500SL 107 with abs problems

[chiwanga]

MY 82 500SL euro has brake problems. I replaced all the pads, and still the brakes are weak. It will not make a panic stop. How do I test the bakes to know if part of the ABS is the problem, or if the master cyl, or booster is the problem?

[GSMITH]

Only way I know to test the ABS is to slam on the brakes on a wet road.
I prefer to do this in an empty parking lot with nothing around to hit.
You should feel it pulse thru the brake pedal. It will only kick in
if the wheels stop spinning with the brakes applied.
If you can not get the brakes to lock up you may need to flush the
brake fluid and or change the rubber brake lines.

After 24 years the rubber brake lines can get clogged reducing the
amount of pressure the brake pad get. Did the pads you took out
show the same amount of wear? A clogged line will usually show itself
as a pad that drags.

If you get the brakes to lock up but the ABS does not kick in there
could be a lot of things to check. The sensors are the only thing that
are cheap. But when they go bad they usually trigger the ABS dash light.

Master cylinder problems usually show up as a brake that slowly falls.
Booster problems cause a hard pedal. And a vacuum leak to the booster
can make you think you have a booster problem.

[JPMOSE]

I recently had a vacuum leak on my 2000 Saab and the booster was weak accordingly. Along with the pedal being harder, the brakes seemed weak overall. Checking the vacuum lines is fairly easy...I would do this first!