Here's one I did.


You really need the area and the little channel the seal fits in thoroughly cleaned before installing a new seal and the pump.

MB actually advises not to use any sealant on the O ring. I use sealant but very, very sparingly.

Most ongoing leak issues were caused by el cheapo pumps not being machined properly.

Use only Laso or Graf pumps.

Changing a M103 pump is a frustrating job. You only want to do it once.

Elcheapo pumps use inferior plastic impellers.
When the pump itself leaks there is evidence such as :