[Toome]

after seeing GR yaris' melt their caliper piston seals on track, i decided to install a titanium brake shim. like the base GRY, our GRC core's dont have brake ducts. so when i dug around, i saw that a company in japan had one sku that covered the GRY and a slew of other cars with OEM brembo 4pot. so i got a set and they fit. i'll have to wait until break in period, fluid refresh before i can test them out on track. i didnt want to have a before session, for the risk of melting the seals. theres already a ton of before data on a lighter car.

View attachment 5881
View attachment 5882
hasnt registered 250F while breaking in the car

I installed these temp stickers as well. These are the temps I registered at VIR in a 25 min session. No TI shims installed since they did not fit...

I have swapped back to OEM pads and observed no melting of the rubber on the caliper piston seals.

 

[black86]

I installed these temp stickers as well. These are the temps I registered at VIR in a 25 min session. No TI shims installed since they did not fit... View attachment 18098
View attachment 18097
I have swapped back to OEM pads and observed no melting of the rubber on the caliper piston seals.

What pads did you use? It was mentioned before that maybe our seals are updated. It's hard to tell from the angles, but did your caliper decal yellow? That seems to be the only reason to use a ti shim on the GRC now.

Edit: updated seal/decal yellowing was from an FB thread

 

[Toome]

What pads did you use? It was mentioned before that maybe our seals are updated. It's hard to tell from the angles, but did your caliper decal yellow? That seems to be the only reason to use a ti shim on the GRC now.

Edit: updated seal/decal yellowing was from an FB thread

Pagid RST 3 pads. My decals had yellowed after my first track day on stock pads. The paint on my calipers has also started to fail in some places due to the heat, but I noticed this before this last track day. Going to see what I can do to replace them under warranty, but not holding my breath.

 

[black86]

Pagid RST 3 pads. My decals had yellowed after my first track day on stock pads. The paint on my calipers has also started to fail in some places due to the heat, but I noticed this before this last track day. Going to see what I can do to replace them under warranty, but not holding my breath.

Oh wow, got pics of where the paint on the caliper is failing?

 

[Toome]

Oh wow, got pics of where the paint on the caliper is failing?

yup. The black is not brake dust. That is a picture of the caliper before I ceramic coated it when I had cleaned it thoroughly.

 

[WolfpackAWD]

After lapping VIR on Friday it looks like a little bit of the brake dust might be "baked" in. Mostly on the parts of the caliper located very close to the rotor (i.e. mostly near the top and bottom).

The spots I circled in blue required a bit more scrubbing than the rest, but the dust came off. The green circles are the spots where I could not get all the dust off. Caliper had been previously ceramic coated but I'm honestly not sure how much that helped. This was after 200+ miles of tracking on Friday (roughly half done in dry conditions, rest in wet).

 

[Toome]

After lapping VIR on Friday it looks like a little bit of the brake dust might be "baked" in. Mostly on the parts of the caliper located very close to the rotor (i.e. mostly near the top and bottom).

View attachment 18105


The spots I circled in blue required a bit more scrubbing than the rest, but the dust came off. The green circles are the spots where I could not get all the dust off. Caliper had been previously ceramic coated but I'm honestly not sure how much that helped. This was after 200+ miles of tracking on Friday (roughly half done in dry conditions, rest in wet).

Thanks for the tip. I’ll see what I can do. What did you use to scrub off the dust?

 

[WolfpackAWD]

I used Americana Global Wheel & Tire cleaner. Americana Global - Premium Car Detailing Products However again, it didn't all come off. A detailer friend recommended I try P&S Wheel Cleaner.


And beyond that here are the brushes I used: Wheel Woolies Wheel Brushes | Chemical Guys Though honestly they're not the greatest. They don't scratch but they're also not great at removing stuff that's really stuck on without a lot of pressure applied.

