SN95 Brake Install on a Fox
Republished from http://www.2kgt.com
We all spend countless dollars to make our steeds go faster. We
research it all; we bolt on blowers, juice em' up, bolt on the
latest heads, intake, cam and raise the compression all in the name
of those extra horses we can tame, that extra tenth in the quarter,
or to beat that guy down the block with the SS Camaro into a
What most of us fail to realize is that its one thing to go
fast, it's another to be able to stop. And by stop I don't mean
'eventually'. I mean now. Quite frankly, the brakes the good old
Ford put on our fearless foxes are marginal at best.
I have owned Project Cobra for almost 10 years now. Ironically,
all I was looking for was a stock AOD GT I could leave stock, maybe
put some mufflers on and rear disc brakes. Well here we are all
this time later and I am still rolling with those pint sized rear
drums and 4 lug wheels. Not that 4 lug is a bad thing, but it
limits your wheel choices and brake options.
My eyes were opened when we bought our 1999 GT, and instantly I
fell in love with the brakes. They felt sure, strong and confident.
Gone was praying for our safety in panic stops. And if you know the
NY Metro area, it's full of them.
Two of my friends had done SN brake conversions and they both
boasted about how they stopped on a dime. Add to that the fact that
17in wheels really fill the wheel wells of a fox
car, and add the fact that I loved the way the wheels looked..
(more on that later)... but mostly I wanted to feel the same way
about the 88's brakes as I did with the 99.
What we are starting with
I suppose I am somewhat fortunate, as in 1987 Ford went to
revised spindles with larger 11in front rotors replacing the
previous 10in setup. Single piston 60mm front calipers apply
pressure. In the rear, the familiar (since the Fairmont days) 9in
drums do their best. But we all know sometimes their best isn't
What we will be installing
- 1994 Mustang spindles, hubs, rotors, dust shields (11in)
- 1999 Mustang GT PBR Dual piston calipers
- Russell DOT Approved Stainless Steel Brake hoses
- 1997 Mustang rear rotors, calipers, caliper brackets, brake
hoses, steel lines, dust shields
- 1995 Mustang GT master cyl
- 31spl SN95 length axles with 3in studs
- Summit adj prop valve
- M2450A FRPP Prop valve plug kit
Hitting the pavement will be 1999 SVT Cobra wheels (17x8) with
the 'correct' silver SVT logo caps, wearing 245/45/17 fronts and
255/45/17 rear tires
My current 26x8.5 DT Drags will be moved from the current "Ten
Hole" wheels to 15x7 SN95 V6 aluminum alloys.
I will not have to run the longer wheel studs with these wheels,
as they are OEM acorn type conical seat lugs. Besides, I didn't
love the way the 3in studs would look coming out of the Cobra
Front upgrade: Disassembly
Remove the wheel and tire from the vehicle, placed securely on
Now you can see the stock brake assembly.
Remove the two caliper mounting bolts (hex head bolts on the
wheel side of the caliper) and disconnect the brake hose from the
hard steel chassis lines. Be sure to use the correct line wrench so
you don't ruin the fitting.
Carefully remove the brake caliper and hose, take care not to
splash any brake fluid on your car, as it will take the paint
Remove the dust cap in the center using a flathead screwdriver,
then remove the cotter pin and castle nut from the center of the
At this point carefully pull the rotor off of the spindle taking
care not to nick the bearings.
What we now have is the spindle mounted to the lower control arm
at the ball joint, the strut on top, and the tie rod towards the
front of the car.
At this point you will want to place a small jack under the ball
joint are of the lower control arm to compress the coil spring and
take pressure off the spindle assembly so you can begin the
disassembly. This is also for safety reasons as once the spindle is
removed there is nothing holding in the coil spring and it is under
EXTREME pressure so be sure the jack is securely positioned and
Remove the three small bolts which retain the dust shield to the
spindle to allow better access to the strut mounting bolts.
The two large strut to spindle retaining bolts can be tough to
remove if they have never been removed before. I suggest having
some penetrating oil on hand, a breaker bar and a cheater pipe. I
have replaced my struts somewhat recently so they weren't too
Remove the two bolts which retain the struts to the spindle,
then remove the cotter pin and castle nut which retain the tie rod
to the spindle, then gently tap the tie rod out, Penetrating oil
and a hammer work well here, its best to tap the tie rod itself and
not the threads for fear of galling. Next remove the cotter pin and
castle nut from the top of the ball joint. At this point there is
nothing but possibly a year of crud and rust holding the spindle
on. Try tapping up with a hammer or mallet. Again the penetrating
oil comes in handy. Should you use a ball joint separator tool,
take care not to damage the ball joint boots.
