Good to review experiences of fellow 400E owners. My experiences are very similar
1. PS pump - rebuilt/sealed approx 50K ago...5 hrs labor..tech advised installing new/rebuilt vs. reseal original makes little difference..they will all re-leak in the 40 to 60K range...Sure enough, I've got aslight leak right on schedule..Tech advised MB has not modified the part to fix the issue.
2. Brakes - I regularly get 3 sets of OEM bads per set of front OEM discs.. I do mostly Atlanta highway driving...that means lots of stop and go and frequent 80 MPH bursts and sudden 80 - 0 stops... I get about 25K per set of front pads.
Question? - '92 400E owners - Disc warping - the OEM's seem to warp badly. Previous threads state that MB changed the brake config on the '93 model to correct issue. What remedies have you '92 owners found assuming you experience the same.
As far as your "dealer" experience - On cars the age of ours, I highly recommend you find a trustworthy independant. In my area, there are at least 3 large MB dealers with good shops. They LOVE to see us old model guys come in... All they see is $$$$$$$ signs.. There are also a half dozen independant shops that offer dealer level service at a lower cost.