Alcon calipers "popping"?

[leviathon]

Ok here's my situation. I have a 06 with a one off made alcon type b front caliper using gt500 rotors and lines. At first this was every so often but now it's everyday. As soon as I put pressure to the brake pedal. The front right pops. It's coming from the wheel and i can only assume it's the caliper...unless it's suspension related which in that case I have Saleen coil overs.


Does anyone have any insight? Anything I'm saying make sense?

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[leviathon]

Alcon* calipers my apologizes

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[oldVOR]

A single pop or multiple?
While moving, standing still or both
Simple things first, have you checked all the bolted connections to ensure it's all tight?

 

[leviathon]

Single pop at the time the brake pedal starts to engage. Yes I've checked all bolts they are good and snug. While moving, however I recall one time it did it standing still however whole moving is consistent.

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[Sky Render]

Geez that's weird. No leaking fluid, right?

Maybe one of the pistons is starting to stick?

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[01yellerCobra]

Possibly missing an anti-rattle clip?

 

[leviathon]

No. The bad thing is that I made this brake set up haha. It's basically a brembo f40 type setup minus a few different things. But on the drive home tonight it wasn't every time I hit the brakes. Really just random and are different levels of intensity

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[leviathon]

Geez that's weird. No leaking fluid, right?

Maybe one of the pistons is starting to stick?

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Your telling me! I'm thinking maybe your right but how do pistons really stick?

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[2Fass240us]

It could be something in the suspension reacting to the brake force. I'd check that everything in the suspension is tight.

If that doesn't fix it I'd remove the caliper have someone SLOWLY press the brake pedal and watch what happens to the pistons. It's possible one is hanging because of friction between the piston and the seal, then gradually overcoming that force and making a popping sound. Just be careful not to overextend the pistons because you'll have to reinstall them. NBD, but it gets fluid EVERYWHERE.

Past that, it'd be really hard to have a "pop" in the caliper without leaking fluid.

 

[leviathon]

It could be something in the suspension reacting to the brake force. I'd check that everything in the suspension is tight.

If that doesn't fix it I'd remove the caliper have someone SLOWLY press the brake pedal and watch what happens to the pistons. It's possible one is hanging because of friction between the piston and the seal, then gradually overcoming that force and making a popping sound. Just be careful not to overextend the pistons because you'll have to reinstall them. NBD, but it gets fluid EVERYWHERE.

Past that, it'd be really hard to have a "pop" in the caliper without leaking fluid.

Your telling me. Sucker is bone dry but I have to go and re bleed the system anyway pedal is to soft for me anyway. This is really mind boggling! I guess I gotta look at the whole side with a microscope

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[2Fass240us]

...but how do pistons really stick?

Piston:seal friction may not be the same across all 4 (6?) pistons, which means the ones with less friction will extend first.

 

[leviathon]

Piston:seal friction may not be the same across all 4 (6?) pistons, which means the ones with less friction will extend first.

Ahh, definitely see your point now. It's a 4 piston. I had another thought that the caliper may not be exactly centered over the rotor think that could possibly do it?

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[oldVOR]

I don't think these calipers have the pad guide plates like the OEM calipers do. I experienced a popping, creaking from one of the thin plates wearing down and the pad having to push across the divot. It did it standing still or moving and stopped once new guide plates were installed.

 

[leviathon]

I don't think these calipers have the pad guide plates like the OEM calipers do. I experienced a popping, creaking from one of the thin plates wearing down and the pad having to push across the divot. It did it standing still or moving and stopped once new guide plates were installed.

Here is the bottom of the caliper if it helps you at all

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[Sky Render]

The guide pins are on the top of the caliper. Can you show us that?

 

[leviathon]

The guide pins are on the top of the caliper. Can you show us that?

This is the top. Well what mine looks like

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[Sky Render]

Yeah...

OEM Brembo Caliper:

The pads have holes that those two pins slide through, keeping them consistently "flat" against the rotor. I wonder if this is your problem? How old are your pads?

 

[leviathon]

Maybe 2 years old. And yeah I thought of that but the way they sit inside are very tight virtually no walking around.

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[2Fass240us]

Your telling me. Sucker is bone dry but I have to go and re bleed the system anyway pedal is to soft for me anyway. This is really mind boggling! I guess I gotta look at the whole side with a microscope

There are tons of fasteners that could have come loose to cause movement. Strut to upright, radial bracket to upright, bracket to caliper, the list goes on.

Given that they're radial calipers, you should check that the brackets are tight to the spindle, radial studs are in tightly, and the calipers are bolted solidly to the studs. Check StopTech literature for torque specs.

I had another thought that the caliper may not be exactly centered over the rotor think that could possibly do it?

I highly doubt that, unless it's WAY off center. But then you'd have two pistons coming out so far they'd be leaking and the other two would barely have moved.

And yeah I thought of that but the way they sit inside are very tight virtually no walking around.

Yeah, I don't think this is an issue. As long and the sides of the pads are tight against the wear plates (the bright stainless pieces on either side) and your bridge bolt is tight, you should be good. I have used 4- and 6-piston Wilwood Superlites and never had an issue with pads moving in any direction besides the ones they're supposed to. And I abuse the brakes on track.

 

[leviathon]

There are tons of fasteners that could have come loose to cause movement. Strut to upright, radial bracket to upright, bracket to caliper, the list goes on.

Given that they're radial calipers, you should check that the brackets are tight to the spindle, radial studs are in tightly, and the calipers are bolted solidly to the studs. Check StopTech literature for torque specs.

I highly doubt that, unless it's WAY off center. But then you'd have two pistons coming out so far they'd be leaking and the other two would barely have moved.

Yeah, I don't think this is an issue. As long and the sides of the pads are tight against the wear plates (the bright stainless pieces on either side) and your bridge bolt is tight, you should be good. I have used 4- and 6-piston Wilwood Superlites and never had an issue with pads moving in any direction besides the ones they're supposed to. And I abuse the brakes on track.

Same, my brakes are definitely used. But oddly enough this side has always given me a problem ever since it was hit 4 years ago. Guess somethings are never the same when it's hit. Everything has been replaced obviously and I didn't even have the brakes then, but when I was measuring up everything to mill the brackets it was a pain. I've never had to touch the left side haha

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