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How can I tell if I have a bad idler arm?
How
easy it to change my front struts?
What are the factory
front end alignment specs?
What are some suggested front
end alignment specs?
What are the offsets for the front and
rear 16 inch wheels?
Will 4th generation wheels fit on my
3rd generation car?
Why does my power steering pump tend to
whine/hiss?
Do my rear disc brakes need to be
adjusted?
How can I tell if I have a
bad idler arm?
Take off the idler arm and it you can spin it around
with ease, then it's probably bad. It also might have slop in the vertical axis
where the two arms are connected, so there will be "give" when pressing the two
arms in toward each other. It's recommended you replace it with a beefier arm
like a Moog or DANA unit that's lubable. You might also want to check the ball
joints for wear too.
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How easy it to change
my front struts?
Use two jack-stands under the front-frame rails, a
hydraulic jack under the "bulb" in the control-arm and a third jack-stand under
the "spindle extension" of the rotor. It's not necessary to remove the calipers
and/or rotors. The upper strut-mounts might need to be forcibly loosened and
then removed. If the old struts are worn out enough, they should just compress
by themselves. The new struts should be able to be compressed by hand and then
positioned in place as fast as possible, before they extend.
For the strut-to-knuckle bolts to loosen, use a pipe
extension to the fixed driver of the socket-set. To tighten these bolts, first
torque them to 170 Nm and then give them an additional turn of 120 degrees. For
the latter, use the pipe-extension again.
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What are the factory
front end alignment specs?
With the stock Good Year 215/65R/15s, the settings
were:
Caster +3 degrees +/- .5 degree
Camber +1 degree +/- .5 degree
Toe in .15 degree +/- .5 degree
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What are some
suggested front end alignment specs?
A table in the Camaro & Firebird
Performance Handbook for 3rd Generation cars lists the following recommendations:
Caster Camber Toe Total
(deg) (deg) (in)
L R L R
Street +4 +4.5 -.5 -.5 3/32
Hard Street Use +5 +5.5 -1 -1 3/32
Drag Racing +4 +4 0 0 1/32
Road racing +6 +6 -1.75 -1.75 Short Course 1/8 out
Long Course 1/16 in
The figures are credited to Global West Suspension
Components and are taken with driver weight included.
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What are the offsets
for the front and rear 16 inch wheels?
0 mm on the front and 16 mm (negative - outward) on
the rear.
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Will 4th generation
wheels fit on my 3rd generation car?
Yes, but you'll need to use 2.5" spacer hubs which
you can get from Vette Brakes in Tampa, FL.
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Why does my power
steering pump tend to whine/hiss?
The 2nd & 3rd generation F car uses a submerged P
pump. It is a rather large PS pump that has a housing full of PS fluid which
surrounds the pump (hence the term "submerged"). The P pump weighs in at eleven
pounds, and is a very reliable unit capable of providing enough hydraulic
assist for everything from a Chevette to a 1 ton delivery van. Because the P
pump is submerged, it also tends to be quieter than the other models as the oil
damps many of the vibrations. In addition, the P pump has been manufactured
since the late sixties, and Plant 3 in Saginaw, MI really has their quality
control dialed in on that assembly line.
The 4th gen F car uses a CB pump. It is not
submerged, and has a reservoir. It is physically smaller than a P pump, weighing
in at about six pounds. It is more suited to passenger cars, as it does not
have the obvious excess capacity of a P pump. The CB pump has many similarities
to the P pump in that it uses a bushing on the
driveshaft, as well as a common
flow control valve. All in all, it is quite a reliable unit, aas long as it is
manufactured in spec.
A TC pump is dimensionally similar to a CB pump, and
can in fact be substituted for a CB pump. The TC is more expensive, and uses a
sealed bearing on its driveshaft. Some critics of the TC claim the sealed
bearing is noisier than the CB pump because of this. You will find TC pumps on
many other GM products, as well as a whole bunch of
Chryslers, Audi's, VW's,
Saab's, and other European manufactured vehicles. I personally like the TC
pump. It was kind of like a hot rod, and we'd sometimes spin them up to 9,000
RPM for 100 hours, at 300 degrees F and they'd look fine afterwards. Some say
the TC was 'overbuilt', and GM was trying to phase them out, except the
customer kept buying them! The TC pump is the lightest of the PS pumps, at just
over five pounds. There exist some aluminum pumps from the late 80's Corvettes
that weight only four pounds that will bolt into a 4th gen. F car. There is
also a new pump called 'direct drive' that runs directly off the cam, but I'll
not go into that because I don't know much about it.
