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Thread: Master Cylinder

  1. #1
    President Member Corvanti's Avatar
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    Master Cylinder

    pasted from another thread that was similar to my problem. thought i should start my own:

    "i went to drive the '51 Automatic 4 days ago and the brake pedal went to the floor. filled the MC with fluid and was fine. today i was going to go for a short drive and the pedal was to the floor again. i saw brake fluid on the garage floor beneath the MC. so she is parked until i can get at least a MC rebuild kit. i will do the lines, wheel cylinders, etc. and if needed, shoes.
    last winter, the right rear wheel would lock up or close to that occasionally but release when applying the brakes enough to warm it up. a bad or going bad wheel brake cylinder?
    i haven't fixed drum brake systems since around 1974, so this will be a relearning experience."

    i got under her and the fluid is coming out between the boot and the housing as shown in the shop manual. i think it needs just a rebuild kit which i plan to order shortly from a Studebaker vendor, then bench bleed it.

    is there anything i should do or look out for? hone out the cylinder? the shop manual is pretty clear cut on removal, etc.
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  2. #2
    President Member thunderations's Avatar
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    When you take it apart, check the bore for pits that may make rebuilding impossible. If the cylinder won't hone to a smooth finish, it will need to be replaced with a new one or sleeved at a machine shop.
    A repair kit is nearly $40 and a brand new master cylinder from our fabulous vendors is only $89.
    Once the master is working properly, it may cause the 4 slave cylinders to leak if they haven't been replaced/rebuilt recently. The next item to watch is the 3 rubber flex lines. More pressure from the new master puts every other part in the hydraulic part of the system under more strain. Have the steel lines been replaced in the last 66 years? They corrode and rust INSIDE, just like the cylinders do.
    You might get lucky, but I don't like to rely on luck when I apply the brakes.
    Last edited by thunderations; 10-05-2017 at 05:23 PM.
    1966 Daytona (The First One)
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  3. #3
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    That particular master cylinder is commonly available new and is fairly inexpensive. Better to replace rather than kit the existing master cylinder.

  4. #4
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    New master cylinders are so cheap that it does not pay to rebuild.
    http://www.autopartswarehouse.com/sh...tudebaker.html

    Robert Kapteyn

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    $32.79 (Dorman) from Rock Auto...

  6. #6
    President Member Corvanti's Avatar
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    ok, messages received.

    i just ordered the complete master cylinder. it should be here by next Thursday.

    i'll post if any problems (or not)...

    then on to brake lines, wheel cylinders, etc.
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

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    check the new ones for rust inside too///

  8. #8
    President Member Corvanti's Avatar
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    update: due some ongoing health problems, i had to take a few days off. today i got the old MC off. the only casualty was a old clevis (cotter) pin. the new MC showed up this morning - put the (automatic) anti creep valve and brake light switch assembly on the new one and bench bled the new MC. i'm going to try to get the MC installed tonight, if i don't fall asleep underneath the car.

    thanks to all that suggested getting a new MC, not a rebuild kit. and places/vendors to purchase one.

    i'm kind of thinking about after bleeding the brake lines/adjusting the drums and all is ok, to put off the new lines, cylinders, etc. for a month or two. the weather is supposed to be great for the next 9 of 10 days and a car show with a good Studebaker presence on the 28th not too far away - Smithfield, NC.

    thanks again for the comments - always welcome here!
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  9. #9
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    Definitely check the brake lines. I just replaced all four wheel cylinders, hoses, and master cylinders on my 57 Golden Hawk. When I put 100 lbs of air pressure on the long brake line to the rear axle hose nothing came out of the other end. The entire line was totally clogged with rusty gunk. When I cut it every foot just to check it out there was not one section that was not filled with rust.

  10. #10
    President Member Corvanti's Avatar
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    still fighting the leukemia but was able to get at the master cylinder again on the '51 Champion. as stated, the M-C is bolted back in and brake lines attached. now i'm having a problem with connecting the M-C "cylinder to pedal rod". there's no room getting the bolt to fit in between the brake pedal extension and the frame.

