Mercedes-Benz Forum banner

1 - 15 of 15 Posts

·
Registered
1990 560 SEL with Euro engine, 1998 SL500 Sport
Joined
·
2,957 Posts
Discussion Starter #1
Hello:

I am new to this group and think it's terrific. I recently picked up a beautiful 1990 560 SEL, 128k. It has a bit of a rough idle so I am attempting to give it a tune-up to see if I can eliminate it. I tried to put on a new distributor cap yesterday and stripped the screw head (phillips) on the original cap. Two of the three screws loosed fine, but the third was really tight and corroded, and easily stripped the head!. I was thinking of using a large drill bit to drill-out the screw head and once the cap is off, remove the remaining threaded shaft from the distributor assembly with a Channel-Lock. What should be an easy task turned sour and I don't want to make it worse! Am I on the right track and has anyone had a similar situation?

Thanks
Greg
 

·
Registered
Depends on the day!
Joined
·
13,337 Posts
you're on the right track... let a Quality penitrating oil sit on it overnight as well.. PB Blaster is my pref'd. Also, hit the head of the screw w/ a punch/hammer a few times (good tap, but not Too hard..).

Best of Luck!
Jonathan
 

·
Registered
1987 420 SEL
Joined
·
2,090 Posts
I had the same problem with mine. Like Jonathan said, spray some penetrating oil and let it sit overnight then tap it a few times and spray it again.

I used my electric drill with the phillips head attachment, put my weight on it and gave it one good boost of speed and bamm it was loose.

Just take your time and be patience!!!
 

·
Registered
1990 560 SEL with Euro engine, 1998 SL500 Sport
Joined
·
2,957 Posts
Discussion Starter #5
Thats a great idea! I have lots of bit attachements on my electric drill so maybe one of them will work better than the phillips screwdriver. I think the penetrating oil will be key!

Thanks again
 

·
Registered
1990 560 SEL with Euro engine, 1998 SL500 Sport
Joined
·
2,957 Posts
Discussion Starter #6
Yes, I think you're right. Everyone I talk to mentions the important of penetrating oil. I should have done that in the first place. thanks for your input.
 

·
Registered
1985 500SEC
Joined
·
200 Posts
graftdesign said:
Hello:

I am new to this group and think it's terrific. I recently picked up a beautiful 1990 560 SEL, 128k. It has a bit of a rough idle so I am attempting to give it a tune-up to see if I can eliminate it. I tried to put on a new distributor cap yesterday and stripped the screw head (phillips) on the original cap. Two of the three screws loosed fine, but the third was really tight and corroded, and easily stripped the head!. I was thinking of using a large drill bit to drill-out the screw head and once the cap is off, remove the remaining threaded shaft from the distributor assembly with a Channel-Lock. What should be an easy task turned sour and I don't want to make it worse! Am I on the right track and has anyone had a similar situation?

Thanks
Greg
If none of the other suggestions work, drill a small pilot hole and buy an 'easy out'. It's a counter clockwise threaded bit. Teutone (aka Horst K)
 

·
Registered
1990 560 SEL with Euro engine, 1998 SL500 Sport
Joined
·
2,957 Posts
Discussion Starter #8
easy out

The screws are fairly small, perhaps no more that 1/4", do you think that is enought room for an easy out? I would hate to drill into the distributor threads!
 

·
Registered
Joined
·
239 Posts
I recently had the same problem with my 1986. The screw in front was the problem, most likely because of exposure to water. After trying everything I drilled a hole in it and used an EzOut. The screw itself broke allowing me to remove the cap. A stub remains there today. Two screws are doing the job just fine. I will drill out the remaining part out one day and tap for a new screw.
 

·
Registered
1990 560 SEL with Euro engine, 1998 SL500 Sport
Joined
·
2,957 Posts
Discussion Starter #10
Got the Distributor screw out!

Teutone said:
If none of the other suggestions work, drill a small pilot hole and buy an 'easy out'. It's a counter clockwise threaded bit. Teutone (aka Horst K)
Thanks Teutone, your suggestion worked like a charm! I didn't even try to do it my way and was a little nervous at first, but a bit of penetrating oil and the easy out is definately the way to go! The car has quite a bit more acceleration but still has a little bit of a rough idle. Onto new wires soon along with plugs and fuel filter.

greg
 

·
Registered
Joined
·
50 Posts
Same issue: two out of three screws stripped. Weeks of PB Blaster and tapping and prayer have yielded my resort to EZout drill out. My question is: These screw/bolts go into an aluminum housing, right? any solvent better than PB Blaster when a screw meets aluminum?
 

·
Moderator
1991 500SEC sub 50K mi. 1987 560SEC Now 150K mi. 2018
Joined
·
4,030 Posts
Same issue: two out of three screws stripped. Weeks of PB Blaster and tapping and prayer have yielded my resort to EZout drill out. My question is: These screw/bolts go into an aluminum housing, right? any solvent better than PB Blaster when a screw meets aluminum?
Hi there,

Having had this same scenario on my SECs during cap replacement, I too used PB Blaster with good result. I had to be patient of course..


Upon installation, I used anti-seize on the three hold-down threads.

MBL
 

·
Outstanding Contributor
350SDL, '17 GLS450, "Grandpa's Roadster" Project Car
Joined
·
3,032 Posts
If you heat the aluminum it will expand more than the steel and you can remove the screw. The problem is (called) dissimilar metal corrosion. PB Blaster and all the other solvent based products are only marginally effective. (My favorite is Aero-Kroil). Anti-seize is good for preventing future problems, but be careful tightening the fasteners. It takes a lot less torque to snap or strip a lubricated fastener than to tighten a dry one.
 
1 - 15 of 15 Posts
Top