Hopefully it helps you a bit, though I agree that some of that looks like discoloration. My AMG's brake calipers are badly discolored, but the car is 11 years old and they were already like that when I purchased it. Here's a photo of the GRC's brake caliper, after a deep cleaning yesterday.

 

[black86]

im with @WolfpackAWD its likely baked on. i also use p&s brake buster and its pretty good even diluted. ive done 8:1 and it still works. im gonna try 10:1 with the brush @WolfpackAWD recommended. i finish it off with p&s bead maker, i dunno if it helps any either.

 

[Toome]

im with @WolfpackAWD its likely baked on. i also use p&s brake buster and its pretty good even diluted. ive done 8:1 and it still works. im gonna try 10:1 with the brush @WolfpackAWD recommended. i finish it off with p&s bead maker, i dunno if it helps any either.

I normally clean them thoroughly with p&s brake buster diluted 5:1. I have even tried isopropyl alcohol before I ceramic coated the calipers. Seems to be baked on or mostly discoloration, but I will try again to clean them this weekend.

 

[WolfpackAWD]

^Damn

Something else that I would recommend, to prevent this from happening at track events. Bring some electric fans with you and as soon as you park the car back in the paddock get the fans blowing on your front brakes. Any baking and discoloration is primarily going to occur once the car is stationary. It can take over 30 minutes for the brakes to cool off enough to be safe to the touch. That entire time the calipers are "baking". Besides that, and Ti shims, I don't think there's much we can do.

 

[black86]

I normally clean them thoroughly with p&s brake buster diluted 5:1. I have even tried isopropyl alcohol before I ceramic coated the calipers. Seems to be baked on or mostly discoloration, but I will try again to clean them this weekend.

oh dang, 5:1... i usually spray the wheels first, and let the brake buster do its thing for 5 minutes or so before i start scrubbing.

edit: i also got a used iK foam pump sprayer from amazon warehouse for 20 bucks. i can see why people pay double that new. the foam is thicc af and doesn't run in 5 mins

 

[Toome]

^Damn

Something else that I would recommend, to prevent this from happening at track events. Bring some electric fans with you and as soon as you park the car back in the paddock get the fans blowing on your front brakes. Any baking and discoloration is primarily going to occur once the car is stationary. It can take over 30 minutes for the brakes to cool off enough to be safe to the touch. That entire time the calipers are "baking". Besides that, and Ti shims, I don't think there's much we can do.

Were you the CE I saw on track (VIR Friday 10/20) that was not with the Toyota group?

 

[WolfpackAWD]

That was me

 

[ND4SPDR]

I spent an absurd amount of money on some ELIG GRY shims shipped from Australia.

$81 for the shims, $55 for shipping to Los Angeles. I'll advise once I have a chance to install them.

 

[WolfpackAWD]

Thanks, let us know. And that's not "horrible" given how niche they are.

 

[black86]

Thanks, let us know. And that's not "horrible" given how niche they are.

so i swapped my 3rd set of oem pads. all seals are good. the clearances are tight between the pins. if i filed 1-2mm it would float perfectly. but for under $60 and no yellow caliper decal. im satisfied with this result. theres an FB member who filed the holes to make it fit better but he had done 1-2 track days already and their caliper decals were starting to yellow. everyone i meet that push these cars wonder how come our times are similar but my decal isnt yellow. then i tell them i put the Ti shim when the car had less than 150 miles on it. also i do a cool down parade lap around the paddock until my oil temps are under 210F like @WolfpackAWD said its just baking when your car sits after a track session.

 

[WolfpackAWD]

Bring air fans with you! And direct onto the front wheels, haha. Most tracks charge to use their electrical outlets, but if you're just running an extension cord for a few small fans they usually turn the blind eye.

 

[black86]

Bring air fans with you! And direct onto the front wheels, haha. Most tracks charge to use their electrical outlets, but if you're just running an extension cord for a few small fans they usually turn the blind eye.

you have brake ducts, you dont need airfans!

 

[WolfpackAWD]

LOL, when the car is parked and not moving!