    DSCF1169.jpg i used the '51 Shop Manual for guidance in removing it and figured "installation is reverse of removal". am i missing something? i wouldn't doubt it, given all the meds i'm taking!
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    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  11. #11
    President Member tsenecal's Avatar
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    I just had the Master cylinder off of my Hawk, and had the same problem. I just loosened the two bolts on the master, allowing it to 'swing out' enough to put the rod in place. Hope this helps, and hope you get it back together for the show.

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    That right rear wheel locking up could be caused by a leaking rear axle seal , Ask me how I know , Ed

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    MC from RockAuto $30 for Centric or $40 for Delco. They are a real knuckle bustin' joy to replace and if they don't work a kit is unlikely to fix it. Patience and lots of Liquid Wrench. Just replaced shoes and all cylinders on my 58 Packard: pulled to the right and the RF shoes were saturated with brake fluid. The owner decided to go cheap and rebuild instead of replace. I have found that a job like removing a balky rusty MC is best done in small doses. Give it a half hour a day and quit before the hammers start flying!

  14. #14
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    On any under the floor mounted master cylinder , I would recommend replacing that setup with a dual master cylinder set up from Jim Turner.http://turnerbrake.com/mcbrackets.html

  15. #15
    President Member Corvanti's Avatar
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    well, i finally got the M.C., rod, bolt and clevis (cotter) pin installed! took the MC off i had to bend the brake pedal extension out about 3/8" to get the bolt and clevis in. but i couldn't get the MC to line up with the mounting bolts - about a 1/2" off behind the bolts. i had one of those "let me sleep on this" nights. sure enough i woke up in the middle of the night with a solution. i took out the mounting bolts and put the rear bolt in the other side of the MC. i had enough wiggle room and space to angle the bolt into the frame mounting hole enough to get the front bolt in correctly. then remove the rear bolt and install the correct way.

    i wanted to share all that in case someone runs in to the same problem. now to hook up the e-brake cable, brake lines, etc.

    to clarify some of the above comments - i purchased the new M.C. from Rock Auto last October - with shipping, it was around $42. it's a Dorman, part# DOR M2796.
    the right rear brake locking up happened in the winter last year (2016/2017). during a few cold spells. it would unlock if i put it in reverse and put the pedal down where it would drag a little (warming it up). then it would be fine and it stopped locking up altogether when the temps warmed up above freezing. i'm hoping that maybe there was/is some moisture in the line. i'll find out when bleed/replace the fluid later.

    thanks for all the help/comments! keep it coming...
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  16. #16
    President Member Corvanti's Avatar
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    May 1 Update

    it's been slow going - i finally got everything connected to the MC, pushed down on the brake pedal and got fluid coming out of the brake line above the anti creep (auto trans) connection. i tightened it - would only tighten about 3/4 of a turn. still leaking pretty bad. looking closely at it, it appears i may have cross threaded it. planning on taking that brake line off but i'm afraid the threads - both male and female connection may be toast.

    has anyone taken the anti creep valve out and run something like a "y line" from the MC to connect both brake lines directly? not sure that's a good idea. i'm getting way past frustrated here.
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  17. #17
    Golden Hawk Member StudeRich's Avatar
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    I guess the question is: do you REALLY need to have the Brake held for you after stopping?

    Can you remember to HOLD the Brake Pedal until the Red Light changes to Green?


    This was a bit helpful in '49-'55 when Automatics were a very NEW thing and misunderstood, but by now I think you will be OK without it.
    StudeRich
    Second Generation Stude Driver,
    Proud '54 Starliner Owner




  18. #18
    President Member Corvanti's Avatar
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    thanks Rich, i think i can handle that.

    i was concerned that it might interrupt the fluid balance going front to rear but if that's not a problem, i'll probably go without it. i will try to take the line off tomorrow and see if i can get it to thread on correctly, but doubtful that will work.
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  19. #19
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    Quote Originally Posted by jts359 View Post
    That right rear wheel locking up could be caused by a leaking rear axle seal , Ask me how I know , Ed
    Agree 100% on this! Been there.

