Expert: jack bahm - 9/15/2008

Question
What should I do to eleminate the shudder/vibration/shaking in the front of a '31 Ford?  The vibration occurs during the last 20 - 30 ft. of stopping and can be varied by easing off or applying more pressure in the break peddle.

Just prior to the problem starting I replaced the linings on the front breaks,  sanded the linings on a belt sander so they conformed to the drums.  I did not turn the drums as they are getting to the max. diameter.
Thanks for your suggestions to make stoping quieter and smoother.  Howard


Answer
It sounds like a shimmy problem.  I just wrote to a guy about this.  Here is what I told him.

OK, here is what you do.  Make sure the strg gear is adjusted at all three points.  End play of the sector shaft, two tooth gear pushed all the way into the worm gear, and the excentric sp??? adjustment.  This is the one that is hard to get to, but it alligns the two tooth gear to the center of the worm.
Tighten the drag link ends so the springs are bottomed out.  I know the book says to leave them loose, but that always causes shimmy for me.  Tighten them ou.
Do the same thing to the tie rod ends.
Make damn sure you have 3/16 in toe in.  Make sure about the toe in.  It is very important.  I have fixed many by doing this, but that toe in is key.
Good luck
jack

Mark, I forgot two more things to check.  Sitting behind the left ft. wheel, grab the pitman arm and try to push and pull it toward you.  If it moves, it is either the pinch blot that holds it on to the sector shaft or the bushings of the sector shaft are worn.  The pinch bolt must be super tight, and the bushings must be tight.  If you have to replace the bushings, it is a big job because it is hard to get the gear out of the car.
Good luck
jack

You may also have the problem caused by a loose bolt that holds the wedge.  It is the large nut with a cotter pin 3/4 in., I think.  It holds the sliding wedge.  If this is not really tight, the brake will shudder as you come to a stop with the wheels turned.
good luck.  Hope this helps.
jack