Distributor cap removal
 

Just looked at the distributor cap on my 420SEL in hopes of replacing it and noticed two bolt heads are sheared off the third one is ok and actually comes out. What is the best way to replace the cap now? I have the new one ready and it comes with new screws. Can I cut it off somehow in hope of removing the studs that are left? Been soaking it in liquid wrench for two days.

Your 420SEl should have 2 distributor caps. As for the sheared off allen head bolts try drilling them and using an EZ-out.

It's a 1988 8 Cyl. Only one cap in front. I'll try the easy-out method.

Do you have any idea how the 2 bolt heads sheared off? Strikes me as very strange. I can't imagine anyone tightening them so much that the heads sheared off, and there is no force on the bolts to cause them to shear off when the engine is running.

Excuse my suggestion that there are 2 distributors on your 420SEL engine. From what I've read on various forums I gathered that the V8's have 2 distributors.

Looks like the previous owner may have tried to remove them and busted two off then called it quits. I am the third owner and the guy I bought it from dosen't know how much work was done on it before him. He changed the plugs and wires but saw the busted distrib bolt heads and said "fergit it!". It must need replacement by now (maybe 6 years).

I have a 87 420sel and it has only one distributor. I believe it is sl500 which has 2 distributors.
since you are changing the cap anyways, why not break/drill/cut the cap and take it out and then use a plier to take out the broken bolts.

GoodLuck and keep us posted

Once you get the distributor cap off be sure to replace the rotor too, and check that the large O-ring is still flexible and not dried out.

OK, going to do the cut off with my dremel. Will let you know how it goes.