Tag Archives: DIY

2.5RS, AWD, Drivetrain, Ej20, forester, gc8, Impreza, JDM, Old School Subaru, STi, Subaru, UK, USDM, WRX

ABS 5.3 Antilock Brake System for Early Subaru Part 5:

ABS 5.3 Antilock Brake System for Early Subaru Part 5:

 

ABS 5.3 Antilock Brake System for Early Subaru Part 5:
Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS.

 

Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS. This system uses a Bosch hydraulic control unit and a Nippon electronic control unit. ABS 5.3 is a four channel control design which can independently control the front wheels and utilize select low control to control the rear wheels (a system which provides the same fluid pressure control for the two rear wheels if either wheel starts to lock up).

Although similar to other Subaru ABS systems, there have been enhancements to component operation and location. Diagnosis has also improved because of the ability of the 5.3 ABS system to communicate with the Select Monitor. The hydraulic control unit or HCU is located under the hood on the right side of the engine compartment. The size of the HCU has decreased by approximately a third from that of the ABS-2E system, used on previous model year vehicles.

The HCU controls brake fluid flow by utilizing eight solenoid valves. There is an inlet solenoid valve and an outlet solenoid valve for each wheel. Mechanically, the inlet solenoid valve is open during normal braking, and the outlet solenoid valve is closed. The HCU also contains a motor and pump assembly, which operates only while ABS is actively controlling the brake fluid flow–preventing a wheel lock.

ABS 5.3: Beginning in approximately December of 1996, a new antilock braking system called ABS 5.3 was installed on Legacy vehicles equipped with ABS.

Externally the HCU of the ABS 5.3 has a relay box attached. This allows troubleshooting of the valve and motor relay area to be kept separate from the troubleshooting of the solenoid valves and pump motor. There are four modes of operation for the ABS 5.3 system. They are normal, pressure-drop, pressure-hold and pressure-increase. When wheel lockup is sensed, Mode Two, Mode Three and Mode Four may be activated. They are described as follows:

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Ej20, ej20G, EJ25, EJ257, gc8, Intake, Intercooler, JDM, STi, Subaru, TMIC, Turbo, UK, USDM, WRX

Boost control systems on a Turbo Subaru:

Boost control system on a Turbo Subaru:

This guide covers most  boost related issues including a short introduction on how your boost systems work. This information is based on the Classic Impreza’s, but will cover the newer WRX/STi cars to a certain extent.

Safe boost levels:

When modding your car without mapping (full de-cat and high flow induction etc) you increase the efficiency of your turbo which could result in engine damage due to lean running at high rpm / max boost. To prevent damage always try and keep your boost level as close to standard as possible until your car is mapped for the increase in boost pressure.

TLDR: Don’t screw with your boost levels until you get the car tuned by someone who knows what they are doing. Otherwise you’ll probably end up with a blown up Subaru.

Boost Issues:

Is the boost control system connected correctly:

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2.5RS, AWD, Drivetrain, forester, Impreza, Legacy, STi, Subaru, Suspension, Transmission, UK, USDM, WRX

Axle general maintenance:

Axle general maintenance:

Front stub axle seal replacements require special precautions. The seals are pressed into a side bearing retainer, which must be removed to replace a leaking seal. The side bearing retainers also control front differential side bearing preload, as well as ring and pinion backlash.

When replacing a stub axle seal, mark the position of the side bearing retainer before un-threading the retainer. Remove only one side bearing retainer at a time, or you’ll risk disturbing the differential adjustments. If you’ve marked the position before removal, the correctly installed position of the side bearing retainer will be obvious, as you will be unable to turn the retainer another complete turn.

Axle general maintenance: A driveaxle for a 2008 Subaru Impreza WRX.

The driveaxles on some Subaru vehicles are pressed into the wheel hub with a light press fit. Blasting the axle out of the hub with an air chisel, center punch or other implement of destruction invites damage to the wheel bearings. All of the force brought to bear by these methods finds its way to the wheel bearings, possibly damaging their races or balls. Special tools are available for removing and installing  press-fit driveaxles. Ignoring these cautions invites a comeback for noisy wheel bearings shortly after your CV axle repair work.

