This was sent to a reader in reply to a request for a procedure. I am stuck
in a hotel in Cleveland, with way too much time on my hands. Sidewalks are
already folded up here, so this one gets the 'special' treatment. This
procedure applies to pre-'95 cars for sure, and may cover the later models.
Be sure you read this whole procedure and understand it completely before
you begin so that you will have all the necessary parts/tools/grease at
hand. Here goes....
First of all, you will do well to get a book to help guide you. Absent the
book, here's the procedure:
You'll need to get the car on stands and take the two front wheels off.
You may find it easier to loosen the lug nuts a little before you lift them
clear of the ground. Be sure to use stands rather than depending on blocks
or the jack to hold the car up.
The brake calipers are held in place by a pair of pins that have a
rubber center section sandwiched by two metal pieces. Take note of the
installed position, with a larger flat side. You'll need to put the pins
back with this larger flat side in the fatter part of the groove in the
caliper-to-knuckle joint. Anyway, you can remove the pins with a hammer and
a fat drift. Just tap on the metal parts, squeezing them as you tap them so
that those little tangs are pushed past the edges of the cast parts. Go
ahead and get them completely out.
With the pins out, you can lift the caliper off. You may need to
compress the piston a bit to get the pads past any ridges on the rotor.
It's OK to use a screwdriver on the pads, but DO NOT PUSH OR PRY DIRECTLY
ON THE CALIPER PISTON. It is a ceramic part, and you will break it. Once
the pads are retracted slightly, you can lift the caliper free. Free the
inner pad from the grooves in the steering knuckle, noting the position of
the anti-rattle clip on the inner pad. You'll need to install this on your
new pad. The outer pad is held to the caliper with those two spring clips.
Pry up a little on the clips while you pull the pad free of the caliper.
It's important to remember that the hose is fragile. Make sure that the
caliper never hangs from the hose, and that you don't pull on the caliper
while freeing the pads. A piece of coat-hanger wire should be used to tie
the caliper to the spring, out of the way.
Once the wheels and calipers are off, the auto hub is held on by some
speed nuts. These are push-on goodies that keep everything together when
the wheel is off. You can carefully pry on them with a couple of
screwdrivers, then turn them to unscrew them once you are back off of the
hub just a bit. This can be a bit of a chore, but resist the urge to pry on
them and bend the tangs the wrong way. It turns out to be more work in the
end.
With the 3 speed nuts off, the auto-locking hub should come off easily.
A gentle pull should get it completely free of the rotor and the splined
stub axle. Inside the hub should be relatively clean and free of grease and
crud. Using a paper towel or a sacrificial rag, wipe the inside to get any
grease that may have migrated down in there from the wheel bearings. My own
procedure is to put a couple inches of ATF, or in my case some synthetic
gear oil, into the hub. Let that stuff soak in while you do the rest of the
procedure. Put the hubs out of the way so they don't get knocked over or
have dirt spilled into them.
There's a retainer ring holding the plastic engagement cam assembly on
the bearing adjustment nut. It fits in a groove in the stub axle. Push it
out with a screwdriver, and put it in a parts tray so it doesn't get lost.
Be careful not to hit the plastic cams with anything that might break them.
With the retainer clip removed, you can now pull gently on the cam
assembly to remove it. Before you pull on it, note how the two halves line
up, with the little wedge sections centered in the gaps in the other half.
You'll need to be able to put the cam sections back in the same relative
positions so you can get the hub back on. Put the cam in the parts tray so
it doesn't get lost or broken.
The next thing to come off is the indexing key for the bearing nut.
This is a small goodie that slides in that groove on the spindle, and
indexes in one of the round relief grooves inside the nut. The key is about
8mm wide, maybe 15mm long, and is in that groove in the spindle. It tends
to get stuck in there, wedged by the pressure of the bearing nut trying to
turn. To unwedge it, put your wheel bearing socket over the nut, and turn
the nut gently towards the back of the car just a slight bit. Feel for the
total amount of play in the nut and the key, and try to center the nut's
position on the key.
Ford shows a guy fishing that darn thing out with a small magnet. I have
had absolutely no luck with their method, and instead use a dentist's pick
with a small hook at the end. I can reach just under the outside edge, and
pull the key out. This takes a bit of patience. Once the key is out, make
sure it ends up in the tray. Then take your socket and unscrew the bearing
nut. Do not even think of trying to get that nut off before the key is out.
With the nut off, you can now pull a little on the rotor, freeing up
the outer wheel bearing. It needs to be cleaned and re-packed with grease,
so drop it in a plastic cup with some solvent in it. I use paint thinner
from the hardware store, and a L. A. Rams beer cup.
