he screwed up on the way out.

.....or the one that quit the job and buttoned it back up cuz he couldn't get it out after he stripped it..you may get this one when he really needs the pump changed...

Update:

The good news is that replacement of the radiator and fan clutch has solved my high operating temperature problem. I've never had to replace a radiator, so this was unusual to me. Temperature is back around 85-90 C, so I have peace of mind for now.

The bad news is that the old fart couldn't get the water pump off. I have two pretty well stripped allens that are going to have to be dealt with when the water pump does go. Who knows how long that will be.

Thank you for your ideas on removing the stripped bolts. I see spot welding in my future. I'm disgusted by the bolts, but will try to not be too pissed. Life's too short.

Peace.

I did the pump on my wife's 91 300 CE this past winter...the right metric allen wrench, heat, PB Blaster and a great deal of patience and mine finally came off. I cannot believe that an experienced mechanic was unable to remove it...I agree with one of the previous posts...find a new mechanic as a great deal of time is required in getting to the pump...now you will have to pay someone else to tear it all down again to replace the pump you wanted replaced in the first place.

Antonino

I have also had success hammering in a slightly oversized torx bit and using that to turn it.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280