Frequently Asked Questions

• A Hybrid Drive Battery is a large battery that assists the engine, providing power to maximize fuel economy. It is usually located behind the rear seats.

• Like most batteries, Hybrid Drive Batteries fail when they lose their ability to hold a charge.

• The vehicle will typically be less peppy and exhibit poorer fuel economy. It may show no/low charge in the morning when you start driving. Certain models will show a warning light on the dash and you will notice the engine revving as well as the battery cooling fan operating at a high speed constantly. Others will show the charge indicator rapidly fluctuate between charge and discharge.

• Dealerships charge around $3,000 to $5,000 to replace a Hybrid Drive Battery and typically require additional components to be purchased. Dorman's program offers everything needed to complete the repair.

• 2 to 4 hours depending on the experience of the qualified technician. Hybrid Drive Batteries should only be replaced by a qualified technician.

• Healthy Batteries will rarely show full on the display. A Prius Hybrid Drive Battery operates between about 60% and 80% of charge to provide longer life. The display is designed to show the battery as half to three quarters full when it is operationally charged.

• Actual miles per gallon depends on driving habits, terrain, and weather as well as maintenance factors such as gas engine state of tune, fuel, bearings and brakes.

• Most Hybrid owners get between 80,000 and 200,000 miles from their original batteries. The replacement battery is warrantied for 36 months with no mileage limit. Dorman replaces the less durable parts in the battery packs with their own improved and upgraded parts and upgrade all cells to the more durable Gen2 design cells. These cells have been reconditioned through their proprietary processes and must pass durability testing before being placed in one of the battery packs.

• A remanufactured component is one that has been rebuilt using repaired existing components and/or new components. Hybrid Drive Batteries are totally remanufactured and tested as complete systems including the battery computer or ECU, harnesses, copper buses, connectors, and frames.

• When one cell has failed, the pack must be completely disassembled to replace the one faulty battery module. Such repairs are short lived at a relatively high cost, without guarantee. It is more cost effective to replace all cell modules at the same time because if one battery has failed, it is likely that the others are nearing the end of their service lives as well. Additionally, it is critical for proper function that all cell modules be at the same state of charge, so if one cell is replaced, it will not be in sync with the original cells.

• It is shipped to the remanufacturing facility so that it does not wind up in a land fill.

• A replacement battery is a fully remanufactured original equipment assembly.

• It has no vintage per se, it is a fully remanufactured and tested assembly compatible with all model year vehicles specific to that particular part number.

• Safety is an important concern when working with the electrical systems of hybrid vehicles, particularly when removing and installing hybrid vehicle batteries. Because of the high voltage that the batteries generate, removing and installing hybrid batteries is an inherently dangerous activity and can lead to serious or even fatal injuries. Suitable training is essential before removing, installing, or servicing this product which should only be attempted by a qualified technician.

Suspension Mounts do one of several different jobs (depending on application):

• Cushions between the strut or shock and the body of the vehicle
• Cushions between the various components of the suspension linkage of the vehicle
• Enhances the handling performance of a vehicle
• Keeps the suspension of a vehicle running smoothly and prevents noise
• Mount bearings provide smooth and consistent turning as the vehicle is steered

• Like all active rubber parts on a vehicle (belts, hoses, balancers, CV boots, and tires) Mounts wear out over time.

• Suspension designs have varied greatly over the past 30 years, affecting the type of mounts used and the failure rates of these mounts. In addition, the trend from passenger cars to trucks and SUVs has also affected this category and increased the number of mount failures.

• Early to Mid 70s - In the traditional RWD designs prior to the mid 70s, shocks and coils were used. Mounting bushings were also often used in these designs. These bushings are failure prone, but are included with replacement shocks.

• Late 70s - In the large-scale transition to fuel efficient FWD vehicles in the late 70s, designers began using the MacPherson Strut. This design is one of the most failure- prone, and includes both the strut mount for load bearing and the bearing for steering.

• Early 90s - Since the early nineties, the switch to trucks and SUVs has resulted in less mount failures because these vehicles use traditional suspensions with shocks that do not use a separate mount.