Of course things don't always go as planned, one side ripped, but
I figured while I was in there I might as well replaced the 15 year
old components with a set of M3075A FRPP lower control arms which
include new bal joints and bushings already installed.
At this point removal of the stock components has been
completed. Once the spindle is removed, it will look like this.
Front upgrade: Spindle Modification
Originally I had planned on using stock SN (1994 to be exact)
calipers. While that would still be a great upgrade for the system,
I found out that the 1999 - up GT/V6s use dual 44.5mm piston
calipers as opposed to the 66mm single piston calipers found on the
94-98 GT/V6. Compared to the 60mm single piston calipers that came
on the 87-93, either would be a wise upgrade. However the PBRs
offer a cost effective upgrade to the SN brakes which retain the
stock 11 inch rotor and with minimal modification will work with
the 94/95 SN spindles.
Here is a host of the 1994 GT/V6 calipers vs the 1999-up PBRs:
I looked to Matt Bobbit's incredibly informative Mustang Brake
Upgrade page for the how to.
It is explained that in 1996 the spindles changed not just in
track width, but at the caliper mounting points, so using 96-98
spindles, modification may not be necessary and the calipers will
be a bolt on affair. What we need to do is 'clearance' the 94-95
spindle to replicate what Ford did in 1996.
Here is the driver's side spindle. We must grind down the
caliper mounting 'ears' a bit. I used a small electric angle
grinder and the process took nearly 10 minutes for each side,
checking the fit of the 99 caliper every few moments.
What you will ultimately end up with is this:
Trial fit the caliper a few times; you will see what is
interfering and what must be removed.
Here is a shot from another angle:
From the back you can see what you are clearancing for.:
Once the spindle clears the caliper, you can mount it and
compare the 99 setup to the 94-98:
Front upgrade: Reassembly
Since the ball joint on an SN95 Mustang is shorter than the Fox
cars, you can one of two things.
- Have 94-95 Ball joints pressed into your control arms
- Use spacers or washers to make up the difference in height
Since I had purchase the FRPP control arm kit (with the new ball
joints) I went with option 2.
I received a beautiful set of machined steel spacers from the
DaSaga Fabrications out of Michigan. They take up the slack
Place the spindle onto the lower control arm at the ball joint,
and then align the upper holes in the spindle with those in the
strut. It will probably help to raise the jack (which has been
supporting the control arm this whole time). Once the holes are
aligned, place the two bolts through and loosely thread the nuts
Place the aforementioned spacers onto the ball joint on top of the
spindle and then thread on the castle nut. Tighten that up, making
sure when it is finally tight the holes for the cotter pin in the
joint itself and the castle nut are both lined up.
Insert and lock down the cotter pin. Fully tighten and torque the
strut to spindle nuts.
If you try to swing the spindle to meet the tie rod end at its
current setting you will find that you have a great amount of toe
in. The vehicle cannot be safely driven like this. I loosened the
lock nut and extended each tie rod 4-6 turns to get the wheels as
straight as I could (to get to the alignment shop).
Now it is time to mount the rotor and caliper. The rotor simply
slips over the hubs, much like a front wheel drive car. Moving on
to the calipers, make sure the pistons are pushed in enough to
clear the new pads. You can use either a disc brake pad spreader or
a c-clamp with an old brake pad. I bought new Performance Friction
pads for the front. Place the loaded calipers onto the spindle, and
thread the two caliper to spindle bolts in the front and the rear
and torque to spec.
I opted to install Russell DOT approved stainless steel brake
lines instead of using the 99-up brake hoses. If you choose to
retain the Ford lines you will need a weather head fitting to adapt
to the fox3 hard line, as the pass side is a different size. I
figured I might as well upgrade, and it is one less connection to
worry about leaks.
As anyone who has installed SS lines on their Mustang can tell
you, you have you grind the 'nubs' that are inside the factory
retaining bracket. I used a dremel and a small grinding wheel.
