Tag Archives: AWD

Maintenance: Subaru Periodic Maintenance Part 4:

Maintenance: Subaru Periodic Maintenance Part 4:

Steering and Suspension:

Steering and suspension parts are a lot like the brake system components. Their proper operation is vitally important to the safety of the driver and his passengers, but it is very difficult to determine how long it will be before any of these components will require attention. That’s why an inspection of all steering and suspension components is required at 15 month/15,000 mile intervals. Changes to these systems may be too gradual for the driver to even notice, leaving it to you to ferret out and correct any wear or damage that has taken place.

Maintenance:Subaru Periodic Maintenance Part 4: Regular checks of the steering and suspension is important.
Maintenance:Subaru Periodic Maintenance Part 4: Regular checks of the steering and suspension is important.

We won’t cover all of the steering and suspension checks here. There’s too much variation between different Subaru models to do an adequate job. What you’re looking for is anything that reduces the original precision of the steering and suspension systems. Perhaps the steering has a little too much play in it or the shocks and struts don’t handle the bumps in the road as well as they did when new. Specific tests for the Subaru model you’re working on can be found in the service manual.

Check the power steering system for dampness or other signs of fluid leakage. The power steering pump reservoir is a good place to start. If the reservoir is low, the fluid has probably leaked out, as it has no place else to go. Approved fluids for the power steering system include Dexron II, IIE or III.


GENUINE OEM SUBARU ATF-HP P/S FLUID QUART BOTTLE

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Antilock Brake System for Early Subaru Part 3:

Antilock Brake System for Early Subaru Part 3:

Damping Oscillations:

An additional benefit of this arrangement is that the mechanical valve damps out some of the unwanted oscillation in the brake pedal as the ABS pump runs. Because of this, the F valve used on the ABS-2SL system is no longer needed and has been eliminated from the circuit.

Antilock Brake System for Early Subaru Part 3: The Legacy RS rally car benefited greatly from having a superior ABS unit.
Antilock Brake System for Early Subaru Part 3: The Legacy RS rally car benefited greatly from having a superior ABS unit.

 

ABS Operating Modes:

To illustrate the four operating modes of this ABS system, we’ll assume that the ECU is operating only the solenoid for the right rear brake circuit. Recall that this circuit also affects the left rear brake circuit through the mechanical valve.

Normal Braking:

• Driver depressing pedal

• ECU passive (monitoring)

• Zero current in solenoid valves

• Pump off

• Plunger piston full right, pressure port open

• Master cylinder pressure supplied to all wheel cylinders

Pressure-Reduce:

• Pump pressure raising pedal

• ECU controlling solenoid valves and pump

• Full current in the right rear solenoid valve

• Pump running

• Plunger piston moves left, closes pressure port; system balances the two rear wheel cylinders.

Pressure-Hold:

• Pedal firm

• ECU controlling solenoid valves and pump

• Half current in the right rear solenoid valve

• Pump Off

• Pressure port closed

• Plunger piston is stationary, maintains reduced pressure in the right and left rear wheel circuits.

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Antilock Brake System for Early Subaru Part 1:

Antilock Brake System for Early Subarus:

A variety of antilock brake system (ABS) have been installed in Subaru vehicles since the first systems were installed in the 1990 Legacy.  In the sections that follow, we’ll give you a brief overview of each system and explain proper diagnostic techniques.

Antilock Brake System for Early Subarus: A Subaru SVX ABS system.
Antilock Brake System for Early Subarus: A Subaru SVX ABS system.

Antilock Brake System for Early Subarus:

Early Subaru Antilock Brake Systems:

The original Subaru Legacy Antilock Brake System (ABS) was licensed by Bosch and manufactured by Nippon ABS, Ltd. The system electronically controls brake fluid pressure supplied to the brake system. This control helps to prevent “wheel lockup” during braking on slippery surfaces and emergency situations. The system includes a fail-safe feature, which indicates a malfunction by illuminating the warning lamp. The system is then returned to a conventional power brake system. The four channel system provides accurate individual wheelspeed control and improves the directional stability of the vehicle during braking.

Antilock Brake System (ABS) Components

• Tone wheels (4)

• Speed sensors (4)

• Electronic control unit (ECU)

• Hydraulic control unit (HCU)

• G sensor (manual transmission models)

• Warning lamp

A tone wheel is attached to each wheel hub and rotates at the same speed as the hub. The magnetic speed sensor is mounted in the axle housing. The notched tone wheel acts as a reluctor which modulates the magnetic field of the speed sensor. The tone wheels are individually replaceable.

The speed sensor provides an alternating voltage signal to the ECU. The alternating voltage and frequency corresponds to wheelspeed.

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Short Shifter Install on 04-07/08-11+ Subaru STi:

Short Shifter Install on 04-07 Subaru STi:

A step by step guide on installing a short shifter for a 04-07 Subaru STi and 08-11+ Subaru STi/Legacy.

OEM Short shifter: Installed and ready to go.
OEM Short shifter: Installed and ready to go.

