[click to enlarge]
One of the most difficult and complex jobs you can perform on your BMW
3-Series is a clutch replacement. For that matter, replacing the
clutch is difficult on just about any car. Fortunately, you're in the
right place here, as I will guide you through the process step-by-step.
The first thing to do
is to make sure that you need to replace your clutch. On my E36 318is,
I found that the clutch was slipping and couldn't move the car at all.
At first I thought that there might have been a problem with the clutch
master or slave cylinders, but upon further inspection, I couldn't find
anything wrong. I looked underneath the car as a friend of mine
repeatedly pushed in the clutch pedal. The slave cylinder and arm was
appearing to work perfectly. That's the strange thing with clutches -
I have replaced quite a few over the years, and almost every time I take
apart the old one, I have a difficult time figuring out what caused it to
fail. Clutch components don't reveal their secrets too easily.
Anyways, there are a
bunch of steps that you need to perform prior to replacing your clutch:
With all of these tasks completed your
transmission should resemble Figure 1.
Now, move to the side
of the transmission and unbolt the slave cylinder (Figure
2). Also, disconnect the backup lamp switch (Figure
3) and detach its corresponding harness (Figure 4).
Support the transmission with your floor jack and remove the lower
transmission support bar (Figure 5). More
details on this can be found in the
Article: Replacing Transmission Mounts. Then, move your floor jack
under your transmission and support it. We will now undo the bolts
that hold the transmission to the engine.
This is where the
going gets tough. First off, the bolts are special Torx head bolts
which require special sockets in order to remove them. You need to
apply a phenomenal amount of force to remove these bolts from the
transmission - if you don't have the right tools, then you will not succeed.
external Torx socket set with sizes from E6 through E16, and you will be
covered for all of the bolts on the car (see Figure 6). These Torx
bolts are used in applications where a good grip is required, and a lot of
torque needs to be applied. The inset in Figure 7
shows two of the Torx bolts that you need to remove.
These bolts will be a
huge pain to remove. See Figure 7 for details
on the bolt locations. The ones on the side and bottom of the
transmission will be relatively easy to remove - those aren't the ones that
you need to be concerned about. The two bolts at the top of the engine
near the cylinder head are very difficult remove - especially the one at the
very top. The reason is that there is no room to easily reach these
and apply any significant amount of force. In order to remove this top
bolt, I used the following tool combination: 3/8 Torx socket, 3/8 1-ft
extension, 3/8 extension u-joint, 3/8 3-ft extension, 3/8 to 1/2 adapter,
3-ft 1/2 breaker bar. This combination of tools was the only way I
could reach the topmost bolt and remove it. I found that I could place
a smaller tool on the bolt, but then I had no leverage to remove it.
With this combination of tools, you basically need to hold the socket in
place with your fingers and have an assistant pull on the breaker bar.
Somehow I was able to use my feet to push on the breaker bar, but I really
wouldn't recommend trying that.
If that top bolt wasn't enough, the starter bolts are even more difficult.
Depending upon your year car, you may or may not have what is known as a
threaded starter. If the starter housing is threaded, then all you
need to do is remove the bolts from underneath the car. If your
starter has non-threaded holes, then you need to place a wrench on the nuts
that are on the opposite side of the bolts. This can be a near
impossible task on the six cylinder cars. In order to reach these
nuts, you will need to remove the six-cylinder intake manifold, which is a
huge project in itself. I will be writing an article on this in the
near future, so never fear. If you have a 318, the good news is that
it is possible to squeeze your hand down into the engine compartment and
reach those nuts. A photo of the nuts that you need to remove is shown
in Figure 8.
With the difficult nuts removed, it's time to pull the transmission away
from the rest of the engine. Make sure you didn't forget any more
bolts on the back side of the transmission - there's at least one that holds
on a metal shield (Figure 9). With the
transmission supported on the jack, simply pull it away from the engine.
If all of the bolts, hardware and accessories are properly disconnected, it
should simply pull away. If you forgot something (very common), go
back and double check everything. It should pull away quite easily -
don't use the grip-of-death to pull it out - you could damage something.
Work slowly and carefully at this point. Also make sure that the
transmission is well balanced on the jack - you don't want it to
accidentally fall on you. Be sure that the transmission is well
supported - don't let it hand on the center input shaft as that could cause
it to bend. Figure 10 shows the transmission
pulling out of the car. Figure 11 shows the
transmission removed from the car.