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2.5RS, AWD, Ej20, ej20G, forester, gc8, Impreza, JDM, Legacy, UK, WRX

ABS for Early Subaru Part 4:

ABS Brake System for Early Subaru Part 4:

Troubleshooting Process:

To troubleshoot ABS systems, it’s best to follow a step-by-step procedure like the one on the 1992 Legacy ABS-2E Service Manual Supplement. Enter the flow diagram with the symptom reported on the repair order.

ABS Brake System for Early Subaru Part 4: The Subaru Legacy RS was known for using this ABS System.

The diagram calls that Trouble Occurs. The first step in the procedure is “Basic Checks.” This calls for a visual inspection to look for obvious problems and includes the following items:

• improper battery voltage
• low brake fluid level
• brake fluid leaks
• brake drag
• condition of the brake pads and rotors
• size, type, and condition of the tires (Check the tires to confirm that they are the correct tires for the vehicle, that they are in good condition, and that they are inflated to the correct pressure).

If you find something wrong at this stage, correct it and see whether it eliminates the reported symptom. If not, continue to Step 3. Step 3 is Self-diagnosis. At this time, put the ECU into self-diagnostic mode, and monitor the ABS warning lamp for trouble codes.

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2.5RS, forester, gc8, Impreza, JDM, Legacy, STi, UK, USDM, WRX

Headlight aiming basics for Subarus:

Headlight aiming basics for Subarus:

Subaru models equipped with aerodynamic headlights require no special fixtures for headlight alignment. Each headlight is equipped with a built-in headlight aiming mechanism. The following sequence demonstrates the correct technique for adjusting the headlights on a Subaru Legacy equipped with aerodynamic headlights.

Headlight aiming basics for Subarus: Some basic headlight adjusting techniques for Subaru cars.

1.) Turn off the headlight before adjusting headlight aiming. If the light is necessary to check aiming, do not turn on the headlights for more than two minutes.

2.) Inspect the area around the headlight for any damage. If the vehicle has been involved in an accident, it may not be possible to properly adjust the headlights until the damage has been professionally repaired.

3.)The vehicle must be parked on level ground and all four tires must be properly inflated.

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AWD, forester, gc8, Impreza, STi, Subaru, Suspension, UK, USDM, WRX

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.

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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AWD, Drivetrain, EJ257, Impreza, STi, Subaru, Suspension, UK, USDM, WRX

Rear strut brace install on Subaru WRX/STi 08+:

Rear strut brace install on Subaru WRX/STi 08+:

This is a step by step guide on how to install a rear strut brace in a 2008+ Subaru WRX/STi. Installing a rear strut brace on a 2008+ WRX/STi is more much more involved than installing a front brace. The chassis is significantly different than the new-age 02-07 Subaru Impreza. The need to cut clearances into the floor for the left and right brackets increases the difficulty for this install.

1.) Only work on one strut tower at a time. Only loosen one set of nuts at a time, and do not put the car up on lifts, jacks, or anything else that lifts the tires off the ground. All of these precautions are to minimize changes to the alignment while working on the installation.

2.) Loosen the left and right hinges on the rear strut brace using the 17mm socket and the 8mm allen head wrench. You want to be able to move the brace around as you attach each side bracket to the car’s strut towers.

3.) Remove the hatch floor and set it aside.

Rear strut brace install on Subaru WRX/STi 08+: Remove the rear floor.

4.) Remove the left and right panels from the wheel covering so that you’ll have access to the tops of the strut towers. Working your finger tips under the edge of the panel and carefully working my way around the edges while pulling away from the wheel cover worked best without requiring any special tools. It also helped avoid scratching the plastic.

Rear strut brace install on Subaru WRX/STi 08+: Remove these panels both both sides with your hands. If you can’t do that gently use a screwdriver to remove.
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AWD, Ej20, ej20G, forester, gc8, Impreza, Legacy, Subaru, UK, USDM, wrc, WRX

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.

 

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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