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The front wiper mechanism on my 1988 Porsche 944 has become a bit slow moving and I plan to fix it. On my car the wiper crank arms go through sockets in a frame, the crank arms are moved back and forth by linkages attached to a motor.

I plan to remove the whole frame from the car, remove the retainer clips holding the crank arms, clean the sockets and arms, grease them, and then re-assemble. I'm not sure what grease is best to use for this application, I have silicone, lithium-12 and copper grease available.

Here's a schematic of the part, see the red circle for the particular problem point.

I plan to use silicone on the linkages (3 and 5 on the schematic) and where they pop onto the crank arms.

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  • Would it be possible to post a picture?
    – Zaid
    Commented Jul 11, 2016 at 8:34
  • My wiper assembly is under a plastic cover, I won't be able to provide a picture of it, I have found a schematic though, and I'll add on edit
    – GdD
    Commented Jul 11, 2016 at 14:51
  • I did a similar operation and you might want to replace the linkages while you are in there. They wear out, and getting the wiper transmission out is such a PITA you don't want to do it twice :-)
    – Ukko
    Commented Jul 11, 2016 at 15:15
  • That's a good point @Ukko, and I'm already there - they are in a box and ready to go.
    – GdD
    Commented Jul 11, 2016 at 15:37
  • @GdD good to hear, I usually have to order the box after I get the parts taken out.
    – Ukko
    Commented Jul 11, 2016 at 15:50

1 Answer 1

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Use the lithium or silicone grease!

Copper grease is primarily used to prevent the seizing of parts which become extremely hot, like the exhaust system. But it is not a lubricant in first place. The grease bounds the copper powder, but isn't made for lubrication, an copper powder in a moving bearing can't be good, even though copper is a rather soft metal. Initially, the grease can prevent corrosion, but when it vanishes, the copper can cause even more corrosion, depending on the other materials. This is one reason why copper grease should not be used for the brakes.

Silicone grease has several advantages: Its viscosity is constant over a vast temperature range, it usually does not harm any rubber / plastic, it doesn't age and so on. But its lubrication performance is not as high as people often think, and it's expensive.

Mineral oil based greases have the best lubrication performance and are cheaper than silicone.

(This is of course just a generic description. There are thousands of lubricants out there with many different properties, all made for special use cases.)

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