Wrenching
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5SFE Rebuild
TRD Sway Bar
Strut Inserts
Crash Bolts
ABS Install
Alignment Tool
Adding Factory ABS to your MR2
--prints best in landscape--
Knuckles | Sensors | Axles
| Hydraulics | ECU | Testing
| Autocrossing
Front trunk parts locator
image (cool and dynamic!)
PARTS
LIST (whooohooo!)
What am I getting into?
The hardest part of this whole operation is tracking down the parts needed
to do the conversion. Assuming you've got all the parts, it's probably
possible to do all the work in a day, though I'd recommend setting aside
two or more. Unfortunately I didn't take any photos during the project
and it's been about 9 months since I did it, so everything is from memory.
Here's a complete parts
list along with part numbers and what other years and models the
parts can be pillaged from. All parts and instructions are for a '93
NA MR2. Other years and turbo cars will have some part discrepencies
but the install should be nearly identical.
Depending on how many parts you manage to find used, the parts themselves
will probably run between $1,000 and $2,000. Though I bought all my parts
individually, the most efficient way seems to be to buy a parts car or
a good ABS-equipped car where you can do a complete swap and sell the
second car complete, without ABS. Certain parts (axles, actuator, proportioning
valve) seem to be hard to find and may have to be purchased new. If you
autocross and aren't signed up with Toyota
Motorsports Contingency do it! You get factory parts for about half
price! Most of the work can be performed at home in the garage. An impact
gun is very helpful, and a shop press is needed to press bearings and
hubs. A factory shop manual is also highly recommended. I will refer to
it when applicable to save time and space here.
Knuckles and Carriers
There are a few things to look out for here. P/S and non-P/S front knuckles
are different part numbers. I'm assuming one has a longer or shorter throw
than the other, but I never checked. Turbo knuckles (front) and carriers
(rear) will work, but if pillaging the whole unit from a parts car, the
rotor dust shields are different and the rear hubs are different. In order
to swap the dust shields the hubs have to be removed, this means pressing
them out which you need to do anyway to swap them. All you need from the
front knuckles are the knuckles themselves, sensors and the ABS spindle
inside the knuckle. If it wasn't for the dust shields you could just swap
the whole knuckle assembly. The rear hubs themselves don't vary w/ABS,
so you can use the ones that came off your car. While you're at it I'd
recommend replacing all (4) wheel bearings. All knuckle and carrier removal
instructions are in the repair manual. Removing knuckles and carriers
will effect alignment. Have your car re-aligned after completing the conversion.
Sensors
Hopefully you've pillaged the knuckles and carriers from a parts car and
they already have the sensors in them. If you're VERY careful I'd recommend
leaving the sensors in while pressing the bearings and hubs. The sensors
can break very easily when removed since they most likely haven't been
touched in 10 years. Certain cars (very few, but we've found some) aren't
pre-wired for ABS, specifically the super-stripper models. The pre-wired
plugs should be taped up in the front, on either side of the spare tire
bin below the strut tower (see image),
and in the rear, one near the fuse box and the other on the cruise control
harness. All four plugs should look identical. The sensors should be more
or less plug and play. You'll need to remove the 4 rubber plugs where
they enter the engine/luggage bays and attach the wire holders to the
inside of the wheel wells (the rears look a little funny but the wire
should be pre-bent to help guide you). Here's a photo, the sensor wire
is highlighted in yellow. Note how it bolts to the subframe:
Axles
Axles, well, are axles. Turbo axles are different and won't work. Make
sure the ABS ones have the ABS spindle on the outboard end, otherwise,
they are identical. I tried forever to find a spindle to just press onto
my existing axles (the part numbers are the same except for the spindle).
Even ACE, a huge rebuilder of axles, told me that they just press a spindle
on there to transform them but after much begging and pleading they wouldn't
sell me a pair of spindles. I ended up buying both axles new through Motorsports.
