Do any of you actually know what the purpose of this is?

[StageLeft]

pin.jpg

I have scoured the net with various keywords and nobody has actually stated what the purpose of the rubber sleeve is on the bottom of a caliper pin. I'm not sure all disc brakes have it, but some do and in some cases the rubber-sleeved pin goes at the top. If it helps lubricate, why doesn't the bottom one have it? I've also run upon people with seized pins and it's because the rubber can toughen up or expand and lock in place. Wouldn't it disproportionately stiffen one pin vs the other leading to uneven braking?

Finally, mine are a bit screwed, so I plan on making new rubber sleeves with some tubing from lowes (I'll dremel wheel the matching grooves in place). Any potential problem with that, assuming I can find the right fit?

 

[Sukhoi]

I can't see that pic at work but I presume you're talking about that little rubber thing maybe 5 mm thick that goes in a grove at the end of the caliper pin. A couple months ago I refurbed my front brakes and had the same question. The two packs of new pins I bought had the slots for the rubber thing on one pack, but the other had no slot. I ended up not putting any of the rubber things on. It seemed like most of the reason my calipers were seizing up was that rubber thing breaking up and getting stuck in the sliding area. So far I haven't noticed a problem.

 

[DivideBYZero]

Just a guess, but is it an anti-squeal device?

 

[StageLeft]

It may have to do with squealing but I know these cause problems for some people as they can get very tight and greatly limit movement of the pin. Using a rubber-destructive grease will certainly come into play here.

I went to Lowes and nothing is suitable as a replacement. They're a bit tricky to find locally. They come with more expensive kits and spare calipers. I may end up going with Sukhoi's approach if all it is has something to do with sound and in his case he couldn't even tell.

 

[AsianriceX]

Are you talking about the slide pin boot?

It stops dust and other garbage from getting in the lubricant in order to prevent the pin from seizing. It's like a CV boot if I'm not mistaken.

My Altima has them on both pins.

 

[franksta]

Originally posted by: AsianriceX
Are you talking about the slide pin boot?

It stops dust and other garbage from getting in the lubricant in order to prevent the pin from seizing. It's like a CV boot if I'm not mistaken.

My Altima has them on both pins.

I thought it was some kind of dust boot as well. It's been a while since I've done any brake work but I vaguely remember them on my F-150.

EDIT: I found them for my truck. Rock Auto calls them caliper guide pin boots
Link

 

[iamwiz82]

It's a boot to protect the pin. The problem being that the boot ends up holding in the dirt and moisture which corrodes the pin. Same thing that happens when you install strut boots.

 

[StageLeft]

Did you guys look at the pic? I'm talking about the rubber sleeve that goes around the pin itself. It's only on one pin, not the bellows-like rubber flexible seal at the end of most caliper pins. Most pins have the typical accordian/bellows type seal to protect the grease and keep the pin clean, but this specifically goes around the very end of one pin (the other end from the bellows seal) and sits actually in the caliper sliding area.

Look at the pic and on the bottom pin that rubber sleeve in the pic wraps around the end of the pin.

 

[Sukhoi]

Actually my brakes do screech like hell. That could explain it. Though they have gotten better after a couple months of driving. I figured it was just from cheap pads.

I still can't see the pic but the thing I'm talking about not putting on is like a mini rubberband.

 

[zerocool84]

It allows you to go back in time to the 1950's

 

[StageLeft]

Yeah sukhoi it's a rubber band type thing that goes around the end. I will be damned if I can find what it does on the net. I've even found people asking what it does and people either have no idea it exists or they have no idea what it does. It's been called a tensioner and also a lock pin, with the guide pin being unsleeved.

Do your brakes screech or squeal? I know that when I redid rears before, without turning the rotors, it took 10k miles before the squeal completely dissipated.

 

[AsianriceX]

Ahh, I gotcha now.

Unfortunately I don't have those on my Altima. They're not listed or shown in the exploded view of my calipers.

My google-fu is too weak to figure out what they are as well.

