SL/R107: Brake warning light.
Super Member
Joined: Aug 2008
Posts: 690
Likes: 30
When I backed my SL out of storage, I too had a red light come on. At first I thought t was the battery charge light, but no - it was the brake light.
I checked and brake fluid level was very low. I topped it up and it took about 1/3 litre. Where did that go? I checked the lines under the car, the hoses at each wheel and the floor where the car had been parked. Nothing.
What I suspect, is that the master cylinder has leaked back into the vacuum chamber. To check this, I need to remove the master cylinder so I can see if the fluid is in the chamber. This car is 54 years old. I have owned it for 37 years and don't recall having ever changed the master cyclinder. So maybe the time has come
Problem is that although they list them, most vendors don't seem to have stock. Or they are in parts of the world where freight to us in Canada doubles the price 
Part is A0024302801.
I checked and brake fluid level was very low. I topped it up and it took about 1/3 litre. Where did that go? I checked the lines under the car, the hoses at each wheel and the floor where the car had been parked. Nothing.
What I suspect, is that the master cylinder has leaked back into the vacuum chamber. To check this, I need to remove the master cylinder so I can see if the fluid is in the chamber. This car is 54 years old. I have owned it for 37 years and don't recall having ever changed the master cyclinder. So maybe the time has come
Problem is that although they list them, most vendors don't seem to have stock. Or they are in parts of the world where freight to us in Canada doubles the price Part is A0024302801.
Super Member
Joined: Aug 2008
Posts: 690
Likes: 30
No stock of Master Cylinder anywhere I checked in Canada or USA, except at dealer. Even Europe showed little. Anyway about C$500 (incl tax & shipping) and I have a replacement. Old one removed. Fluid sucked out and attempt made to swab inside of booster. M/C seals onto a painted surface! Some of the paint damaged, so at present cleaning up that surface and re-painting. Won't install new M/C until the seal area is fully cured.
MBWorld Fanatic!
Joined: Sep 2018
Posts: 3,248
Likes: 936
From: New Orleans Area
2015 E400 Sedan
Could it be the brake pads are worn and need replacement?
If memory serves me correctly, MB the pad sensor was a plastic coated pin like thing on end of wire that would be inserted into pad and would ground out on rotor when pad wore away setting off dash light.
I just cannot remember what the warning light on Dash was as it has been many years since I worked on these era cars during summer mechanic job while in HS/College
If memory serves me correctly, MB the pad sensor was a plastic coated pin like thing on end of wire that would be inserted into pad and would ground out on rotor when pad wore away setting off dash light.
I just cannot remember what the warning light on Dash was as it has been many years since I worked on these era cars during summer mechanic job while in HS/College
Super Member
Joined: Aug 2008
Posts: 690
Likes: 30
Could it be the brake pads are worn and need replacement?
If memory serves me correctly, MB the pad sensor was a plastic coated pin like thing on end of wire that would be inserted into pad and would ground out on rotor when pad wore away setting off dash light.
I just cannot remember what the warning light on Dash was as it has been many years since I worked on these era cars during summer mechanic job while in HS/College
If memory serves me correctly, MB the pad sensor was a plastic coated pin like thing on end of wire that would be inserted into pad and would ground out on rotor when pad wore away setting off dash light.
I just cannot remember what the warning light on Dash was as it has been many years since I worked on these era cars during summer mechanic job while in HS/College