After a few tries, the SS hose slipped into the bracket and the
OEM retaining clip was slipped on.
Using a line wrench and an open end, seat and tighten the fitting
from the fox3 hard line into the SS coupler.
Voila!!! The finished product. 1994 spindles, hubs and rotors,
99 PBR calipers, Russell stainless steel hoses and Performance
friction pads. Its Ford OEM stuff and light years ahead of the
stock fox3 stuff.
Here is a picture of the 99 Cobra wheels and 245/45/17 Goodyears
on the front. Wow those are big! And aren't those brakes
Under the hood
When we last left our project car, the front upgrade had been
completed. Here is a picture of with the new wheels mounted on the
The next step will be to upgrade the master cylinder to
accommodate for rear disc, and gut the stock proportioning valve
and run an adjustable unit.
At the pass side firewall, you will see two brake lines joined
by a simple brass union. Perhaps Ford thought ahead? Perhaps we
just got lucky.
In any event, use a line wrench and an open end to remove the
brake union from between the two lines. Be careful not to round the
edges of the brake fittings. Once you remove the union, you will
see that there really is nothing holding these lines other than the
tension of being bolted together. Carefully bend them back a bit to
make room for what will be installed next.
I purchased an adjustable proportioning valve from Summit Racing.
They sell it under the Summit brand, but it is actually
manufactured by Wilwood, as are many on the market. Thread in the
supplied adapters and wrench it onto the brake lines where the
union once was.
Make sure all fittings are tight, the port labeled "inlet" facing
the master cylinder.
Next up we will replace the std fox3 master cylinder with a
larger 1 1/16" bore 1995 Mustang GT master cylinder. An added bonus
is that this MC retains the stock low oil sensor, unlike the
earlier SVO/Lincoln metal units.
Using a line wrench, remove the two brake lines from the factory
prop valve to the master cylinder (at the MC). Don't forget the
other brake line which connects at the bottom of the MC. Next
remove the two nuts that retain the master cylinder to the brake
booster. It's tight but an open end wrench will get in there little
You are now looking at the stock prop valve and booster. You
might have noticed that the fox3 master cylinder has 3 lines going
to it. The SN95 master has only 2, hence the need for a 3-2 port
conversion kit to make it work.
I ordered a kit from Matt90GT, which included a "T" fitting, an
adapter and a metric union to mate the third line which formerly
went under the master cylinder to the stock prop valve.
Because of production variances, I was unable to use the kit as
delivered. The "T" port was facing the engine compartment. Matt
recommended I file some material off the top of the "T" which I
tried. Several attempts and I finally got the T port to face
somewhat backwards. However, the other fitting supplied in the kit
was a compression fitting as opposed to an inverted flare. I opted
to 'modify' the kit using an 8in section of 3/16 line and a
3/16IF-10M adapter. This would allow me to eliminate the third
fitting and run straight to the union and, in turn, the third
Confused? Good. Here's a pic: (never mind the fitting on the top
of the "T", that was just for testing)
With the steel line I was able to bend the line to reach the T
port in the fitting, then route it cleanly to join with the third
Next we must 'gut' the factory prop valve, removing its
internals. Simply remove the nut at the front of the stock valve,
but be careful the spring will pop out! Behind the spring is a cup
and a plunger.
Transfer the O-ring from the old cap to the new FRPP plug you
have purchased (M2480-A) and reinstall.
You have just gutted the prop valve and it is now nothing more
than a fluid transfer fitting, the valve you installed on the pass
side is what you will be working with.
Now install the 95 MC. It will slide onto the booster studs,
tighten the nuts securely.
Then reattach the two remaining prop to MC brake lines. I bench
bled the master cylinder before installation. I recommend you do
the same. Plug in the low fluid sensor.
The 95 master cylinder looks perfectly factory, as does the prop
valve conversion lines. You surely have a lot of air in the lines,
so if you were to drive the car at this point be sure to BLEED
THEM!!! I am waiting to finish the rear brake setup before I bleed
Bringing up the rear Part I
Ok, so the front is completed and under the hood is ready to
roll. If you recall from our last pictures our project pony was
still wearing the Ltd Edition white ponies (those will sincerely be
missed as they have been on the car almost 10 years!) on the
The first order of business is to raise the back of the car and
safely support it on jack stands. Remove the rear wheels.
