P3 Brake Job

[destructure00]

Sweet! Mine are in transit, will be here Tuesday. Looking forward to installing along with the XT910 rear pads. I was looking at my front rotors yesterday while the car was parked and I can't see the holes anyway, so I don't think there's going to be much visual difference between the fronts and rears.

Awesome!

With the rotors slightly wider, does that change the offset of the wheel at all?

It's the equivalent of adding a 2-3mm spacer.

 

[beastmode13]

Awesome!

With the rotors slightly wider, does that change the offset of the wheel at all?

The 1mm increase of the rotor does not impact the offset of the wheel. The increase of approximately +3mm from the aluminum rotor hat thickness over the stock stamped steel rotor hat decrease the offset of the wheel. My +35mm offset is now effectly +32mm.

 

[destructure00]

@beastmode13 thanks again for your detailed explanation of the rear pad installation. I referred to it a couple times trying to get the parking brake to retract while installing my XT910 pads and RB rotors this evening. Got it all done thanks to your photos and instructions.

 

[beastmode13]

@beastmode13 thanks again for your detailed explanation of the rear pad installation. I referred to it a couple times trying to get the parking brake to retract while installing my XT910 pads and RB rotors this evening. Got it all done thanks to your photos and instructions.

That's awesome! Did you remove the heat shield as well?

 

[destructure00]

That's awesome! Did you remove the heat shield as well?

I haven't yet but I am planning to pull them when I bleed the brakes for my next track day on Aug 24. I have 1.5L of Motul and some heat reflective tape ready to go

Do you leave yours off full time, or just remove for track use?

 

[beastmode13]

I haven't yet but I am planning to pull them when I bleed the brakes for my next track day on Aug 24. I have 1.5L of Motul and some heat reflective tape ready to go

Do you leave yours off full time, or just remove for track use?

I leave them off full time. The only time you will generate much brake dust is at the track. In daily street driving our brakes are hardly used at all, so the purpose for the dust shield is near zero.

 

[Dangerous Fish]

Something to consider, if you drive on the freeway in rain frequently, is that backing plates will help keep water, mud etc. off the discs. They aren't just there to prevent brake dust from getting on the suspension/bodywork.

 

[FlyNavy01]

Yep, rotor shields are actually to protect the rotors from road debris, water (rust), etc... not the other way around.

 

[destructure00]

I'm in Phoenix, it's pretty dry here. I may just leave mine off as well.

 

[beastmode13]

Something to consider, if you drive on the freeway in rain frequently, is that backing plates will help keep water, mud etc. off the discs. They aren't just there to prevent brake dust from getting on the suspension/bodywork.

Yep, rotor shields are actually to protect the rotors from road debris, water (rust), etc... not the other way around.

All true. No argument from me. More information for people to make an informed decision for themselves.

I drove cars without dust shield in Seattle for 10+ years without any problem of the sort. That place is pretty much wet nine months out of the year. The only time I had an issue with dirty getting into the brake was DirtFish Rally School with one of their Subies. A rock got wedged in between the caliper and the wheel barrel and proceeded to grudge a groove through the wheel. We only found out about it when the tire went flat in an instant. And those cars are equipped with gravel scrapers between the wheel hub and the wheel barrel to clear rocks. Fun times.

 

[beastmode13]

After almost a week and 283 miles, the EDP (electrodeposition paint) on the friction surface is replaced with a nice even layer of brake pad material. The crosscut pattern on the fiction surface turns out to be complementary to the brush finish of my wheels.

 

[beastmode13]

Addendum to the rear RB rotor installation.

RB rotor is 1mm thick than stock, additional piston retraction beyond what tow mode provides will not be enough. Removal of the EPB motor then wrenches the driving screw clockwise one full turn will to retract it enough to clear the thicker rotor without any issue. The detail on how to remove the EPB motor was covered by one of the first couple of posts.

 

[beastmode13]

I am swapping out the XT910 to XRT970 in preparation of 8/30 track day. The XT910 was used for five 15min sessions at Laguna Seca a few months ago, plus 1200 street/highway miles which does not contribute to much pad wear.

Measurement of XT910 rear pads. The new pad is 9.7~10mm.
After five x 15min sessions.
Right/inside(piston) 8.24/8.58 (leading/trailing) - Right/out - 8.59/8.16
Left/inside - 8.13/8.24 - Left/out - 8.3/8.00

Analysis of wear.
1. Laguna Seca is a counter-clockwise track; there are more left turns than right turns. From the extra wear of left rear, one can deduce the traction control is using the left rear brake to facilitate rotation of the car.
2. The rear pad has some unusual wear behavior due to the stagger pad alignment. As pointed out in previous posts, the rear inside and outside pads are not alignmented. The trailing 7/8 of the pad is lined up with the inside pad, while the leading edge is ahead of the inside pad. This causes the trailing edge of the outside pad to wear more than the leading edge. The inside pad wears as expected, with more wear on the leading edge.
3. To even out the pad wear, I would rotate the entire set of the pads from one side to the other side of the car. When doing so, the inside pad remains inside, but the leading edge will flip. With a typical caliper, rotating inside with the outside of the same caliper would do the trick. Anyhow, learning something new about the P3 every time I work on it.

Previously taken photo of the staggered pad arrangement.

