Quite a common thing on RX-8s for the rear discs' inside faces to be barely making contact.
Why, I don't know or really care, as it's not the end of the world to just fit new discs and be done with it. Just be sure that everything is working correctly and off you go.
-= Rotormelon Money Pit Build of Tasteless Questionable Bodgery =-
Yes I now have new discs and pads all round.
Pagids on rear came with the protective paint mentioned above. Much easier than the eicher ones I ended up with on the front to clean.
My only remaining niggle is a squeal at very low speed light pressure breaking. Coming from Fronts.
Sunlight Silver 231
Pete/Peter him/he/hrh couldn't really care as have 3 siblings and was lucky not to get called by the dogs name.
Not all paint is created equal and I've managed to burn/blister "caliper paint" and "engine enamel" when applied to the discs and then taken for a track day - despite limiting the sessions to sub-15 minutes and doing a cool-down lap.
Exhaust manifold paint seems to be the only thing that stays on, also unlike the stuff that some aftermarket discs come painted with...
Old thread resurrect…
I purchased a new set of Mintex discs and 1144 pads via Questmead, a suppler recommended on this forum. They even chucked in a club discount .
I’ve got myself a can of black Simoniz 800 degrees VHT spray paint to protect them from rusting. My question is, should I mask up the friction surfaces before painting, or can I let the pads scrape off any paint that they come in contact with.
Conflicting reports on the internet - some say the paint will contaminate the pads, others say it won’t. I’m keen not to ruin my brand new expensive 1144s. But, I suspect that painting the full rotor will give maximum protection against rust creeping in from the outer edges of the disc and reducing my friction area over time.
This rust creep has happened on the inside rear discs that are fitted to my R3 currently. I’ll be lubing up my calliper slider pins to ensure they’re working properly to cover off all bases!
Last edited by R1DSO on Sat Sep 04, 2021 10:46 pm, edited 2 times in total.
2009 R3 in sparkling black
Racing Beat REVi ram air duct
K&N panel filter
Suffix C Mazda coils
Magnecor leads
Racing Beat header / mid pipe
RRP engine mounts
Hel braided brake lines
Carbotech XP10 pads / Mintex discs / Motul RBF600
Russell speed bleeders
Michelin Pilot Sport 4S tyres
R-Magic shift knob
Heel/toe pedal mod
Mask most of the friction area, letting the paint bleed in a few mm on the inside and outside edges, using the old discs as a guide.
This allows the pads to wear an exact edge, without worrying about contaminating the pad material.
That sounds like a sensible compromise, thanks Dave. Will give that a shot tomorrow .
Once my old discs are off, I’m also planning on giving my hubs a good wire brush and clean, before spraying a couple of coats of VHT paint on them to prevent future rust build up.
2009 R3 in sparkling black
Racing Beat REVi ram air duct
K&N panel filter
Suffix C Mazda coils
Magnecor leads
Racing Beat header / mid pipe
RRP engine mounts
Hel braided brake lines
Carbotech XP10 pads / Mintex discs / Motul RBF600
Russell speed bleeders
Michelin Pilot Sport 4S tyres
R-Magic shift knob
Heel/toe pedal mod
Don't apply any paint to the hub faces that the discs mount to, as this must be a clean metal-metal contact.
Oh really?! Glad I mentioned that then . Minimally, I was going to paint the inside of rotor hub as I thought the rust could cause issues preventing the two surfaces from being completely flush.
I’ve seen vids of people applying copper grease to the hub which, as far as I’m aware, is a waste of time as this stuff bakes and loses its anti-seize properties with heat.
2009 R3 in sparkling black
Racing Beat REVi ram air duct
K&N panel filter
Suffix C Mazda coils
Magnecor leads
Racing Beat header / mid pipe
RRP engine mounts
Hel braided brake lines
Carbotech XP10 pads / Mintex discs / Motul RBF600
Russell speed bleeders
Michelin Pilot Sport 4S tyres
R-Magic shift knob
Heel/toe pedal mod
No paint, no grease.
They shouldn't rust together if they're clean enough to create an air-tight seal.
You need metal-metal contact to ensure that the discs run true and also so the wheel studs are only needing to apply a clamping force and aren't under any shear load, as they would be if the surfaces could slide.
The same applies between the hub-disc and disc-wheel.
These users thanked the author warpc0il for the post:
No paint, no grease.
They shouldn't rust together if they're clean enough to create an air-tight seal.
You need metal-metal contact to ensure that the discs run true and also so the wheel studs are only needing to apply a clamping force and aren't under any shear load, as they would be if the surfaces could slide.
The same applies between the hub-disc and disc-wheel.
Nice one, thanks for the guidance Dave. Much appreciated .
I’m hoping these new Mintex discs and pads will fix my track day hot brake judder issue I’ve posted about on a previous thread. Will follow-up on that track day thread once I’ve put the new gear properly through its paces .
2009 R3 in sparkling black
Racing Beat REVi ram air duct
K&N panel filter
Suffix C Mazda coils
Magnecor leads
Racing Beat header / mid pipe
RRP engine mounts
Hel braided brake lines
Carbotech XP10 pads / Mintex discs / Motul RBF600
Russell speed bleeders
Michelin Pilot Sport 4S tyres
R-Magic shift knob
Heel/toe pedal mod