Now, the whine you hear when you rev your pump is one
of three things. The first is the whine caused by pressure relief. It sounds
kind of like a 'Shhhhhhhhh!' If you turn your wheel until it wont turn anymore,
the fluid flow to the pump is cut off, and the pump is forced into pressure
relief. On the F-car, this means a pressure of between 1200 and 1600
PSI. The
pump has to recirculate this high pressure fluid within itself because the
fluid has nowhere to go. If left in pressure relief for very long, the fluid
can quickly exceed 325 degF, and break down, causing the pump to begin
experiencing metal-to-metal contact.
The second noise is caused by
cavitation. As you
increase pump speed, more and more fluid is forced through the ports per unit
time. There comes a velocity where the fluid just doesn't want to move that
fast, and the vanes inside the pump will cause a vacuum, which is instantly
filled with oil vapor. When the vane reaches the high pressure port, this
vacuum cell is opened into a high pressure cell, and oil rushes to fill the
void. A little 'sonic boom' results. These individual 'booms' are virtually
microscopic, but they add up. What they translate into is a sound that sounds
suspiciously like a whine. Now every pump
cavitates. It's in the nature of
moving fluid. By smoothing the radius of the ports, and relocating supercharge
holes (I'm not going into that), engineers can reduce
cavitations or push the
frequency spectrum of the whine to a less noticeable
frequency. It is, in fact,
where the bulk of pump engineering hours are spent.
Anyway, that funny high pitched whining that Mike
Martin is hearing after his autocross run is the third type of noise. This type
of whine is from the oil being aerated. When the pump is really screaming, the
oil in the reservoir really gets churned up. This allows the occasional air
bubble to pass into the pump, where it is totally
pulverized into smaller
bubbles. Eventually, the oil gets enough of these bubbles in it that you begin
to hear it. If you want to really experience aeration, just run your pump low
on oil!
None of these three types of noises will cause your
pump to die. What kills a pump is heat and oil viscosity breakdown. The
pressure relief example will overheat a pump in the extreme case causing
galling of the bushing, or wear of the pump ring. The
cavitations example, when
extreme, like 7000-9000 RPM endurance runs, will cause
micro fractures to the
pump internals and literally blow little flakes of metal off the walls. The
extreme aeration example will cause increased heat to the internals, because
air does not carry the heat away like oil does. But the common denominator to
these is the word EXTREME. Most PS pumps never see this kind of duty, unless
the person runs their pump low on oil. But none of us does this, because we all
check our PS fluid as often as we check our trans fluid, right?
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Do my rear disc brakes
need to be adjusted?
A technical service bulletin described this for
early-mid '80s rear disk brakes. It seems that the rear disks in these cars
would be adjusted by applying the emergency brake. When you pull the emergency
brake lever up, the lever turns this little device called an actuator screw.
This little screw type device is also on a ratchet, so that pulling the e-brake
up, turns the screw. But letting go allows the ratchet part to function and set
the pads at that time. So, using the emergency brake is mandatory for
maintaining the rear disk setting on early model rear disk units.
But, here's the problem with them. There's a little
spring on the actuator screw assembly that allows the pads to back-off from the
disk a little bit before the ratchet mechanism is engaged. This must be done,
otherwise full brake pressure would be left on the pads when the e-brake is
released. Well, that little return spring K-factor was not correctly chosen
from the factory, and the result is that the ratchet NEVER functions after the
actuator screw gets a little dirty. Hence, the pads simply work their way out
all the way when the e-brake is used. Using the e-brake all the time seems to
keep the actuator free for a longer period of time, but even with the correct
spring weight and screw, the e-brake is required to adjust the parking brake
actuator.
The TSB states that cars with a manual tranny are
eligible for a free fix as the e-brake is required to park the car, but the
auto is not eligible. Why? Only GM knows. However, fixing it yourself should be
relatively easy. The rear wheels are removed, and there is a nut on the back
side of the brake caliper that holds the parking brake lever. Remove the nut,
lever, and soft grommets. Put a large washer over the shaft to act as a spacer,
and then put a wrench on the hex of the shaft, and tie it down with the nut.
Turn the wrench to back the brakes off. After a while, this will over travel,
as if there was a one way clutch. Tighten the shaft to see where the hex is
when the pads are tight against the rotor. If it is in a spot that the parking
brake lever will fit, and turn about 1/3 of its travel to tighten apply the
brake, then it is good. If not, try again.
This will remove some of the brake pedal slop also.
It's supposed to be self-adjusting (apply parking brake thirty times), but it
is common for it not to work.
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