ABS is activated on dry and slow speed on my 560SEC 1989
 

This car is driving me really crazy.

I changed the break the four pads and the four discs and the break master cylinder (ATE brand) and replaced the break fluid. I also made fix with the original tools for the four break clapper. All parts was Mercedes-Benz original including the fluid. And I still have the ABS works always and the break is not strong enough. The air hose is fine and no air leak. What to do?

You need to clean the ABS sensors. Ocassionally brake dust can get on them causing them to trigger at low speed.

Matt.

I did that before, sorry I forgot to mention it but the same problem!

My W126 does this once in awhile, the ABS sensors go bad. They are like $150 each and I am not sure how to test them. So you have a 50/50 shot of replacing the faulty one.

My car only does it once in awhile, sometimes the ABS light comes on as well. For now I am living with it but if it gets worse I'll replace them.