Re: Brake Shoe Centering Measurements

Posted by DJ.Voyce on Sep. 25, 1998 at 03:20:51

In Reply to: Brake Shoe Centering Measurements
posted by Kevin Daly on Sep. 24, 1998 at 14:46:20

G'Day Kevin,
In "theory" the contact surface of the brake shoe should be equidistant from the drum in all positions, however, due to the expander mechanism only operating on one side of the shoe this is not always practical & certain allowances must be made to prevent the brakes from binding or dragging. I may pick up some flak from this, but I'd say you should followLes Andrew's advice & leave a little clearance on the very end of the expanding side of the shoe, providing the rest of the shoe (at least 80%) measures zero clearance. The closer you get the settings to an almost zero tolerance situation (without dragging) the better your brakes are going to work. The good news is that the closer you get them to spec, the quicker they'll bed in & the more efficient they'll be. This also prevents any wide-eyed, teeth clenching stopping situations. A good tip whilst we're on the subject of mechanical brakes (from a naturally lazy person)is, if you ever have reason to remove the brake shoes for any reason other than re-lining them, always re-fit the components in the same position as they were removed. This will prevent you from having to set everything up from scratch again & your brakes will (hopefully) work just as well as they did before they were stripped.
Regardz
DJ.
OutOfAfrica A's
: Hi Folks,
: I understand the importance of centering one's brake shoes to their drums as well as matching the shoes radius to the turned drums.
: If I were using the K.R. Wilson brake shoe centering gauges to center my new shoes, should the fixed vs. expanding measurements be exactly equidistant from the center of the spindle/axle?Bratton's catalog suggests that the distances are equal on both the fixed and expanding ends of the shoes.
: Les Andrew's book suggests a zero measurement on the fixed end and .010-.015 measurement on the expanding ends for both the front and rear brakes!
: Who is correct?I think Les is correct.I believe that since the shoes are expanded only on one side, that the expanding side has further to move before it contacts the drum.The fixed side is the pivot point for the expanding shoe movement and therefore the fixed side requires very little movement before shoe to drum contact is made, thus Les' slightly less than equal measurements.
: Would any of you care to give your thoughts on this one.I like to understand these types of theories before I apply them!
: Thanks in advance for your responses.
: Regards,
: Kevin Daly

Follow Ups:
Thank You DJ! Kevin Daly Sep. 25, 1998 at 06:46:26(0)

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