• Today - SUV consumers have since demanded that the handling of these vehicles be better and many OE designs have switched back to MacPherson Struts. This return to MacPherson Struts has improved the long-term opportunities for this product line.

• Normal Load Cycling from the vehicle?s weight and driving fatigues the rubber in the mount causing failure. A "clunking" noise coming from the suspension when the vehicle goes over bumps is a sign of a failed mount.

• Normal Aging of the mount causes "set" in the mount. This set orients the position of the mount in a loaded state, decreasing its effectiveness. Poor vehicle handling results causing the driver to experience a looser ride as the vehicle tends to throw the riders, rather than hugging the road.

• Salt, Heat, Temperature Cycling, and Exposure to Ozone degrade the natural rubber leading to rubber failure. The failed mount results in noise and poor ride-ability.

• Bearings Wear Out due to normal vehicle weight, vibrations, load cycling, and driver habits such as frequency of steering. Worn bearings cause memory steer, where the vehicle turns in the direction last turned.

• On all FWD vehicles and a large percentage of later model RWD cars, the OE manufacturers have replaced the belt driven cooling fans with lighter, more fuel-efficient electric fans. Eliminating the belt drive frees up horsepower resulting in enhanced fuel efficiency. The electric fans allow the engine to be cooled only when the temperature reaches a preset level or when the AC/defroster puts a higher than normal load on the engine.

• The most common mode of failure is electric motor burnout. When a radiator fan motor fails, the customer will experience an overheating condition, which if not repaired immediately, can result in other engine damage, including leaking head gaskets as well as warped or cracked heads and blocks. The replacement of an electric fan motor is difficult, time consuming, expensive, and potentially damaging to the remaining plastic components. Most plastic shrouds and fan blades are not available as separate units from either the OE dealers or the aftermarket.

Save Valuable Labor Time

• A complete assembly allows you to save time and free up valuable service bay space.
• Avoid the risk of damaging the plastic components and having to contact the customer and resell the assembly.
• In some cases, replacement of both fan motors plus labor can be as expensive as a complete fan assembly with shroud, fan and harness.
• Replacing only one motor, on a two motor assembly, sets you up for a comeback when the second motor fails down the road.

Some OE assemblies have motors that are riveted to the plastic shroud making them difficult to replace. Other assemblies have shrouds or fan blades that frequently crack when the motor fails or when trying to replace the motor.

• The distributor directs the voltage from the coil to the correct cylinder to ignite the spark plug at the correct time. The engine's distributor controls the spark needed to complete the combustion cycle.

• Distributors can fail for a variety of reasons. The electronic components inside can burn out. The shaft bearing can wear out causing the shaft to wobble and spark timing to be effected. The drive gear can wear and cause erratic operation. Environmental conditions such as heat and moisture also can accelerate failure. Seals and shafts can wear allowing oil to get into the electronics. When the distributor fails the vehicle will not function properly and may not start. You can not put off replacing this part.

• All Dorman Distributors are made using new components and come as ready-to-install complete units. You can be sure that the part will fit and function like an OE unit.

• A Harmonic Balancer performs multiple functions on today's vehicles.

• The primary function of a Harmonic Balancer is to dampen engine vibrations. The balancer acts to disperse the "harmonics," or vibrations that occur during normal engine operation. In essence, the Balancer acts as a "shock absorber" for rotational movement.

• The Balancer also provides power for alternators, A/C compressors, and power steering pumps. Some applications provide sensor inputs for the CKP (Crankshaft Position Sensor) and number 1 cylinder location.

Harmonic Balancer failures are typically the result of:

• Heat
• Salt
• Ozone attack on the rubber damper
• Stress on the rubber damper from integrated drive and accessory pulleys
• Damaged sensors resulting in faulty inputs to the CKP / ECM

Worn or broken Harmonic Balancers can cause:

• Torsional Engine Vibrations
• Excessive Belt wear, slapping, squeal, and thrown belts
• Excessive gear ware
• Broken accessory drive
• Loose flywheel or pulley bolts
• Loss of horsepower

These tools are both expensive and difficult to find. Most DIY'ers and many repair shops try to pry the pulleys off and hammer them back on. The plastic Pulleys will shatter and the steel Pulleys will bend making reuse impossible.

