I'm done with this rear brake!!!

[Austin1992]

Edit: I believe the issue may have been the slides binding up or the piston was not seated (screwed back in) in the caliper. With that many sessions on the pads you really need to rotate them but again they are sliding calipers, they should move by hand easily. Also make sure the parking brake is adjusted properly.

Done a lot of brake jobs but a little lost when you say (screwed back in). Could you shed some light on this?

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[shogun32]

Done a lot of brake jobs but a little lost when you say (screwed back in). Could you shed some light on this?

The rear brake is not an in/out piston. It twists as it goes in and out - ok that phraseology isn't right. It operates on a screw mechanism to increase torque, thus clamp force. So every pad change you must twist the piston to retract it. And also make sure you index the pins on the backside of the pad to the slots in the piston.

 

[WCRookie99]

New friction disks on 2 piece rotors new DTC 30 pads bedded pads 35 to 5mph 10 times and 45 to 5mph 3 times moderate braking let cool. 1 autocross event 5 runs 65sec long + 8 20min track sessions at mid Ohio (best lap was sub 142 so the were getting some use). Outer left rear pad is worn more that the inner. this caliper obviously need a rebuild. I also have a crack in the right front friction disk that makes it unserviceable. I will need new friction disks all round and more rear pads plus a rebuild on the LR caliper at the least. I already have another set of DTC 60 from pads NIB.

Opt 1 stick with the 2 piece rotor setup above and rebuild both rear calibers.

Opt 2 pull the two piece setup and give away what's good with the sale of DTC 60 front pads NIB rebuild my rear calibers and reinstall the stock brakes.

Opt 3 GT 350R brake kit from LMR. only worry in my rear wheel fitment since I have 2 sets of HP wheels with good autocross and street/track tires.

Few things:

Unless you’re IMSA endurance racing, then rear calipers are fine. Even the Boss 302R used these calipers without any issues in 4 hour races granted 10 years ago.

#1 You must unplug the Stability control or Dyno plug, on the front left fender. It just comes on way too much. You can’t just turn it off by the switch on the dash.

#2 The 2-piece rotors are not the issue, the rear brake pads are way too aggressive. The stock M1 pads work fine as you want the rear pads softer than the fronts. If you don’t believe that and hell bent on “race” rear pads you must still have a pad that don’t leave groves in your rotors.You’re just creating unwanted problems and overheating the rear Calipers with such an aggressive rear pad. Plus you’re not stopping any better or faster.

#3 Someone said don’t use the brakes that much and “roll” through the corners, he’s actually 100% correct.

#4 Approximately 90% of all braking comes from M1 front brakes, you should NEVER have this issue. Road America is as hard on rotors as Mid-Ohio, I’ve never seen rear rotors as bad as yours.

Lastly, racing or track days are a weird sport. You rarely get the straight story because people either want to sell you something or they never know when/if you’ll be a competitor someday, so the real answer is hard to find. Or there’s just too many variables so it’s hard to diagnose the actual problem. Or people think they know better but experience is the key.

Good luck, my 2c.

 

[Optimum Performance]

Done a lot of brake jobs but a little lost when you say (screwed back in). Could you shed some light on this?

The rear caliper has a integral parking brake mechanism. This has been in use for the last 45 years or so. My very first experience with them was a 1970's Lincoln Versailles 9" Disc Brake Rear Axle I built for my Fairmont in the 1980's.
The parking brake mechanism is a screw that as the parking brake is cycled it will auto adjust for pad wear. The mechanism only has the amount of throw given by the cable movement, so if the pad is worn down the pad will never touch the rotor, unless it is adjusted out.
When you install new pads you need to rotate the caliper piston back into to its starting point so the piston will be retacted into the caliper. You can not just push the piston in like you do in the front.

I'm slightly concerned this is not common knowledge, it's in every service manual, everyone seems to make a different version of the service tool.

