# Seized Caliper...I think.



## Grug (Aug 20, 2009)

Well, my '97 4WD HB has been prone to bouts of sitting for periods of time and I think this lack of use may have buggered up a caliper.

I took the truck for a drive today and there was an awful pull to the ditch (all the time, not just braking). There was also that unmistakable smell of hot brake pads. I stopped the truck and the right front wheel was very hot.

Took it home and removed the wheel. I lifted the caliper off the pads and compressed it a little with a C-clamp. That worked...until I pressed the brakes again. Then here was serious drag on the wheel.

So, caliper for sure? Maybe a collapsed rubber line to that wheel? Thoughts?


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## GeoBMX4Life (Mar 25, 2010)

Pull the sliders out and re-grease them...happened to mine before.


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## Grug (Aug 20, 2009)

Well, the slider bolts seemed to be moving fine. However, I did remove them and dab on a little 'Never-Seize'.

Something I did notice (which is probably a game changer) is when I compressed the pistons with the C-clamp, I noticed brake fluid weep out of one of the rubbers...uh-oh.

It's a little annoying as both front calipers are only two years old.

Now, for a physics question. I get it that the caliper squeezes the shoes against the rotor, but what releases the shoes from the rotor when the caliper releases its pressure? When I lever the stuck caliper off the shoes, they're still 'stuck' on the rotor.

Does the rotating wheel (rotor) provide the energy that allows the shoes to be 'broken' from their death grip on the rotor?


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## Grug (Aug 20, 2009)

I've been watching You Tube videos of folks installing new disc brake pads and I gotta' say something must be wrong on my HB.

The folks I've been watching just take the new pads and snap them into position by hand. That is so not the case with my brake pads. With mine, you have to pry and tap with a hammer to get them to go into place.

What's up with that?


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## smj999smj (Jan 1, 2006)

You shouldn't use never seize on slide pins; use brake caliper grease or silicone grease made for brake parts. Copper impregnated grease (aka PBC Grease) should be used on the slides and shims. Since the caliper is leaking, you know you need a new caliper and I prefer to replace in pairs. Anytime I replace a caliper, I install a new brake hose. It's good practice and can prevent a lot of headaches. As far as the piston releasing, the combination of the released hydraulic pressure on the piston and the rotating piston causes the pads to retract slightly. Always use a quality brake pad when replacing them. I've used or have found "cheap" pads and sometimes the backing plates were too tight of a fit within the caliper mount bracket, thus they would not slide. In those cases, the ends of the pads had to be ground down or filed to get the to fit properly. I like to go with Akebono ACT Ceramics, which come with new hardware and Akebono is an OEM supplier of brakes to Nissan. Raybestos Professional Series Ceramics are also very good.


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## Grug (Aug 20, 2009)

Hey there, smj.

It's interesting you mentioned grinding the pads' backing plates to make them fit a little 'looser' (man, but they go in there tight). 

When I was trying to get them back in after I examined the claliper, I thought a fella' could just tweak them a little with the Dremel or mini-grinder, but then I thought, "No, I can't do that. I'll probably mess up some brake geometry or balancing..." 

Oh well. I'm off to the parts store. I'll keep you folks updated.

*sigh*


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## smj999smj (Jan 1, 2006)

They should be snug, but still be able to slide back and forth easily. The slides, themselves, do wear over time and if you are purchasing pads that do not come with new ones, I recommend replacing them at least every other pad replacement. The area of the caliper mount bracket in which the slides snap into should be cleaned up with a small wire brush. If they are considerably rusted, a will use a file to clean them up.


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## Grug (Aug 20, 2009)

Ok...update (I wish everyone with a problem would give us updates).

So, I replaced the caliper. To get a core credit charge I didn't realize that I ALSO had to take in the bracket (held on with two 19mm bolts). D'oh! (Anyways, I'll return the bracket later and get my core charge back...no biggie.)

But here's what I found interesting. The old pads fit much nicer into this new caliper / bracket set up. I elected to not change the pads as there's lottsa' life left in 'em. So I'm not gonna have to tweak the pad backing plates with the Dremel. Who-rah!

The new calipers grab and release like they should, but the brakes still need to be bled as no one's around right now to pump the pedal for me. Any takers? I'll supply the beer. 

I'm hopeful I can get away with just bleeding that wheel, but we'll see. If all four wheels need to be bled it's no big deal as I know the bleeder screws will all turn.

I'll post again after a bleed and a road test.


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## Grug (Aug 20, 2009)

Well, I bled and road tested and much was very surprised to find that the replacement caliper was defective. During the road test I stopped when I noticed my pedal getting more and more spongey. Stopped and inspected the front wheel and found a puddle the size of a coffee cup coaster!

I beat it for home thinking that I didn't have either the main line or the bleeder nipple tight enough. Both were fine. The fluid was running out of one of the two pistons in the caliper!

Called the parts store and they've got one on order for me.

This ever happen to anyone.


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## smj999smj (Jan 1, 2006)

Yeah. Reman parts are what they are. Sometimes you get a good one and sometimes you get a bad one. It's best to go with genuine Nissan remans when possible, but they aren't cheap. There's trade-offs with everything.


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## Grug (Aug 20, 2009)

Well, got the second caliper installed, bled and road tested.

So far things seem to be good. No leaks and brakes are good. Was able to bleed just the wheel on which I was working.

(BTW, the guy at the parts store said that once in a blue moon they get a defective caliper, but he hadn't seen one in awhile.)


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