|Alfa Romeo GTV6 Site:
European Car Magazine - GTV6 Project
European Car Magazine - May 1995
Author - Paul Mitchell
Photos by the author
|Since 1910, when Alfa Romeo began producing
performance cars, Alfds engineers have considered braking to be one of the most critical
of all performance characteristics and worthy of the extensive attention they devoted to
innovative solutions. While Ford was stamping out Model Ts and As, and other European
manufacturers were producing cars not much more sophisticated, Alfa Romeo was building
1750cc supercharged dual overhead cam sports cars. These Alfas were fitted with aluminum
drums that provided superior braking, which allowed Alfa Romeo to win many Grands Prix and
open road races. During this period, Alfa Romeo won several World Championships.
From this beginning, through the 159 Alfetta G.P car and its massive disc brakes, the 2000 Sportiva with its inboard rear drums, and the Giulietta, with its beautifully cast aluminum three-shoe drums, Alfa braking system evolution has been marked with extraordinary capability and innovation.
Among recent Alfas, the 116 chassis cars-the GTV-6 and Milano - certainly deliver on the promise of the past. Their demise in 1986 and 1989, respectively, was not due to any inherent flaws but rather was a economic decision made by the Fiat Group, which had recently purchased Alfa Romeo (along with Lancia, Ferrari and most everything else Italian).
This decision was based on the margin of profit from the production of these models. They were simply too expensive to produce. The large number of aluminum castings associated with an aluminum engine and rear transaxle, the rear inboard disc brakes, and the de Dion tube and Watts linkage of the rear suspension were all very costly items to make, usually found on far more expensive cars. It's just, simpler and cheaper to make front-wheel-drive cars, as evidenced by Fiat's entire line; or the lines of most other manufacturers for that matter. All of the things that made the GTV-6 and Milano unique in performance and personality, and make them fun to drive and own, eventually killed them.
The braking systems of the Milano and the GTV-6 are virtually identical. It begins with a vacuum booster manufactured by Alfred Teves GmbH (ATE) coupled with a simple dual-circuit master cylinder of the same brand, though occasionally one by Benditalia sneaks through. The master cylinder actuates Brembo dual-piston calipers in the front and very unique adjustable twin piston calipers by ATE mounted inboard at the transaxle in the rear. Spinning through both sets of calipers are Brembo rotors. The 116 chassis cars have 10.4-in. vented rotors in the front and 9.8-in. solid rotors in the rear.
This system is quite capable of handling velocities achieved by the GTV-6, and compares favorably when considering the swept area-to-weight ratio to that of other sports cars. The system is a forthright design requiring little special attention. With the exception of the rear calipers, knowledge of standard braking systems will carry you through most maintenance procedures.
Our testing brought two areas to our attention. First, that the factory supplied 195/60-15 tires provided a contact patch too small to match the ability of the brakes, and that the OEM brake pads, though not bad, could definitely be improved upon.
Having taken care of the tires in our previous article, our goals were to improve upon braking ability substantially, while maintaining safety and full function under all conditions found in everyday street use, such as a panic stop with cold brakes, as well as conditions most people will never experience, such as competition use. We also sought to enhance, or at least not adversely affect, ease of maintenance and reliability. Keep in mind that any ill-advised modifications, such as increasing caliper size without a commensurate increase in rotor swept area, could easily result in Racer X being well on his way to becoming Patient X. Additionally, should any regular maintenance be neglected during hard usage, such as regularly changing the brake fluid, Racer X may well become a familiar face to everyone down at ICU.
To avoid the obvious disadvantages of these concerns, such as orthopedic traction and physical therapy, stay with modifications which you know have been track tested, preferably through constant competition. Those who race wont stay with any modifications that won't help them win, and sanctioning bodies won't allow unsafe modifications.
In our testing, we employed a pyrometer and tempilables (an adhesive label which when applied will provide a temperature reading during operating conditions) to determine pad and fluid selection.
It was known beforehand that the OEM flexible brake lines would be replaced with Shankle stainless steel lines. This is a very worthy modification, even for cars which are to have no other modifications. Along with being more resistant to damage, they will provide better pedal feel. To run through our new lines we wanted to select a fluid that provided a higher boiling point than those commonly available. It was known that the brakes would be subjected to very hard use in autocross and club racing. Also desirable was a low hygroscopic rating. Other things in your life may retain water, but your brake fluid shouldnt.
Much discussion still continues regarding silicone brake fluids. Though essentially non-hygroscopic, silicone fluids contain more air than standard DOT 4 fluids. With up to 15% retained air, silicone fluid can cause a spongy brake pedal feel, though I'm sure many people have become accustomed to this. In comparison, glycol fluids retain only about 5% air. I felt that it was an unnecessary burden, when there are high quality glycol fluids available which provide all the desired characteristics without having to replace all the seals in the entire system, a standard precaution when using silicone fluid in a system which previously used DOT 4. Also, silicone is not compatible with all seal materials, and I was not prepared to find out if the seal in the GTV-6s were of the wrong type.
