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  #1  
Old 08-29-2017, 11:44 AM
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Distributor Stuck in Block

Greetings,

I have a stuck distributor on a '68 230 with the M180.949 six cylinder engine. The distributor appears to be stuck in place and will not rotate for me to adjust the engine's timing.

I have, so far, squirted penetrating oil where the cast iron distributor meets the aluminum base, and where the aluminum base meets the block, and let it soak overnight a few times. I have gently tapped the bottom edge of the distributor with a small hammer to try and shock it loose with the penetrating oil. I have also run the engine up to full temperature to warm up the block where it is hot to the touch, and then attempted to move the distributor using the methods described above. All have been unsuccessful so far, and the distributor has refused to budge.

The clamp screw and the bolt on the fine adjuster have been loosened when I try to move the distributor. There is also a third screw on the aluminum base where it mates to the block which I removed.

As for the engine's history: it has low miles since a rebuild about 25 to 30 years ago. The distributor has likely not moved since at least 1994 or 1995. The engine runs well with minimal oil consumption.

I think what is going on is there is some corrosion where the cast iron and aluminum surfaces mate up.

Does anyone have any advice or further options I can pursue without damaging the distributor?
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  #2  
Old 08-29-2017, 07:51 PM
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Do a search of the vintage section, there was a post similar to yours.

Don't tap too hard on the distributor, the housing can crack.
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  #3  
Old 08-29-2017, 08:40 PM
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You are trying the right things, continued patience along with penetrating oil when the engine is hot is a good procedure. Could also try getting the engine hot and cooling the distributor with ice...expand the block while contracting the distributor then add penetrating oil.

Can you put channel locks with the teeth wrapped in tape and gently turn the distributor ONLY at the base?

The timing can also be set by sacrificing some dwell angle/point gap.

Good luck!!!
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  #4  
Old 08-30-2017, 07:07 PM
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Maybe alternate with something cold? If you hold canned air upside down and squeeze, the stuff that comes out will freeze stuff. Maybe you can shrink the metal on the dist. enough. - just throwing that out there for consideration.
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  #5  
Old 08-31-2017, 05:31 PM
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Generally speaking hitting rusty things with the impact or an air chisel is a big help. I've only ever encountered stuck distributors on cheap to replace domestic stuff and I have broken some. Be careful not to crank on it. What I would probably do is run an impact on the retainer bolt or one near the distributor while trying to gently work it back and forth with channel locks.
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  #6  
Old 08-31-2017, 09:27 PM
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That might be a good idea. It's been a few days, and that cranky old distributor still won't budge. I'm thinking that I may start looking for an extra distributor to have on hand in case I end up having to resort to more "violent" tactics.

As an interim solution, I was able to adjust the point gap to where I could get the engine to idle OK so I can putter around without any difficulty. That came in handy as I needed the 230 Fintail's large trunk to remove stuff from a storage unit today.
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  #7  
Old 09-19-2017, 11:23 AM
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Fast forward 20 days of penetrating oil, and the distributor still won't budge. It likely has not moved in 25 years or more. I have decided to order a replacement unit on E-bay, which I will have rebuilt by a distributor shop. When that is finished, I am going to do whatever it takes to get the pre-existing distributor out, even if it needs to be broken.

The picture below is of the replacement distributor core that I ordered. It is coming with its aluminum mounting bracket.

I suspect that there is (in the pre-existing distributor in my car) galvanic corrosion between the cast iron distributor case and the aluminum mounting bracket. I think that if I can remove/destroy the aluminum mounting bracket, the pre-existing distributor will come out.

When it comes time to replace the distributor, I will also check the grounding strap on the engine, and clean/replace it and/or its connections if necessary to prevent any electrical aiding of future galvanic corrosion.

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  #8  
Old 09-25-2017, 02:57 PM
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If worse comes to worse just replace the entire distributor housing. It is just bolted to the front of the engine and is not hard to replace.

A worm gear comes out of the block to drive the distributor gear which is actually not connected to the distributor. It is a free floating gear that turns a cog inside the distributor housing tube. This cog fits into the bottom of your distributor and turns the shaft.