• Reduced fuel efficiency
• Vehicle will not start

Traditional Design

• Frayed, cracked or hardened rubber dampers prevent the balancer from functioning properly resulting in unusual engine vibrations or a shifted timing mark. Seal surface wear on the balancer shaft results in oil leaking from the front timing cover seal.

Integrated Design

• Defective integrated design balancers will cause belts to slip and misalign, resulting in excessive belt wear and squeak. The outer hub slips on the inner hub and will not drive the other essential pulleys.

Diagnostic (Rock-Crusher) Design

• With this design, the balancer is relied on to provide diagnostic computer information. "Windowed" vanes are incorporated for speed and reference data. This design is susceptible to damage from rocks and road debris which can become trapped, or damage the sensors, resulting in faulty inputs to the computer and possible ignition failure.

Exhaust manifolds do many different jobs (depending on application) including:

• Transporting extremely hot exhaust gases (up to 1400 F) from the cylinder head to the exhaust piping.
• Providing mounting for Oxygen sensors, AIR piping, and EGR piping.
• Sealing the engine head and exhaust piping to prevent fumes and noise from escaping the engine compartment.

• One of the goals of today's car manufacturer's is to design lighter vehicles to boost fuel economy. To that goal, the Manifold design trend since the late 1970s is to reduce weight and make a thinner, weaker Exhaust Manifold that is more prone to cracking than in the past.

• This design trend along with leaner fuel mixtures, lighter weight OEM castings, welded tubular steel Manifolds, an aging vehicle population and normal wear and tear has created a climate where Exhaust Manifold failures are increasing daily. This results in an incredible opportunity to increase Exhaust Manifold sales.

• Exhaust Manifolds can fail for some of the same reasons as any other type of exhaust part. Heat, thermal stress, and corrosion can produce cracks that result in leaks and noise. When a manifold fails there is a pulsing noise ranging from a soft ticking to a loud booming depending on the size of the leak. The hot gases can burn nearby wires and hoses, causing additional damage. Additionally, carbon monoxide vapors may find their way into the passenger compartment with potentially deadly results. The Manifold must be replaced when it fails.

• This refers to the On-Board Diagnostics Generation Two. This is a system that has the ability to test various systems and components and inform the driver when a fault has occurred, which will cause the vehicle to put out excessive emissions. This system first became available on passenger cars starting in 1995 model year and starting in 1996 for light duty trucks with a gross vehicle weight under 8500 lbs. Currently, OBD ll aftermarket Catalytic Converters are not legal for sale or use in the state of California.

• The brake cable is responsible for the application of parking or emergency brakes for rear disc or drum. It transmits actuating force from the parking brake pedal or handle to the rear wheels. There are front and rear cables, with rear usually being split into left and right. On some vehicles, due to overall length of the vehicle, there will be an intermediate cable to link the front and rear (e.g., pickups).

• Brake cable failure occurs primarily due to the inner cable fraying or corroding, causing the cable to bind within the casing. Sticking brake cables can cause rear brakes to drag and contribute to premature brake lining wear and poor performance. The failure rate is higher in northern states where vehicles encounter snow and salt conditions, causing corrosion of brake cables.

• Brake hoses and steel lines connect the hydraulic components of the brake system. They provide a means of transmitting hydraulic pressure from the master cylinder to each of the brake actuating devices at the wheel, such as the caliper or wheel cylinder. As an added feature, Dorman Brake Hoses are packaged with new copper washers where needed to assure proper sealing.

• Brake hoses typically fail internally with little or no external signs other than a bulge or cracking in the hose. When the liner of the brake hose is torn or separated it can act as a check valve, trapping brake fluid under pressure, not allowing the brake shoes or pads to properly return when the brake pedal is released. Catastrophic failure occurs when the hose bursts or breaks through under pressure.

Brake hardware consists of drum and disc hardware. The major components can be found in the following kits:

• Drum brake hardware: return springs, hold-down cups, pins and springs, self-adjusting cables, levers, adjusting screw assemblies and adjuster screw springs.
• Disc brake hardware: anti-rattle clips/pins, rubber components, disc brake guide bolts and pins.

