<VV> Brakes grabbing

Dale Dewald dkdewald at pasty.net
Sun Jul 26 22:46:48 EDT 2009


Hello Stephen,

It seems that you have had no end of trouble with the brakes on your car 
ever since the dual master cylinder was installed.  This comment from your 
recent post may be the clue to many of your problems:

>When this is happening, the car does not move
>forward in drive, no gas, after taking the foot off of the brake.
>Sometimes putting my foot under the pedal and bringing it towards me
>will cause the brakes to release.

This sounds to me like a mis-adjustment of the push rod between the brake 
pedal arm and the master cylinder.  It appears the there is not enough free 
play to allow the master cylinder piston(s) to fully return. This prevents 
the opening/uncovering of the return line ports, which allow fluid from the 
wheel cylinders to flow back.

Four weeks ago I installed a dual MC conversion in my wife's '65 Monza.  I 
had to adjust the push rod shorter to get proper free play for the new MC.

Stephen, check the clevis/push rod assembly on the brake pedal arm up under 
the dash.  Adjust it so that there is 3/8" to 1/2" of free play at the 
brake pedal before the MC is engaged.  Do this and check in with your results.

Check also that the brake light switch is adjusted so that the lights come 
on about at the mid-point of this free play.  This way you can touch the 
pedal and light up the brake lights as a warning to following motorists 
without actually applying the brakes.

Dale Dewald
Hancock, MI



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