How To Install a Big Brake Kit
By Rob Robinette
Do you need bigger brakes?
The stock 3rd gen RX-7's brakes work fine for everyday sports car
driving but on the race track when exposed to continual high speed deceleration the 11.5
inch diameter by 0.8 inch wide vented front brakes are shown to be a weak link. The stock
brake rotors are too small, thin and retain too much heat. The heat is transferred to the
brake calipers which in turn heats the brake fluid beyond its boiling point. When the
brake fluid boils the gas bubbles in the brake lines compress and absorb the pressure
placed on it from the brake master cylinder. The brake pedal gets spongy and you
experience brake fade.
The Mandeville Autotech Big Brake
kit with 18 inch OZ Mito Modular wheels
Hot brakes can warp your rotors and Sandy Linthicum fried his front
wheel bearings after 40 hours of track time because the stock rotors got and stayed too
hot. The small brake cooling ducts in the R1 chin spoiler don't help much and a more
direct form of brake cooling would be beneficial, but nothing beats more "swept"
area for the brake rotors. Brakes work by converting the car's kinetic energy to heat and
the larger the rotor (the larger the swept area) the more rotor you have to dissipate
heat. Converting the front brakes to a larger rotor (usually 12 ¾ to 13 inches in
diameter) is the best way to prevent brake fade and damage caused by overheated brake
rotors. Larger rotors also give the calipers more leverage to work with.
Ultimate
Garage/Move It/Porsche Brembo upgrade with 17" wheels, rotors are
12.67x1.25 inches (about $2,800)
Note: An RX-7 with upgraded rotors and calipers will
not stop any shorter than stock until brake fade is encountered--as long as the stock
brakes can lock-up and activate the Anti-lock Brake System (ABS) system--the stopping distances
will remain virtually the same as stock. After repeated stops (or possibly one stop from
very high speed with race tires) an upgraded car will out perform a stock braked car.
Braking distance will immediately improve when tires with more grip are used because more
tire grip will allow more deceleration before and during skidding (ABS operation).
The bottom line is a big brake upgrade is a benefit
experienced only during track style driving, although there is always the
aesthetic benefit of large rotors behind the spokes of your wheels.
A potential downside of a brake upgrade is increased brake pedal
travel. If the big brake kit has larger (or more) brake caliper pistons than stock, more
brake fluid will have to be pushed through the brake system to move the pistons. Some
people have upgraded the brake master cylinder to the larger one from the 93 Mazda 929.
See the 929 Master
Cylinder Install How To. I upgraded my master cylinder just to get a
shorter, firmer brake pedal stroke.
The brake bias may also shift to more front brake bias because a
larger front rotor gives the caliper more "leverage" to stop the wheel. This
bias shift may be offset by the new larger caliper's requirement for more brake fluid flow
(more pedal movement). The ABS system will mask this problem by activating on the front
brakes until enough brake pressure is applied to the rear brakes to cause them to activate
the ABS too. You can install a brake proportioning valve to tweak the bias back to the
point where the front brakes lock-up just before the rears. With the Mandeville upgrade I
had to dial down the front brake pressure with a proportioning valve to prevent the front
brakes from locking up much earlier than the rears. See the Brake Proportioning Valve Install How To.
Warning
Don't install a big brake kit yourself unless you are a very
competent mechanic. A single point failure in the brake system will result in the total
loss of brakes and possible damage/injury/death! A brake shop can install a big brake
kit for you.
The Mandeville Auto Tech Big Brake Kit
I followed Sandy Linthicum's lead and decided to install the big
brake upgrade from Mandeville Autotech (Roger Mandeville, (864) 582-0038, rmandeville@mndspring.com, 350 Simuel Rd, Spartenburg, SC 29301, mail: PO Box 1867, Zip 29304). For
$995 Mandeville sent me two 13 inch diameter by 1.1 inch wide vented rotors (not 12 ¾
like most other 3rd gen upgrades) with CNC machined aluminum rotor hats, brake caliper
widening adapters, longer caliper bridge bolts, longer brake pad retaining pins, and two
brake caliper extension brackets. The kit widens the stock calipers to reach around the
wider rotor. The Mandeville kit uses the stock calipers because they are quality, light
weight aluminum units that work great with a larger rotor. The brake rotors are custom
made Coleman rotors. Replacement rotors are available from Mandeville for around $300 per
pair. You can get the rotors heat treated and cross-drilled for an additional $150. An
added benefit to the Mandeville kit is that you won't have to upgrade the master cylinder.
