There are times when I think owning old MB's is like some sort of incurable addiction. I saw a 91 350 SDL advertised at a car lot close by and thought I would go look at it. I own a 90 I have restored and my excuse was I might get some kind of idea how much mine was worth. The car was in really good shape, ran well. They had it listed for $3450 reduced from $4750. Anyway, having owned and worked on these before I took off the coolant reservoir top and low and behold --- lots of oil. Told the guy he had a big problem. Head gasket blown or cracked head. He says, 'Make me an offer." I told him I would give him $1500 as a parts car. Well, I own it. Took the head off. My problem is I can't get the pre-chambers out. I have the tool from doing the head on my 90. They came out fairly easily. Have this one fastened to my bench top. Got on it with a breaker bar with a 4"pipe on it until the breaker bar started to bend. HELP I don't really want to heat the aluminum head with a torch. Anyone had this problem before? What can I do?

It sounds like you got quite a deal there. I've had a craving to find a S350D with a blown engine, and put a 3L OM603 in it instead. Incurable addiction it is. Never owned an S body and happen to have a spare engine that nobody was interested in so I'm going to store it a while or sell it later.

you said you had a 4" bar on it, I think you meant 4 ft, right?
I think you need to try a impact tool. Resist the temptation to heat the part as the aluminum will conduct it right away. The dissimilar metals can make for a very tight bond and you might destroy something trying to get the PC out.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

yikes, no replies, guess I'll go and get a 3/4" breaker bar and a longer pipe.

hey I replied!
before you do anything read Meles issue with damaged PC in his rodbender engine:

You don't want to wind up like that.
Is it possible to not remove the PC chamber and go on with life? the head needs to be pressure checked and most likely a skim cut to assure its really flat.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Thanks for the reply. Yes, 4 feet. Tried a 1/2 " impact wrench before the breaker bar. Will get a 3/4" breaker and adapter. Soaking the joint in penetrating fuild. Problem is I can't get the head planed with the pc chambers in. Sort of a sticky wicket.

Ah yes, unless you want to shaved off the tip..
Well, if its going to a machine shop they should be able to remove the chamber but most shops would not take responsibility of the chamber is destroyed trying to torque it out and the consequent labor to get the remains out of the head. I've not any experience with a stuck PC myself, been lucky I guess.
if all else fails I have a good running OM603 3l engine f.s ....

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Are you speaking about the Prechamber Retaining Ring being hard to get out or the Ring is removed and the it is the Prechamber that is not comming out?
The Prechamber Retaining rings on an Aluminum head have about 3/4" of threads on them.

I am guessing it is the Ring because the Prechamber is pulled with a Side Hammer.

I have heated a lot of Aluminum parts with a Propane Torch and have never melted any so far.

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84 300D, 82 Volvo 244Gl Diesel

Melt point of aluminium is 1050-1100F degrees if I remember right. No way a simple plumbers type torch will get that hot I believe.

Especially with the applied heat being wicked away. Heating up a little and hitting the ring with cold spray may break the bond. Several cycles of heating and cooling the area first. You may have a white oxide bond and that stuff can be tough.

Safer approach than only brute force in my opinion.

A Propane Torch gets hot enough to melt Aluminum but the heat Transfer on a big chunk of Aluminum like a Cylinder Head is great enough to keep you from easily melting
part of it.

As an example if you cut a strip of metal off an Aluminum Beverage Can you can melt it with a Propane Torch.

Heating also allows also helps allow Penatrating Oil go to wick in.

I only had experience with one Aluminum Mercedes Head and it was much harder to get the Retaining Ring out (no heat or Oil used). I did this with one of our Members (Cylinder Head only) in a Parking Lot.

As you said I think the heat is safer too because the Aluminum can gall if it stickes to the Steel Ring.

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84 300D, 82 Volvo 244Gl Diesel

I've been doing this on my 1993 300sd mercs. I did plumbers torch (used yellow kind which is hotter). I researched and found that an extremely effective penetrant is a 50/50 mix of acetone/atf. After heating quickly used old plastic vac hose with finger on end to dribble the mixture around. Let is sit overnight, plumbers torch again, and it broke loose. I had no luck without doing this. I've gotten two rings and a prechamber out this way. My other prechamber has stripped threads. One caveat is I have not run either car since doing this (both are down right now). I did not go crazy with the torch, but gave a pretty good dose of heat. Mechanically inclined cousin of mine talked of liquid nitrogen on the prechamber or ring to make them freeze and contract to break the bond. Acetone is main ingredient in finger nail polish remover and can be gotten cheaply from walmart. Don't blow torch the acetone mixture. I wiped it up before hitting with the blow torch the second time.

Success! Let the rings soak overnight in penetrating oil and tried again with breaker-- no luck. Being an old guy I remembered I had a !/2" manual impact tool from my days before air wrenches. Got it out, put it in the MB tool and hit it 5-6 times with a 4# hammer. Got on the breaker bar again and it broke lose. After that flipped the head over and drove the prechamber out with an aluminum drift and my trusty 4# hammer. All is right with the world. Hope this will help someone with the same problem!

It can be included in the DIY section.
Was the Mercedes Tool you used a one for the splined Collar/Ring or the slotted Collar/Ring.

Old School Hand Impact Werench pic.

Attached Thumbnails

 

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84 300D, 82 Volvo 244Gl Diesel

Interested to see if the head is now warped.

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1995 E420 Schwarz
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#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Doubt several heating and cooling events would warp a bolted down head. There really is no other choice anyways the way some things are seized up.

You could even tear the threads out or a piece of metal if really unlucky with just brute force.

Hope you didn't damage the ends of the PC by driving them out. The PC puller is the way to go.
Good luck