Take a good look at those drums, this will be the last time you
will see them on the car!
Make sure the e-brake is not on, and remove the rear drums
themselves. Remove the differential cover and drain the gear oil
I used James Adkin's excellent tech article for a 8.8
rear gear swap. It explains how to remove the axles, so I will just
go over the basics here.
Using an 8mm box wrench (or socket, but clearance is tight),
remove the crosspin retaining bolt. Gently push the crosspin
inwards a bit, maybe an inch to half an inch. Rotate the
differential about 180^ until you see the crosspin sticking out of
the differential. Gently pull it free and out.
Push the axles inwards and the C-clips which retain the axles will
drop into the houseing (right into the gear oil of course!). When
you hear the clip drop, carefully slide the axle out of the axle
housing. Take special care not to drag the splines on the oil seal
or you will be replacing those as well.
Now is a good time to replace those bearings and seals you might
have been waiting to do. Mine were in good shape, so I left
Remove the four drum to axle retaining bolts, using a socket and
a combination wrench. Remove the steel brake lines from the wheel
cylinders using a 7/16in flare nut wrench.
Once you are finished, simply pull the entire drum off as one
OK folks, we're down to the rear axle housing. Inspect the seals
at this point for tears or leaks.
Install the rear brake caliper mounting brackets (they are labeled
"L" and "R") onto the housing using the original nuts and bolts (my
kit came with SN95 buts and bolts so I used them. I opted to
install the dust shields on the brackets as one unit, but they can
be done seperately as well.
Now we are getting somewhere. At this point it's time to install
the axles. Since the project car's rear axle had already been
modified with a 31 spline FRPP traction lok, we ordered up a set of
31spl SN95 length Moser axles from Dave at JDs
Note that the use of SN95 length axles will widen the rear
track by .75in. Comparing the 31spl fox length axles to the SN95
length gives some insight as to the difference.
Carefully insert the axle shaft into the axle tube, once again
taking care not to damage the oil seal. When both axles are in,
place the c clips into the slots at the end of the axle splines. At
this point, reinstall the shaft and retaining bolt you removed
previously. You can now replace the rear axle cover and fill the
rear to capacity with 80W90 API GL5 gear oil. Don't forget the FRPP
At this point we can begin to install the remainder of the rear
brake parts. A big thank you to Terry at Midwest Mustang for the
parts and the excellent packaging. All hardware was also included,
saving me a trip to the parts store a few times.
Mount the anti-moan bracket on the axle tube much like a muffler
clamp, lining up the two holes with the holes in the inside of the
caliper mounting bracket. Do not fully tighten the two 9/16 nuts at
this time, just snug them up.
Place the rotors onto the axles, and the calipers onto the
rotors / caliper braket. Line up the mounting hole and sandwhich
the caliper bracket between the caliper and the anti moan bracket.
Insert and tighten the two caliper mounting bolts.
It should be noted that without the anti-moan brackets the
calipers will fit loosely. Initially, I forgot to put the brackets
on, and was puzzled as to why the calipers were not fitting tight
despite the bolts being all the way in. The AM brackets take up the
space and all was well. Now you can fully tighten the four AM
bracket to axle tube nuts (2 per side).
Remove the upper caliper to bracket bolt, and swing the caliper
off the brake pads/rotor. The Mustang uses free floating single
piston calipers int he rear, but unlike the fronts, the pistons
must be rotated CW while they are pushed in. The local Auto Zone
had the tool for rental and it worked perfectly.
Once the piston is fully compressed, put the anti rattle clips
(two per pad) on the pads and then carefully place them into the
bracket assembly on the rotor. This takes a bit of finessing, but
can be done.
If the piston is compressed enough, you can then swing the
caliper back up and over the pads. Insert and tighten the bolt you
removed perviously. The completed rear brake assembly (minus brake
lines and ebrake cables) will look like this.
OK! Now we're getting somewhere!!!
Bringing up the rear Part II
I purchased rear brake hoses for a 1995 Mustang GT application.
Unfortunately it took about a week to get them, so that held up the
project a while.
Installation is pretty straightforward, place a 1/4 inverted flare
male to 3/16 inverted flare female adapter onto the brake hose,
then thread the fox steel line carefully into the adapter using a
The rear brake hoses feature a locating tang and retaining bolt.