  20. #20
    President Member Corvanti's Avatar
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    well, i messed up big time today. while looking for a wrench for something else, i found a 3/8" flare nut wrench. got back under the '51. it turned the nut on the upper brake line a couple of revolutions. pumped the brake pedal a couple of times and it still had a small drip. got back under and tightened it a bit more. all of a sudden it got loose enough to turn it by hand. stripped the heck out of it. checked the reservoir - it was almost dry - filled it back up.

    i'm about to take the 2 lines and anti creep valve off. i'm thinking i will have to take the MC off and bench bleed it again.
    is that correct?
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  21. #21
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    Single master cylinders do not need to be bench bled. Just fill it and pump the pedal. Also, bleeder screws do not need to repeatedly opened and shut whilst bleeding. Push a small dia hose over the screw and submerge the other end in some brake fluid, then just pump the pedal till no more bubbles come. You can usually do eight strokes before having to refill.

  22. #22
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    Ross is right. Google "Pop bottle brake bleeder" to make a simple one man brake bleeder. they are shown in all the old (50 year plus) mechanics books. Small bottle ok, no need for a 2 liter size!

    Bench bleeding makes the job easier, but once on the car, do not remove to do that again, just add fluid and keep going.

    As far as the hydraulics are concerned, there is no difference from drum brakes to disc brakes. No air in system, pads or shoes need to be close to the drum or disc, replace old rubber, etc, etc.
    Frank DuVal

    50 Commander 4 door

  23. #23
    President Member Corvanti's Avatar
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    alright! pieced a few parts together with the help of the local Napa guy. just got the MC to brake lines together - and no leaks.

    next i'll start bleeding the brake lines. i'm hoping everything there "co-operates". then back to the MC to adjust the free play in the brake pedal and adjust the parking brake.

    BTW: i do have a manual vacuum pump for the brakes that i picked up at Harbor Freight 6 or 7 years ago. i haven't used it since that time on some "brand X" i was flipping.

    just had a thought: should i adjust the pedal/parking brake before bleeding? seems to me that it wouldn't matter since the lines will be sealed up.
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  24. #24
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    Quote Originally Posted by Ross View Post
    Single master cylinders do not need to be bench bled. Just fill it and pump the pedal. Also, bleeder screws do not need to repeatedly opened and shut whilst bleeding. Push a small dia hose over the screw and submerge the other end in some brake fluid, then just pump the pedal till no more bubbles come. You can usually do eight strokes before having to refill.
    Easier said than done! My bleeders ('46 M5 pickup) have 3/8" hex heads. Not exactly conducive to slipping a clear tube over to seal it without dripping brake fluid everywhwere, like you would on a more modern bleeder nipple.
    Ted Taylor
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  25. #25
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    Quote Originally Posted by tedtaylor View Post
    Easier said than done! My bleeders ('46 M5 pickup) have 3/8" hex heads.
    Why not fit the proper tube over only the end of the bleeder, it's round.....
    64 GT Hawk (K7)
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  26. #26
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    Quote Originally Posted by 64V-K7 View Post
    Why not fit the proper tube over only the end of the bleeder, it's round.....
    No it's not. Exactly my point. I don't have the normal typical round headed bleeders that look like grease joints, i have actual flat faced hex head bolts with a hole in the middle where fluid comes out all over. No way to put a round clear tube over a hex head bolt. Am i the only one with such original type bleeders?
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    Last edited by tedtaylor; 05-09-2018 at 10:06 AM.
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    President Member TWChamp's Avatar
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    The only thing I can think of for that bleeder is to go to the hardware or hobby store and buy a foot of thin wall brass tube that fits snug into the hole, cut off an inch or so, then use plastic hose over the short brass tube.

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    Is there some reason you can't replace the bleeders with the other style?