 

[Austin1992]

The rear caliper has a integral parking brake mechanism. This has been in use for the last 45 years or so. My very first experience with them was a 1970's Lincoln Versailles 9" Disc Brake Rear Axle I built for my Fairmont in the 1980's.
The parking brake mechanism is a screw that as the parking brake is cycled it will auto adjust for pad wear. The mechanism only has the amount of throw given by the cable movement, so if the pad is worn down the pad will never touch the rotor, unless it is adjusted out.
When you install new pads you need to rotate the caliper piston back into to its starting point so the piston will be retacted into the caliper. You can not just push the piston in like you do in the front.

I'm slightly concerned this is not common knowledge, it's in every service manual, everyone seems to make a different version of the service tool.

I have heard of it now that you mention it, didn’t know it was like that on my car though so thank you. My mustang is the first vehicle I’ve owned/worked on with rear disks

 

[TRDFurgesson]

Few things:

Unless you’re IMSA endurance racing, then rear calipers are fine. Even the Boss 302R used these calipers without any issues in 4 hour races granted 10 years ago.

#1 You must unplug the Stability control or Dyno plug, on the front left fender. It just comes on way too much. You can’t just turn it off by the switch on the dash.

#2 The 2-piece rotors are not the issue, the rear brake pads are way too aggressive. The stock M1 pads work fine as you want the rear pads softer than the fronts. If you don’t believe that and hell bent on “race” rear pads you must still have a pad that don’t leave groves in your rotors.You’re just creating unwanted problems and overheating the rear Calipers with such an aggressive rear pad. Plus you’re not stopping any better or faster.

#3 Someone said don’t use the brakes that much and “roll” through the corners, he’s actually 100% correct.

#4 Approximately 90% of all braking comes from M1 front brakes, you should NEVER have this issue. Road America is as hard on rotors as Mid-Ohio, I’ve never seen rear rotors as bad as yours.

Lastly, racing or track days are a weird sport. You rarely get the straight story because people either want to sell you something or they never know when/if you’ll be a competitor someday, so the real answer is hard to fine. Or there’s just too many variables so it’s hard to diagnose the actual problem. Or people think they know better but experience is the key.

Good luck, my 2c.

I have a comment for #3.

If your hypothetical maximum corner speed is 80mph, and your speed is 110mph before the braking zone. From what I can tell your suggesting backing up my braking point 2-3x? I can show you what happens when the Camaro in front of me tried to to roll turn 1 at Mid Ohio too fast. Fast Forward to 19:00…. And turn 1 just got a repave so there is good predictable grip. My dash displayed speed is fast by about 2-3 MPH for every 50MPH. My car originally being a non HP car came with a tire 27.5” dia. vs my HP tire dia. of 26.4”



This is From Harrys lap timer on Monday after riding with that instructor in his Mach 1 and trying some different shifting points he suggested. 3rd-4th entering the first LH turn of the bus stop before the keyhole, and 3rd to 4th and the end of thunder valley entering turn 13. This did improve my lap time.

 

[WCRookie99]

I have a comment for #3.

If your hypothetical maximum corner speed is 80mph, and your speed is 110mph before the braking zone. From what I can tell your suggesting backing up my braking point 2-3x? I can show you what happens when the Camaro in front of me tried to to roll turn 1 at Mid Ohio too fast. Fast Forward to 19:00…. And turn 1 just got a repave so there is good predictable grip. My dash displayed speed is fast by about 2-3 MPH for every 50MPH. My car originally being a non HP car came with a tire 27.5” dia. vs my HP tire dia. of 26.4”



This is From Harrys lap timer on Monday after riding with that instructor in his Mach 1 and trying some different shifting points he suggested. 3rd-4th entering the first LH turn of the bus stop before the keyhole, and 3rd to 4th and the end of thunder valley entering turn 13. This did improve my lap time.

Ok love your camera and good driving. Only suggestion in regards to #3 is turn 6 you seem to ride the brake, that corner for sure is a corner you should hit ABS and back off. (Or once really good, “almost hit ABS”) then roll off. Same with turn 1, hit the brakes hard (for one second or so and roll off). Totally opposite of driving to the grocery store.

The brake foot action is, super hard and roll off vs hit brake and gradually harder.

Anyway, Penske already has his drivers for next year, so no need to over drive because if you do it wrong, that’s what it will feel like.

My humble opinion, Enjoy….

