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

Slumone · Jul 24, 2020

They are a bit more different than a coating. A bit too different for me to run them comfortably. Here are some shots of the rotors themselves, as you can see the castings themselves are different and the one that came in the plastic bag is the prettier of the two on the right.

198 is the rotor the Ford Dealership offers though they gave me when I told them where I got the 54 from. Anyone need a BRR-54?

Wayne Waldrep · Jul 24, 2020

I'm blind....I see no difference...lol. Seriously..I don't.

Slumone · Jul 24, 2020

Wayne Waldrep said:
I'm blind....I see no difference...lol. Seriously..I don't.

Yeah there is 90% chance I am overthinking this but I have completely swapped my entire suspension, third member, as well as braking and steering systems since the last time I drove this car. If swapping a single rotor gives me that much less to potentially troubleshoot, I think its worth the effort.

claypoolxx · Oct 3, 2020

I did what I think is a proper swap, but I am having some issues. I have a good brake feel and strength, but the pedal feels too low.

Here's what I have on my 93 mustang gt:
1. stock front calipers
2. stock brake booster
3. 93 svt cobra r master cylinder
4. rear calipers and discs from a 94 gt
5. willwood proportioning valve

If I did my calculations correctly I have a 15.6 ratio for the pedal feel. I like the feel and the stopping power, but there is too much dead space at the top of the pedal. any ideas? Thanks for any help

Mustang5L5 · Oct 3, 2020

Make sure booster pushrod lenght is adjusted properly. If it’s not out far enough, the dead space will give you the feel of extra travel at the beginning of your braking stroke

claypoolxx · Oct 3, 2020

Mustang5L5 said:
Make sure booster pushrod lenght is adjusted properly. If it’s not out far enough, the dead space will give you the feel of extra travel at the beginning of your braking stroke

I didn’t think that was possible.

claypoolxx · Oct 3, 2020

claypoolxx said:
I didn’t think that was possible.

Ok. Just checked YouTube. Looks pretty easy. Thanks.

Slumone · Oct 3, 2020

claypoolxx said:
Ok. Just checked YouTube. Looks pretty easy. Thanks.

This is decent. I had a better one but cannot find it now.

Got A Soft Brake Pedal? How to check the Booster Pin to Master Cylinder Gap | Master Power Brakes

techtalk.mpbrakes.com

Rdub6 · Oct 14, 2020

I’m throwing this question out in this thread, because nothing I search comes up with an answer.
I’m planning on 5lug rear disc swap with 94-04 calipers. I bought fox length axles with sn95 flange. They did not come with wheel studs. Are 3” studs the proper length for this conversion?

This is the part number I keep seeing the most, but no confirmation for working with this swap. Any help would be awesome!

https://www.summitracing.com/parts/mor-46180

Mustang5L5 · Oct 14, 2020

I have a set of 94-98 axles handy.

They are 2.25" long total length.

I guess that would be 2.00" underhead length. 3" would work, they would just stick out further. Depends on what wheels you are running and if you are adding spacers

Rdub6 · Oct 14, 2020

Mustang5L5 said:
I have a set of 94-98 axles handy.

They are 2.25" long total length.

I guess that would be 2.00" underhead length. 3" would work, they would just stick out further. Depends on what wheels you are running and if you are adding spacers

Thank you! I’m 99% committed on the FR500 wheels from LMR. I do not want to run spacers! I thought the 3” sounded too long, especially for the acorn style lug nuts!

KRUISR · Oct 14, 2020

As listed on rockauto, stock '95 5.0L rear wheel studs...

More Information for PTC 97284

Rdub6 · Oct 14, 2020

KRUISR said:
As listed on rockauto, stock '95 5.0L rear wheel studs...

More Information for PTC 97284

That just set off one of those “dumbass” moments. I was searching....Foxbody/ 5lug disc swap/ etc. Should’ve just searched for a stock SN95 stud! TY!

claypoolxx · Nov 10, 2020

claypoolxx said:
I did what I think is a proper swap, but I am having some issues. I have a good brake feel and strength, but the pedal feels too low.

Here's what I have on my 93 mustang gt:
1. stock front calipers
2. stock brake booster
3. 93 svt cobra r master cylinder
4. rear calipers and discs from a 94 gt
5. willwood proportioning valve

If I did my calculations correctly I have a 15.6 ratio for the pedal feel. I like the feel and the stopping power, but there is too much dead space at the top of the pedal. any ideas? Thanks for any help

So, I've had a chance to mess with it more. I adjusted the rod on the brake booster, but that's not it. I lengthened it a little bit and the pedal felt good, but when I went for a short drive the brakes were dragging. I loosened it just a little and now its back to how it was before, with too much dead space at the top of the pedal.

Now something I didn't think to mention is that I don't have the parking brake connected. My buddy told me that the rear calipers adjust themselves with the parking brake and without one the pistons retract too far and the dead space I feel is the pedal taking up all of the dead space. Does that make sense? Also, I always planned on getting the parking brake working, but figured I could wait a little. Is there a kit that I can get to set up the parking brake? I've seen people do it many different ways, but I'm looking for easiest way.