  29. #29
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    both very good suggestions. i was just working with what was original.
    While i'm at it, does anyone know what the little slotted head screw thingy is right below the bleeder? I did NOT take it off or attempt to remove while i rebuilt the cylinders, but did wonder what the heck it was for.
    Ted Taylor
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  30. #30
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    The little plugged hole is for manufacturing purposes--that is how they drilled the passage into the cylinder.

    Still think that a good soft piece of vacuum tubing with no fabric reinforcement will fit over your bleeder screws adequately. Since drum brake master cylinders have check valves there is no tendency for the fluid to draw back in while bleeding.

  31. #31
    President Member Corvanti's Avatar
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    Quote Originally Posted by tedtaylor View Post
    Easier said than done! My bleeders ('46 M5 pickup) have 3/8" hex heads. Not exactly conducive to slipping a clear tube over to seal it without dripping brake fluid everywhwere, like you would on a more modern bleeder nipple.
    i believe one of the accessory nozzles on this HF kit will fit your your small opening. might have to hold it in place until the vacuum starts. grab a 20% off coupon from their circular and it'll be $20.

    https://www.harborfreight.com/brake-...kit-63391.html
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  32. #32
    President Member Corvanti's Avatar
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    Bleeding the Brakes

    It's been slow going due daily post chemo treatments, but I just started 3 days a week so I should get more work time in.
    I've had to put over 2 quarts of brake fluid through the right rear and still getting large bubbles going thru the vacuum line. Went over to the left rear and still getting the big bubbles. I checked the lines coming out of the MC and there are no leaks, or anywhere else. I haven't let the MC reservoir run dry.
    So what am I missing?
    It's been several years since I've bled drum brakes but never a Studebaker or where the MC is under the floor.
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  33. #33
    President Member TWChamp's Avatar
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    Are you using pressure on the master cylinder to bleed the brakes, or are you using a vacuum pump at each bleeder?

    I prefer the pressure bleeder, but will have to use my vacuum pump to do the same thing on my 1950 in a couple days.

    BTW, you do have ONLY one bleeder open at a time, I hope.

  34. #34
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    You are drawing in air around the threads of the bleeder screws. This is often the case with vacuum bleeding. I am sure there is no air in the cylinders by now, but your life would be much easier if you just shoved a hose over the bleeder screws and submerged the other end in a bit of fluid in a jar. Then just pump the pedal till no bubbles appear in the jar.

  35. #35
    President Member Corvanti's Avatar
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    ^^yeah, only 1 bleeder at a time open using a vacuum pump at the wheel.

    ^Ross i think you nailed it! i went to pumping the brakes with a line and a jar. got no bubbles in the left rear, which i reopened from yesterday and very few bubbles in both the fronts.

    the problem is the brake pedal still goes to the floor with many pumps and everything buttoned up. i guess i'll start over from the right rear and try it again.

    also, it looks like the MC rod could be adjusted about 1/3 inch. but it seems i'd get some pedal where it is.

    thoughts?
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

  36. #36
    President Member TWChamp's Avatar
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    Are the shoes all adjusted to a light drag?

  37. #37
    President Member Corvanti's Avatar
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    finally - SUCCESS!!! i bled the wheels one more time and adjusted the MC rod and i got pedal. in fact, too much pedal - i'm going to have to back the rod off a bit to get the 1/8 to 1/4" free play. after that, adjust the parking brake and i should be good to go.

    i noticed the brake lines were flowing freely while bleeding. they are steel lines to the rear and fairly short rubber lines in the front. if all works well on the test drive, i'm not going to go into the hubs and check the shoes, etc. - mainly due to the illness and the fatigue.

    while (still) up on jack stands, i noticed some of the undercoating had come off and a few surface rust spots.

    i'll get that later. for now i just want to drive her!

    thanks for all that contributed to the thread...
    Kerry. SDC Member #A012596W. ENCSDC member.

    '51 Champion Business Coupe - (Tom's Car). Purchased 11/2012.

    '40 Champion. sold 10/11. [IMG][/IMG] '63 Avanti R-1384. sold 12/10.[IMG][/IMG]

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