Tools needed:
10, 12, 14, 17mm wrenches
Jack Stands
Jack
Needle nose pliers

Short Shifters used:

Subaru OEM Short Shifter 04-07 STi:

Genuine Subaru STI Short Throw Shifter – 6MT

Subaru OEM Short Shifter 08-11 STi, WRX, Legacy:

Genuine Subaru C1010AG001 STI Short Throw Shifter

 

Step 1: Once the car is up on jack stands / a lift, you want to support the transmission and remove the rear cross member. You will need to remove it later anyway, it also makes it much easier to work without it in the way. I used a bottle jack and block of wood to support the tranny, but im sure a transmission jack would work much better if you have one.
This picture shows the cross member removed.

Short shifter: This picture shows the cross member removed.
Short shifter: This picture shows the cross member removed.

Step 2: Once the cross member is unbolted you will need to unplug the 02 sensor, and unclip its harness from the cross member. It is held by two plastic clips that can be pushed out of the holes in the member without much trouble.

Short Shifter: O2 sensor is held by two plastic clips that can be pushed out of the holes in the member without much trouble.
Short Shifter: O2 sensor is held by two plastic clips that can be pushed out of the holes in the member without much trouble.

Step 3: Remove the bolt from the lower rod, I believe it is a 14mm. The nut on the other side is attached to the bracket, so you don’t need a wrench on it. I found that ratcheting wrenches work best for most of these bolts.
The bolt that needs to be removed is the one going through the rubber bushing shown in the upper right of this picture.

Short Shifter: The bolt that needs to be removed is the one going through the rubber bushing shown in the upper right of this picture.
Short Shifter: The bolt that needs to be removed is the one going through the rubber bushing shown in the upper right of this picture.

Step 4: Now you can disconnect the reverse lockout cable. It is held in with a pin that can be pulled out with a pair of pliers. I stuck an Allen wrench through the cam as shown in the Cobb short shifter install when I removed it just in case. There is a washer on the lockout cable that may be stuck in the grease, you will want to take it off and set it aside so it doesn’t get lost. The lockout cable can be seen on the left side of the picture above. You can now move the lower rod down, and move the lockout cable out of the way.

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Rear Wheel Bearing Repair 02-07 Subaru WRX/STi

Rear Wheel Bearing Repair 02-07 Subaru WRX/STi: This is a write up on how to replace your rear wheel bearing for your 02-07 WRX STi.

DISCLAIMER: WORKING ON YOUR CAR IS DANGEROUS. IF YOU FEEL YOU CANNOT COMPLETE ANY OF THESE TASKS, DON’T DO IT, THESE PARTS HOLD YOUR SUSPENSION AND WEIGHT OF YOUR CAR. THIS IS A REFERENCE ONLY! do not attempt.

Tools:
– 32mm Socket (axle nut)
– 19mm, 17mm, 14mm (suspension, and brake parts)
– Needle nose
– Sockets, breaker bar
Torque wrench
– Access to a press
– I used a 36mm to press the bearing
– 26-27 mm for the hub

Parts
– Check with your local Subaru dealer
– Or use online sites or vendors!

Parts I Used
Rear Wheel bearing – #28016PA010
Oil Seal #1 – #28015AA080
Oil Seal #2 – #28015AA070
Rear Axle nut – #28044AA001

Rear Wheel Bearing Install

– First you need to break the torque on your lug nuts
– Get your rear in the air and stable (your going to put some stress on some parts)
– Remove your wheel

Rear Wheel bearing: Remove your wheel and Locate your axle nut and "uncrimp" it.
Rear Wheel bearing: Remove your wheel and Locate your axle nut and “uncrimp” it.

Locate your axle nut and “uncrimp” it. After its uncrimped, make sure you have your parking brake on really well. Either break the torque on it and back it off so its hand tight accessible, or remove it all together.

- Locate your axle nut and "uncrimp" it - After its uncrimped, make sure you have your parking brake on realy good. - Either break the torque on it and back it off so its hand tight accessible, or remove it all together
– Locate your axle nut and “uncrimp” it
– After its uncrimped, make sure you have your parking brake on realy good.
– Either break the torque on it and back it off so its hand tight accessible, or remove it all together
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Clutch replacement for a Subaru WRX/STi:

How to replace a Clutch for a GD Subaru:

This procedure was performed on a MY04 STi with some modifications which may or may not be relevant for the purposes of this How-To. This procedure is only ONE way of removing the transmission and is not meant to be the be-all method. This is a DIY on your driveway process only. If you have access to a lift, this would be the preferred and safest method.

Perform this procedure AT YOUR OWN RISK.

Clutch: STi Transmission
Clutch: This procedure allows you to remove the transmission from a Subaru STI for the purpose of gaining access to the clutch and flywheel system for inspection and or replacement

This procedure allows you to remove the transmission from a Subaru STI for the purpose of gaining access to the clutch and flywheel system for inspection and or replacement.

This procedure allows you to remove the transmission without the benefit of a lift and is meant as a DIY for the weekend warrior. This is by no means a simple or easy procedure and it requires a good deal of strength. IT IS RECOMMENDED YOU HAVE A FRIEND THERE TO HELP. You will need a second pair of hands at times.

