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Thread: Brake Fluid vs Hydraulic Fluid

  1. #1
    President Member 53k's Avatar
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    Brake Fluid vs Hydraulic Fluid

    I'm trying to get the modified '53 Commander Starliner drivable (thread http://forum.studebakerdriversclub.c...on-my-driveway ).
    It has a hydraulic clutch. The master cylinder is dry. I would have filled it with DOT3 brake fluid, but there was a can of hydraulic jack fluid in the trunk which made me think maybe that is what the previous owner(s) used.
    What is the harm of filling it with brake fluid if hydraulic fluid had been used before? What about hydraulic fluid if it had brake fluid before?

    Paul Johnson, Wild and Wonderful West Virginia.
    '64 Daytona Wagonaire, '64 Avanti R-1, '53 Commander Starliner, Museum R-4 engine, '72 Gravely Model 430 with Onan engine

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    FWIW, I've installed a bunch of hydraulic clutches and every one of them used brake fluid.

    jack vines
    PackardV8

  3. #3
    President Member r1lark's Avatar
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    I've had several cars ('60s/'70s) that had hydraulic clutch actuation, and they used brake fluid.

    Might be worth 'flushing' the system good when you bleed it - flush a good bit of brake fluid thru it flush out an jack fluid that might be left in it.
    Paul
    Winston-Salem, NC
    Visit The Studebaker Skytop Registry website at: www.studebakerskytop.com

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    President Member 53k's Avatar
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    Thanks for the good replies. I did hear from a previous owner and he said it was filled with brake fluid. I'm going to try to smell the remnant of fluid and if it smells like brake fluid, I'll try that. If I can find the bleeder valve on the slave cylinder, I'll probably flush it anyhow. I just didn't want to have to take off the master cylinder (tough location against the frame), but it looks like it's been leaking so I may have to anyhow).

    Paul Johnson, Wild and Wonderful West Virginia.
    '64 Daytona Wagonaire, '64 Avanti R-1, '53 Commander Starliner, Museum R-4 engine, '72 Gravely Model 430 with Onan engine

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    Agreed -
    The materials used (rubber, aluminum, stainless steel, iron) and the action of the clutch master and slave cylinder...is...and does exactly the same thing as what the brake master and wheel cylinders do.

    Brake fluid (dot 3 or 4), should be used...as has been noted by others..

    Mike

  7. #7
    Silver Hawk Member Milaca's Avatar
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    Years ago when I began driving gravel truck for my dad's excavating business, I drove a beat-up 1969 Ford F-9000 and it had a hydraulic clutch. I was hauling gravel for a township road one day when the clutch pedal no longer did anything....dont recall if I had the transmission in neutral or in gear when I discovered this. Anyway, I stopped along the road to diagnose the problem when I found that the clutch linkage was connected to a master cylinder (didn't know it had a hydraulic clutch until then), which I opened up and found empty. Being out there alone, I had to find some way of getting this thing to work, so I searched in the cab for some fluid and found a quart bottle of Dexron (used it in the leaky power steering) and poured it in. Gave the pedal a few pumps, and it worked! Dont know how being that I didnt bleed the system, but all worked fine and I continued hauling with it. Never did replace the fluid, but two years later it was parked in the pasture as the 1160 Caterpillar diesel engine was shot. I never did like that truck...

    In the middle of MinneSTUDEa.

  8. #8
    President Member 53k's Avatar
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    Quote Originally Posted by 53k View Post
    Thanks for the good replies. I did hear from a previous owner and he said it was filled with brake fluid. I'm going to try to smell the remnant of fluid and if it smells like brake fluid, I'll try that. If I can find the bleeder valve on the slave cylinder, I'll probably flush it anyhow. I just didn't want to have to take off the master cylinder (tough location against the frame), but it looks like it's been leaking so I may have to anyhow).
    Decided the fluid in the bottom of the master cylinder was brake fluid so I jacked up the car, put HD stands under the frame and crawled under tracing the clutch fluid line. Found the slave cylinder OK, but the bleed valve is on the bottom of it. I'm thinking I won't be able to get all the air out that way. I only had a little less than a pint of DOT3 and I went through that still getting bubbles in the bleeder line. I tried the pedal anyhow and got no motion of the slave cylinder. So, tomorrow I guess I'll go buy a quart or two of fluid and keep at it

    Paul Johnson, Wild and Wonderful West Virginia.
    '64 Daytona Wagonaire, '64 Avanti R-1, '53 Commander Starliner, Museum R-4 engine, '72 Gravely Model 430 with Onan engine

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    Yep, the bleed screw has to be the highest point in the slave cylinder or you'll never be able to get all the air out of it.

    jack vines
    PackardV8

  10. #10
    President Member 53k's Avatar
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    Quote Originally Posted by PackardV8 View Post
    Yep, the bleed screw has to be the highest point in the slave cylinder or you'll never be able to get all the air out of it.

    jack vines
    Thanks. I can't believe they put it together that way. I hope I can flip it 180 tomorrow without running in to more complications.

    Paul Johnson, Wild and Wonderful West Virginia.
    '64 Daytona Wagonaire, '64 Avanti R-1, '53 Commander Starliner, Museum R-4 engine, '72 Gravely Model 430 with Onan engine

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