W124 Pulsing Brakes
 

I have been experiencing intermittant pulsing in the brakes on my 87 300D. Sometimes they pulse annoyingly when braking at any speed, and other times it's hardly noticeable. Though it's always there.

At first I thought the rotors were warped. But is there possibly a problem with the ABS system?

DS
87 300D
Northern Iowa

If the brake feels like the ABS is cycling, but you know that it's not, check the individual axle trigger wheels in front and the adjacent wheel speed sensors. If you see a damaged wiring connector, bent sensor or anything out of the ordinary be suspicious. If everything looks good - read this article about caliper pins.
PINS

This happened to me on a 92 124 body. It came on rather quickly really - within a matter of weeks it was quite noticeable. I could not see that the rotors were warped but apparently they were as I put on new ones and the problem went away. The problem rotors had no writing stamped on them at all - which I'm told means that they were probably Chinese knockoffs. I put on new German Balo rotors and they have been fine since.

Problem solved!

It seems that when the rotors and pads are worn significantly, that the abs system does some weird things, pulsing etc. I changed all with new parts and it's like driving a different car. The pads by the way, were really close to the end of their life and had no wear indicator wiring. In fact, I think that because they were so worn, that it was unsafe overall. The rotors were cheap Chinese knockoffs, which were showing obvious cracking as well as being warped.

I replaced the front bearings at the same time so all is well with the front end.

DS
87 300D
Northern Iowa