Brakes

[LARRY C]

We have a 1968 250SL W113 body. I am having a hard Brake petal. We have replaced pad,caliper,brake hoses and Master Cylinder. We replaced the booster with one for a 280SL 002 430 68 30 the one it calls for is the 000 430 55 30. The only difference we saw was the way the vac hooked to the booster. We still have the same problem. I am trying to find out if the internal working of the booster would be different

[Tyler S]

Make sure you have the check valve in the booster hose to the intake manifold installed in the correct direction. It can be checked by verifing vacuum at the hose/booster location with the engine running.

[cfm65@me.com]

Hi Larry,
Dont try setting the pedal too high. Ensure enough free play in order for the system to relieve the pressure.
Often we all make the same mistake. Once we get the brakes sorted, we try adjusting for minimum free play and often do not leave enough space to release the build up.
Regards
Chris

[Benz Dr.]

Hi Larry,
Dont try setting the pedal too high. Ensure enough free play in order for the system to relieve the pressure.
Often we all make the same mistake. Once we get the brakes sorted, we try adjusting for minimum free play and often do not leave enough space to release the build up.
Regards
Chris

I agree. Many boosters can be adjusted to minimum free play but some will lock up after using the brakes a few times. Generally, you should be able to feel free play at the push pin after adjustment before you test drive your car.

[LARRY C]

As I had stated in my last message. The 1968 250SL we are working on has a 9"brake booster from a 1968 280SL. It is a new booster. The 68 250SL came with a 8" booster but all we had to change was the way the VAC hose hooked to the booster. All brake parts are new, pads,rotors,calipers,hoses lines and master cylinder we still have a hard petal. You really have to press hard to stop. The vac is good at the booster new hose and check valve.
Any Suggestions??
Larry Childress
Service Manager
Eurotech German Car Service

[stickandrudderman]

The bellcrank bearing can seize but this normally causes the brakes to stick on rather than a hard pedal.

[Tyler S]

Verify that you have at least 15" of vacuum from the engine. Another issue could be the pads themselves. I have run into hard brake pedal issues on other cars because of the compound used in the lining is too hard. The only other issue would be an incorrect master cylinder with the wrong size piston. Did you run into this problem after replacing components or was component replacement because of this issue?

[Shvegel]

Just to back up what Tyler said my father in law had issues with the brakes on his 911 being inefective when cold.  He thought he needed "better brakes" but I told him he needed less high performance brakes.  So often people fit ceramic or high performance brakes to a car when the factory pads do a better all around job especially when cold.  We switched back to factory pads and it works fine now.  I had EBC "Red stuff" pads on my car when I bought it and they drove me nuts.  When I hit the brakes on an off ramp halfway down they would finally start to grab.