Front Disc Brake Slide Pins - Question

[fourbangingfun]

Hey everyone.

So today I pulled apart the front brakes on my 07 sedan. It has 170k miles, and the rotors/pads were replace at 100k miles. The bottom slide pin was frozen in place on the right front wheel. I was able to pull it out, clean it on a wheel brush, lube with anti-seize and reinstall.

My question is this: that lower pin had a rubber ring around it towards the end of the pin. It was all chewed up and destroyed. I ended up just pulling it off (along with the one on the opposite side) and installing the pin without the rubber ring.

Will this cause any problems? I don't really see what the purpose of that rubber ring is, as the hole for the slide pin has a dead end at the bottom of it.

Thanks :headbang:

[WeeYari]

I've wondered that myself but have never researched it. I suspect that it's purpose is to seal in air that gets compressed at the end of the pin when braking. This compression is then used to help back the pad away from the rotor when braking pressure is let up.

That's my thought on it.


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[fourbangingfun]

I've wondered that myself but have never researched it. I suspect that it's purpose is to seal in air that gets compressed at the end of the pin when braking. This compression is then used to help back the pad away from the rotor when braking pressure is let up.

That's my thought on it.


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Ah, that's a good thought. I noticed the pins really wanted to push back out on their own when I inserted them. The side that was frozen had significant pad wear, probably from being stuck in contact with the rotor. I'll need to order a new set of pins when I replaced the pad.

[toyotavios_11]

better get a rubber replacement as soon as possible
the rubber is to prevent debris go into the slide pin holder

[CoryM]

The rubber tube on the pins are just there to reduce the chances of having a rattle, or clunk. Without them, the calipers can audibly rattle on bumps, or when applying brakes. Pins that have the rubber tubes are more likely to seize up since the rubber is sticky. Make sure to lube them well.

It won't hurt anything for it to be missing. Chances are the Toyota clearances are tight enough to keep it from rattling. However, the rubber dust boot on the outside is definitely critical to keep the pins moving freely and not wearing the bores from dirt.

Cheers.