Once the rotor is off, you'll want to pull that inner bearing, and the
seal. From the outside face, a longer drift or punch will push on the cone
of the bearing. This drives the cone out the back, pushing the seal out
ahead of it. Seal goes to the tray, bearing goes in the solvent. Keep the
bearings separate so you can mate the same cup in with the same cone on
assembly.
Get as much grease out of the rotor as you can. You'll put new grease in
there after the rotor is machined. A little of that solvent and a rag will
do wonders.
By now, you have the makings of a brake job lying on the floor. Rotors
go to the machine shop to get trued, pads and seals get a ride to the parts
store for replacement. While the rotor is being turned, clean and inspect
the bearings for scraping, galling, wear, discoloration, etc. Any suspect
parts should be replaced, along with its mate. That means that if a bearing
cone is renewed, its mating cup in the rotor must be replaced also.
Pack the bearings carefully with the correct grease. Ford recommends
grease that's normally used in extreme pressure duty in CV joints. When the
rotors are back, install the packed bearings in the rear of the rotors, and
put in new wheel seals. Once the seals are in securely, fill the area
between the bearing and the seal with grease. Now the rotor goes on the
spindle, and the inside of the rotor should be filled a bit with grease
also before installing the outer bearing.
The retainer nut goes on after the outer bearing, and holds the whole
works together. Ford recommends that the nut be tightened firmly to 'seat'
the bearings, turn the rotors a few revolutions, then back off of the
tension. Re-torque the nut to 15 inch-pounds, and install the key. If the
slot for the key doesn't line up, move the nut slightly until it does. It
is important that the bearings be installed with the correct torque and
pre-load, so that they are not burned up from being over-tightened. 15 inch
pounds are a casual turn on the socket with no handle on it-- just your
hand turning it.
The cam goes back on next. This is a bit of a chore, since you need to
line up the tang in the bore of the cam with the key slot in the spindle.
Push the cam on so that those friction pads slide up on the machined
shoulder of the bearing retainer nut. Resist the urge to remove or adjust
or stretch or even look funny at those garter springs in the cam assembly.
Have patience, and work carefully to avoid damage to the plastic cams or
the pads or the springs. Here's a tip from Tom Scanlan about getting that
cam back on. Tom has found that a short piece of 1-1/2" PVC pipe makes it
easy. The inner dimension nearly matches the cam diameter, and the PVC pipe
makes it possible to push evenly around the cam without deforming it. An
easy push with my palm and the spring loaded cam pops onto the shaft.
Once the cam is installed and pushed back tight, reinstall the retainer
clip in the groove in the stub axle. You may need to pull a bit on that
stub axle to get the groove exposed to where the ring will slide on. Be
careful when you tap on this to seat it-- don't hit the plastic cams!
The hub has been soaking a while now, so carefully drain out the ATF or
gear oil from the hub, and slide it on the stub axle splines and the
spindle. Those long fingers inside the hub must line up with the gaps next
to the wedges on the plastic engagement cam. If the cam is installed
correctly, then turned so that the two halves are lined up like they were
in step 7 above, you'll be able to slide the hub on easily until the back
face mates against the face of the rotor. If it sticks and won't slide on
easily, don't force it-- just pull it off and try again.
Once the hub is up tight against the rotor, put those 3 flat speed nuts
back on to keep the hub in place.
Install the inner brake pad in the steering knuckle, with the spring
anti-rattle clip in the groove where it was before. It helps if you clean
the rust and crud out of the groove where the pad sits. A very thin film of
waterproof grease in these areas will prolong pad life.
Before you install the outer pad in the caliper, take a few seconds to
compress the piston in the caliper. Use a c-clamp, and squeeze the piston
back in using the old inner pad to protect that ceramic piston from the
clamp. Be careful not to damage the boot that seals the outer edge of the
piston.
Snap the outer pad into the caliper, making sure that the spring clips
are fully engaged, and seated in their recesses in the caliper casting.
Be sure all the rust and crud is out of the areas where the calipers
slide in the knuckle, and also where those rubber-and-metal pins sit. A
thin coating of waterproof grease will keep things working smoothly. Slip
the caliper over the rotor and the inner pad, and get it lined up with the
grooves for the pins. A thin film of that wonderful waterproof grease on
the pins will keep them sliding smoothly. Install them, noting their
positions from when you took them out. Be sure they are tapped in securely,
and that the little tabs are engaged so they won't slide out.
With both calipers installed, seat the pads on the rotors by gently
pushing on the pedal with the engine off. Don' press more than about half
way down on the pedal so that there is no risk of damage to the master
cylinder. Just do it a few time until the pedal comes up nice and hard.
