I have read in earlier posts that a special tip is needed to grease the door hinges..../...
Here are some M-B door hinge tips:The hinges of M-B's from the fifties and up to the beginning of the eighties certainly need to be greased.
Neglect will surely lead to creaking doors, worn hinges that result in the door blade sagging, and the mechanism may even seize eventually.
The design is such that the hinge pin has a groove in it, and a ball valve is at the bottom of a small, conical opening in the middle of each hinge.
To grease these hinges, you need a pointed nozzle on your grease gun. I use a separate, small gun for this purpose. The pointed
type of grease gun is used for chainsaws, so you may try such a supplier to obtain one.
The grease injected will travel along the groove in the hinge pin and exit at the top and bottom ends.
Two problems are common:
1) Conical opening is painted over (from factory or by previous restorer)
2) Grease in hinge has hardened from age and neglect
No 1) is handled by cautiously scraping and removing paint layer.
No 2) can be more troublesome. Try heating the hinge with a heat gun or even a hair dryer blower.
This may soften the old, hardened grease. Then try to inject fresh grease, while metal is still hot. Beware of paint going
bubbly or blackening. If this approach does not help, take the hinge off car and disassemble it.
To judge just how worn your hinges have become, you can lift at the rear edge of your door. Play should be minimal.
/Hans in Sweden