A good fluid to use is ATE SL DOT 4 brake fluid (available from Alfa Ricambi of Glendale, California. Alfa Ricambi is also the source of the aforementioned Shankle stainless steel brake lines. Shankle and Alfa Ricambi provide excellent performance and original Alfa pieces, many that may be difficult to find elsewhere, and always priced within reason.). After testing several brands of brake pads, we selected Repco Metal Masters. Another pad we considered were the Ferodo brand street pad. They provide comparable performance and are readily available. The Repco pads provided consistent performance and feel through the full range of conditions we encountered through our testing. Though Metal Masters, like most semi-metallic pads, will cause your rotors to wear more quickly than organic pads, few would argue that the improved performance is worth that small price.
When it came time to decide on what to do with the standard Brembo rotors, we were faced with our most trying decision. Feeling compelled to make some kind of improvement, and with Alfa Ricambi offering cross-drilled rotors which would undoubtedly perform as intended, it was difficult to accept that no changes needed to be made. We have experienced absolutely no brake-fade with the system as it is. So we felt there was no justification for installing the cross-drilled rotors.
Occasionally, other GTV-6 owners report that they are not as fortunate and experience some degree of brake fade during extreme use. Of course, I cannot account for the unknown variables that could contribute to these complaints, but I'm sure that cross-drilled rotors could definitely help ease the pain of these anguished souls.
Though we chose not to install the cross-drilled rotors, we are including removal and installation instructions in our tech procedures for those who may choose differently or require new OEM rotors. Also keep in mind that when resurfacing rotors, a non-directional cut is preferable to a standard circular cut, though not absolutely necessary. Many machine shops are able to perform non-directional resurfaces, often using a flat wheel resurfacer. And remember that Alfa rotors may only be machined once. Minimum front rotor thickness is 20 mm and the rear is 8 mm. Replacing the rotors with new ones as opposed to resurfacing seems reasonable, particularly when one considers the cost of new components, rotor.
At this point, with the rotors off the car, would be the time to replace your front wheel bearings. Though many Alfas pass the I 00,000 mile mark with their original wheel bearings, taking such chances with a car that will be driven hard and quickly would be ill-advised. The substantial amount of safety and reliability gained will certainly offset the small investment in labor and expense.
When undertaking any of these upgrades or maintenance outlined on these pages, keep in mind that along with steering, the braking system is the most critical of all systems in your car. Any repair or modification improperly done will affect safety in an adverse manner that will likely result in injury.
When handling braking surfaces, pads and rotors, prevent these surfaces from coming into contact with any type of lubricant or hydraulic fluid. Pads which have become saturated or even slightly soiled with brake fluid or grease must be discarded. Rotor braking surfaces may only be cleaned with alcohol or a quality brake solvent.
Seals should be inspected for leaks and deterioration, and if any are found, the caliper should be rebuilt or replaced immediately. GTV-6 and Milano rear calipers can only be replaced. Due to the unique construction of the rear caliper, attempting to disassemble them is not advised. When adjusting the rear calipers, following the instructions provided here is essential. When rotating the adjusting screws, care must be taken to not go beyond the adjusting screw limits, which will result in damage to the adjusting screw seals that will cause them to leak, and necessitating replacement of the complete caliper.
The technique for bleeding the rear brakes is unique to these models and any deviation from these instructions will provide an improper bleeding, not ensuring that all air has been removed from the system. To facilitate this procedure, you'll find a bleeding bottle to be indispensable. A simple expedient one may be made from a clear plastic bottle and two 3-ft lengths of 1/8-in. I.D. fuel line. We used a one-liter bottle so that the entire system may be bled at all four corners without having to stop and empty the bottle. Simply poke two holes in the cap and insert the two lines until the ends just reach the bottom.
All pad retention pins and springs should be inspected for rust and damage and replaced as necessary. And never reuse a cotter pin. The following procedures are also found in the factory service manual I and I recommend to every owner that one should be on their workbench. They are available through Alfa Ricambi for approximately $75 and can easily save you that amount the first time it's needed.
Alfa Ricambi can also provide all the items used and mentioned in this article at prices often substantially below your dealer or local parts house.
Installation of the Shankle Stainless Steel Brake Line
Begin by withdrawing all existing brake fluid from the master cylinder reservoir with the syringe. Place the car on jack stands and remove the front wheels. Clean the calipers and all fittings to be serviced with brake cleaner and allow to dry. Removal and installation of the lines is essentially the same for the front and rear, so these instructions will cover all three lines.
Required Tools and Supplies
Brake System Bleeding (Non-ABS):
Replacing Front Rotors and Wheel Bearings
Brake Pad Removal/Installation
The following procedures are conducted with the car raised on jack stands and the front wheels removed.
Having done all of these procedures to our GTV-6, the braking performance has been greatly enhanced.