Loose Screw :-) - PeachParts Mercedes-Benz Forum

#1 12-14-2002, 06:50 PM

Howdy all. Was tooling happly down the road yesterday and suddenly the '76 280S just stopped. Got it on side the freeway scratching my head trying to figrue it out. Decided it not safe having 65 MPH drivers comming at my backside had it towed to home. After a hour of searching I found the hold down screw for the breakers (points) have come loose. When resetting the dwell found the screw would not tighten. Got another 4mm screw and the same thing happened. Was going to retap it to 5mm, but then discovered the breaker mounting hole is made for a 4mm screw.
Have placed teflon tape on the screw and loctite without success. Any ideas?

Thanks all!

psfred · #2 12-14-2002, 07:00 PM

Well, you could either find another distributor, get the parts for the one you have (new plate, etc), drill it all out if you dare, or just toss the points and get a Pertronix or Crane optical unit and fix the whole thing at once.

I'd personally go for the optical breakerless unit, much less trouble in the long run.

Peter

240 Ed · #3 12-14-2002, 08:59 PM

I put one of these electronic gizmos on my XJS (V-12), and it works a charm!

Cheaper to find a junkyard one though...

#4 12-15-2002, 12:56 AM

Thanks all for your replies.

Well short of placing a sheet metal screw to replace the machine screw will go for the breaker less ignition. Or, don't know about the interchange from a '76 280S to a '77 280SE distributor which already breakerless. Wonder if this would swap over?

Thanks again.

leathermang · #5 12-15-2002, 11:07 AM

I will tell you what I would do... I would be looking for a magneto... just like on my Gravely two wheeled walking tractor and my IH tractor... I am old enough that I remember when Mallory and some other people came out with the IR stuff and I put some on several cars.... none lasted more than one year...My aunt had to be towed about 30 miles to a small town in south Texas and the guy converted back to original stuff ( 1970 MonteCarlo )
Magnetoes make it where your ENTIRE electrical system can go out and you can still drive home ( in the daytime hopefully )...Puts you much closer to Diesels for reliability of combustion..Race cars used them , and you could even get them for Volkswagons... etc...Vertex was a common name back then...
And if one fails 25 years from now... you can take it to any alternator shop and them fix it... a very simple mechanism...

ctaylor738 · #6 12-15-2002, 11:38 AM

There are two ways to go "breakerless."

Pertronix - replace the points with a "hall effect" mechanism and upgrade the coil, but keep your transistor unit.

Crane - replace both the points and transistor unit and the coil for best effect.

Depends on how original you want to stay.

Randy Durrance has a great web site on this. Durranceeng.com. He could probably fix you up with a replacement plate as well.

psfred · #7 12-15-2002, 12:47 PM

Gympie:

So long as you take the whole system, the swtich to the 77 breakerless will work fine. Coil is going to be different, probably, and you need the swtichbox, too, or it won't work.

Distributor advance curve may be different, but you will probably not notice.

Peter

#8 12-15-2002, 01:15 PM

Once again, thanks all! You have given me much to ponder on which avenue to take on this.

Did a visit to Randy D's site and like the Pertronix idea. Seem's less of a modification than adding an additonal box to the system as others do. Just wondering about the coil upgrade although. Have a Bosch Blue coil now. Would a change over have to be done? Will do more investigation on the coil spec's later. Also, wondering if the Pertronix requires the same hold down screw to be used as the breakers? If so, I'll still need to have the breaker plate replaced.

Appreciate your help guys and thanks again. If you have time today, all good kharma is needed for the Broncos.

leathermang · #9 12-15-2002, 04:52 PM

I used a B-Blue on several of my cars... I don't know for sure but I suspect that that means it is for conventional systems...
When using an electronic/capacitor discharge the magnetic pulse is produced by a blast from the capacitor instead of the colapse of the magnetic field... so the coils are wound differently because of that difference...

If you will mail me the plate which is stripped I will fix it and send it back...email or pm me...I will need to buy a metric tap/drillbit... so the total cost will be $5 if you are interested....

Greg

240 Ed · #10 12-16-2002, 05:01 AM

Greg,
That is what I would do too. Just tap in a new screw hole, problem solved!

But I think I would probably go up to the next size available, which would be an SAE size. If you jump to the next metric, many times it is a significantly larger screw.

Just a thought.

Gympie, it really is rather easy to do, just buy the tap and the appropriate drill bit -the size will be written on the tap packaging.

leathermang · #11 12-16-2002, 09:34 AM

Dear Ed,
That is not exactly what I had in mind... he had mentioned not wanting to go to a larger size...so I was going to use an old fashioned Pexto " hand" punch (two foot handle ! LOL ) to cut a plug, then if the plate was flat mark the center of the original hole out far enough with witness lines to use the punch on the plate, then silver solder or weld the plug into the hole and retap to the original size...if the plate was not flat I would drill the hole in the plate then put in the plug...
Pretty much back to stock unless someone examines it with a microscope... LOL

neileg · #12 12-17-2002, 04:38 AM

Or....

Take the plate out. Using a small punch and hammer, gently peen the area around the stripped hole to stretch the metal and close the hole up slightly. Be careful or the plate will distort. Run a standard size tap through the hole (or a standard bolt with a couple of flats filed on it) to clean up the thread.

This technique works well on most sheet metal applications.

I would hesitate to use welding or soldering as this will introduce distortion unless you're very lucky or skillful.

240 Ed · #13 12-17-2002, 06:19 PM

...wow. Isn't this forum great? you learn all kinds of stuff here.

leathermang · #14 12-17-2002, 06:58 PM

Neil,

I am very lucky

The problem with just peening is that it is clearly going to make the good contact with the screw less than new metal... and the question is.. why did the original with full contact strip out ?

Another method, when the plate is out, it to epoxy a (I would use brass) nut of the correct size under that hole... if clearane is tight just grind it to make it thinner....then use a brass screw in that position and you won't have to worry about electro corrosion messing with those threads...

#15 12-18-2002, 01:54 AM

Thanks All for your input.

Sorry to be away from the disucssion, but was called out of town for a few days. But looks like you all brain stormed this out pretty well and are ready to try out for "Junk Yard Wars" or even better the "Monster Garage".

You are all ahead of me in the project as I don't even have the breaker plate out as yet. Gave it a short go this evening and had a problem in getting it out. Tried to lever it out with a screwdriver but was afraid that I may distort it in the process. Will try a puller manana.

Was thinking if a M3 Helicoil would do the trick. Not much to bite the coil into, but just a thought. Thanks for all your suggestions on how to do this. Think what I will do is to check the bone yards around to see if another distributor is available. Then to just swap plates. But have to get them out first.