They took a while to get so order them early. Make sure you don't pry
the axles out of the tranny, this will bend the dust shields. Put a crow
bar or similar piece in one of the "steps" on the inboard half-shaft
and pound it out. The manual has details on axle removal. I think it can
be done w/out draining the tranny fluid if you're quick :)
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Hydraulics
Pretty much everything between the brake booster and the flex lines needs
to be replaced on the front of the car. Though I got mine used, buying
a new master cylinder would probably be a good idea. They aren't that
expensive relative to the total project cost. If you find a yard or parts
car that has the right actuator (the turbo and NA ones have different
part numbers), make sure you get everything between the master cylinder
and the actuator along with it (master cylinder, 2 hard lines, proportioning
valve w/bracket, 2 more hard lines, actuator w/3-piece mounting bracket--third
piece shares a bolt with the rear of the mounting bracket but sits underneath
the car near the steering rack). With the exception of two of the hard
lines and the mounting brackets, everything in that list is NA/turbo specific.
You will need to find the proportioning valve used, somehow, because it
apparently isn't made anymore. The actuator is quite expensive new ($1,400
list I think) so spending some time and finding a used one is worth it.
Hydraulics Removal
Start by draining the fluid out of the entire system. You do this because
you will be replacing every hard brake line ahead of the passenger compartment.
The rear hard lines remain the same. The easiest way to do this is by
opening up one caliper bleeder at a time and pumping fluid through until
air comes out, then closing the bleeder so only one is open at a time.
Once the fluid is drained you can start removing parts. Hold a rag under
hard lines as you open them so brake fluid doesn't go all over the luggage
bay, it will eat through paint. Remove the hard lines from the master
cylinder, unplug the cap plug, and remove the master cylinder from the
brake booster via the 4 nuts. The non-ABS proportioning valve sits on
the right side of the spare tire bin. Disconnect the hard lines connected
to it and remove it.
Now the hard part. Removing the driver side hard line to the LF wheel
is fairly straightforward. Removing the one that goes to the rear is also
not too bad, it connects to the rear line right at the front "firewall".
Be careful to not accidentally open up the clutch line, it's right there
as well. The hard line that goes to the passenger side wheel is another
story. It sits behind the A/C lines, behind the P/S pump, behind the clutch
line, behind the P/S control box, and happens to be one continuous line
from the prop. valve all the way to the RF wheel. Now I would say to just
cut it, but your practice in "gentle bending" when removing
it will help you "gently bend" the new one when putting it in.
I did not touch/remove the A/C line, clutch line, or P/S pump when doing
my conversion. I did remove the battery and loosen or remove most of the
stuff in the passenger side of the luggage bay. It probably took me an
hour to get the old line out and another hour to get the new one in, be
patient. Just remember to make as wide radius bends as possible and bend
the line as little as possible.
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Installing ABS Hydraulics
--click here for a
parts locator image--
The ABS brake lines to the front wheels and rear connector should install
very similarly to the old ones. The only difference is that the new ones
start where the actuator sits rather than the old prop. valve. Install
the hard lines before the actuator just so you have more room to work.
Install the three actuator mounting brackets (2 sit below the actuator
in the engine bay, the third shares the rearmost bolt with the other two
but mounts under the front tub near the steering rack). The actuator should
drop right into the brackets once they are in place. The actuator is labled
on both the inlet and outlet holes for the brake lines so you know which
slot is the RF, LF, and rear. After all of your "gentle bending"
they may not line up perfect. The actuator plugs into two or three plugs
that reside on the harness that sits right below the strut tower.
Next, install the new master cylinder and proportioning valve. The master
cylinder should be "bench bled" before installation. The factory
repair manual shows how to do this. Basically you fill it up and manually
pump the cylinder so fluid comes out the two holes. Depress the cylinder
so fluid comes out, hold a finger over each outlet creating an air tight
seal, then release the cylinder. This allows the cylinder to suck new
fluid into the chamber. Repeat a few times until no air comes out of the
holes when depressed. Another way to do this is to connect hard lines
to the outlet holes in the master with flexible hoses on the ends. Run
the hoses back up into the reservoir and just pump the master over and
over so that fluid circulates through.
The proportioning valve mounts via the bracket to the two lower studs
of the master cylinder. It may be easier to hook up the two hard lines
between the master and prop. valve before you put them on the car. Finally,
connect the two hard lines from the prop valve to the actuator. Every
new connection that you have made should be cleaned thoroughly and sprayed
with leak trace powder so you can see if there are any leaks in the lines.
