Performance Motor Works

What are some types of TPMS are in use today?

Indirect System: Uses the ABS wheel speed sensors to monitor the rolling radius of the wheel and tire assemblies. Rather than directly monitoring tire pressure, the ABS measures the rotational speed of each tire. If one tire starts to spin faster than the others, the ABS determines that a tire has become smaller and has likely lost air pressure. This is done by measuring tire rotations within a given distance. A tire that has a reduced rotation that meets a predetermined percentage is considered to be low on air pressure.

Direct Systems : This system monitors the air pressure in the tires with a wheel mounted sensor. The direct type of TPMS can detect actual pressure levels and transmit the information to the driver more quickly. Tires are monitored individually by sensors attached to a special tire valve, or strapped to the drop center of each wheel. Each sensor monitors and transmits tire pressure and temperature every few minutes. The temperature is monitored to compensate for cold and warm pressure variations. In order to reduce battery consumption, the sensors revert to a “sleep” mode when the vehicle is parked or not moving. During this “sleep mode,” sensors may only activate and transmit signals about every 45 minutes.

To avoid damaging sensors when mounting and demounting tires, it is beneficial to know where the sensors are located. Sensor assemblies are commonly attached to the valve stem, with the valve stem acting as an antenna to assist with transmitting RF signals. They may also be strapped to the drop center of the wheel. If this is the case, the sensor assembly should be located in-line with the valve stem valve stem acting as an antenna to assist with transmitting RF signals. They may also be strapped to the drop center of the wheel. If this is the case, the sensor assembly should be located in-line with the valve stem.

To avoid damaging sensors when demounting tires, do not break the bead within 45 of either side of sensor assembly locations. Be careful not to damage sensors when mounting tires as well. Sensors are not repairable and require replacement if damaged or when their

battery is completely drained. It is recommended that the sensor be carefully “dropped into the tire” prior to demounting to avoid damage. When reinstalling the sensor, it is suggested that the locknut, gasket and valve stem be replaced and torqued to the proper specification. It is also necessary to use the proper valve cap as it is also an integral part of the system. It may be necessary to reprogram the TPMS when the tires are rotated, when a new sensor is installed, or after the vehicle loses power. This usually requires a scan tool andmay involve the use of a special magnet. Refer to the vehicle service manual to

properly reprogram the TPMS.

Preventative Maintenance

The Automotive Maintenance and Repair Association (AMRA) recommends to its members that (1) Brake fluid be tested for contamination at OEM recommended brake system inspection intervals, and (2) that a Brake fluid replacement service be performed, for most vehicles, when testing shows copper content exceeds 200 ppm. The AMRA Technical Committee reached these conclusions after extensive study of industry data, including a review of SAE Papers, US Government reports (NHTSA and NIST) and independent laboratory studies, among other resources. The data showed that this increased presence of copper contamination predetermines the rapid growth of iron con-tamination and corrosion which has shown to impede future brake system performance.

Braking System

What is a braking system?

An automotive braking system is a group of mechanical, electronic and hydraulically activated components which use friction / heat to stop a moving vehicle.

How does a braking system work?

When the brake pedal is depressed, the pressure on the brake pedal moves a piston in the master cylinder, forcing the brake fluid from the master cylinder through the brake lines and flexible hoses to the calipers and wheel cylinders. The force applied to the brake pedal produces a proportional force on each of the pistons.

The calipers and wheel cylinders contain pistons, which are connected to a disc brake pad or brake shoe. Each output piston pushes the attached friction material against the surface of the rotor or wall of the brake drum, thus slowing down the rotation of the wheel. When pressure on the pedal is released, the pads and shoes return to their released positions. This action forces the brake fluid back through the flexible hose and tubing to the master cylinder.

What components are in the braking system?

Disc Brakes
Disc Brakes are comprised of a disc or rotor, a caliper assembly, disc brake pads and the wheel bearings and hardware necessary to mount the components on the vehicle. The caliper is connected to the master cylinder through tubes, hoses and valves that conduct brake fluid through the system.

Drum Brakes
Drum Brakes are comprised of a drum & backing plate, a hub or axle assembly, brake shoes , wheel cylinder, wheel bearings and hardware necessary to mount these components on the vehicle. The wheel cylinder is connected to the master cylinder through tubes, hoses and valves that conduct brake fluid through the system.

Brake Fluid:
Brake fluid is a type of hydraulic fluid used in brake applications for automobiles and light trucks. It is used to transfer force under pressure from where it is created through hydraulic lines to the braking mechanism near the wheels. Braking applications produce a lot of heat so brake fluid must have a high boiling point to remain effective and must not freeze under operating conditions. Brake fluid is also designed to protect against corrosion of the system materials it contacts, however those corrosion inhibitors deplete over time. Excessive moisture is also an issue. MAP continues to seek additional information from brake fluid manufacturers and other technical experts to identify the point of vaporization that may seriously affect braking efficiency and safety.

Your driving type or vehicle usage may affect the maintenance intervals below. You should follow the manufacturer’s service schedule that best matches your vehicle’s operating conditions.

Proper Maintenance Helps Extend Vehicle Life!

Those recommendations may include:

• Change your engine oil every 3 months or 3,000 miles
• Check your tire inflation pressure monthly
• Rotate your tires every 6 months or 5,000 to 8,000 miles
• Change the engine air filter annually or when visibly restricted.
• Inspect Brake System every 12 months or 15,000 miles

AMRA/MAP believes that this information is accurate and reliable and does not endorse, approve or certify such information, nor does it guarantee the accuracy, completeness, efficacy, or timeliness; reliance on it should only be undertaken after a detailed review of the applicable OE publication(s).

AMRA/MAP is not responsible for, and expressly disclaims all liability for damages of any kind or consequences thereof, arising out of use, reference to, reliance on, or performance of such information.

If you own a BMW, Audi or Volkswagen, and you live in the Roseville area of Sacramento, we are always happy to answer your questions.

Performance Motor Works believes in providing our customer’s with the best possible service at an affordable price. To help educate our customers we have put together some ideas for when you need to have us work on your automobile. Read the rest of this entry »

Have Your Engine Cleaned From The Inside Out

Protect Your Investment

Since your car was new, dirt, varnishes and carbon deposits have been forming in your vehicles’ fuel system, on the intake valves and in the combustion areas. These contaminants can rob your vehicle of performance, feel economy, increase harmful emissions and could lead to costly engine repairs if left untreated.

When you drive, do you:

• Notice a loss in acceleration or power?
• Notice your engine hesitating, idling rough or stalling?
• Get fewer miles of driving per gallon of gasoline?
• Do you worry that you may not pass your next smog test? Read the rest of this entry »

If you own a BMW, the only way to obtain and analyze the onboard computer’s fault codes is with the GT-1. Performance Motor Works has invested significant money to provide our technicians with the best test and diagnosis equipment available. We work on all BMW automobiles in a timely and efficient way to provide our customer’s with the highest quality at an affordable price.  So, just in case you are wondering what the heck is a GT-1? Read the rest of this entry »