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

FoxtrotTangoWhiskey

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Oct 7, 2016
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. If you are buying new, get the 1993 Cobra booster.
I heard of people that did and didnt have fitment issues with the '93 cobra booster. I saw that it was about 50/50 in the LMR review section. The people that got it to fit without banging the strut tower said to just take your time and remove the wiper motor, can anyone verify this?
 
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Mustang5L5

Mod Dude
Feb 18, 2001
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It's been a while, so not sure. Maybe just 1/4" or so? I used a hacksaw and then ran a die over the thread to clean up the threads.

How much I took off is unknown. When you remove the old one, you can see how much stud protrudes past the nut


Sent from my iPhone using Tapatalk
 
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FoxtrotTangoWhiskey

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Oct 7, 2016
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It's been a while, so not sure. Maybe just 1/4" or so? I used a hacksaw and then ran a die over the thread to clean up the threads.

How much I took off is unknown. When you remove the old one, you can see how much stud protrudes past the nut


Sent from my iPhone using Tapatalk
It sounds very do-able! Thanks!!! I actually have a 2nd hand tap and die set. My dad was diesel mech for a while, so I started to inherit the tools he dont use anymore.
 

sawdeanz

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Sep 6, 2016
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Emergency advice please!!!!

How important is the adjustable prop valve? Just went to go pick up my 90 gt from getting a turbo coupe axle swap. I assumed (or misunderstood) that it would include this part but he elected not to install one. Taking his word I got about a mile before it became apparent that the rear brakes were engaging full time (even with no foot on brake pedal). Although I've done quite a bit of research on the swap I don't really understand brake systems that well (which is why I took it somewhere). Could this be a symptom of skipping that part? Parts that I verified myself included '93 cobra MC, conversion lines and prop valve (but not the rear adjustable valve and stock booster). I'm supposed to hear back this morning, he claimed there was something wrong with a caliper and that he would rebuild it this morning, but I'm not sure what that means exactly.
 

G00nies

Active Member
Nov 7, 2014
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Just completed the rear Build (8.8" 4.10 gears 1997 GT axle)
and installed. Just finished flaring the line into the brake hose, so Still need to secure the hose to the axle.
I actually used outer rear brake hoses from one side of a 2002 Ford F250, they worked perfectly on either rear caliper. Harvested the rear axle brake junction from my 1992 axle with center brake hose.

***Zip ties are not permanent!lol...Like I said, not finished securing the rear hose/line yet. More pics to some
 

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G00nies

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Nov 7, 2014
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You did a bang up job G00nies, but i'm surprised you used rubber lines! :confused:
Thanks. Well, this is my first one. I figured that hoses to a fabricated hard line would be better ?? Dunno.
I managed to harvest the old hardline and use the junction portion to the main hose as a tie in point. Didn't really explore or consider other options. Just finished the front and will do the master /booster tomorrow.
 

stang89bidges

5 Year Member
Mar 14, 2014
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Best pedal feel would be hard line all the way to the brakes, but in the front that's impossible, so stainless steel braided is the way to go so you don't end up with a squishy pedal feel(expanding rubber on hard brakes). Just a preference really, depends on what your goals are for the car.

But again, great job, looks real nice!
 

G00nies

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Nov 7, 2014
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Best pedal feel would be hard line all the way to the brakes, but in the front that's impossible, so stainless steel braided is the way to go so you don't end up with a squishy pedal feel(expanding rubber on hard brakes). Just a preference really, depends on what your goals are for the car.

But again, great job, looks real nice!
Just completed bleeding the system to ensure no leaks, then gonna swap the master booster and prop valve and flare some lines. More pics to come...
 

G00nies

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Nov 7, 2014
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So....waiting on this from LMR to complete the hydraulic part of the conversion

mm-mmbak8_4322.jpg
 

jrhill87

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Feb 8, 2017
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Looking for some help with stuffing 18x9 wheels under my notch. Current suspension as follows: stock kmember, stock front and rear control arms, Koni shocks and struts, eibach pro kit springs. Wheels I will be putting on are Roush wheels with 28mm offset. Will I be ok on the front with 94-95 spindles?
 

