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Need help with Modern Motorsports Xtreme 13" Brakes, Seriously!


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Need help with Modern Motorsports Xtreme 13" Brakes, Seriously!

 

This is for my 2JZ-GTE supra powered 240Z.

 

I have a track day 24th so I need help ASAP. please.

 

 

I had the stock brakes and the car stopped on dime (at least once).

 

I got;

Modern Motorsports Xtreme 13" Brakes with the supplied pads

A Brand new Nabco 15/16" master cylinder

A Wildwood rear valve (open all the way now)

A Bendix Vac Booster 222-0 0122 (I believe it is a 6" model)

 

I cannot skid the tires in a wet parking lot! The pedal feels very hard. Like I am not getting vaccum assist.

 

What is the problem?

 

I though about

new pads

7/8 Master cylinder

larger booster?

Maybe a pinched line. I have no idea.

 

Please let me know.

 

 

Also I need to know what caliber the PBR are so I go the autostore and buy replacement pads and rotors. Thanks! :blink:

Edited by cyrus
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Your stock s booster is not Powerful enough to handle the Master and calipers. In addition it may be old and siezed up. You should test it out buy pumping the brake pedals a few times then start the car. With the car on the brake pedal should depress as the vacuum assist would kick in. Further more i purchased a new remans booster and it was still horrible ao i opted to upgrade to a z32 sual diaphram abs booster with a z32 bm57 17/16 master brake cylinder which can take even mighty thora hammer strikes. Most likely the s30 booster isnt sufficient so youd have to upgrade to a modern booster.

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Cyrus, what year is your z and is the booster stock? Is it possible when you changed the master cylinder the reaction disc slipped [search hbz for the thread + fix]. Do you have pedal travel then it feels like it hits a mechanical stop [this could be reaction disc problem]? Click here for the sticky thread on the reaction disc.

 

I have the mml 13's, 15/16 maste, stock booster [1973 larger version of the 240's] and have no problem locking the fronts. PBR calipers came in 2 versions both from various Ford [Mustang Cobra & R] & GM vehicles [older Corvette & Camaro with 1LE package] and all take the same pads-here are Hawk numbers. Calipers came in 2 flavors; 38mm pistons & 40mm, larger piston models have the fine thread for flex line and smaller the course thread. I have both and each work fine.

  • Pads: Hawk [HP+] HB111.N610, [blue 9012] HB111.E610

  • Rotors: Coleman 800-221-1851, larry x120 or glen x122. Rotor dimensions on file call to order. ~$135 each, add $16 each for slots. Coleman racing Products, N 1597 US41, Menominee, MI 49858

OE Calipers sources:

Chevy

Model Drive Body Notes

1988-89 CAMARO ALL All avail body w/1LE Perf. Pkg

1990-92 CAMARO-RS /z28 1 ALL avail body w/1LE Perf. Pkg

1988-96 CORVETTE ALL avail body types

1990-95 CORVETTE-ZR-1 ALL avail body types

Ford

Model Drive Body Notes

2001-01 MUSTANG-BLT ALL avail body types

1994-94 MUSTANG-CBR ALL All avail body types

1996-01 MUSTANG-CBR ALL All avail body types

2003-04 MUSTANG-CBR ALL All avail body types

1995-95 MUSTANG-CBR R ALL avail body types

1995-95 MUSTANG-CBR SVT ALL avail body types

2003-04 MUSTANG-MACH 1 ALL All avail body types

Pontiac

Model Drive Body Notes

1988-92 FIREBIRD 1 ALL All body w/WS6 Perf. Pkg

1989-92 FIREBIRD-FORMULA ALL body w/WS6 Perf. Pkg

1988-92 FIREBIRD-Trans Am ALL body w/WS6 Perf. Pkg

1989-92 FIREBIRD-Trans Am GTA ALL body w/WS6 Perf. Pkg

1989-89 FIREBIRD-T/A GTA SE ALL body w/WS6 Perf. Pkg

Edited by 1 tuff z
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Hey Cyrus -- I had the exact same problem with essentially the same kit.

 

For me, it was the pads. I swapped them out with Hawk HP+, bedded them in, and now my brakes are incredible.

 

Mine is also a 240z, only difference is I'm running a 15/16th master. Also using the stock booster with no issue whatsoever. I pulled my hair out over this one, ripped basically everything apart trying to figure it out, then pulled one of the pads and realized it had an almost glassy-glaze to it. I'm convinced the pads are meant for track-only and need to be heated to a ridiculous level before they'll actually grab or perhaps before the factory glaze beds off of them (you can see more of the standard rough material below the glaze on the sides). I was going to try to lathe off the top-coat, but the Hawk HP+ pads have been working so well I haven't bothered.

 

I'd suggest you pull one of them and see if you see something similar. If so, feel free to let me know if you'd like me to track down the specific product code for the Hawk pads I ordered. They were Mustang Cobra pads for the PBR calipers but IIRC there are two different types available and it does matter.

 

Good luck!

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In my post above the Hawk PN's are listed for HP+ & Blues...

If so, feel free to let me know if you'd like me to track down the specific product code for the Hawk pads I ordered. They were Mustang Cobra pads for the PBR calipers but IIRC there are two different types available and it does matter.

 

Good luck!

 

 

 

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Update;

 

 

I ordered Hawk HPS pads for a 2002 cobra. The front set works the rear does not! ARRRRRRRRGGGGGGGH! I need to try to figure out what the rear calipers are from. My buddy said a 1LE but did not know the year.

 

The car stops 20% better but is still pretty poor compared to his S2000. I have to push about 3 times harder to stop. I am wondering about the vacuum booster. Any info?

Edited by cyrus
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Cyrus -- Yes, 100% there is a difference.

 

Also, did you order the part numbers I PM'd you? They worked perfect for my fronts AND rears. Actually, you definitely did not as you mentioned Hawk HPS.

 

Personally, I have had terrific success with the HP+ and blues, but hated the only set of HPS I ever purchased. To me, they didn't squeak or dust much, but were very temperamental. Required a lot of heat to bite, and felt like squishy-poo (technical term) when cold. Just my personal experience. DEFINITELY swap that line and report back... after re-bleeding... This will also alter your brake bias -- so re-adjust your prop valve accordingly. Likely this is why you were bottoming it out on adjustment...

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I called Hawk and the rep told me the dust, squeaking, and rotor wear was an issue on the HP+. He recommended the HPS. Either way the car use to stop on dime with raybestos 29 dollar pad and stock brakes, so I need to figure out the present system without going to aggresive pads. I am stumped.

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I too hated my HPS's, used them for a bit but found that only a couple sessions on the track burned through them. With the HP+ they last close to 2 years and are ok for the street as well. Lots of dust [at the track only] nearly zero rotor wear in the rear and some in the front-but looks nearly the same as our daily drivers [ie-not excessive]. My front rotors last about 2 years as well.

 

I'd call and switch the order to HP+ if not too late and/or return the HPS's when they arrive.

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So you have their monster rear brakes. At 13" they should provide more than enough to lock the rears first-as I found on my first run after upgrading to the silvermine rears from the mml 240sx rears [and had removed my prop valve]. First run locked the rears-drove carefully home, reinstalled the prop valve and began adjusting it after. Were the pads & rotors bedded in properly?

 

Again, I would not use the Hawk HPS's as I easily wore them down to nearly nothing during a 2 day event, the HP+ [while I'm sure they're not the best pad] last me significantly longer. HPS & HP+ both create plenty of dust on the wheels.

 

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