What have you done to your RX-8 today????

[Humane-Hobgoblin]

Might look into that set up if your headlights are anything to go by!


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[Rusty Nightspring]

Give it a go.

Doesn't take too long but it is a bit disconcerting taking wet and dry to a headlamp.

UV resistant Clearcoat is a must as a finisher otherwise they'll go cloudy within a couple of months.

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[Humane-Hobgoblin]

Yeah that’s the one thing that sounds weird!

But results prove otherwise!


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[mrspiller]

Restoring RX8 headlamps.
Step 3:
Ensure area is clean and dry, use a clean microfiber cloth to ensure a good quality surface.
Carefully mask off the headlamp and surrounding area.
Accidentally pick up tin of etch primer instead of clear coat and apply a good layer!

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[nightfire10]

Not right place for it but !

[jondkent]

If only someone made a poster of that, need it for my man cave.

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[New Duke]

I've started investigating what did this to fresh pads on the drivers side at Snetterton yesterday.
Driving home from Norfolk was a challenge.

[13Black]

What pads are they?

Sticky piston or guide pins is likely culprit but do investig9

[warpc0il]

Fake pads?

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[New Duke]

Thanks Nick. They're the same Brembo made OEM pads I've used for 18 months now. The pads on the other wheels wore normally and have loads of meat left.
Just checked the pins and they were gliding fine so have just cleaned, lubed and popped them back on with some fresh pads for the school pick up.

You're probably on the money with the piston. The brake engages fine but doesn't release fully. The volume of the metal grinding last night highlighted that. So the brake was likely on the whole track day (and the last week of heavy road driving).

Picture of flakey piston below. It's rusted away a lot so I'm thinking about replacing it anyway. I wonder if the ring thinning away could have made it overheat. Dunno!

EDIT: Could be fake, thanks Dave. I usually buy from ECP for my sins and assumed they'd be safe.

[13Black]

Recently I had a piston that you could just about push in and out with a G clamp but sticking enough it was to get the brakes hot and wear down unevenly.

[johnbb99]

One thing that most people forget is that there's no return spring in a disc brake caliper, unlike the old drum brakes.

While it only requires a tiny movement to create clearance between the pad and rotor, to release the brakes, the only force that's doing this is the recovery of the distorted piston seals.

The rubber seals have a square cross-section and, while the initial outward movement of the pistons slides through the seals, as soon as significant pressure builds in the line then the seal grips the piston and the final movement, pressing against the disc, distorts the square section into a lozenge-shape. When the line pressure is released then the tension within the seal grips the piston and pulls it back, as the seal becomes square-section again.

Anything that stops the seal gripping, like wrong lubrication, or makes the seal material hard, like wrong lubricant, excess heat or old age, means that neither the initial distortion or recovery of the seal takes places and the pad is left in contact.

If the piston isn't too tight to move then any vibration in the mechanism and/or run-out of the rotor will know the pads back sufficiently not to bind, after a delay.

If the piston is tight to move then even good seals might not be able to overcome that tightness to pull the piston back and create clearance.

[nightfire10]

MOT'd passed ,saturday cat off de'cat back on ready for SPA

[New Duke]

Thanks for the caliper advice guys. Got new pads fitted and did 100 miles tonight. It doesn't appear to be sticking anymore. Maybe compressing the piston earlier 'unstuck' it. I don't want to risk it happening on track again though and will keep a hawkish eye on the pads.

Looked at big brake kits and laughed at the price. So will ask a friend to fabricate a pair for me if he's up to the challenge. There are CAD drawings online based on common 4,6 and 8 pot designs as a starting point. Failing that I'll try to find some good condition used calipers.

[13Black]

It's the kind of thing that is unlikely to have been a one-off. Brakes aren't electronic after all. Something physically was amiss, and that is likely to still be there. Slight corrosion on the piston in the right spot will do it, wear the pad down far enough to that spot and with the large amount of pedal pressure, you'll be able to hop the high spot past the seal but there's no chance it's gonna let go by itself.

With SrsSam rebuilding front calipers in his sleep now, I think it's a no brainer to get them off and sorted.

[warpc0il]

It could have been a dodgy ABS sensor or associated wiring.

These sensors are also used by the DSC to determine wheel rotation speeds, along with inputs from steering angle and yaw sensor.

If an ABS sensor on a different wheel was playing up, such that the wheel appeared to be rotating slower, then the DSC might having been applying the brake this one to correct the apparent skid, eating the brake pads.

I've seen cars at track days, being driven by guys with lead feet, where the brake glowing it's the one you'd expect, based on the braking areas, and has just been the DSC keeping the car from flying off into the boondocks.

[13Black]

I recall Huw having a problem eating rear pads that was down to ABS/DSC interfering just enough to kill the pads but not enough to feel.
Could be an avenue to explore if you track with DSC on - I couldn't stand it but that probably says much more about my driving (errrrr...) 'style' than the car.
I can't remember exactly what was causing it with Huw's car.

[New Duke]

Thanks guys, really good and helpful thoughts. The DSC was being particularly aggressive, I assume down to me running smaller wheels.

I'd forgotten about Sam refurbing calipers and will check if Adam's are also still for sale.

My friend is keen to make some big calipers which could be a fun, maybe long term experiment. Got options

Had my first hot start fail trying to leave track too. So it's all going on right now

[zippyonline]

My friend is keen to make some big calipers which could be a fun, maybe long term experiment. Got options

I've got a Big Brake Kit from the group buy that I've decided to sell, it was on the classified but expired - and er I better renew my membership too I just noticed
They're new/unused, and I live in Colchester too

[SAS]

Thanks guys, really good and helpful thoughts. The DSC was being particularly aggressive, I assume down to me running smaller wheels.

I'd forgotten about Sam refurbing calipers and will check if Adam's are also still for sale.

My friend is keen to make some big calipers which could be a fun, maybe long term experiment. Got options

Had my first hot start fail trying to leave track too. So it's all going on right now

That’s no good mate you might have to save for a engine rebuild instead of a supercharger.

[qwakers]

i had a (single) hot start issue in the same situation at jdm combe. i just put it down to heat soak. its never done it again.

[New Duke]

Am hoping it was down to the engine still being very hot (after running hot all day) and a one off. But yeah, otherwise the supercharger fund gets wiped out.
Gonna get a comp test done soon.

[13Black]

Hitting that sweet spot where the PCM switches parameters between temperatures can make it have a hiccup starting sometimes. If that's the case then nothing to be alarmed about.

[Harrizone]

Haydn do not be alarmed this has happened to me and some other of the regular track layers on hot days and after some enthusiastic track action.

[New Duke]

Thanks gents. That's encouraging!