On the pass side you have to drill holes, on the drivers side they
are already present. Some 'finageling' with the steel line is
necessary due to the adapter fitting. I opted to cut and re-double
flare the steel line but it still wasnt cut back enough. But it
worked out. Make sure you have a DOUBLE flaring
tool and you are well practiced, otherwise you will end up with
leaking fittings.. this is a very bad thing on brakes!!!
Have someone step on the brake pedal and check for leaks. If
none are present, go ahead and bleed the brakes, working your way
towards the master cylinder from the pass side rear wheel.
PR-DR-PF-DF is the order you want to follow. You want to turn the
adj prop valve knob all the way in before bleeding, then after you
are done, turn the knob all the way out, then 4 turns initial
adjustment. You can go from there.
I then brought the car to North Shore Tire in Lynbrook, NY for
an alignment. Even though I thought I had turned out the tie rods
enough, I still had an incredible amount of toe in.
I pretty much idled the car there. It should be noted that the
255/45/17s did not rub the rear fenders, despite the car about
3/4in lower with the Steeda Sport springs. I feared they might rub
but thusfar have proved fine.
The guys at North Shore did a computerized alignment, taking
care of my baby, I even let him test drive it!
They made sure the steering wheel was straight and the car tracked
Immediately the ride smoothed out, I guess the front tires
fighting each other down the road is a bad thing. Also the front
tire rubbing was gone. I had clearanced one side front spat, now it
was all good.
Well the car sure looks the part, but the brake pedal was hard
as a rock. Like stepping on concrete. I guess the combination of an
aftermarket cam (less vacuum) and the stock 88 booster wasn't
enough to give a nice pedal with the larger bore 95 master
cylinder. Luckily I bought the 95 master with the booster attached
so it was time to give that a shot.
Brake Booster Install
I drove the car as it was with the stock booster, but the pedal
feel was very heavy, almost like stepping on concrete. It had no
Since I already had the 1995 Mustang GT booster (purchased with
the master cyl), I decided to 'drop' that in.
The booster is secured under the dash by four retaining nuts.
Begin by removing them. Laying on your back on the door sill isn't
fun, but it's not that bad. The rod from the booster passes through
the brake pedal and the brake light switch. It is secured by a
small clip, which a needle nose plier will be able to get to. Note
the placement of the parts along with the plastic spacers
Unbolt the master cylinder from the booster and carefully move
it out of the way. You may choose to remove the hydraulic lines
from the master, I did not. There was enough room to carefully move
the master away. Remove the brake booster vacuum line from the tree
on the firewall and carefully remove the booster from the car.
Side by side, you can see the sheer size difference between the
two boosters. The SN95 is much larger and holds much more vacuum
for a softer pedal feel. The length is about the same.
I had been forewarned that the booster, being larger, might
require some clearancing and/or elongating of the mounting holes to
install. So I test fit it, and of course, no dice. Not even close
to fitting. Enter the hammer and I began 'clearancing' the strut
tower. The task of test fitting and then removing was tedious, time
consuming and boring. but it had to be done a little at a
It was then I realized that although the strut tower now had
enough room, the bolt spacing was a bit different from the fox to
the SN95 at the rear mounting studs.
I started by enlarging the upper pass side hole, then the lower
drivers. This only took a little bit with a drill and a dremel.
I made a template out of cardboard and found that the pass side
lower hole was off by about an eighth of inch, so I drilled the
hole and elongated it to meet the original one. Note the pencil
drawn circle is the current location on the fox. Remember to drill
the bracket behind the firewall as well.
This will all be covered up by the booster (thank goodness!)
After much trial and error, drilling and grinding, the booster
somehow (and much to my delight) popped right into place. I reused
the same check valve and vac line, and reconnected it at the vac
tree. Go back under the dash and torque down the retaining nuts on
the inside. Note: the SN95 uses a different thread than the fox
booster, so make sure you have the correct nuts.
There ya go. All done and looks factory. Although if you look at
it, you will surely wonder how the heck it got in there!
Front brakes have now been upgraded
to 13in Cobra specs!
31spl Moser Axles
Rear Brake Parts, Master cylinder, booster
Rockville Center, NY
Russell Brake Lines
Summit Racing Equipment
Wheels, prop valve and prop plug