TheSamba.com :: View topic - '74 super too much free play in brake pedal

Wed Jun 12, 2013 8:44 pm

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?

Wed Jun 12, 2013 8:48 pm

mrbuchholz wrote: 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.

1/4 inch seems too little free play to me. I'd split the difference and go for about 1 inch measured at the top of the pedal.

Thu Jun 13, 2013 3:38 am

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.

Thu Jun 13, 2013 4:26 am

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.

Thu Jun 13, 2013 7:33 am

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?

Thu Jun 13, 2013 7:56 am

mrbuchholz wrote: ...
And pedal travel is how far down to the floor it will go?

Well, yes, sort of. Pedal travel is how far the pedal can go. If the brakes are working properly, it won't go all the way to the floor. So, just measure from the back of the pedal down to where the pedal would hit the bulkhead if it could. You need 7 7/8 inches.

Read this thread, it's all been covered before.
http://www.thesamba.com/vw/forum/viewtopic.php?t=402239&highlight=brake+pedal+adjust

Thu Jun 13, 2013 11:21 am

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

Thu Jun 13, 2013 6:03 pm

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