'74 super too much free play in brake pedal

[mrbuchholz]

We have new brakes on . We have bled and adjusted. Driven it a little but the free play is about 2 inches now.
I have been reading about the master cylinder rod adjustment
There are 2 nuts on this rod and when I turned the front one a bit it tightened up the free play to about 1/4 inch.
Any wisdom on this.
The chances that someone else has messed with it are high. It has been through so many owners who have never finished it to the road.
What is the 2nd nut for? How do I know if I have done it correctly?

[Cusser]

[Q-Dog]

The correct way to set pedal freeplay is by adjusting the pedal stop on the floor. There is a minimum amount of pedal travel you must maintain in order for the dual circuit system to function properly in the event of a failure in one circuit. Normally the pedal rod does not need ever to be adjusted. On a standard Beetle, the pedal travel should be 200mm (7 7/8"). Adjust the pedal rod ONLY after you have set the correct pedal travel.

This should all be covered in your Bentley Service manual.
_________________
Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[jlex]

The second nut is a lock nut. The front one you turned adjusts the length of the rod. The rear one locks/unlocks the rod before/after the adjustment is made.
_________________
jlex.
'70 std. "Elsie"
'88 Carrera

[mrbuchholz]

Thanks
I will look in the Bentley again.
Trying now to remember what kind of hole the bolt for the pedal stop was in, for adjusting. We put in a new floor pan. Seems like we might have had to put a hole.
When I had moved the back screw up next to the front screw it seems that they were not tight. Before I started to move the front screw it was all the to the back of the pushrod next to the back bolt.
And pedal travel is how far down to the floor it will go?

[Q-Dog]

[mrbuchholz]

Thanks...I have started reading through the thread links...Great info!

[Tim Donahoe]

The freeplay, measured at the tip top of the brake pedal should be 3/16 to 9/32 inch (or 5 to 7 mm)--before you meet resistance. That's not a lot--and very close to the one-quarter inch you mentioned. You do this adjustment, as already mentioned, by moving the stop plate.

But ... since you messed with the pushrod length, you want to start at the source and re-adjust it so that it's screwed in until it stops--then screw it out one-half turn. This should get you the factory setting 1 mm distance you need from the tip of the rod to the piston (John Muir). Then tighten the lock nut.

The stop plate, however, is supposed to take care of the pedal adjustment. Do you have a stop plate? or just a hole in the floor.

It's funny, though. My free play is a good inch and my brakes work just fine in my '74 SB. But I'm changing over to front discs soon--with a new German MC, so I'm going to follow my own advice then and adjust to specs.

Tim

Tim