By modifying the stock calipers Mandeville can charge less than half
of what everyone else charges for a big brake kit. The aluminum rotor hats reduce weight
so Mandeville's rotors actually weigh less than the stock, all iron rotors. The brake
upgrade works great. I did have to dial down the front brake pressure using the
proportioning valve but the brakes just don't fade. You can always send your calipers in to Mandeville and
he'll do the mod. The kit does requires 17 inch or larger wheels and doesn't include
stainless steel brake lines. See the
Brake Line Install How To.
The Mandeville Autotech Big Brake
Kit (with painted stock calipers)
[I will enclose info specific to the Mandeville kit in
brackets.]
What's needed for the install
Hammer type impact screwdriver with large Phillips head bit (a must-have), ½ inch
breaker bar for high torque bolts, large and small torque wrenches, 8mm wrench and a 10 mm
flare nut wrench (you'll round off the fittings if you try to use a normal 10mm
wrench--it's a good $10 investment), 14mm and 17mm sockets [Mandeville kit: 10mm and 8mm
(big) Allen sockets, tin snips and grinder or power sander.]
How to install a big brake kit
Jack the car and remove the front wheels, it's best to raise the
entire front end because you will have to bleed both sides after the install anyway. Turn
the steering wheel to make access to the caliper easier. It's a good idea to disassemble
one brake at a time so you can reference the other caliper when you're putting the caliper
and brake pads back together.
Remove the brake pads by removing the brake pin M clip and then
sliding out the retaining pins (hold the M springs while you slide out the pins or they
may pop out). You may have to spread the pads a little to loosen them enough to slide them
out of the caliper. A pair of needle nose pliers works pretty good as a spreader.
Warning Do not touch the brake pedal while the pads are out.
Put down some newspaper to catch the brake fluid. Use a 12mm wrench
to disconnect the brake line at the caliper (where the brake line meets the caliper's hard
brake pipe) and plug the brake line. I used a small rubber vacuum hose plug.
Widening the calipers for the Mandeville Kit
[If you don't plug the line all the brake fluid will drain from the
system when you split the calipers. Trust me on this one. Remove the caliper's four 14mm
bridge bolts and split the caliper. I had to use a ½ inch breaker bar to loosen the
bolts. Watch for the rubber ring seals that are sandwiched between the caliper halves.
Install the new rubber seal rings into the circular groove cut in the caliper widening
spacers and install the two spacers with the ring seal placed against the caliper half
still mounted to the car. Use the new longer bridge bolts to secure the caliper halves and
spacers. Make sure all four (two stock, two new) rubber seal rings stay in place while you
bolt the caliper halves back together. Torque the caliper bridge bolts to 35 foot pounds]
Caliper spacers and longer bridge
bolts for the Mandeville install (stock rotors have not been removed
yet)
[Mandeville big brake kit specific instructions are in brackets]
Remove the two large 17mm bolts that hold the caliper to its mount
and remove the caliper (or hang it with safety wire or a bungee in place from the coil
spring). I had to use a ½ inch breaker bar to loosen the bolts. Don't mistake the
caliper's four 14mm bridge bolts for the two caliper mount bolts. The RX-7 Workshop
Manual cautions you against loosening the bridge bolts. You will see two large
Phillips head screws and one empty hole in the brake rotors (you'll use the empty hole to
brake the disks lose). Use an impact screwdriver with a large Phillips head bit to remove
the two rotor screws. You will have to use an impact wrench, there is no way these screws
are coming out with a normal screwdriver. After you get the screws out put one of them in
the empty hole and drive it in using the impact wrench. This will break the rotor loose
and allow its removal.
[The brake rotor air guide needs to be modified or removed so it
will clear the top and bottom of the new rotors. I trimmed off about1/4 inch on the top
flange and removed the bottom flange completely using tin snips. Just slide on the new
rotors and you'll see what you have to remove (see photo above). You can ditch the thin
metal shim that went between the caliper and caliper mount. The caliper mounts have to be
slightly modified to fit. See the caliper modification diagram below to see what to grind
or sand off. I tried a die grinder but I got much better results using 6 inch circular 60
grit sandpaper with my electric drill. Just keep grinding until the caliper extension
brackets and calipers fit. Mount the supplied caliper extension bracket using the supplied
Allen head bolts and torque them to 58-72 foot pounds. Slide on the new rotors and then
mount the caliper to the caliper bracket and torque it to 58-72 foot lbs.]
