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Selection of a brake fluid is primarily dependent upon car usage. For owners who do most of their driving on the street, older models have done well with the Castrol GTLMA, and either the Porsche DOT 4-200 or ATE 200 equivalent should work just fine with periodic changes on the late models. If a lot of long autocrosses or high-speed track events are driven, the higher performance fluids can provide greater resistance to boiling. In addition to worn rotors, a number of classic symptoms can warn the owner ahead of time that some of the components in the system need help. If an owner smells brake fluid in a non power-brake, rear-engine Porsche upon entering the car after it has been closed up overnight, it may be a sign that the rear seal in the master cylinder is leaking and allowing fluid to run out into the foot pedal area. This can be bad news if it isn't attended to promptly, because the fluid will attack not only the painted surfaces, but also the original plastic pedal bushings in the pedal cluster and then work its way down the tunnel of the air-cooled engine cars. It should be noted that current factory plastic replacement bushings are brake fluid proof. Usually there is nothing wrong with the main part of the master cylinder and it can be fixed just by replacing the rear seal. Component RepaiRs The later 911 power brake type master cylinders have two pressure sensor switches and an electronic sensor turns on the brake failure light if there is a pressure difference. If the brake failure light goes on, the front circuit may have to be opened and the battery temporarily disconnected to re-equalize the pressure and return the sensor back to its normal condition. If one brake light switch fails, it is a good idea to change both switches at the same time. Flexible brake hoses gradually lose their strength after a number of years of exposure to contaminated brake fluid on the inside and road debris on the outside. After 12-15 years, owners have experienced flexible hoses that become partially or completely clogged. In others, the hoses become soft and weak. After a number of years, replacement with new hoses is prudent preventative maintenance. If the owner maintains his brake awareness and includes brake maintenance along with his other regular maintenance routines, he will have few brake problems and will always be able to enjoy the superior braking power that came with his Porsche. 1. A. Caldwell, "Disk Brake Update," Porsche Panorama, October, 1998 (Up-Fixin der Porsche, Vol. 11, page 65). RefeRenCes 2. A Caldwell, "Disc Brake Maintenance," Porsche Panorama, October, 1998 Up-Fixin der Porsche, Vol. 8, page 160. 3. PCNA Technical Bulletin No. 84-01, Group 47, "DOT 4 Brake Fluid Now Used in Production," July 27,1984. 4. B. Anderson, "Brake Fluid," Up-Fixin der Porsche, Vol. 7, page 162. Haury's offers a wide selection of services: - Expert collision repair services for the discerning enthusiast BY enthusiasts - A selection of enthusiast-minded loaner vehicles, including a 2008 BMW M3 and a 2008 MINI Cooper S - Free loaner cars offered with a major repair service - Porsche and BMW club track inspections - Pre-purchase inspections of both engine and structural repair, to set your mind at ease when looking for a new car - General engine maintenance including 30/60/90K service - Structural frame repair and welding equipment that meets Porsche certification guidelines - Porsche Club members receive a 5% discount (up to $250) - We also have Collision Consulting services on-site, which can help you navigate a difficult insurance claim and provide diminished value or total loss appraisals. HAURY'S LAKE CITY COLLISION Specializing in collision repair, service, and modification to European, Japanese, and high-performance vehicles. 11514 Lake City Way Northeast, Seattle WA 98125 1-877-249-0868 /// 206-365-1565 /// http://www.hauryscollision.com/ 38 June 2011