@destructure00 had pointed out a c-clamp might be necessary to get the hydraulic piston to retract enough for new pads or rotor install. I use a hack to this done. Angle the pad into a wedge position to create a larger opening that is big enough to go over the edge of the rotor. Once position the pad/caliper on the edge of the rotor, a couple of firm push of the caliper toward the center of the rotor/axle will push back the piston and get the caliper on the rotor in one motion. A couple of millimeters might be the limit of this hack. If the piston needs to be retracted more than that a c-clamp or piston press would be more appropriate, please use your best judgment.

A minor upgrade, see if you can spot it in this photo.

A proper M6-1.0 x 16mm flat head countersunk screw to replace the stock hex bolt.

 

[MarcG]

I am swapping out the XT910 to XRT970 in preparation of 8/30 track day. The XT910 was used for five 15min sessions at Laguna Seca a few months ago, plus 1200 street/highway miles which does not contribute to much pad wear.

Measurement of XT910 rear pads. The new pad is 9.7~10mm.
After five x 15min sessions.
Right/inside(piston) 8.24/8.58 (leading/trailing) - Right/out - 8.59/8.16
Left/inside - 8.13/8.24 - Left/out - 8.3/8.00

Analysis of wear.
1. Laguna Seca is a counter-clockwise track; there are more left turns than right turns. From the extra wear of left rear, one can deduce the traction control is using the left rear brake to facilitate rotation of the car.
2. The rear pad has some unusual wear behavior due to the stagger pad alignment. As pointed out in previous posts, the rear inside and outside pads are not alignmented. The trailing 7/8 of the pad is lined up with the inside pad, while the leading edge is ahead of the inside pad. This causes the trailing edge of the outside pad to wear more than the leading edge. The inside pad wears as expected, with more wear on the leading edge.
3. To even out the pad wear, I would rotate the entire set of the pads from one side to the other side of the car. When doing so, the inside pad remains inside, but the leading edge will flip. With a typical caliper, rotating inside with the outside of the same caliper would do the trick. Anyhow, learning something new about the P3 every time I work on it.

Previously taken photo of the staggered pad arrangement.
View attachment 443451

@destructure00 had pointed out a c-clamp might be necessary to get the hydraulic piston to retract enough for new pads or rotor install. I use a hack to this done. Angle the pad into a wedge position to create a larger opening that is big enough to go over the edge of the rotor. Once position the pad/caliper on the edge of the rotor, a couple of firm push of the caliper toward the center of the rotor/axle will push back the piston and get the caliper on the rotor in one motion. A couple of millimeters might be the limit of this hack. If the piston needs to be retracted more than that a c-clamp or piston press would be more appropriate, please use your best judgment.
View attachment 443445


A minor upgrade, see if you can spot it in this photo.
View attachment 443446

A proper M6-1.0 x 16mm flat head countersunk screw to replace the stock hex bolt.
View attachment 443447

Thanks for sharing, and cool tip on the flush screwhead!

I’m having the same setup installed, RB rotors on stock P3D+ calipers with XT910 pads.

What wheels & tires are you running for track these days?

 

[beastmode13]

RE71R 265/35/19 on FastWheels FC04 19x9.5+35. I have a second set of FC04 coming, so I might let my VS Forged VS16 full forged 19x9 go in a month or two.

 

[MarcG]

RE71R 265/35/19 on FastWheels FC04 19x9.5+35. I have a second set of FC04 coming, so I might let my VS Forged VS16 full forged 19x9 go in a month or two.

View attachment 443612

View attachment 443613

Looking good! Those FC04 wheels are light. Where did you buy them from?
I’m also considering RE71R tires as a track set. Have you already tracked them? How do you like them?

 

[beastmode13]

Looking good! Those FC04 wheels are light. Where did you buy them from?
I’m also considering RE71R tires as a track set. Have you already tracked them? How do you like them?

I purchased the FC04 through 1010Wheels. They were engineered for Fast Wheels’ factory Ford Mustang racing team in some Canadian race series, so they are light weight and strong enough for track duty.

I use the RE71R/FC04 setup at a two days event in June, kept them at 33psi hot. Car, tires and wheels performed well beyond my driving capabilities.

 

[Lunares]

I purchased the FC04 through 1010Wheels. They were engineered for Fast Wheels’ factory Ford Mustang racing team in some Canadian race series, so they are light weight and strong enough for track duty.

I use the RE71R/FC04 setup at a two days event in June, kept them at 33psi hot. Car, tires and wheels performed well beyond my driving capabilities.

How do you feel about that PSI? I run 265/35/18 (so step down in diameter) for autocross (so lower speed but more cornering). I end up aiming for something around 40, 42 PSI hot because without more negative camber I'm still burning the outside edge far more than the center. Figure running the slightly higher pressure can help with that.

 

[beastmode13]

How do you feel about that PSI? I run 265/35/18 (so step down in diameter) for autocross (so lower speed but more cornering). I end up aiming for something around 40, 42 PSI hot because without more negative camber I'm still burning the outside edge far more than the center. Figure running the slightly higher pressure can help with that.

32/33 is great for traction but not for preventing edge roll of front tires. RE71R has decently stiff side walk so the roll isn’t too bad, got to the top of the triangle indicator. More negative camber will address the roll issue.

 

[Lunares]

32/33 is great for traction but not for preventing edge roll of front tires. RE71R has decently stiff side walk so the roll isn’t too bad, got to the top of the triangle indicator. More negative camber will address the roll issue.

Yea in autocross I have hit my triangles with 42 psi. I have actually completely erased them on one side but that's more because of spinouts than driving