2005 Mustang GT Under
Drive pulley Installation Instructions
instructions are for installing a set of MotoBlue
Underdrive pulleys on a
2005 For Mustang GT, but these instructions may be applicable for other
Before you start, make sure you have all the necessary tools, rent them
have to. My local Auto zone has a loan a tool program and they lent me
what I needed except for the power tools.
Quick inventory first. The MotoBlue
kit comes with an
idler pulley, a bolt for the idler, the water pump pulley and the
pulley. During the install you will reuse the 4 original 10 mm bolts
water pump pulley and the 18 mm crankshaft pulley bolt. Other
systems may not include the idler pulley. Steeda does not.
Get a paper and pencil and draw out all of the pulleys and how the belt
around them. Believe me you will need this. I did not do it and had a
tough time trying to figure out how to put the #$$%%% belt back
I recently found the following diagram that shows the propper belt
2) 5" or smaller impact wrench gun (an impact ratchet does not have
power for the crankshaft bolt)
3) 10 MM socket, 18 MM impact socket and 24 MM socket
4) 1/2" ratchet
5) Harmonic balancer install kit. ; OEM Part Number
27144 or equivalent
(shown on left in picture below
6) Harmonic balancer puller - OEM Part Number 27139 or
(shown on right in picture below.
7) Large Rubber band
8) Dremmel tool with metal cut off wheel or smaller bolt for
bracket (see step 11 below)
9) two adjustable wrenches
I could not find any instructions for the MotoBlue
pulleys but I was able to reference some Steeda
instructions. Though the pulleys might be different, the procedure is
Here are the steps for the removal/installation:
1) The Steeda instructions say to disconnect the
battery but I don't see the need for it, I'm not going to be touching
2) Remove your air cleaner tubes. This will give you more
clearance. Othesr have recommended removing the radiator fan
involves draining the Antifreeze reservoir and the Power Steering
reservoir and removing them first. I did not see the need for
this. The clearance
is tight, but sufficient to complete the job.
3) Loosen ALL of the bolts BEFORE removing the
belt. I made the mistake
of removing the belt first and then all of the pulleys turned freely.
bolts on the water pump are 10mm. The bolt on the crank shaft is 18 MM.
have said you can remove it with an impact ratchet but I wasn't able
impact ratchets are only rated for 40-60 Ft-lbs of Torque. I
tried a very
long torque wrench on the crankshaft bolt and it had over 120 Ft-lbs on
tried getting a long pipe to fit over the end of the torque wrench for
leverage, but that did not work either. I wound up having to go to
buy their smallest impact gun. It only measured 5" and it was just
enough to fit.
4)Make sure the torque gun is set to
counterclockwise. This new gun I was using had a little push button to
the direction and the fit was so tight that the button kept getting
and the bolt kept getting tightened instead of loosened. Also, make
air compressor is set at the maximum rating for the gun (mine was 90lbs
set the compressor to 100) and that the compressor stays on . My
compressor blew a circuit
breaker and just kept
emptying. I didn't realize it did not have enough air for the gun until
was almost empty.
5) Verify your belt orientation picture is correct and remove the belt.
To remove the belt, use a 1/2 ratchet and insert it into the square
on the tensioner pulley (this is the idler pulley with the long
arm) and push down on it. After removing the belt, remove the pulley on
the water pump. Don't put the new one on yet, this way you'll have more
room to work. Screw the waterpump bolts back into the water
pump so you won't loose the bolts.
6) Remove the old idler pulley and bolt. You wont' need the old bolt,
using the new one. Install the new idler pulley. It works great, much
friction then the stock pulley. The pulley goes on with the C clip
towards you. If you put it on the other way, the pulley binds up
engine. Once you have the pulley installed, tighten it with the bolt
provide you. The washer on the stock bolt is much too large and will
the pulley. When you're all done tightening the idler pulley, it should
7) Remove the crank pulley. Make sure you use the right tool. The first
time, Autozone gave me
a pulley puller and it was not big enough.
You need a harmonic balancer removal tool. There are 2 types. The first
flat piece of metal with three long slots. There are long bolts that
these slots and screw into the crank shaft pulley. Then there is a very
bolt that screws in the middle. The other type has three claws that fit
the crank pulley. There is a pin (use the shorter one) that goes inside
crank shaft and then a long screw that screws through the claw and
pulley out. The MotoBlue crank shaft pulley takes the
first type but the one in the car takes the second. This claw puller is
very difficult to use, the claws keep slipping. I worked on this for
hours before I thought of putting a rubber band around the jaws to keep
This worked like a charm. Use a 24 MM socket to tighten the bolt on the
The following picture shows how the puller fits around the
It’s impossible to see this on the car but by seeing the
you should get a better idea of how the tool fits on the crankshaft.
8) Boil the new crankshaft pulley for about 10 minutes, not much
idea here is that the heat will make the pulley expand and thus make it
to install. While it is boiling, put some grease on the crank shaft to
pulley go on. Not too much, keep it clean. Using ultra black gasket
a dab in the notch key area of the underdrive
so when you install it no oil can get out.
The pictures below show the old and new crank shaft pulleys.
much smaller the new underdrive
pulley on the right
the new water pump pulley (on the right) is much
larger then the original:
the crank shaft
pulley lining up the key notches. You'll need a good set of gloves so
burn your hands. Use a harmonic balancer install tool to "press" the
new pulley onto the crank shaft nice and even. You will need
to use the
M12x1.5 mm adaptor on the tool. The picture below show how
the tool is
put together. Install the adaptor onto tool.
Install the bearing
and then the nut as shown below.
the tool is quite simple. Screw the tool onto the
crankshaft and tichten
the nut as much as possible by
hand. Then, just hold the end of the tool with a wrench and
wrench to tighten the large nut.
10) An alternate method of installing the crankshaft pulley is
recommended by Steeda.
They recommend the torque turn method. Steeda
claims it is more accurate. The torque turn method
measures how much the bolt is stretched which is really what is
Friction from the bolt head and washer is a factor which leads to
torque of a fastener. Use the original 18 MM bolt and tighten as
Torque to 67lb-ft. this
step seats the balancer
Loosen half turn. this step relieves all stress on the bolt
Torque to 37lb-ft , this step pre-torques the bolt before bolt to
friction becomes an issue
Tighten an addition 90 degrees, the fourth step stretches the bolt to
11) install the water pump pulley using the original bolts. Finally,
your belt using the diagram you drew. Make sure the belt sits properly
of the pulleys. Note that there is a bolt coming out of the
alternator bracket on the left side of the engine that interferes with
the MotoBlue water pump
pulley. Make sure that there is
sufficient clearance between this bolt and the Water Pump pulley and
belt. I did not notice this at first and it destroyed the
belt when the
engine started. To solve this problem, I cut 1/16”
from the end of
the bolt using a cut off wheel on a dremmel
tool. Start the engine and watch the belt to make sure it is
Reinstall your intake tubes
and enjoy the extra HP.