Passenger side vibration

[PainlessCandy]

My theories at this point include:
- the ball joint starting to fail, thus allowing movement when it gets bumped but settles back into place when weight is transferred left to right and back
- the shock absorber on that side having worn valving that allows a vibration to oscillate when paired with a brand new shock on the opposite side
- the wheel bearing or CV axle being worn slightly enough that they cannot detect play in it when tearing down the parts, but when they are moving at speed allow for the vibration
- the bolts tying the two pieces of the rotor together loosening allowing the rotor to vibrate

The fact that heavy braking eliminates the vibration but light braking does not completely confounds me. The Acura owners who were experiencing a similar problem placed blame on the upper and lower ball joints, but that was not verified; the only thing that they could verify is that it was not the brakes which is also my opinion after the dealer tore down the rotor, cleaned it and the hub and replaced everything while measuring the rotor run-out to be well within spec.

I have also noticed that the vibration gets started more easily the harder I accelerate. I hope all of this helps narrow it down a little. If it helps I can post the write up the tech did.


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[webby]

I just realized you had the r1 brakes. You had issues with those initially grabbing/rubbing and never got a response from them, because they were at SEMA? Your rotors being really hot (even once) without braking means they are seizing. Rotors don’t just get hot without the pads clamping down. A failing suspension part isn’t causing the rotor heat.

A bad suspension part wouldn't cause a wheel to heat up. I would inspect the pins in the brake caliper to see if they are seizing the caliper and it wouldn't hurt to lube them up at your mileage, especially if you haven't done that before.

This ^


View: https://m.youtube.com/watch?v=C3N-aBP0fcs

 

[PainlessCandy]

I just realized you had the r1 brakes. You had issues with those initially grabbing/rubbing and never got a response from them, because they were at SEMA? Your rotors being really hot (even once) without braking means they are seizing. Rotors don’t just get hot without the pads clamping down. A failing suspension part isn’t causing the rotor heat.




This ^


View: https://m.youtube.com/watch?v=C3N-aBP0fcs

I did finally get that sorted out. The caliper I overheated (rear driver side) was leaking, but it was incredibly hard to tell because the leak was so small and the e-brake setup they use made it so that air did not get into the lines quickly. Over time air finally made it's way to the ABS unit and then I started having really weird issues. Once the air was flushed from the system everything went back to working like normal. (It's worth noting that when I had this problem it was very obvious that the one caliper was gripping more than the others; this vibration and braking hard enough to stop the vibration does not exhibit the same symptoms of pulling hard to one side.)

If it is the caliper seizing, what could cause only one caliper to grip while none of the others are activating specifically when the brake pedal was never pressed?

From what I can tell, that caliper is not gripping the rotor in the same way that it would when you put your foot on the brake pedal. When this happened the other night, I believe it was the rotor vibrating between the pads at speed that caused it to heat up. This would be very similar to a seized caliper, except that the rotor moving side to side causes the friction instead of the pads clamping down. Like I said, I'm not sure what would cause this, but I find it hard to place blame on the caliper when there is no way it could have clamped on its own (or is there?).

These calipers have knockback springs that keep the pads almost touching the rotor at all times, so when there is a fluctuation in the rotor run-out it hits the pads and is obvious - many times I have felt the slight imperfections in the rotor when taking a hard, slow turn as the hub flexes and you get a tiny bit of natural rotor run-out. The vibration is similar to that feeling, but way more exaggerated.

I have looked many times to see if the caliper could be causing the issue, but seizing calipers only seem to occur in floating setups; there aren't any moving parts to get stuck in a fixed caliper. The only thing that could cause it to stick in that way would be corrosion build up or something getting caught in between the pad back and the pistons/dust boots, and there just isn't room for anything to get in there. I will ask to see if they cleaned up the pads and piston heads on the caliper when they tore down the rotor as I'm not sure if they did, and if not I will be doing just that.

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[PainlessCandy]

I do have an inquiry placed with R1 about this issue, just in case they have any ideas. I'm waiting on their lead engineer to return from being overseas to be able to have a conversation with him, hopefully that happens Monday.

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[webby]

Yeah fixed versus floating is true. There are threads on other forums about wilwood bbk pistons seizing. Supposedly there aren’t seals on theirs. I don’t know enough about it though.

 

[PainlessCandy]

Yeah fixed versus floating is true. There are threads on other forums about wilwood bbk pistons seizing. Supposedly there aren’t seals on theirs. I don’t know enough about it though.

Very interesting. When I bought my kit, they offered a number of options including stainless steel pistons, but after I had opted for that option they came back and told me that they recently updated their design to include much thicker dust boots and that they no longer fit the stainless steel pistons. I will have to ask their engineer if the new part that was featured in my kit could be causing an issue now.

Two things are for certain: Accelerating hard aggravates the problem and turning hard to the right makes the vibration go away entirely until you straighten out and the weight on the front end is even (I spent some time in an empty parking lot on the way home after it started vibrating tonight and felt it more when circling left, almost not at all when circling right).
Edit: three things, it is getting worse/happening more often.

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[PainlessCandy]

Got the rest of the Hasport mounts in.

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