Caliper and caliper mount
modifications for Mandeville kit
Reverse the removal instructions above to install the new rotors.
[The Mandeville rotors do not use the Phillips head screws.]
Torque the Phillips head screws to 87-130 inch
pounds (8-11 foot lbs) and the caliper mount bolts to 58-72 foot lbs. Install the brake
pads, [new longer] retaining pins, M springs and pin retaining M clip. Reconnect the brake
line and torque it to 113 to 190 inch pounds (10 to 15 foot pounds).
Bleed the brakes thoroughly. See the Bleed Brakes How To. If you
followed my advice and plugged the brake line you should have a minimum of air in the
brake lines and you shouldn't have to bleed the rear brakes.
Make sure you have a firm brake pedal and apply brake pedal pressure
for about 30 seconds to check for any fluid leaks at the brake lines and calipers. Test
the brakes carefully before trying them at speed. Take it easy on the brakes for
a while to allow the pads/rotors to bed in.
I installed Hawk HP+ pads in the front and I didn't like the way they grabbed
and dusted. I put the stock pads back in and like it better. The Hawk HPS would
probably be a good pad to use all around with this setup.
I painted my calipers using Folia Tec brake caliper lacquer (Ultra
Performance 800-43ULTRA $49.95). Use a fresh, soft, camel hair, 1/4 inch wide paint brush
and heed the temperature range for applying the paint.
Enjoy your new brakes.
Rob Robinette
Other Big Brake Kits
By Sean Higdon
M2 / AP RACING
13" Front Brake Package
Calipers, mounts, rotors, lines, pads (very good
reviews) $2795
The AP racing was not available from Stillen even though they sell it for
other cars.
Brembo (Porsche - Move-It)
From the Ultimate
Garage
$2795
http://www.ultimategarage.com/bbmazda.html
From the site it looks like the Porsche-Brembo's are modified (i.e. bigger
bolts 12mm instead of 8mm)
Sean Higdon
More Big Brake Kit Info
By Wael
You might want to consider the Mandeville brake kit, it's inexpensive
but it does not increase your brake pad surface (actually you lose a tiny bit),
but it does increase the size of the rotors to 13" so they are able to
handle more heat [and the swept area is greatly increased]. Roger uses
the stock calipers, rebuilds them, adds a spacer in the middle and sends you
13" Coleman rotors with aluminum hats, bolts are drilled and safety wired.
Cost runs about $1100, you can tell him to powdercoat the calipers any color
which will age better than paint (most get them powdercoated red but feel free
to be creative:).
I bought the Mandeville kit but never installed it, sold it to Dana Salb
once I caught wind of M2's (Mostly Mazda) kit. Tony D. just installed his
Mandeville kit this week and it took no time to install (KD Rotary installed
it). They clear most 17" wheels but like all big brake kits you will have
to either remove the backing plate of snip the top lip off. I went with the M2
AP kit, it is top notch. Brian uses the CP5200 caliper (go to http://www.apracing.co.uk
) with Champ Car rotors (13") pre-bedded. The pad surface is increased by
exactly 200% over stock and are also exactly 200% thicker. Using AP calipers has
a big advantage over the Mandeville (which is excellent value for the money BTW)
in pad selection. With stock style calipers you are really limited to Hawk pads,
with AP a whole big selection opens up.
I have not installed the Movit (Porsche-Brembo) brake kit but another member
had them, and we weighed them, the calipers were about 9lbs, rotors 25lbs,
the AP Racing were 6lbs calipers, 13lbs rotors [remember we're talking
unsprung weight here]. Mandeville were the same as stock, can't remember
the caliper weight, but I remember the rotors were 15lbs. M2's rotors of
course are top notch, they don't rust easily like the Coleman rotors on the
Mandeville but the M2 kit is much pricier of course. Overall I am extremely
happy with the M2 AP-Racing kit, I know at least 4 other members on the list
running the M2 kit. Brian also gives you the option to upgrade to 6 pot AP
calipers for about $200/side or so.
But to get this out of the way, as most know I am biased towards M2, as most
of us are in someway with a vendor, we all have out baggage so keep that in
mind. I actually have fierce loyalty to certain tuners and vendors.
I am sorry I have no experience with the Stillen-Brembo kit, I am sure it's
good too, but check on pad selection and
rotor replacement pricing when making your decision, as well as
turnaround time. I can't wait until Movit offer the new ceramic rotors (you just
know they're comming :) It should keep the market on it's toes...good luck and
hope my response helps you in some way.
Wael
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