Now, you will want to remove the pressure plate (Figure
12). On this particular car, I found that some of the pressure
plates bolts (Figure 13) had problems with rounding
out when I went to remove them. If this happens, then dig out your
trusty Dremmel tool and cut them off in about 1 minute (Figure
14). Don't waste your time trying vice-grips or other foolish
methods - you can cut them off, and you don't need to worry about damaging
the pressure plate because you're going to be replacing it anyways.
When you're ready to remove the last bolt, grab the pressure plate with one
hand - it's easy for it to fall off when the last bolt is removed. The
disc should also pop out when you remove the pressure plate.
With the pressure
plate removed, you should be able to see the flywheel (Figure 15).
This particular flywheel was used on a E36 318is with air conditioning.
For some reason, the AC 318s used a dual-mass flywheel (probably to reduce
vibrations from the high compression 4-cylinder engine).
Unfortunately, this flywheel can be expensive to replace - more on this
later. The next step here is to remove the flywheel bolts. You
can use a socket and breaker bar, or simply zap them off with an impact
wrench. I used a handy electric one here (Figure
16). With the bolts removed, your flywheel should be able to be
tugged off of the crankshaft (Figure 17).
Figure 18 shows the flywheel removed from the
Let's talk for a moment about clutch kits. Figure
19 shows one of the Pelican Parts Super Clutch Kits. With the
exception of the flywheel, these kits
contain everything that you need for your clutch job:
- Pressure Plate
- Clutch Disc
- Throw out bearing
- Flywheel bolts
- Flywheel seal
- Pilot bearing
- Throw-out arm pivot & clip
- Clutch alignment tool
The dual mass
flywheel is shown up close in Figure 20. This
flywheel is two-piece and bonded together. This changes the natural
frequency of the flywheel and reduces vibrations in the engine. For
this particular car, I probably could have substituted a non-dual-mass
flywheel, as I don't use the air conditioning system very often.
Figure 21 shows the pressure plate up close along
with some new pressure plate bolts. If you damaged yours removing the
pressure plate, you will want to replace them with new factory ones.
Now, let's turn our
attention to the transmission which we removed from the car (Figure
22). Begin by removing the throw-out fork. The fork is
attached at one end with a small metal clip (Figure 23).
Remove the fork from the transmission by disconnecting the small plastic
pivot from the hole in the transmission (Figure 24).
The fork, new throw-out bearing, clip, and new pivot piece are shown in
Figure 25. Assemble the clip onto the pivot
as shown in Figure 26. Lubricate the whole
pivot piece well with some white lithium grease (Figure
Now, we'll work on the throw-out bearing guide tube. This is the
small tube that the throw-bearing rides on when the clutch is disengaged.
As the throw-out bearing slides back and forth on the tube, the have a
tendency to wear out. A new guide tube and transmission mainshaft
seal are shown in Figure 28.
Figure 29 shows the old guide tube installed on
the transmission. Remove the bolts that hold the guide tube to the
transmission (Figure 30). Remove the guide
tube, and underneath you will find the mainshaft seal. Using a small
screwdriver, punch a small hole in one of the indents in the surface of
the seal, and pick out the old seal (Figure 31)
and remove it (Figure 32). Clean out the
inside of the bore where the seal fits (Figure 33),
and install the new one. Tap it in lightly with the end of an
extension, taking care to make sure it doesn't go in cocked (Figure
34). Figure 35 shows the new seal
installed, flush with the flange. Now install the new throw-out
bearing guide tube (Figure 36), and apply a
liberal coat of white lithium grease (Figure 37).
Now, take the new throw-out bearing (Figure 38),
place it on the throw-out arm, and attach the arm to the transmission (Figure
39). Your throw-out arm is now ready for assembly back into the
car. You might also want to clean up the input spline with a wire
brush at this time.
your back-up lamp switch is giving you trouble, now is the perfect time to
replace it. Figure 40 shows the hole in the
transmission where the switch goes. Figure 41
shows the new switch. Figure 42 shows the
new switch installed in the side of the transmission. Pretty easy.
Use a new sealing ring on the switch when you install it.
Now would also be
an excellent time to replace your starter, if you've been having problems
with it. Access is very easy at this point - the removal process is
somewhat difficult later on. The starter is easily accessed, as
shown in Figure 43. The only difficulty is
disconnecting the wires from the opposite end. Before you even go
near the starter, verify that the battery is disconnected - the starter
has live voltage from the battery going to it at all times!
