How hard is the Neutral Safety Switch to Replace?
 

How hard is it to replace the NSS in a 1984 300D?

Mine is about to go. Only starts in "P" about 20% of the time. Will still start in "N" most every time without issue but I need to replace it soon.

Thanks in advance for any help.

PS -- Got a busted header too. How hard is that to replace? Can't get a good patch on the flexible pipe.

More likely than not you need new bushings in the rod that connects the far end of the shift lever with the arm that goes through the neutral start switch into the transmission.

If there's any fore-aft play in the shift lever whatsoever, you need new bushings.

If you have trouble starting, put the shift lever in neutral and move it a little bit forward of backward and you'll probably find a sweet spot that allows you to start.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Depends on whether there are bolts or slotted screws holding it on.

If bolts, easy, if screws, well, a PITA if you cannot reach the top one.

Check the bushings, they are cheap, but a ***** to get in sometimes -- I take the lever off the tranny.

To change switch, jack up car (can't reach it on the ground, I don't think), pull plug off, remove alinkage and lever (usually held on by a pinch bolt you will have to remove completely, won't come off till you do), and you may need to remove the lever that operates the switch. Switch is held on by three screws, fits over the shaft going into the tranny.

Install new switch, install lever, loosen screw for switch actuating lever, and put tranny in neutral if it isn't there. Line the hole in the lever up with the hole in the switch (a small drill works nicely) and tighten screw. Reattach linkage and plug wire in.

Peter

bushing and switch replacement
 

I also like to remove the tranny mount. Start with the tranny in park. Put a jack under the back of the tranny housing watching out for the speedo cable near the output shaft. Remove the 4 bolts holding the mount to the undercarriage and lower the back of the tranny a couple inches with the jack. This increases the room available to replace the switch on the drivers side of the tranny and also remove the linkages. To install the bushings, grease them on one side and they pop into the linkage bracket fairly easily. Inspect the tranny mount with a flashlight to determine if it should be added to your future replacement tasks.
One additional thing I like to do before I start this job is stop by the car wash and clean the underside of the car on the drivers side, the tranny mount area and the drivers side of the tranny. I prefer to work on clean cars. The jobs take a lot less time, I can see what I'm doing, since parts are not caked with grease, and tool cleanup is shorter when the job is done.