Rear brake pad crooked?

T_C

T_C

Joined
Mar 8, 2012
Messages
3,532
Location
St. Louis, MO
Bike
2005 St1300
Okay, I know this is in dire need of replacing, but before I tear into it (since I don't have pads to put on anyway).

What can cause this level of off-kilter pad wear. I pulled the pin and it doesn't seem to be binding the pads. Can one of the pistons be sticking on one side and pushing unevenly?

rear-view.jpg

A closer view:
rear-closeup.jpg
 
Wow, that looks horrible.

Looks like the left side pad is blocked on the glider pin thingy there. That pin should be nice, clean and shiny, so the pad can move freely left to right. Maybe even half the caliper is blocked this way, can't remember exactly how the rear caliper works on the ST.
You probably need to replace that pin and maybe some rubber parts that allow the caliper to slide over it.
 
Looks like a lot of corrosion going on if you ask me. I would see about cleaning those up real good and getting some high temp brake grease (for the pins) before putting on a new set of pads.
 
I think it was installed incorrectly and thus the bad wear - IMO, get some new pads and install them correctly. There's a soft metal bracket in the front of the caliper you have to line up the pads in or they will seat incorrectly.

See here:
https://www.st-owners.com/forums/showthread.php?101206-ST1300-Rear-Brake-Piston-Cleaning

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+1. Looks like it wasn't seated correctly.
Either that front H shaped pad spring in Joe's picture isn't there or wasn't seated correctly or the pad tang wasn't properly engaged.
I'd replace the pad retainer pin and o-ring along with the new pads.
 
T_C said:
I pulled the pin and it doesn't seem to be binding the pads.
Click to expand...

from the picture it appears that the pistons are trying to move the pad forward, but the pad metal frame was binding on the pin. Instead of sliding along the pin, the pad rotated as far as it could until it used up the tolerance of the hole diameter to the pin diameter. Note that the piston is only contacting the pad frame at the very top of the piston bore.

Mellow may be right that there's something else in there contributing to the problem, cause I've never seen a pad hang up quite like that before, but that pin is ugly looking too! Take it apart and clean/lube it and you should be able to see if there's any other problems once you're in there.

A closer view:
rear-closeup.jpg
 
It is possible it's the corrosion.. that pin should be clean to allow the entire pad to move vertically... so it's either not seated and/or that pin is so bad it's hanging there - the more I look at the picture it makes more sense.
 
I think the comment about the pad tang may be more likely. Its at the top, so consistent with the bottom rotating while the top hangs. As corroded as that pin looks I'm suspecting that it wouldn't have enough resistance to rotate the pad like that, but with all automotive weirdness I never say never.
 
Now- that's some REAL ate-up corrosion right there. Looks like the pad-arm cannot slide away, when the pucks are engaged. Dude there's a overhaul needed here. The whole assembly! Just say'n.....!
 
It's not quite as corroded as it looks, that's just the joys of wintertime riding in the midwest. A little bit of road grime makes everything look horrible.
Here is an overall picture, the white gray is just grime with a bit of salt... salt that needs to get rinsed off.
overall.jpg

While I was in there I did pull the bin and used a brass brush to clean it up a bit. It pulled out really easy, so I don't think that was the binding part.

Hopefully new pads are here by the weekend and I can get them put into place while the next round of snow comes through the area. 71 for a high today, 75 for tomorrow and then snow on Wednesday.
 
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That does look like either the pad is hanging on the pin or the spring above the pads is causing the issue, or both.... that needs a real good strip and clean and a bit of reprotection...
 
Mellow said:
It is possible it's the corrosion.. that pin should be clean to allow the entire pad to move vertically...
Click to expand...
Actually its most likely the cause...
Winter/bad weather riding requires some additional maintenance and somewhat enhanced service protocols...

On my rigs mentioned pins get wiped clean, and receive a slight smear of copper lube over their entire length before installation... this prevents corrosion nearly entirely, thus no stuck/uneven worn brake pads...
 
Another cause could be hanging on part #5 in this diagram. The spring is supposed to push the pads down but if the edge of the pad got hung on the side of the spring it could stop it from sliding against the pad and cause this type of wear.
 
Byron said:
Another cause could be hanging on part #5 in this diagram. The spring is supposed to push the pads down but if the edge of the pad got hung on the side of the spring it could stop it from sliding against the pad and cause this type of wear.
Click to expand...

We have a winner! Been finding this alot lately mostly after tire or pad changes.
 
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