Disc Brake Pads

From the Liar's Lair; 8 October 2010 --

The other day my Son-in-Law was helping me with a job that needed two good men. Well, the Son-in-Law was one good man and we got the job done despite the obvious deficiency. But this isn't about the job -- or even the Son-inLaw. This is about the disc brakes on the "Red Rocket".

As we rolled down the road, a strange noise appeared whenever Grumpy applied a long, light pressure on the brakes. Son-in-Law opined that it was the right front brake. Grumpy's faulty hearing was just able to confirm that there was, indeed a strange new sound emanating from the proud Red Rocket but Grumpy sure couldn't tell where it was coming from. But for sure, it was happening everytime the brakes were applied ever so lightly for more than a few seconds.



Left Front Disc Brake
(Looking Forward)



Right Front Disc Brake
(Looking Forward)



So tonight, Grumpy dismounted all four wheels on the Red Rocket and examined the disc brake pads on each hub. Here are the results: 

Notice, just above the hub in either photo, and next to the polished disc rotor, the 3/16" thick brake pad. Looking very carefully you can see the springy metal "tell-tale" extending toward the disc from on top of the pad backing. This "tell-tale" is placed such that it will contact the disc rotor when the pad is less than about 1/16" thick; the idea is to alert the driver of the need to replace the pads before the metal backing comes into contact with the rotor, causing a disgusting grinding sound and much damage to the rotor disc. The right front shows a similarly thick brake pad remaining; with about 85,000 miles onthe odometer, Grumpy estimates that these pads are "good" for at least another 40,000 miles before needing change. Of course Grumpy will plan to spot check them again every 10,000 miles (when he swaps the front tires, left to right). This very long brake pad life is predicated on conservative braking -- using engine compression as much as possible, by downshifting on long down-hill stretches, and by letting up on the gas early upon noticing a red-light or STOP sign up ahead, or traffic slowing down.



Right Rear Disc Brake
(Looking Aft)



Left Rear Disc Brake
(Looking Aft)

 The rear disc brake pads are apparently about half as thick as the fronts; either that or they have undergone more wear than the fronts. The emergency brake on this Honda Accord is applied to the rear disc brakes by a mechanism of which Grumpy is not sure. But the fact that the rear brake pads get wear due to the emergency brake application could explain more wear here. Even assuming that the rear brake pads were originally the same thickness as the fronts, Grumpy estimates that these should also be good for another 40,000 miles. However, since Grumpy plans to rotate the rear tires to the front at about 107,000 (after 40,000 miles on this set of tires), he will reassess the expected life of the rear pads at that time.

Unless the little "Tell-Tale" squeakers alert him before that!