[stonep]

I have just replaced the front original (sintered metal) brake pads on my '02 FXSTB. One pad is nearly worn through and the other pad only half worn or less. My Tech suggests uneven pressure from brake pistons, but this seems to defy Newton's 3rd law...Any advice on whether a fix is needed?

 

[stonep]

I appreciate your advice - many thanks.

 

[petrock]

Yes this is "normal", but is something you need to keep an eye on. SEDELUXE05's explanation is correct. But another reason, which is very common and an easy fix, is that the brake pads aren't sliding very well inside the caliper. So, for example, when both pistons go to push the pad. If the top part of the pad slides easier then the bottom, over time the pad will begin to wear unevenly because the top part of the pad will connect with the rotor first (and ultimately a longer amount of time).

So check the caliper slider pins (usually covered by a rubber, accordion style boot/tube), and clean/grease if necessary. Also check the surfaces of the caliper that the pad will slide against. Make sure they aren't dirty/rusty/pitted. Clean them off as well as you can. I like to put a little dab of all purpose grease on those surfaces (note: NOT on the pad or the rotor, ONLY on the surfaces on the caliper that the pad slides against) to ease in the pads movement in the caliper. If you get any grease on the rotor or pad, make sure to clean it off with some brake cleaner before going for a test drive.

Good luck...

 

[crash1292]

I dont agree with this statement posted on lyndalls site
"The likelihood is that the pistons that are closest to the source of hydraulic fluid will move initially while the pistons that are furthest away from the source of hydraulic pressure will in all probability hardly move at all."

first of all,brake fluid is NOT compressable
if you have 100psi of pressure generated by the master and each each piston has a exposed area of say 1 sq inch....you have 100psi on each and every piston....if one moves before the others its because it has less friction than the rest.....just my opinion..and as you can see I dont have a opinion

 

[petrock]

No it is correct. The piston is on one side (the outside in most applications), so the piston will have contact with only one pad. When the piston moves, one pad (the pad it has contact with, the outside pad) will begin to move. When the pad comes in contact with the rotor, the piston will continue to apply presure, pushing the outside part of the caliper away from the rotor which inturn drawns the inside part of the caliper (and the inside pad) towards the rotor causing the inside pad to come in contact with the rotor... Over time, that short (very short) delay of when the outside pad hits and the inside pad hits will add up and the outside pad will wear faster.

 

[stonep]

About 30,000 miles. The mechanic had a hell of a job getting the pins to slide through the replacement pad holes. Sounds like the pins might not be allowing the pads to slide across evenly.

 

[Martin64]

30000 thats the problem right there.

I respectfully disagree. I have one bike that has almost 50,000 miles on it with the stock (original) pads on the front and it has nothing to do with any lack of maintenance. It has to do with the type of riding I do, which is mostly freeway. High mileage on a set of pads doesn't necessarily mean any lack of maintenance.

 

[Martin64]

I'm sure that some will disagree with me for this, but I've found that a trip to the car wash every couple weeks or so really helps keep all that from building up. The car washes spray wands we have now (here in town anyway) don't have alot of pressure (or as much as they use to have), but they do have enough to get the bikes components pretty well clean.

 

[PeterV]

Keep those wands pointed away from the wheel bearings.

 

[stonep]

The original HD pads were sintered metal. My tech tells me that uneven pad wear is fairly normal. I treat my brakes reasonably gently and regularly clean rotors with brake cleaner. I've just changed to EBC organic pads and after a 100 mile run in, I tried a couple of hard stops - it felt like ther were no brakes and no way could I lock up front wheel even at low speed. I didn't like the poor brakling capacity, but maybe they havent been run in properly yet? I am thinking of changing back to sintered metal pads despite all the stuff about them wearing rotors, etc. At least they grab hard and stop well. What do you guys like as brake pad compounds? All advice appreciated.