Nightstang00

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Mar 20, 2017
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about to do 4 Lug rear disc under stock 10 holes



I am trying to keep the stock appearance of my car and want rear disks and am about to convert using essentially:

North Racecars brackets (allow 1993 Cobra/TC parts with stock 5.0 axles...keeps offset where it should be)

http://www.northracecars.com/brackets.jpg

Stock 1993 Cobra parts (either Raybestos or Ford, I have the part #s at home)
Booster (Raybestos)
Master Cylinder (Raybestos)
Emergency brake cables (Raybestos)
Calipers (Cardone Reman Ford units)
Pads (Ford)
Rotors (New Ford, now obsolete. I just had them cryo treated as well :)
Rear brake lines (Ford, used)

Thats it for the bolt is stuff. Don't forget you will need a proportioning valve:

I will be using a wilwood BPV-1
and to use a 1993 Cobra MC in a regular Fox you will need a Master Cylinder adapter kit, I will be using Maximum MotorSports MMBAK-3

and the emergency brake handle needs to be modified. I forget how. I bought a NOS one and sent it to someone on eBay and for $25 he modified the handle. I don't know exactly what needs to be done...but I know it is important.

Hey , do you happen to have the part number for the brake booster. I wanna order one from auto zone and I’m asked “Need to know diaphragm diameter. It's 7.250 or 8.750” , would you happen to know or have the part number?
 

Mustang5L5

Mod Dude
Feb 18, 2001
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Hey , do you happen to have the part number for the brake booster. I wanna order one from auto zone and I’m asked “Need to know diaphragm diameter. It's 7.250 or 8.750” , would you happen to know or have the part number?

If you are looking up parts for a 1993 cobra, it's the larger of the two. For some reason the standard 5.0 booster also comes up. You want the bigger diameter one
 
Sep 22, 2017
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Nightstang00

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Mar 20, 2017
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The plate that bolts to the rear, that the caliper mounts on to, are they specifically made for certain calipers. Example: Lmr sells the plates for cobras and Gt/v6 for the 5 lug conversions. I want to know if I have to buy this kit or can I just go to a junk yard and get the plate to mount the calipers. I have a fox body rear.
 

Mustang5L5

Mod Dude
Feb 18, 2001
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The axle bracket is made for a certain offset and rotor diameter. There's one bracket for the GT/v6 rotors (10.5") and another for the cobra 11.65" rotors.

The LMR brackets I believe are offset to use stock fox offset 5-lug axles. If you use the factory sn95 brackets, you have to run the 94-98 axles which push the rear wheels out 0.75" each side.

Need to pick your wheels first, then choose the proper offset. If you want a chance at running fat rear tires you want the stock fox offset brackets
 
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Mustang5L5

Mod Dude
Feb 18, 2001
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Junkyard pickers basic 5-lug conversion parts list

Front:

Spindles off 94-95 Mustang (any model).
Dust shields off any 94-04 mustang
Rotors off any 94-04 Mustang V6/GT
2-piston Alum calipers off a 99-04 V6 Mustang
Pair of front brake lines off 99-04 Mustang

Rear:
Pair of 5-lug axles off a 94-98 Mustang V6 or V8

Brake parts can come from any 94-04 Mustang. They are all the same but the main difference is you cannot use the 99-04 axle shafts. You want
-Calipers, rotors, axle brackets, anti-moan brackets, dust shields
-Parking brake cable guides that are bolted to the sway bar bracket


Booster:
Any 94-95 Booster, or 99-04 V6 vacuum booster. Avoid the 96-98 v6 vacuum boosters. Avoid a booster where a leaky MC caused the front under the MC to corrode. If any brake fluid gets on the rubber, it will deteriorate and leak. DOn't take the risk due to the PITA job of swapping these. May be advised to go reman here.

MC. Ideally you want a 1.00" bore here for this setup. That means 1993 Cobra whick you'd have to buy new. You can snag a 1999-2004 V6MC which is also 1.00" bore, but the fitting sizes are unique so you'd have to make the lines. You can TRY a 94-95 V6/GT master cylinder which is 1 1/16" bore, but the pedal might be a tad bit too firm for your liking.


Misc. You'll need to buy a few additional items, such as e-brake cables. , Adjustable prop valve, and the prop valve plug.

Here's your basic instruction manual.

http://static.summitracing.com/global/images/instructions/fms-m-2300-k.pdf