Fill the master cylinder with fluid (if you have an autofill bottle fill
it up and set it on the master) and begin filling/bleeding the system.
I made at least three or four passes to bleed the system, the first one
just to fill it and not worry about bubbles. I've heard of some nightmares
about having air stuck in the lines but never had it happen myself. Driving
a car up and down some steep hills and bleeding the system again might
not be a bad idea. Here's what the completed installation looks like:
--click on image to enlarge--
Insatlling ABS ECU
Make sure you get the mounting brackets with the ECU. The best place to
get one is off another '93 NA or turbo car. I've heard the brackets aren't
produced anymore. The ECU mounts behind the glove box. The glove box is
pretty easy to get out, just a few screws under the dash and one or two
inside the glove box. Once it's removed you'll see a 1.5-2" tube
running across the car behind it (Yes! We drive tube frame cars! OK, not
really). You'll notice the brackets are contoured to fit on the tube.
Two screws mount to the tube and another to the center dash area. Find
the plugs that plug into the ECU first (only the correct ones will fit),
then bolt it up.
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Victory?
On my car all of the little resistors in the front fuse box were already
installed, as was the "ABS" light on the dash. Assuming the
sensors, actuator, and ECU are plugged in, you should be able to turn
the key to the "ON" position and have a yellow "ABS"
light shine proud on the lower left corner of the dash. Look quick because,
like the P/S light, it will only illuminate for a few seconds.
Testing
As with any brake work, you should test the new system somewhere very
safe with one hand on the e-brake in case of emergency. Drive the car
slowly and use the brakes to test their effectiveness. After some slow
speed testing you should check the brake fluid level, bleed the system
entirely again, and check all of your leak trace powder to make sure there
are no leaks. Do a couple more slow speed stops after this to confirm
proper brake operation.
Now the fun part: testing the ABS! I chose a not-crowded, wide freeway
offramp with plenty of runoff room to do this. Basically clean all the
loose crap out of the car (autocrossers should have this done already)
and find a place where you can stand on the brakes safely. If everything
is working you should hear the tires lock for a millisecond and then feel
the pedal pulsing under your foot as the ABS does it's thing. On my car
I heard a loud moaning from the actuator initially, so don't freak out
if some wierd noise comes from the front of the car. For some reason I
don't hear the noise anymore so I either got used to it or it went away.
I'm guessing whatever pump works in the actuator may have been dry in
mine and made some noise as it got itself back up to operating condition.
If the ABS doesn't kick in and the tires are definitely locking up you'll
want to do a diagnostic on the system. Similar to pulling codes with the
check engine light, the ABS light will throw a code if the system is working
improperly. This is a good thing to check even if the system appears to
be working properly. The factory manual details how to pull ABS codes
from the computer. A friend of mine ended up having a couple bad sensors
that needed to be replaced.
Autocrossing with ABS
Well worth the time and effort, you should notice one immediate advantage:
no flatspotted tires! It did take me a while to get used to the ABS system
on course, but once I did I think it helped improve my times by at least
a couple tenths, sometimes more, especially on courses where you have
a high speed section leading into a tight turn. It helped reduce my braking
distance allowing for later braking. Initially I had some trouble dealing
with turning into a corner while the ABS was engaged. At the 2002 El Toro
Pro we had a third gear section leading into a very tight turnaround in
back. I felt like I was having trouble getting the back end to break loose,
as if the front end was still locking up and washing out while the ABS
kept the rears from locking. My codriver, on the other hand, had no such
problem. I'm guessing I was coming into the corner in a straight line
with the ABS engaged and then turning in too hard/quick. Since the front
tires were already at the limit of the traction circle in a straight line,
turning them in quickly caused them to immediately break loose and lock
up, sliding sideways. The ABS probably tried to compensate for this by
basically backing the brakes off so far that I shot right past my apex.
Or maybe I just drove like crap :)
Questions and Feedback
If you have any questions feel free to email
me. I tried to make this a quick writeup rather than a step-by-step how-to.
I think the factory manual does a good job of detailing the removal/installation
of most parts for this conversion. That said, if there is anything here
that looks too vague or seems to be missing a step please let me know
and I'll go into more detail. Good luck!
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