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Flywheel: Flywheels for Subaru WRX/STi’s FAQ

Flywheel FAQ:

How does a lightweight flywheel improve performance? A transmission can be thought of as a fulcrum and lever in a car. First gear has a really long lever; second gear has a shorter lever, etc. The lever represents the mechanical advantage that gears give your vehicle. When your car is moving, you have two factors that are present during acceleration, one is driveline losses, which are constant and the variable, which is vehicle weight and the mechanical advantage supplied by each gear.

Flywheel: SPEC flywheels are CNC manufactured at an unheard-of .001 tolerance, in an industry where the standard is .010. This precision manufacturing process ensures perfect balance and a perfectly flat bedding surface for the clutch disc, both of which also contribute to the ultimate in safety for competitive environments. All SPEC flywheels carry SFI certification.
Flywheel: SPEC flywheels are CNC manufactured at an unheard-of .001 tolerance, in an industry where the standard is .010. This precision manufacturing process ensures perfect balance and a perfectly flat bedding surface for the clutch disc, both of which also contribute to the ultimate in safety for competitive environments. All SPEC flywheels carry SFI certification.

While changing to a lighter flywheel will give the user little to no changes on a dyno, the apparent changes are quite dramatic due to the greater mechanical advantage. Consider these made up figures for consideration: Drive line losses, 45 pounds and vehicle mass (weight) at the driveline (remember your gear’s mechanical advantage reduces your actual car weight). We know that within reason, vehicle mass is a constant.

Now imagine if you reduced the driveline loss from 45 to 35 with the use of a lightweight flywheel. Since the engine has less drivetrain losses to compensate for, this means the “gained” horsepower can be applied to moving the vehicle mass. Using mathematics, one can realize that the higher you go up in gears, the less effect that a lightened flywheel will have to the overall equation.

Are there any downsides to a lightweight flywheel? While the performance characteristics of a lightweight flywheel seem to be the perfect solution, there are compromises:
a. Low end performance is affected. This usually means that higher revs are necessary for smooth starts due to the reduced rotational mass. For drag racers, this can be a BIG issue.
b. Possible missfire check engine light.
c. Possible chatter, like missfire this affects some users and not others.

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Clutch: Subaru WRX/Sti clutch FAQ

Clutch: Subaru WRX/Sti clutch FAQ

The first impulse when clutch shopping is to get “too much” clutch. This is often a very big mistake, as there will be compromises in the different types and compositions of clutches.

Clutches hold Torque, not Horsepower:
Most performance enthusiasts relate more to horsepower numbers rather than torque, but clutch capacity is measured in terms of torque. Think in terms of a high rpm 250 HP Honda Civic versus a 250 HP Ford Powerstroke turbo diesel. The truck will need about three times the clutch capacity because the engine produces about three times the torque.

Choosing what’s best for you:
It may be difficult to know what clutch is right for a particular application since there are so many different levels of personal tolerance and many variations in design. Some people can tolerate clutch chatter, or noise, or heavy pedal effort, or shorter clutch life, higher cost, or other trade-offs. But why tolerate unnecessary issues if you don’t have to? Get the clutch that suits your needs.

What are the various clutch materials? Other than unique or specialized compositions, clutches are generally comprised of:

1. Organic
2. Kevlar
3. Ceramic
4. Feramic
5. Carbon (initially invented in 1998 by Alcon Components for the Subaru World Rally team )
6. Sintered Iron

Depending on manufacturer specifications, this list also shows the general order of the amount of force the clutch materials can hold.

Organic: Metal-fiber woven into “organic” (actually CF aramid with other materials), original-equipment style. Known for smooth engagement, long life, broad operating temperature, minimal-to-no break in period. Will take hard use, somewhat intolerant of repeated abuse (will overheat). Will return to almost full operational condition if overheated. Material is dark brown or black with visible metal fibers.

Kevlar: High-durability material more resistant to hard use. Engagement is similar to organic, but may glaze slightly in stop and go traffic, resulting in slippage until worn clean when used hard again. Higher temp range in general, but can be ruined from overheating; will not return to original characteristics if “cooked”. Material is uniform yellow/green and may look slightly fuzzy when new.

Ceramic: Very high temperature material. Engagement is more abrupt. Will wear flywheel surface faster, especially in traffic situations. Due to it’s intrinsic properties, ceramic has a very high temperature range. Material is any of several light hues – gray, pink, brown.

Feramic: This unique clutch material is one that incorporates graphite and cindered iron. The result is a friction material that offers good friction coefficient, torque capacity, and smoothness of engagement.

Carbon: Very high temperature material. Engagement is more abrupt. Will wear flywheel surface faster, especially in traffic situations. Slightly more durable and flywheel-friendly compared to other aggressive clutch materials. Material is black.

Sintered Iron: Extremely high temperature material. Engagement is extremely harsh and is generally considered an “on/off switch” both due to it’s characteristics and the clutch types this material is generally associated with. It requires a special flywheel surface. Material is metallic gray in color.

 

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