Check for leaks, leftover parts, etc. Remedy as necessary.
Put the wheels back on, and snug them up securely. Put the car back
down until the wheels are touching the ground, then torque the wheels nuts
progressively and sequentially until you get to 100 ft/lbs. Then lower the
car the rest of the way, install the caps or wheel covers, and road test
the car carefully. BE SURE that there is a good pedal height before you
take the car out of park.
Some things to think about:
You'll need new wheel seals during this procedure so get them before
you start.
There's a list of other services to be done that are quite convenient
to take care of while you have the rotors off. The needle bearings inside
the spindle need to be greased, and the right front driveshaft splines need
a bit too. The u-joints in the front need to be checked/replaced as
necessary.
Dirt and grease are the enemy of brakes. Keep grease and stuff off of
the rotors. Do not handle the pads with greasy hands. Use a good spray
brake cleaner to get all the grease and fingerprints off the rotor before
installing the pads.
Those caliper slides are on the 7500-mile service schedule for grease.
Penalty for ignoring this is warped rotors and abbreviated brake life.
Replace the rear shoes when you do the front pads. Old rears may look
fine, but they force the front to do much more of the work. The fronts are
already too small, so anything the rears can do is a help. Shoes are cheap,
you are going to the same brake parts store, and your hands and tools are
already out.
Besides the little hook pick (dental pick) to get that little key out,
you'll need a socket for the bearing nut. This is a 2 3/8" tool, with
rounded corners for the nut. Mine is made by OTC, and should be available
at a better parts place. There shouldn't be any other really special tools
to get. A can of brake-clean will help, and you'll need that grease for the
bearings.
The brake fluid should be changed every two years or better. If your
fluid is discolored to red or brown, that's rust from moisture in the
fluid. Get some new stuff in there to try and stop the damage. Moisture and
the rust in the fluid damage cylinders, calipers, ABS parts, and the steel
brake lines-- all of them. If you have a manual transmission, change the
hydraulic clutch fluid too.
Brakes are one of the most financially rewarding do-it-yourself tasks, but
there is also a large risk you are assuming. A lot of the cost of the
service is liability insurance for the brake shop. In spite their best
efforts, things happen. And there isn't much forgiveness. If you make a
mistake, you may not notice it until you really need the brakes to work in
a jam.
Perhaps you are already a fair mechanic, and you feel comfortable with the
task. Perhaps you have a neighbor or friend who is in a position to help
or advise if you get in a bind. Just take your time, be extra careful, and
have patience.
As always, the directions and advice given here are without warranty of
any kind. This is free advice, offered at that face value. If you are not
familiar or comfortable working on this critical safety system, have it
done professionally.
Contributed by Jeff Mellon
Thanks for the info presented. I just followed this drbob procedure on my
'93 with 4WD. I also used the Haynes book. A couple of hopefully helpful
comments on this 23 step guide:
Step 6. Ford put in upgraded cam assembly while under warranty. Mine is
not like the Haynes book or as described. My cam has the split nylon ring
with garter spring -- but the rest of the assembly appears to be cast zinc
alloy. No plastic washers either.
Step 9. This is the procedure that really hurt me. After reading this
seal removal procedure, I whopped the heck out of the inboard bearing race.
I couldn't drive the seal out by tapping on any part of the bearing assy.
I then did what Haynes recommended: Use a long skinny screwdriver slid in
to the side of the bearing till in contact with the seal. Hit screwdriver
and seal pops right out.
Step 10. I think it's important to state that the bearing cones must be
pressed in/out by a shop --- so no yahoo like me starts trying to knock it
out with a screwdriver and hammer. Also, Ford used an adhesive to further
secure the seal. I may use a little RTV silicone there. Also, no mention
is made of lubrication of the cam assy. Haynes does not mention it per se,
but in their lubrication specification section they say that the hub assy.
is lubed with bearing grease. Neither of these sources mention how much
grease to use. Step 5 suggests that very little grease should be seen in
the hub itself. I will go ahead and lightly grease the cam assy. I used
synthetic ATF on the hubs per the guide -- seems good.
Step 14. The axle spacer washer was omitted here and also not mentioned in
step 7. This special washer goes behind the clip.
And then, in the "Some things to think about" section, I'd recommend that
new hub "O" rings be added to the buy-list. Also in this section mention
is made of the need to lube the driveshaft splines (right side per owner's
manual). The Haynes book procedure entails major disassembly of the front
end for this task!!! I see no "tricks" for this job on the Explorer page.
And the spindle bearings -- how to get grease to them doesn't even appear
in Haynes as far as I can tell.
