Brakes lock up

BRIANGAILEY

MEMBER
1991 MERCEDES BENZ 190D
2.6L
6 CYL
2WD
260,000 MILES

I have a 1991 Mercedes 300e and the brakes lock up while driving down the road. As I am driving the brake peddle gets hard and doesn't move and the brakes lock up. I have replaced the brake booster, master brake cylinder, all 4 calipers, all 4 brake hoses and swapped out the abs control box and I have no idea what to do next. Can someone please point me in the right direction?

1 Reply

MHPAUTOS

MECHANIC
31,937 POSTS

Check that you have pedal clearance between the brake pedal and the master cylinder, you should be able to feel a few mm free movement when you push the brake pedal down, there will be adjustment on the pushrod into the booster.