 

[TRDFurgesson]

I got tired of screwing around and went with Essex AP Racing front and rear.

I like the anodized dark grey Radi-CAL 25mm version. I also will be without parking brake since it never gets used anyway. (no inspection requirement)
https://www.essexparts.com/ap-racin...ompetition-brake-kit-generic-front-9668-372mm
https://www.essexparts.com/ap-racin...ompetition-brake-kit-generic-front-9668-372mm
Same as yours just not nickel. I think I would prefer the 1.11 pads since they would be easier on the friction disks. A few questions... Are you running the pad tensioners? The burnishing / bedding option is confusing. It seems like they come pre bedded either way just don't have to wait 2 days for an extra $100? I'll be returning my brakes to stock since I have two more possible autocross events OCT NOV WX permitting until she get put up on jack stands for the winter. I keep her tucked away until low temps don't drop below 45 in the spring. So I have a little time to refine my options unless they have a major Black Friday sale...

 

[Knockdown]

@TRDFurgesson

I am running the anti-rattle clips, on the front you need to bend them out a bit so there is pressure on the pads but you can still get the cross bolt in without breaking your thumb. I did have Essex burnish the rotors, still shipped the same day I ordered them. Essex recommended the 3.12 pads f&r so that’s what I’m trying first, they do stop nice but sound like a school bus. I have DS2500 pads for the street.

I went back and forth on the ebrake, especially since I have an A10, but it was fairly simple to add since I was putting on a X pipe anyway.

 

[shogun32]

show you what happens when the Camaro in front of me tried to to roll turn 1 at Mid Ohio too fast.

I think his point and mine was most people drive way too slow on corner entry. Not you specifically

 

[hsteel]

The point about nannies being turned off kind of got skipped over. Are you turning off advanced trac? I was cooking rear brakes until I did that. They step in way too early

 

[mustang5o]

If you're OK spending the AP Racing is the way to go. Maybe Baer as a second choice. The cheaper options are GT350R brakes (possibly needing new wheels) or Willwood to keep your wheels.

 

[Biggsy]

I dont have much to add outside what has been said but I would try doing the maintenance stuff first. If money is no object then I guess AP brakes are the way to go. I guess I just dont understand if the Mustang cars competing in National events and setting track records are on stock calipers, then why the need to change? Or maybe its not for me to understand because my bank account wont allow me to lol. I do understand that not everybody wants to compete.

BTW I have had great success with Pagid RST3/RSL29 set up

 

[TRDFurgesson]

If you're OK spending the AP Racing is the way to go. Maybe Baer as a second choice. The cheaper options are GT350R brakes (possibly needing new wheels) or Willwood to keep your wheels.

I've given up on the notion of 350 brakes. I really like my two sets of HP wheels. Besides I'm afraid that I would roast those brakes in the course of a few months... putting me back in the same boat. The more I learn about AP Racing / Essex brakes, the more I am convinced they will be the best if only choice.

 

[GTP]

I have a comment for #3.

If your hypothetical maximum corner speed is 80mph, and your speed is 110mph before the braking zone. From what I can tell your suggesting backing up my braking point 2-3x? I can show you what happens when the Camaro in front of me tried to to roll turn 1 at Mid Ohio too fast. Fast Forward to 19:00…. And turn 1 just got a repave so there is good predictable grip. My dash displayed speed is fast by about 2-3 MPH for every 50MPH. My car originally being a non HP car came with a tire 27.5” dia. vs my HP tire dia. of 26.4”



This is From Harrys lap timer on Monday after riding with that instructor in his Mach 1 and trying some different shifting points he suggested. 3rd-4th entering the first LH turn of the bus stop before the keyhole, and 3rd to 4th and the end of thunder valley entering turn 13. This did improve my lap time.

Hey Bobby, have you ever hit the leading curb edge going into Turn 5 at Mid Ohio? I hit it pretty hard and then developed a buzzing sound when driving normal around-town speeds. Haven't swapped either right-side hub out yet, but I will this week.

Play the second video (with Harry's timer) from 20 seconds and I think you hit it there, too, but not as hard as me. Nice fast driving BTW.

Here is my curb strike:

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