Hi everybody,

This is a 1987 420 SEL or 126.
I plan on changing the rotor and distributor cap and the plug wires this weekend. How do I get the rotor out? Is there a nut/bolt under it that needs to be loosened? I can't seem to find anything that points to the rotor.

Your help is as always appreciated.

Reinhard Kreutzer

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I checked ALLDATA and they show no bolt holding the rotor to the dist. shaft.

Thanks inspector1

So do I just have to pull on it? I always hesitate to just pull on something fearing it might break ...

Yes, sorry that I did not elaborate, but all I have now is my opion, which I seldom offer.

But from the schematic, it LOOKS like it pops on/off, you might remove the dust cover and peek under it.

man, that thing is EXPENSIVE!, I just tuned up my 91 Trooper, and the rotor was $5.

Good Luck.

Thanks bribenz and inspector1,

bribenz, I assume you have done it before so you are offering more than just an opinion, you are offering experience? So I give it a careful pull.

Thanks again

Reinhard Kreutzer

So why replace it?

Yes, it just pulls off. Pushes back.

J. Boggs

Thanks JBoggs,

they are about 5 years old and I have a slight "disturbance" at idle. When you feel at the edge of the rotor, you can feel roughness. The metal spots at the cap also have a black horizontal dash, i.e. burnt copper. I hope the picture shows it. The plug wires (I know it's not the wires but the plugs at the end) are all above 1300 ohms resistance and they are silicone, not copper. I will replace them with Beru's.
I put in already new plugs when I took the pictures and measured the resistance a few weeks ago.
I'll put some dielectric grease on the contact points and that will hopefully take care of that slight unevenness at idle.

Any more tips or things I should do? Grease the rotor shaft?

Thanks again

Reinhard Kreutzer

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Corrosion - I had the same thing on my 560sel. The rotor was really on tight. Try to get some penetrating oil up under the rotor and carefully try to put back and forth turning pressure on the rotor while pulling up on it. Don't be a bear in a china shop - just take your time and it will eventually come off. When you get it off you will find the distributor shaft under it is rusty and corroded from moisture. Clean the shaft with very fine sandpaper and put some vaseline or other lubricant on the shaft before putting the new rotor on. If you want to speed up the process - or if yours is really on super tight - cut the old rotor in half with a dremel to remove and clean and lube as above. Sounds harder than it really is. Good luck!

Thanks moedip,

I thought the metal shaft on which the rotor sits was part of it. Now I understand it better. (I don't have the new parts yet). I have 220 sand paper that should do it and the trusted dielectric grease that I put on anything electrical to prevent moisture.

Thanks everybody.

Reinhard Kreutzer

Well, the wires, rotor and cap have been replaced.

To recap, the resistance in the old wires (cap to cap) were between 1300 and 1400 ohm, with 1300 being the "replace" limit as per CD.
The new Beru's are between 1135 and 1162.

The rotor looked like the attached picture and came off without much problem.

The only fly in the ointment is the fact that each four wires were surrounded by a black plastic hose to hold them together. I could not thread the plugs through that hose and therefore cut it like a spiral. Then, after the wires were in, silver duct tape to hold the spiral together. Visually not satisfying... I might wrap it with black tape later.
The Beru set is 2 long wires (for passenger side) and 6 shorter wires.
I did take off the air cleaner housing. I did not need to disconnect anything but the connector on the idle valve and the connector on the temp. sensor next to it and one vacuum line on the driver side.
Took me about 2 hours.


The test drive did not show any "disturbance" at idle any more, although the real test might come with more humid weather.
I think the car also starts better. We'll see tomorrow when cold.

Thanks again everybody.

Reinhard Kreutzer

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