KRUISR · Nov 10, 2020

I would disagree with the statement that the parking brake adjusts the rear calipers. They are disc brakes, just like front brakes they are adjusted by brake fluid not returning to the reservoir. If you look at rear calipers, there is a spring that pushes the parking brake arm back to a home position. So long as that arm is back to home position brake performance should not be affected.

Some calipers have pistons that must be rotated to retract when replacing brake pads, but I do not think that is related to parking brake movement. Think of all the automatic equipped cars that NEVER use their parking brake, yet the rear brakes work fine and stay adjusted.

As far as setting up parking brake, I used 94/95 cables, I modified a parking brake handle from an '01 (to get proper spring to apply correct tension to cables) by cutting an moving the rear mounting tab forward 1". The rest bolts up and fits perfect. You will also need the front cable mount (see SN cars for the factory mount or fab your own - as I did). Otherwise it is pretty straight forward.

claypoolxx · Nov 22, 2020

I had the brakes vacuum bled and it did the trick. Brake pedal feels pretty good. Now onto the myriad of engine codes and leaky transmission. Thanks for the help.

mustang33189 · Dec 22, 2020

Mustang5L5 said:
70/30 is the ideal goal.

EDIT: I remove my bias calcs as I found some mistakes. I'll update when I get what I think are accurate numbers

If the rear end of your car was heavy, say with an IRS, then I think the 99-04 Cobra/43mm rear setup may work fine.

As for master cylinder, it's going depend highly on the entire combo. With the ATS Brembo's, a 1" bore MC might be a tad soft with the 43mm rears, but the 1 1/16" bore MC might only be slightly firmer than a factory 94-98 Cobra setup.

Mustang5L5 said:
According to MM, factory bias is 73/27 with the 38mm rears.

Changing to 43mm rears and the 11.65" rotor, I get 68% front/32% rear. I believe 70-75% front is considered ideal.

Keep in mind, if you buy the 43mm rears, you still need the SN95 pad hanger bracket. You can't use the Taurus one.

Unsure if these are the Cobra ones.

1994-2001, 2003-2004 Ford Mustang Brake Caliper Bracket - A1 Cardone 14-1042 - Rear Left - PartsGeek.com

Buy 1994-2001, 2003-2004 Ford Mustang Brake Caliper Bracket Rear Left A1 Cardone for a low price of $20.72 at PartsGeek. FLAT RATE SHIPPING on most A1 Cardone 14-1042 orders.

www.partsgeek.com

Mustang5L5 · Dec 22, 2020

I can’t tell what I wrote and what the question was?

mustang33189 · Dec 22, 2020

Mustang5L5 said:
According to MM, factory bias is 73/27 with the 38mm rears.

Changing to 43mm rears and the 11.65" rotor, I get 68% front/32% rear. I believe 70-75% front is considered ideal.

Keep in mind, if you buy the 43mm rears, you still need the SN95 pad hanger bracket. You can't use the Taurus one.

Unsure if these are the Cobra ones.

1994-2001, 2003-2004 Ford Mustang Brake Caliper Bracket - A1 Cardone 14-1042 - Rear Left - PartsGeek.com

Buy 1994-2001, 2003-2004 Ford Mustang Brake Caliper Bracket Rear Left A1 Cardone for a low price of $20.72 at PartsGeek. FLAT RATE SHIPPING on most A1 Cardone 14-1042 orders.

www.partsgeek.com

So I have the front ATS conversion on my 01. If I do the

Mustang5L5 said:
I can’t tell what I wrote and what the question was?

Not sure where my original question went... lets try again... I have the ATS already installed on the front of my 01 gt. I have added weight up front with the coyote swap, blower, cooler, and extra fluid. I have the battery related to the rear and a roll cage as well. Would I benefit from the 43mm rear upgrade? Also will my factory master cylinder support both the ATS and 43 mm calipers?

Mustang5L5 · Dec 23, 2020

The factory MC would support the calipers. Hydroboost is different than vacuum type boosters. Where Ford used a different size for each vacuum brake setup, they only used 1 MC for the differenve brakes with hydroboost. 1” for 96-98 and 1 1/16” for 99-04.

your stock 99-04 calipers actually have less piston surface area than the ATS brembos. So changing to the 43mm rear calipers would still be around what your stock setup was in terms of surface areA. So yes, it would work with the MC

as to it the bias would be correct? I cannot answer that. Do you actually have a front/rear weight bias? Or just making assumptions as to how the vehicles weight has changed? If you are using the rear GT brakes, The bias is probably still fairly front heavy even if you’ve added weight up front. You might want to consider the Ford M-2300-M kit in addition to the 43mm rears. That bias would be pretty close to stock.

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

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Before I post a pic, do you have one of yours?

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That is…until I whipped out my Bissell

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So while I wait to figure out my rear end issues

That is…until I whipped out my Bissell

So while I wait to figure out my rear end issues

So while I wait to figure out my rear end issues

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