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| The unique brake fluid reservoir that was on The Alfatross when I got it--not original equipment! Is it trying to tell me something? |
The brakes were the first thing to go. Not the brakes themselves, but one of the hard brake lines that finally rusted through, bleeding all the fluid out of the reservoir. So it was fitting that the brakes were the Alfatross' first major system to be restored--well, that and the fact that brakes are easy and inexpensive to fix!
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| The parts of the original reservoir. The metal parts are in perfect condition, but the rubber seals, some of which are quite complex, are shot. |
Now, years later, I am once again wondering if I should have paid more attention to what that strange, apparently unique reservoir was trying to tell me. One restoration expert I showed it to said he thought it was a combination of a container made by one manufacturer and innards made by a different one. But why replace the original with this oddball reservoir? It is obviously much more expensive than the original reservoir. And what is it supposed to do, anyway?
A normal reservoir is just an empty can with a wide mouth at the top and a tube at the bottom eventually connecting to the master cylinder. Why all the rubber, brass, and steel parts inside the aluminum can? Was it an effort to treat some chronic problem the brake system was having? Am I now experiencing the same problem? Could it be manually "pumped up" to serve the same function as a brake check valve, always maintaining positive pressure within the system to keep the springs on the shoes from retracting the shoes so far that a single pump of the brake cannot supply sufficient fluid?
When we were preparing The Alfatross for the 2016 Arizona Concours we worked for hours trying to get a "hard" brake pedal. In the end, we drove with a pedal that went to the floor every time with very little effect. In preparation for the Santa Fe Concorso a few months later, we bled the lines repeatedly, took the master cylinder out for bench testing, and adjusted and readjusted the shoe-to-drum configuration. Finally, we disconnected the hard line from the master cylinder to the rear brake line and relied solely on the front brakes. That worked well enough for a stop gap solution, but two years and a lot of other experimentation later we're still scratching our heads.
A couple of weeks ago I sat down to list all the elements of a non-assisted drum brake system:
- Reservoir
- Fluid
- Master Cylinder
- Pedal
- Hard Lines
- Soft Lines
- Wheel Cylinders
- Shoe-Drum Articulation and Adjustment.
Then I started checking each of the elements. Remembering that The Alfatross was 14 years old when I got it and had 6 owners before me, each check started with the question "correct part?".
- Reservoir: Girling reproduction of original. Nothing to go wrong!
- Fluid: DOT 5. Rubber parts in system show no signs of degradation. Other 1900 SS cars using DOT 5 report no problems.
- Master Cylinder: 1" bore. Disassembled and bench tested, no leaks. Fluid volume displaced per stroke = 20 ml.
- Pedal: factory Brake Pedal Ratio appears low, ca. 4:1.
- Hard Lines: All new cunifer, double flare ends. No leaks. Lines bled using:
- Foot on pedal activation
- Lever attached to pedal shaft under car
- Suction at bleeder
- Under pressure from reservoir
- Gravity (horizontal)
- Gravity (tilted) Not tried yet!
- Soft Lines: New reproductions, nominal.
- Wheel Cylinders: Original front cylinders nominal. Rear original 1 1/8" bore cylinders improperly restored.
- Shoe-Drum Articulation: Linings nominal. Drums nominal. All adjustments nominal.
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| Each stroke of the piston expels 20 ml of brake fluid into the system. Note the scale on the right is in mm. Is that the correct volume? Who knows? |
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| Bench testing the master cylinder. The Starbucks mocha frappuccino bottle makes a great reservoir! The m/c passed all the tests with flying colors, so not the source of the problem! |
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| How to bleed brakes single-handedly: The black lever arm is bolted to the bottom of the brake pedal shaft. Pushing it to the left emulates foot pressure on the pedal. The spring scale at the other end of the lever holds pressure on the master cylinder while the bleeder screw is closed. |
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| An exploded view of one of The Alfatross' rear brake cylinders. The parts circled in yellow (two backing discs and a spring) were lost by the restoration company I sent them to . . . |
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| . . . and replaced with just a spring! Lesson: Trust, but verify, the work you parcel out to other people. |
Analysis of the elements of The Alfatross' brake system, combined with the very important clue provided by the oddball reservoir on the car when I acquired it, suggests that it had a "preexisting condition" adversely affecting its brake system. Good thing I didn't tell Grundy about that!
But what, exactly, was the nature of the condition? Over the next couple of weeks I am going to properly restore the rear wheel cylinders, make sure the pushrod between the end of the brake pedal shaft and the master cylinder allows the master cylinder its full travel range, prime the master cylinder and rear wheel cylinders before installing them, and gravity bleed the entire system. I may even experiment with a check valve on the hard line to the rear brakes. In the meantime, if anyone out there in Blogland has ever seen a reservoir like the one that came with The Alfatross and knows what it is supposed to do, PLEASE comment--The Alfatross needs a solution!