 

[StageLeft]

Hell I just ran through news groups. Typically the threads go exactly like the one we're having here, where some think the question is about the rubber dust boots and others are surprised the things exist when explained and then others still wonder if they can either do without, because it caused a seized pin, or what the heck it's for. The guy at advance auto parts had no clue, either, despite looking like he's worked on cars all his life.

If I cannot get them to slide like greased lighting later I'm just going to do without. I think brake function cannot possibly rely on a tiny bit of rubber in the pin, it must be some kind of a vibration/sound damping approach although I still can't really see how it would do that. Perhaps frequencies in the caliper can make sounds but when they hit this pin with its rubber they die on the spot, so there's a reduction in sound (?). I've got a new stereo in the car soon anyway, so sound won't matter.

 

[RayH]

I think it's designed to keep grease on the pin, preventing it from migrating into the empty space behind the pin and helps evenly redistribute grease as it moves slightly in and out each time the brakes are used. Not sure why it would be on one pin and not the other unless the backside of the pin is exposed to the outside of the caliper.

 

[SonicIce]

Originally posted by: DivideBYZero
Just a guess, but is it an anti-squeal device?

thats what she said

 

[LTC8K6]

It looks like it is designed to seal the hole, with the grooves designed to hold the lubricant.

Like a rubber bushing. Why it would only be on one though....

 

[StageLeft]

Originally posted by: LTC8K6
It looks like it is designed to seal the hole, with the grooves designed to hold the lubricant.

Like a rubber bushing. Why it would only be on one though....

Those are replacements, btw. On the originals the grooves actually go longitudinal, to allow lube to flow around.

Well, these are turning into a real bitch to locate. Advance auto parts' online store doesn't mesh with in store; part numbers have changed. I'm not buying a $55 caliper kit for a piece of rubber and cannot seem to find in the hardware store a suitable replacement, so I'm leaning to rubber-less replacements at this point.

 

[LTC8K6]

What car is this again?

 

[LTC8K6]

http://info.rockauto.com/getim...Raybestos/H16013-1.jpg

These Raybestos bushings have longitudinal grooves...

 

[StageLeft]

Originally posted by: LTC8K6
What car is this again?

2000 maxima

 

[LTC8K6]

Yeah, those Raybestos ones fit.

8 bucks from Rock Auto.

 

[StageLeft]

Originally posted by: LTC8K6
Yeah, those Raybestos ones fit.

8 bucks from Rock Auto.

Oh hell.

Can you think of a potential local supply; like maybe they fit on some popular GM or something and I can search locally for that? I really really need the car back on the road on Monday!

EDIT: God Bless. I have found them online at advance auto parts, too, i I search for caliper bushing. They're not available locally, though, but maybe I can find something. Before I was finding nothing but wasn't using that key word.

Looks like I may have found a bushing kit at a local napa, but since they keep banker's hours I'll wait till the morning. It comes with silicone grease in a tiny pouch, unfortunately, because I spent $15 on a big tub of the nice silicone grease today already I'm taking no risk with a petroleum based lube, even if it says it's safe for rubber. I think there's a good chance it screwed these sleeves up.

 

[LTC8K6]

According to Rock Auto they fit a lot of vehicles...

Raybestos H16013


ACURA (1986 - 1988)
FORD (2006 - 2008)
HYUNDAI (1989 - 2006)
INFINITI (1991 - 2008)
KIA (2001 - 2008)
LINCOLN 2007
MAZDA (2004 - 2007)
NISSAN (1985 - 2007)
SUBARU (2003 - 2007)

 

[marifca]

I have tested this issue. While changing brake caliper pins for some noise issue I bought only the Pins thinking that the rubber boot and the bush (small hollow cylinder of rubber that goes at the end of the pin) are OK. When I removed the pins I found that the bush was damaged and could not be used any more. And in my Altima's front right brake caliper, the top right pin does not have any rubber bush, only the bottom one has it. So, I decided to go without the rubber bush and installed everything. After running for a few days I found that there is a groaning noise which happens while releasing the brakes at low speed. Then I installed the bush and the noise was gone. So, this tiny thingy is "important" :\

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