Brakes The Ultimate 4-lug/5-lug Brake Conversion/upgrade Thread

Mustang5L5 · Aug 27, 2015

The T/C calipers are 45mm vs the sn95 38mm rear calipers, so with the sn95 mc you aren't pushing enough volume for the setup.

Two options...svo MC or swap to the 38mm sn95 calipers.

Are you running that setup 4-lug or 5-lug?

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Carl H · Aug 27, 2015

5 lug using Mazda MPV rotors and NRC brackets.

I got rears for a song so I think my engine bay is gonna go old school with the SVO mc.

Mustang5L5 · Aug 27, 2015

If you do that, keep in mind the fronts are 66mm calipers vs the 73mm used on the SVO. You may find yourself with a slightly firmer pedal than you'd like. In that case, your only option will be to SN95 booster the car to get more assist.

Carl H · Aug 27, 2015

Ok, I'll have to keep that in mind. Do you think the larger rears will help offset the smaller fronts though? Since I'm losing 7mm in the front but gaining 7mm in the rear it 'should be a wash but I'll have to the math on it to be sure.

Carl H · Aug 27, 2015

I did the math and wow, with TC rear calipers and SVO fronts with a SVO mc the ratio is over 18. Definitely not a wash...math rules all.

I would end up with my current calipers and SVO mc at a 15.70 ratio. Heck of a lot better than over 17!

Mustang5L5 · Aug 28, 2015

Carl H said:
Ok, I'll have to keep that in mind. Do you think the larger rears will help offset the smaller fronts though? Since I'm losing 7mm in the front but gaining 7mm in the rear it 'should be a wash but I'll have to the math on it to be sure.

Sorry, I was 2 glasses deep in some scotch last night. I overlooked the fact that the SVO rears are 54mm vs the TC's 45mm calipers.

So with that said, your total surface area with the 66mm/45mm setup would still be slightly less than the SVO's 73/54mm setup. With the SVO MC it puts your pedal ratio around 15.7 which would be better than the 17.5 you currently have (higher number equals softer pedal feel)

Also keep in mind the SVO MC is tiny, so if you decide the pedal feel is a little firm, you can look into a booster swap

NightFury · Aug 31, 2015

Mustang5L5 said:
Also, does "double pumping" the brake pedal while stopping build the pedal up and give better brake response?

It didn't help before, but I haven't tried it since replacing my rear calipers.

Is it possible there could be air trapped in either the stock or aftermarket proportioning valves? That seems like the only other place air could be. I've bled the calipers about 4,000 times and I see no air bubbles.

I also pulled off the fronts and watched the pistons move as the brake pedal was depressed, so I know they aren't seized. The pistons moved one at a time but I assume that's normal. When I clamped the one that moved the other one moved fine.

I'm about to take the new rears for a test drive. If it all still doesn't work, I'm gonna be at my wits end.

Mustang5L5 · Sep 1, 2015

Double pumping usually is a sign of air in the system. If it makes no difference, and your pedal is rock hard when the engine is off, I wouldn't think there would be air in the lines.

So that leads me to asking what sort of brake pads are you running?

NightFury · Sep 1, 2015

Oh, with engine off? Then yes, double (even triple) pumping will build up pressure. Should I crack the nuts on the prop valves and bleed those? I'm running out of places to check.

Using Hawk ceramic pads.

Mustang5L5 · Sep 1, 2015

Sorry. Engine on. Does a quick double pump buiuld pressure? If not, then it's prob not air in the lines.

With the engine off, after a few pumps the pedal should be rock hard

NightFury · Sep 1, 2015

Mustang5L5 said:
Sorry. Engine on. Does a quick double pump buiuld pressure? If not, then it's prob not air in the lines.

With the engine off, after a few pumps the pedal should be rock hard

So the new rears feel better and the system appears to be working correctly based on what you're describing. I'm wondering if maybe I was just expecting more out of the upgrade. The car stops but I can't lock up the wheels. Could that be a brake pad issue?

Might not be a fair comparison but when I get on the brakes in my 2012 Edge Sport, my sunglasses fly off my face. I don't get that sensation here.

Mustang5L5 · Sep 1, 2015

Depends on which hawk pads you have. The streets or the race compounds. The more aggressive versions require a little more heat before they begin to bite. When cold, they just feel weak.

I also wonder if your booster is working properly. Was it new, or a used unit?

NightFury · Sep 1, 2015

Pads are performance ceramic (yellow box). And the booster pushes the MC just fine. If it wasnt working, wouldn't it be stiff?

NightFury · Sep 2, 2015

Oh and the BB was a rebuilt unit.

Mustang5L5 · Sep 2, 2015

I'm puzzled. Your setup should be performing quite well. It's been done plenty of times. Gotta be something simple being overlooked.

NightFury · Sep 3, 2015

Mustang5L5 said:
I'm puzzled. Your setup should be performing quite well. It's been done plenty of times. Gotta be something simple being overlooked.

Do you think I should take it all out and start over? I'm tempted to get the prop valve eliminator kit from Maximum Motorsports to eliminate the possibility of air being stuck in the stock valve. Like you, I'm out of ideas. Unless air is stuck somewhere that can't be bled out, I'm not sure what else to do.

Mustang5L5 · Sep 3, 2015

I don't think it's air though. If it was air, you would be able to tell by double-pumping the pedal while under braking and see the pedal effort become better. Since you said that that does not change how the pedal responds, I don't think air is the case here.

Are those front calipers used? How well did the pistons retract when you pushed them in? Did they move easily?

NightFury · Sep 3, 2015

Mustang5L5 said:
I don't think it's air though. If it was air, you would be able to tell by double-pumping the pedal while under braking and see the pedal effort become better. Since you said that that does not change how the pedal responds, I don't think air is the case here.

Are those front calipers used? How well did the pistons retract when you pushed them in? Did they move easily?

Pistons moved freely. Required minimal effort to return them into the bore. Slide pins also moved freely. Can I fly you out to California to look at it for me? haha.

90sickfox · Sep 3, 2015

94-95 spindles
98 brake booster
98 prop valve
2004 cobra front rotors
2004 cobra calipers
2004 cobra IRS rear brakes
2001 e brake handle
2001 e brake cable bracket bolted to tunnel 2004 cobra e brake cables
SLP line lock
Ran hard brake line to factory Y at IRS rear
Braided hoses ran up front for cobra front calipers.

Stops on a dime no issues...roasts tires really good too

NightFury · Oct 21, 2015

So Mike, I started re-reading these to see if I missed anything, and twice you mentioned the use of the 94+ SN95 MC when using the PBR calipers. I know you say the 93 Cobra should work fine but it seems like maybe you used to prefer the 1 1/16" MC for that particular upgrade?

87-93Â Ford Fox Body Mustang Brake Upgrades

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Brakes The Ultimate 4-lug/5-lug Brake Conversion/upgrade Thread

That is…until I whipped out my Bissell

New Member

That is…until I whipped out my Bissell

New Member

New Member

That is…until I whipped out my Bissell

New Member

That is…until I whipped out my Bissell

New Member

That is…until I whipped out my Bissell

New Member

That is…until I whipped out my Bissell

New Member

New Member

That is…until I whipped out my Bissell

New Member

That is…until I whipped out my Bissell

New Member

Wasn't a pretty sight...and I've got big hands

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