Now, it's time to
turn our attention back to the flywheel end of the engine (Figure
44). We'll now replace the flywheel pilot bearing and the
flywheel seal (Figure 45). The pilot bearing
holds the transmission input shaft in place and aligns the transmission up
with the crankshaft. To remove the flywheel pilot bearing, you may
need a bearing puller (Figure 46). Place the
puller inside the bearing and use a socket on the puller tool to slowly
remove the bearing out of the crankshaft (Figure 47).
On my 318is, I used the bearing puller, only to find out that I could have
reached in there with my pinky finger and pulled the bearing out.
Try pulling it out by hand before you resort to using the puller.
The new bearing should fit easily inside the hole in the crankshaft.
Use a deep socket to evenly tap in the bearing (Figure
Now, using a screwdriver, puncture and remove the flywheel seal (Figure
49 and Figure 50). Be careful not to
damage any of the side surfaces where the seal mates to the engine case.
Take your new seal and coat it with a light touch of Curil-T (Figure
51). Then install it onto the engine, taping lightly around the
edge with the end of a 3/8 extension (Figure 52).
Tap lightly and carefully - make sure that the seal doesn't become cocked
in its bore. The installed seal is shown in
Figure 53. Clean up the left over sealant as shown in
Now we're ready to reinstall the flywheel onto the engine (Figure
55). Always use new flywheel bolts, and have your flywheel
resurfaced at a machine shop if you are planning on reusing it.
Install the new flywheel onto the engine (Figure 56).
Install the new flywheel bolts and torque them down (Figure
57). You must use a torque wrench and a flywheel lock to tighten
the flywheel. I use a simple flywheel lock that is basically a strip
of metal with two large slots in it. This allows you to attach the
lock to a bolt affixed to the engine case, and one affixed to the
flywheel, where the pressure plate bolts normally mount. This
inexpensive lock works great on almost any car (Figure
58). With the lock in place, torque the bolts (Figure
59). Figure 60 shows the flywheel
installed with all the bolts properly tightened to the proper torque.
With the flywheel
mounted, now take your clutch alignment tool and place it in the center of
the pilot bearing. Install the clutch disc (Figure
61). Then install the pressure plate onto the flywheel,
compressing the clutch disc (Figure 62). Use
new pressure plate bolts if you damaged them when you removed the old
pressure plate. When the pressure plate is tightened down to its
proper torque, remove the alignment tool. The disc, pilot bearing
and pressure plate should all be aligned, as shown in
Balancing the transmission on your jack, mate it back up with the engine.
Be careful not to let the transmission mainshaft support any of the weight
of the transmission - keep it balanced well on your floor jack. You
may have to play around with the height and rotation of the transmission
to get it to line up well with the engine (Figure 64).
Once you have everything aligned, reattach all of the Torx bolts that you
removed (Figure 65 and Figure
66). Remember to use a wrench on the nuts in the engine
compartment if your starter isn't threaded through (Figure
Reattach your slave cylinder, the backup lamp switch, the driveshaft, and
the exhaust. At this time, I also recommend that you bleed your
clutch system (Figure 68 and
Figure 69). See the
Technical Article on Bleeding Brakes for more details.
Hmm, I wish I could say this was an easy job, but it's
not. It's not impossible, but there's a lot of stuff to remove and a
lot of tricky spots. However, with the 70+ photos provided here, you
should have a good chance of success! If you would like to see more technical articles like this one,
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Matt McCabe adds:
There are two pieces of information I learned
from this adventure that may be worthy of inclusion in your article:
On my car, there is an alignment
pin at the top of the starter housing. This may be a feature of the
non-threaded variety to ensure proper alignment. This was slightly corroded
and did not fit nicely back into the corresponding hole in the bell housing
without a fair amount of polishing of the pin & hole to remove the
corrosion. This is something that deserves attention since it has to fit
nicely or you will bend your starter mounting bracket and ruin your
Praise be to the BMW engineers,
because there is a hole in the 6 cylinder intake manifold that allows access
to the top nut on the starter housing. It is actually a hole in the plastic
webbing between the tubes for cylinders 5 & 6 (or 1 & 2?). With a carefully
placed box wrench, you can get to the top nut on the back of the starter
housing. I only discovered this & realized what it was while cleaning my
manifold before re-installation. I found the attached photo online that
clearly illustrates the hole Iím describing:
Anyway, I hope this
information is helpful to other DIYers out there, and I truly appreciate you
sharing your vast knowledge via the Pelican Parts site!