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Old 10-20-2017, 09:06 PM   #26
fdryer
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Join Date: Jan 2006
Location: NYC
Posts: 41,046
 

2003 L-Series 3.0L Sedan
Default Re: Drum Brake Adjuster Kit Question

Quote:
Originally Posted by cuetip View Post
....Anyway, the problem with the drums going out of adjustment persists. Using the parking brake does indeed cause increased pedal travel. I have to adjust the star wheels by hand to restore the pedal height each time I use the parking brake....Could the master cylinder have an internal leak? My theory is that using the parking brake resets the adjusters to the proper position. However, because there is an internal leak, it's preventing the wheel cylinders from fully extending out each time the pedal is pressed. Could this be possible?
How can a leak in the master cylinder disappear every time you readjust the rear brake drum star wheels? The fact that the star wheels need repeated resetting points to possibly the star wheels or the parking adjuster mechanism are on the wrong side - reversing, retracting when using the parking brake. Star wheels (when in correct positions with correct adjuster mechanisms) adjust to expand (jacking apart the brake shoes to effectively keep them close to the drum internal surfaces, reducing piston travel when braking. The master cylinder either leaks internally with worn piston seals or not. A leaking or damaged master cylinder will not be corrected by star wheel adjustments. Readjusting star wheels each time to restore brake pedal travel to minimum points away from the master cylinder.

Getting back to basics, left hand drive cars for America means the driver sits on the left side of the car (standing behind the car). Driver's side is left, passenger side is right. Star wheels are designed for 'RIGHT' and 'LEFT' side installation because one star wheel has reversed threads that cannot be used in the wrong side - either it works in reverse or doesn't work at all. If a star wheel were placed on the wrong side and still works, it simply retracts (shortens) its arms and allows brake shoes to move away from drum surface, increasing the distance the brake wheel cylinder needs to travel before shoes contact drums. This is purely a mechanical functional description and if you're not familiar with left/right threads, how star wheels are adjusted manually and then adjusted with the parking brake lever, retracting/extending star wheels in relation to drum brakes, you're likely to become confused and frustrated. At the least, knowledge and familiarity with mechanical principles is needed when working on drum brakes. Hydraulics are the same whether its drums or disc brakes.

If you have to, removing one drum and carefully examining and exercising the parking brake cable next to the drum should engage the star wheel and turn it so the arms spread (extend) to move the brake shoes closer the the drum. If you cannot determine what's wrong, there's no shame here and seeking help from a brake shop is needed. Do not let this go without a solution.

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