• Stressed, fatigued or broken disc and drum hardware will cause excessive noise, result in premature brake failure, or cause catastrophic failure of braking at the wheel. Caliper bolts rust and corrode, hampering caliper movement and causing excessive and uneven pad wear. Worn self-adjusting parts will not allow shoes to be adjusted properly, resulting in a low brake pedal and uneven braking.

• The master cylinder is the heart of the brake hydraulic system. It converts the mechanical force of the pedal into hydraulic pressure sent to each wheel. The master cylinder consists of a casting with a cylindrical bore that contains a push rod, pistons, and seals. A brake fluid reservoir is mounted on top of the casting assembly or integrally cast into the unit. Dorman Brake Parts offers completely NEW master cylinders.

• Master cylinder failure occurs when the seals become damaged or the bore becomes scored or corroded. Brake fluid can leak past the seals resulting in a loss of braking pressure and/or leakage at the firewall/power brake unit. The power brake booster is often damaged due to the leakage of brake fluid into the diaphragm.

• Wheel cylinders are found on all drum brake assemblies. They convert hydraulic pressure into mechanical pressure at the wheels. They only operate when the master cylinder activates them through hydraulic pressure. Wheel cylinders consist of a casting with a cylindrical bore, one or two pistons, cups, a spring and dust boots.

• If the seals become damaged or worn, or the bore becomes scored or corroded, brake fluid can leak past the seals, resulting in loss of braking pressure and system fluid as well as contamination of the brake shoes. Symptoms include uneven braking, loss of braking, and "grabbing" brakes.

• A device, located in the fuel tank that measures the fuel level.

• A float (usually made of a coated foam substance)

• A swing arm for the float

• A variable resistor

• A series of feed, return and vent tubes welded into a round housing

• Electrical harness for the variable resistor

• Electrical harness for the fuel pump negative and positive feeds

• A fuel strainer

• Tank sending unit lock ring and O ring seal

• Fuel pump coupler hose and clamps

• The variable resistor uses a rheostat to vary the amount of ground signal

• The ground signal reading determines the fuel reading on the gauge

• The resistor is directly connected to the float arm

• The fuel level determines the position of the resistor

• Rust damages the feed/vent tubes

• Fuel/vent lines damaged when fuel pump is serviced

• Floats lose the protective coating (causes float to sink)

• Feed/vent tubes damaged or broken off when servicing fuel filter or rubber fuel lines

• Rheostat becomes defective (wire breaks or wears out)

• Float damaged when servicing the fuel pump (Float is damaged when trying to twist the arm out of the sending unit hole in tank)

• It’s cost and time efficient

• Higher profits

• Ease of installation

• Prevents comebacks

• Unit may fail shortly after tank/fuel pump service

• Fuel lines and fittings are damaged during service/too long to repair

• Floats often go bad or are damaged

• Complete product (includes strainer, etc)

Hydraulic clutch systems are used with manual transmissions, contain a clutch master, a clutch slave and a hydraulic hose or line.

• Clutch master: very similar to the single system brake master. It is a single piston, single outlet cylinder that, when actuated by the clutch pedal, transmits hydraulic pressure to the slave cylinder.
• Clutch slave: very similar to the brake wheel cylinder, mounted external to the transmission. When pressurized it causes separation of the clutch disc and pressure plate, effectively separating the engine from the transmission and allowing the shifting of gears. A second design of the clutch slave is the concentric slave cylinder, which is located between the clutch assembly and manual transmission.
• Repair Kits: components necessary to rebuild the cylinder if the bore is in sufficient condition. Note - concentric slaves and composite (plastic) cylinders cannot be rebuilt.

• Hydraulic clutch systems are subject to 7 times the potential wear of brake hydraulic systems. This factor is due to the number of shift cycles or applications required. Fluid contamination and age of vehicle also contribute to failure on this system. Failure of the hydraulic clutch system will affect transmission performance and usually immobilizes the vehicle until repaired (inability to shift gears).