In this episode of DIY's Classic Car Restoration, the process of restoration continues on the 1969 Alfa with the refurbishment of the rear brakes and suspension. Both suspension and brakes are completely overhauled on this car in an effort to bring those systems back to near-new condition while retaining some of the European racing heritage that went into the design of the Alfa Spider. Components replaced and restored in this phase of the restoration include the rear control arms, coil springs, shock absorbers, mechanical emergency-brake system and rear disc-brake components. Overview: Rear Brakes and Suspension
One of the reasons the Alfa Spider was so popular in the late sixties is because of its legendary handling capabilities. The design of the Alfa Spider grew out of the company's efforts to create a road-racing contender, and much of the car's success on the track as well as the roadway was because of the racing-design suspension and brakes. In restoring the rear brake and suspension, considerable effort is taken to revive the kind of performance handling that was characteristic of the car when it was new. As with many aspects of the Alfa, some attributes of the rear suspension system are essentially unique to this vehicle model.
- The rear axle on the Alfa (figure A) separate left to right, in contrast to most contemporary rear-wheel drive cars in which the axle separates front to back.
- At the bottom of the axle is an inspection plate (figure B) that can be removed to allow inspection and maintenance of the contents of the differential housing, and access to the pinion and pinion-bearing.
- Left and right lower control-arms (figure C) sit directly beneath the coil springs and shock absorbers.
- Higher up, the reaction trunnion is regarded as the heart of the Alfa's performance suspension. This structural support is largely responsible for the dramatic cornering capabilities that are characteristic of this car. The front end of the Alfa tends to over-steer -- meaning that the front-end essentially controls the car as it goes through corners. The reaction trunnion (figure D) adjusts the rear axle, letting it to follow precisely through the turning radius, thus allowing for remarkably tight and fast cornering.
- A rebound strap serves to limit the downward travel of the rear suspension and helps keep it attached to the rear of the car (figure E).
- When Alfa switched from drum brakes to disc brakes, servo-controlled hydraulic calipers (figure F) were added, used with rotors as is typical with disc brakes. However, these rotors were unique in that they incorporated a component similar in appearance and function to a brake drum.
This "drum" functions as part of the mechanical emergency (or parking) brake system, which could be used to stop the car in the event of a failure in the hydraulic (disc) brakes. This essentially provided the vehicle with three separate braking systems: the front servo-supplied disc brakes, the rear servo-supplied system and a mechanical brake system. In the event of a complete failure in the hydraulic braking system, the mechanical brake could be used to bring the Alfa to a controlled stop.
This backup braking system -- another product of engineering for racing safety and efficiency -- made the Alfa a safer and more advanced vehicle for driving on the road. Because it worked so well, the separate mechanical brake system was maintained on Alfa Romeos right up through the nineties-era models.
RESOURCES :
Alfa Romeo Owner's Bible: A Hands-On Guide to Getting the Most from Your Alfa
Model: 0837607078
Author: Pat Braden
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Bentley Publishers
Alfa Romeo Spider: The Complete Story
Model: 1861261225
Author: John Tipler
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Crowood Press
Original Alfa Romeo Spider (Bay View Original Series)
Model: 0760311625
Author: Chris Rees, James Mann
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Motorbooks International (MBI Publishing)
Essential Alfa Romeo Guilia & Giulietta Coupes & Spiders: The Cars and Their Story 1954-95
Model: 1870979591
Author: David Hodges
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Motorbooks International (MBI Publishing)
Alfa Romeo: The Spirit of Milan
Model: 0750919582
Author: David G. Styles
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Sutton Publishing
Classic Car Restorer's Handbook: Restoration Tips and Techniques for Owners ...
Model: 1557881944
Author: Jim Richardson
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H.P. Books
Classic Car Restoration Guide: The Complete Illustrated Step-By-Step Manual
Model: 1850108900
Author: Lindsay Porter
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Haynes Publishing
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