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    Results 1 to 19 of 19
    1. #1
      Join Date
      Jul 2009
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      Cypress, TX
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      Trouble with Wilwood master cylinder

      Finally gave up trying to bleed my rear brakes and took it to the shop. I've got a Wilwood master, wilwood calipers on all 4 corners , a booster and an adjustable valve in the rear line. The shop tells me that the rear brakes portion of the master cylinder isnt supplying pressurized fluid. They recommending getting a new master. Not much to go on, but has anybody else had problems with their Wilwood master?
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    2. #2
      Join Date
      Jul 2009
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      Cypress, TX
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      I'm considering putting OEM master on at least temporarily. Anything I need to do to the OEM master to accommodate disk brakes on the rear?
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    3. #3
      Join Date
      Mar 2013
      Location
      Beaufort,SC
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      329
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      The cylinder swap should be find the proportioning valve adjusts pressure. did you bench bleed the M/C?

    4. #4
      Join Date
      Jul 2009
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      Cypress, TX
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      Yes, I bench bled.

      Quote Originally Posted by no go nova View Post
      The cylinder swap should be find the proportioning valve adjusts pressure. did you bench bleed the M/C?
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    5. #5
      Join Date
      Mar 2013
      Posts
      88
      Country Flag: United States
      I see sooooo many brake issues on not only this forum but others as well. One issue that so many times is overlooked is the "volume" issue. When brakes are upgraded this must be considered. In short, the master cylinder when depressed all the way (many have a 1.00" stroke) displaces X amount of fluid. This amount must be more than the volume of the area in each caliper after the pistons are moved completely out and applying pressure to the pads. IF it is not, you will have poor or no brakes. Most of the time you will find, your master cylinder is just too small.

    6. #6
      Join Date
      Jul 2013
      Location
      St Louis
      Posts
      213
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      Quote Originally Posted by terrydmorgan View Post
      Finally gave up trying to bleed my rear brakes and took it to the shop. I've got a Wilwood master, wilwood calipers on all 4 corners , a booster and an adjustable valve in the rear line. The shop tells me that the rear brakes portion of the master cylinder isnt supplying pressurized fluid. They recommending getting a new master. Not much to go on, but has anybody else had problems with their Wilwood master?
      Im having the exact same problem, Ive even swapped out Wilwood MC. I just assumed it was air, I mean how could 2 Wilwood MC be bad, right lol? BUt I have yet to be able to bleed the rear.

      Pontiac Powered 72 GTO

    7. #7
      Join Date
      Jul 2009
      Location
      Cypress, TX
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      317
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      I don't think volume is my issue. I'm just not getting any pressure out of the rear port. Unfortunately, Wilwood's tandem aluminum master cylinder doesn't have a rebuild kit. You have to send it in for repair.


      Quote Originally Posted by IMPALA MAN View Post
      I see sooooo many brake issues on not only this forum but others as well. One issue that so many times is overlooked is the "volume" issue. When brakes are upgraded this must be considered. In short, the master cylinder when depressed all the way (many have a 1.00" stroke) displaces X amount of fluid. This amount must be more than the volume of the area in each caliper after the pistons are moved completely out and applying pressure to the pads. IF it is not, you will have poor or no brakes. Most of the time you will find, your master cylinder is just too small.
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    8. #8
      Join Date
      Jul 2009
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      Cypress, TX
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      I'm about to try a second master cylinder too. I'll let you know if that clears up my proble. What are the odds that there are 4 bad master cylinders?

      Quote Originally Posted by Gratefuldiver View Post
      Im having the exact same problem, Ive even swapped out Wilwood MC. I just assumed it was air, I mean how could 2 Wilwood MC be bad, right lol? BUt I have yet to be able to bleed the rear.
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    9. #9
      Join Date
      Jan 2006
      Location
      Oregon
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      1,773
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      How did you bench bleed the master cylinder? Recirculation or plugged port method? If you used the recirc-method with the tubes and fittings supplied with the master cylinder, I would still suggest that you confirm the MC is fully bleed by plugging both outlet ports and verifying that the piston hydraulically locks after about 1/8" of stroke. If it doesn't, then you either have air in one or both chambers or you have a bad seal. If it's air, slowly stroke the piston and watch for air bubbles returning into the reservoir...if it improves, then you know that was most likely the issue. if you stroke the piston repeatedly without any sign of air, then it's probably fluid bypassing a seal internally.

