'65 230SL Brake Problem

[n/a]

Hey all,

I recently changed one wheel cylinder, the master cyl and brake booster on my '65 230SL which had NO brakes previously. I have bled the system, pumped the pedal with engine off, felt good. Once I started the engine, I all of a sudden got a lot of free play in the pedal and it won't return to it's normal position, I have to lever it back with a screwdriver. The eccentric bolt at the back of the booster is properly set (notch pointed backwards). I can't figure out why I'm not getting a pedal return!

Any ideas?

[n/a]

HA!

Figured it out.

The pivot behind the brake booster bracket at the bottom was beginning to seize up. A little spray lube and good as new. Also, on the brake pedal softness, I just needed to bleed the brakes manually, the old fasioned way. I had used a vacuum bleeder the first time and I guess they're not as good with older brake systems. Whew!

[jeffc280sl]

Glad you solved your booster problem.  I had a similar problem with mine.  The connection bolt at the booster / brake pedal connection can't be so tight that the brake pedal arm is ridgidly fixed to the booster.  If it is the vacumm seal on the booster will not seal tightly as the pedal is depressed.  The pedal arm actually moves a little downward as the brake pedal is depressed.   Because of this it will push the brake booster arm down a tiny bit and cause a vacumm leak.  If the connection is flexible the brake booster arm will be pushed without the downward force and the seal will remain in tact.  It's kind of hard to explain but I hope you can understand given your experience.

Jeff C.
1970 280SL 4-speed

[graphic66]

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