0M617 crank pulley removal issues - PeachParts Mercedes-Benz Forum

pmi · #1 01-03-2005, 03:25 AM

I'm looking for suggestions as I'm between a rock and a hard place on an 83 300SD - trying to remove the crankshaft damper/pulleys so I can clean up the front end of the motor and install a new crank seal. The six socket head cap screws for the crank pulleys are extremely corroded - my attempts to get at least two free so I could use a proper puller resulted in rounding out the inside of what is left of their little rusty brown heads. I then tried a three arm puller in a pathetic attempt to dislodge the whole assembly, but it became clear that I was applying a dangerous amount of force and getting no movement. So, I wanted to ask the forum for any bright ideas or neat tricks that may have worked before. This vehicle is a piece of work - everything in the engine compartment looks like it has been in an extended salt spray corrosion test. Thanks, Mack

Pete Burton · #2 01-03-2005, 07:56 AM

You need to use penetrant and patience on those. Clean out the recesses thoroughly and then drive the allen socket all the way in before you try any others. It's possible you can drive a cheap socket over the outside of the rounded heads to remove them, but sounds like you've already learned a good lesson from those. Depending on how clean your engine is you can probably be helped by applying some heat to those screws, but don't go nuts. Good luck!

engatwork · #3 01-03-2005, 09:00 AM

You can always drill the heads out. I would be reluctant to try to do it this way unless the engine was on a stand or the radiator/condenser were out of the way.

#4 01-03-2005, 10:03 AM

I had quite a fight with the same a few years ago. Got a propane torch head in there and heated each of the screws for a long time, then used penetrant again. They came loose with that.
Mch easier to access them with the radiator out of the way.

rwthomas1 · #5 01-03-2005, 10:10 AM

I had 3 of these socket head bolts try and round off on me when trying to remove them. I found that there was crud in the sockets keeping the hex bit from bottoming completely. After scrapping the crud out and blowing with compressed air I placed the hex bit in the offending bolts and fully seated them with a hammer. Even though they were rounded out this did the trick and they came out. I put never-seize on the bolts for reinstallation.... RT

pmi · #6 01-03-2005, 10:13 PM

Thanks for the good info - I have the radiator out, and will apply heat & penetrant. I've had great luck with "Rustbuster" by Robertshaw in the past but I didn't have any on hand when I started this debacle. Seriously, these bolt heads may be too far gone - I have never seen such corrosion. I cringe at the thought of drilling them out and using a screw extractor, but that is probably where I will end up. Thanks again.

FrankM · #7 01-03-2005, 10:30 PM

you can take an air chisel to the heads. Pop them right off. The remaining shaft will unscrew easily once apart.

Brian Carlton · #8 01-03-2005, 10:46 PM

Quote:

Originally Posted by pmi

I cringe at the thought of drilling them out and using a screw extractor, but that is probably where I will end up.

FrankM is correct in this approach. Do not drill out the screw with the thought of using a screw extractor. Use an air chisel, or drill to remove only the heads. Then remove the pulley. Now that the screws are not under tension, they should be able to be removed with vice-grips. If the threads remain difficult, you now have direct access for the addition of penetrant and/or the application of heat.

pmi · #9 01-03-2005, 11:00 PM

Roger that, thanks - I didn't make the connection regarding the effect of the bolt being under stress. My little el cheapo air chisel can just reach the bolt heads, but at a very acute angle due to the depth of the pulley. It looks like the pulley face surrounding the bolt heads may take a beating, so I'll drill out as much of the head as I can first. Thanks again for the clarification.

FrankM · #10 01-03-2005, 11:08 PM

Quote:

Originally Posted by pmi

Roger that, thanks - I didn't make the connection regarding the effect of the bolt being under stress. My little el cheapo air chisel can just reach the bolt heads, but at a very acute angle due to the depth of the pulley. It looks like the pulley face surrounding the bolt heads may take a beating, so I'll drill out as much of the head as I can first. Thanks again for the clarification.

you can heat the end of the chisel red and bend it slightly, no to much. you may gain a good bite under the head..

pmi · #11 01-17-2005, 04:40 AM

Corrosion is the gift that just keeps on giving, and if you turn wrenches long enough I guess your number finally comes up. This was the ugliest thing I've wrestled with in a long time. Never could get a satisfactory bite with an air chisel, bent or straight. I finally had to use a dremel tool (mirror guided) with heavy duty cutoff wheels to remove the allen heads, and then hammered the damper/pulley assembly off (I have replacements). I say assembly because they are fused together by dissimilar metal corrosion. The top washer under the crank bolt was also rusted in place to the pulley - I had to scrape around its perimeter, apply RustBuster, then drive it out with a brass drift - and it looks like there should be something like 2 mm of radial clearance between it and the pulley/damper - that's ugly. The remnants of the six allen head screws did freely came out of the crank balancer, just as predicted, and it looks good. Thanks again for all the good advice. BigMac

FrankM · #12 01-17-2005, 08:23 AM

Quote:

Originally Posted by pmi

Corrosion is the gift that just keeps on giving, and if you turn wrenches long enough I guess your number finally comes up. This was the ugliest thing I've wrestled with in a long time.

Wow, you certainly had a good workout. We all need that once in awhile to stay inshpae..

Glad you were able to resolve it without getting into a crankshaft issue too...

tomm9298 · #13 01-17-2005, 12:30 PM

A few years back the head bolts, also hex, rounded out on a 1969 MB 230. I used a set of Snap On Tornado sockets. It was easy with a 3 foot pry bar as an extension!!! Maybe they still sell them.

ykobayashi · #14 03-15-2014, 04:09 PM

Ahhhh the search tool. Others have felt this pain too.

So today I went in to change some belts and figured I'd do the front seal that has a very slow drip. It seemed pretty easy and I ordered up the parts. This is the 300sd.

Aww man. I can't get the six pulley bolts off. I cleaned them out and got a tight fitting socket Allen in there and started turning...and turning and turning. H.ll I rounded out the first one. So I thought I better stop and post and think.

I don't think my 240d was ever changed. It drips but it is tolerable. I wonder if I should just back off and put the new seal and spacer on the shelf before I get into more trouble. Dang it!

Diesel911 · #15 03-15-2014, 04:55 PM

Someone just used these on the Allen Head Blots of a Oil Filter Housing.

You are looking at the business end of the Socket that gets pounded over the Bolt. Regular Auto Part Stores sell them; I got Mine on sale at Sears and I think eve Harbor Freight has their version of them.