Brakes Wilwood 4 Lug Brakes on 1990 Mustang GT

drummerkid14

Member
Nov 30, 2011
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I went and looked at a 1990 Mustang GT the other day that had front and rear Wilwood brakes on the 4 lug hubs. The front was a Wilwood hub, 2 piece rotors and 4 piston calipers, and the rear was stock axles, 2 piece rotors and 2 piston calipers. Was there ever a kit offered for the Mustang like this, or was it pieced together from Wilwood? The front wheels stick out about an inch wider than stock, and the rear looks to be stock width. I think the calipers might be forged Dynalites, and I am curious if they are good for every day use?

Thanks for the help
 
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2000xp8

SN Certified Technician
Aug 8, 2003
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I'm pretty sure there were drag brake kits.
Were the rotors thin?
Not aware of any 4 lug street brakes.
 

drummerkid14

Member
Nov 30, 2011
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So an update. I found part numbers and took some measurements. The front brake set up is 12.19" diameter, 1.25" thick 2 piece HD 48 rotors on 170-2637 hats. The front calipers are Superlite IIA 4 piston. The rear are 12.19" diameter, .81" thick 2 piece HP 32 rotors on 170.2637 hats. The rear calipers are Dynalite II .810 wide 4 piston. Front rotors need replaced, and the pads are made by Hawk.

Now the master cylinder has been updated to accommodate the 4 disc set up, but the brakes are not as strong as they should be. Would a cobra booster help me out? Or how could I increase the pressure being applied to the calipers?

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Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
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Do you know the specs on the calipers in terms of piston diameter and number of pistons? Do you know which MC was installed?

Honestly, without that info, can't really determine if the system is mismatched, or has a failure somewhere contributing to the weak performance of the brakes.

How easy is it to obtain parts for that setup? I've never seen it?
 

drummerkid14

Member
Nov 30, 2011
15
2
13
Do you know the specs on the calipers in terms of piston diameter and number of pistons? Do you know which MC was installed?

Honestly, without that info, can't really determine if the system is mismatched, or has a failure somewhere contributing to the weak performance of the brakes.

How easy is it to obtain parts for that setup? I've never seen it?


The master cylinder is a Bendix 5269A, I can not find out anything about this. I called Bendix and they said they sold the company that makes the master cylinders back in 2014. The booster appears to be stock.

As far as part sourcing, Wilwood has been great to work with. Parts are easy to source, but a bit expensive. Had to get new crossover tubes for the rear and spent about $30 on those.

The fronts are 1.75" pistons, and the rears are 1.375" pistons. Wilwood still sells the piston and o-rings for these, so they can be rebuilt. I can also change the rotor hats to 5x4.5 to switch to 5 lug. So that is a plus.

The biggest downside other than the poor braking performance right now is that the front wheels are pushed out about an inch, but I think this is due to the Wilwood hubs.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,570
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Massachusetts
Assuming these are opposing 4-piston fronts and 4-piston rears, I calculate out 9928 mm^2 of total caliper piston clamping area.

That puts you a little larger than a 94-98 GTV6 setup (9092mm^2) but much smaller than an 84-86 SVO setup which uses a 1 1/8" bore MC

SO yes, 94-95 GT 1 1/16" MC I think is your only option unless you look aftermarket. I would run the booster as well
 

drummerkid14

Member
Nov 30, 2011
15
2
13
Assuming these are opposing 4-piston fronts and 4-piston rears, I calculate out 9928 mm^2 of total caliper piston clamping area.

That puts you a little larger than a 94-98 GTV6 setup (9092mm^2) but much smaller than an 84-86 SVO setup which uses a 1 1/8" bore MC

SO yes, 94-95 GT 1 1/16" MC I think is your only option unless you look aftermarket. I would run the booster as well

Awesome thank you, I will order the 94/95 GT booster and master cylinder. I also think that getting the new rotors on will help as well. These ones are pretty worn and have a lot of piston out of caliper to make contact.
 

2000xp8

SN Certified Technician
Aug 8, 2003
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Looks like a pretty nice setup that could really look good.
When you change the MC i'd consider doing the lettering white or gray and removing all the paint from the crossovers and the hardware. They will look notably nicer.
 

drummerkid14

Member
Nov 30, 2011
15
2
13
Looks like a pretty nice setup that could really look good.
When you change the MC i'd consider doing the lettering white or gray and removing all the paint from the crossovers and the hardware. They will look notably nicer.
I will soon. I ordered all new crossover tubes since I took the photo. So they are nice and clean, I will probably order new bleeders when I change out the rotors.