Brakes

[Hawk]

The brakes on my 280 SL went out completely and then the next day they were back up. Any ideas what is wrong? Thanks

[Cees Klumper]

I'd guess the master cylinder (or the brake booster). Never had this happen though so not sure.

[Hawk]

Thanks

[Pawel66]

Have you examined for traces of leaks across the brake system components?

It is also important: where they "out" because the pedal went to the floor with no braking effect or the pedal was hard and the braking effect was very weak?

If the latter, that suggests the faulty booster. Particularly if you also heard a loud hissing sound and your idle revs went significantly up.

[Hawk]

Brake pedal went all the way to the floor with very little braking effect. I can see no evidence of brake fluid leakage.

[Vander]

Brake master cylinders can leak internally into the booster.

[Pawel66]

Yes, well, I am not educated in this, so to me if pedal goes to floor it usually means a leak somewhere: master cylinder, lines, hoses, connections, brake force regulator, calipers.

I did not know it could be internal to booster as Vander kindly described.

Could be old/damaged hoses that get swollen...

But maybe pedal in the floor can also be something else - mechanical connection at the booster?

[Flim]

Were you driving or had been driving at the time when this happened or did you notice this when the car was cold?

If brakes were fine when you started the journey and then the pedal went to the floor after driving - it may suggest a stuck brake caliper piston. This can happen through worn brake caliper seals.

Checking the temperature of each wheel/hubcap after a gentle drive may indicate the wheel/wheels where the suspect caliper may be.

Charles