      Even if you don't have a rebuild kit, you can still pull the piston assemblies out and make sure there isn't a chip or something causing the issue.

      Tobin
      KORE3
      It's what I does.

    10. #10
      Join Date
      Jul 2009
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      Cypress, TX
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      Thanks for the tips Tobin. I bench bled using the re circulation method. I'll Block em off and see what happens.

      Quote Originally Posted by Apogee View Post
      How did you bench bleed the master cylinder? Recirculation or plugged port method? If you used the recirc-method with the tubes and fittings supplied with the master cylinder, I would still suggest that you confirm the MC is fully bleed by plugging both outlet ports and verifying that the piston hydraulically locks after about 1/8" of stroke. If it doesn't, then you either have air in one or both chambers or you have a bad seal. If it's air, slowly stroke the piston and watch for air bubbles returning into the reservoir...if it improves, then you know that was most likely the issue. if you stroke the piston repeatedly without any sign of air, then it's probably fluid bypassing a seal internally.

      Even if you don't have a rebuild kit, you can still pull the piston assemblies out and make sure there isn't a chip or something causing the issue.

      Tobin
      KORE3
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    11. #11
      Join Date
      Jul 2013
      Location
      St Louis
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      213
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      Not trying to hijack but what I think I found today was the rod in the booster was extended to far and it wasn't letting the MC come all the way back down. I also capped all 4 ports on the MC and bench bleed till I had no bubbles and I could hardly even push it in anymore as Tobin said. Have to go to the kids game now so Ill post results final results later. I can say for sure the MC is good


      Pontiac Powered 72 GTO


    12. #12
      Join Date
      Sep 2014
      Posts
      130
      Country Flag: United States
      First rule of MC install mechanics. The pushrod must not hold the MC piston from returning completely.

      If the piston does not return completely the relief/fill port will not be uncovered.

      Most boosters have an adjustable tip on the pushrod.

    13. #13
      Join Date
      Jul 2009
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      Cypress, TX
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      Well, how about that. I bench bled using the plugged port method, and air bubbles were ejected into the reservoirs during each stroke for about 10-15 strokes. After that, the air bubbles stopped and the piston hydraulically locked after about 1/8" stroke. I guess my master cylinder is good and my mechanic is mistaken. I'll reinstall the master and try and bleed the whole system. Never heard of the plugged port method of bleeding before this, but it looks like a real winner. Thanks Tobin!


      Quote Originally Posted by terrydmorgan View Post
      Thanks for the tips Tobin. I bench bled using the re circulation method. I'll Block em off and see what happens.
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    14. #14
      Join Date
      Jul 2009
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      Cypress, TX
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      Brakes are working! Turns out we needed to adjust the plunger in the booster. Car stops well with no squeeling, shaking or shuddering. Thanks for all the help guys!

      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    15. #15
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      Jul 2013
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      St Louis
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      Good deal, looks we both had the same issues.

      Pontiac Powered 72 GTO

    16. #16
      Join Date
      Nov 2014
      Location
      Byron, Ga
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      99
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      terry, what size wilwood master cylinder are you using?


      '66 Chevelle BBC/TKO600r, Holley Sniper EFI, Tanks Inc, RideTech Air Ride, Wilwood, Billet Specialties Toploaders 19"/20", Nitto NT555G2, Octane Lighting LED, DIGI-TAILS Front & Rear, Randy's Spoiler

    17. #17
      Join Date
      Jul 2009
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      Cypress, TX
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      My records show that it is a 1" Wilwood dual master cylinder, but I wouldn't swear that to be true. Is there any way to tell without tearing it apart? Part number?
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend

    18. #18
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      Jul 2013
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      St Louis
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      There is a 1" stamped on the MC

      Pontiac Powered 72 GTO

    19. #19
      Join Date
      Jul 2009
      Location
      Cypress, TX
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      317
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      Yep, it's a 1" master cylinder.
      1969 Camaro - LSA motor, 6L90 transmission, TCI front subframe, TCI torque arm rear suspension, Ford 9" rearend





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