You can usually find these on evil bay. Just make sure the rotating gear is in good condition.
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  #9  
Old 09-28-2017, 09:07 AM
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So if I unbolt the aluminum housing, should the distributor just lift out vertically?
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  #10  
Old 09-28-2017, 01:41 PM
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Quote:
Originally Posted by CTD View Post
So if I unbolt the aluminum housing, should the distributor just lift out vertically?
CTD:

Although you have provided pics of the possible replacement parts, could you also post a couple of pics of the offending distributor as installed.
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  #11  
Old 09-28-2017, 02:37 PM
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Quote:
Originally Posted by CTD View Post
So if I unbolt the aluminum housing, should the distributor just lift out vertically?
No. If you unbolt the housing the entire housing will come off the front of the engine with the distributor still stuck in it.

This would be a last ditch sort of thing. You would have to discard the distributor and the housing.

A good photo of the housing from the manual would do a better job of explaining this than I could, but the connection between the gear coming out of the engine, the one that drives the distributor, never touches the distributor. It touches/meshes/engages with a gear mounted in the housing. This turns a flange that is meshed with the bottom tabs of your distributor and this turns your distributor shaft.

The best overall solution is to pull the distributor from the housing with the housing mounted on the engine. But it just cannot be done then replacing the housing and distributor as a unit is about your only choice.

And.... Removing the housing from the engine and then trying to pull out the distributor is not wise since you would still need something solid to hold the housing while you applied pressure to the distributor. The housing is currently bolted to the engine and it would be harder to imaging a more secure mounting point to pull the distributor from.

By the way, there is a large nut in the center of the housing. Don't bother with removing this as it is only a cover nut and once you have it off there is nothing under it but a nice view of the gear coming off of the engine. But when you unbolt all the bolts holding the housing to the engine the housing will usually, with a light tap, lift right out of the engine compartment.

Remember: This is a solution of last resort. Mercedes built the engine this way in case the solution was needed.

But once you have decided to spend the extra on the housing assembly removing and replacing is not a big job.
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  #12  
Old 10-01-2017, 03:51 PM
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Slide Hammer time

I had the same issue.
Spent a lot of time trying different things. Oil didn't seem to work for me either. I tried heating the area around the base of the distributor with a torch. I packed a plastic bag with ice and put it around the distributor at the same time. I thought the temperature differential might work. NFG.


I found a listing on ebay for the same part number distributor as mine. Evidently, there are quite few different ones used on these cars and they are not interchangeable (I believe). Luckily I didn't need it.
I eventually wound up buying a decent slide hammer set from ebay. I used a gear puller around the body of the distributor with two hose clamps to keep the jaws closed. I then threaded the slide hammer into the puller. Still took quite a while to get that sucker to break loose.
This was on a cast iron (steel?) distributor housing which looks identical to the one in the previous postings photo.


You may want to try using a plastic bag taped up around the distributor base. Put some Evapo-rust in the bag so it can soak into the joint. Might work.
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  #13  
Old 10-01-2017, 08:03 PM
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If you have never used a side hammer... They can be tricky to line up and get ready to use on a part, but when you slide the hammer it will put force on the part you can't apply with any other tool.

Are they a bit tricky to set up? Yup. Are they worth the trouble? You betcha!
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  #14  
Old 10-02-2017, 09:47 AM
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Well, my replacement distributor has arrived in the mail and it looks to be in good condition (but in need of a good cleaning). I am out of town, but I will give the stuck distributor another go this November. When that time rolls around, I'll see if I can free it up with some strikes from a good-sized hammer. If no readily available 'traumatic' force techniques get it out, I'll get a slide hammer and try the puller method that TommyMacDaddy mentioned. With the 'new' distributor on hand, I don't mind if the old one gets cracked or mangled in its removal.
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  #15  
Old 10-02-2017, 07:26 PM
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The pic in post 7 shows an aluminum adapter. Have you removed the bolt that holds it down then tried to pull / turn? If it is a stud, double nut then remove stud.
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