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    Results 1 to 19 of 19
    1. #1
      Join Date
      May 2020
      Posts
      52

      Wilwood brake system spongy pedal issue

      Hello! I am currently battling an issue with my brake system and figured this would be a good place to seek help. I am currently running a wilwood forged narrow superlite 6 piston setup in the front, and their forged dynalite 4 piston in the rear with their 1 inch manual master cylinder and the proportioning valve that comes with it in the kit. When pressing the pedal, it is soft for the first half travel, them gains light resistance at the bottom of the throw. If you pump the pedal once then it has a proper pedal feel. I have both bench bled the master and re bled the entire system several times but nothing seems to be working. I am currently using both front outputs from the proportioning valve (one for each front caliper). The brake pedal pushrod is hooked up in the correct spot (the top hole) and I am currently struggling to diagnose the issue.



    2. #2
      Join Date
      May 2014
      Location
      Stanislaus County Ca.
      Posts
      176
      Country Flag: United States
      Just to confirm, did you bleed both sides of the calipers, not just the outside bleeder ?

    3. #3
      Join Date
      May 2020
      Posts
      52
      Quote Originally Posted by ilikeike View Post
      Just to confirm, did you bleed both sides of the calipers, not just the outside bleeder ?
      Yes I did!

    4. #4
      Join Date
      Sep 2010
      Location
      Beach Park IL
      Posts
      2,838
      Country Flag: United States
      On the top of the caliper?

      Is there any free play in the pushrod? Worded another way, make sure there is no pre load on the piston in the master cylinder.

      If it pumps up, there is air in the system still.
      Donny

      Support your local hot rod shop!

    5. #5
      Join Date
      May 2020
      Posts
      19
      Could be a bad batch of fluid.
      Also we had a recall on brakes where the inner lining of the brake lines had a chemical reaction with fluid.
      We replaced fluid and all fine.

    6. #6
      Join Date
      May 2020
      Posts
      52
      Quote Originally Posted by dontlifttoshift View Post
      On the top of the caliper?

      Is there any free play in the pushrod? Worded another way, make sure there is no pre load on the piston in the master cylinder.

      If it pumps up, there is air in the system still.
      Yep! bled the top of the caliper. Also checked the pushrod and there is no free play, nor is there free load. The pushrod is currently sitting neutral on the piston. We plan on re bench bleeding the master as well as the whole system this weekend.

      - - - Updated - - -

      Quote Originally Posted by CTK View Post
      Could be a bad batch of fluid.
      Also we had a recall on brakes where the inner lining of the brake lines had a chemical reaction with fluid.
      We replaced fluid and all fine.
      I'll look into that! with the amount of times I have re bled the system and still have had the same issue I would think the fluid wouldn't be the culprit, however I'll check into using a different brand next time I re bleed it!

    7. #7
      Join Date
      May 2014
      Location
      Louisville, KY
      Posts
      57
      Country Flag: United States
      I just fought a Wil wood master on my set up, bench bled, used speed bleeders, used a pressure bleeder, nothing worked. After pulling and reinstalling several times, I decided to open up the master to look inside. I pulled the snap clip and found the rear piston had scuff marks on the piston and had scored the bore of the master cylinder. Bought a new Wilwood master, bench bled and installed. Now have great pedal feel. If you’ve tried everything else, disassemble the master and check the pistons and bore, mine had very light scratches and scuffing that allowed air into the system.

    8. #8
      Join Date
      May 2020
      Posts
      52
      Quote Originally Posted by grease View Post
      I just fought a Wil wood master on my set up, bench bled, used speed bleeders, used a pressure bleeder, nothing worked. After pulling and reinstalling several times, I decided to open up the master to look inside. I pulled the snap clip and found the rear piston had scuff marks on the piston and had scored the bore of the master cylinder. Bought a new Wilwood master, bench bled and installed. Now have great pedal feel. If you’ve tried everything else, disassemble the master and check the pistons and bore, mine had very light scratches and scuffing that allowed air into the system.
      Will do! I am going to be pulling off the master cylinder this weekend, so I will pull it apart and take a look!

    9. #9
      Join Date
      Jun 2012
      Location
      Chicago burbs
      Posts
      247
      Country Flag: United States
      Quote Originally Posted by The_Oldsmobeast View Post
      Will do! I am going to be pulling off the master cylinder this weekend, so I will pull it apart and take a look!
      Brake can be frustrating, but it seems like you've got a good handle on troublshooting. As far as bench bleeding, I can say this...
      bleeding with the tubes that loop around and push fluid/air bubbles back into the top of the master do not work. There is no indication that you have all the air out of the master. you can cycle the piston for half an hour, and visually there may be no air. but that doesn't mean that there isn't a pocket hiding somewhere.

      Plugging both ports and cycling the piston is the only way I've been able to have success. I get out all the obvious air, then tilt it up and cycle. tilt it down, sideways. Give it little taps with a screwdriver handle(actually knocks some of the tiny guys loose from the bore to escape). You can see the tiny air bubbles escaping back through the ports through the reservoir. I know I'm done when the piston doesn't move at all--like...not even half a freakin mm.

      The plastic plugs that shipped with my rockauto MC worked great. If you don't have those, you can cut a short piece of tubing, fold it over on itself several times and bash it shut with Mjolnir.

      I really hope this helps man, good luck this weekend.

      1969 442 6.0L LQ9 T56
      Fab9 w/ custom 3 Link conversion
      FAYS2 Watts link
      Thanks to Mark at SC&C for his honesty and passion for the sport, and Ron Sutton for the wealth of knowledge that has helped shape so many of the cars on this site.

    10. #10
      Join Date
      May 2020
      Posts
      52
      Quote Originally Posted by jetmech442 View Post
      Brake can be frustrating, but it seems like you've got a good handle on troublshooting. As far as bench bleeding, I can say this...
      bleeding with the tubes that loop around and push fluid/air bubbles back into the top of the master do not work. There is no indication that you have all the air out of the master. you can cycle the piston for half an hour, and visually there may be no air. but that doesn't mean that there isn't a pocket hiding somewhere.

      Plugging both ports and cycling the piston is the only way I've been able to have success. I get out all the obvious air, then tilt it up and cycle. tilt it down, sideways. Give it little taps with a screwdriver handle(actually knocks some of the tiny guys loose from the bore to escape). You can see the tiny air bubbles escaping back through the ports through the reservoir. I know I'm done when the piston doesn't move at all--like...not even half a freakin mm.

      The plastic plugs that shipped with my rockauto MC worked great. If you don't have those, you can cut a short piece of tubing, fold it over on itself several times and bash it shut with Mjolnir.

      I really hope this helps man, good luck this weekend.
      Thank you for the tip! I will give that a shot. And sweet car! mine is a '70 Cutlass S

    11. #11
      Join Date
      Oct 2014
      Location
      DFW, Texas
      Posts
      422
      Country Flag: United States
      I was able to use a vaccum pump with a nozzle end in the master cylinder to get the last bit of air out of mine. I know it should have gotten out during master bleeding, but it's an idea.

      Are you able to drive the car? If so, I usually like to go for a drive once I have a decent/reliable pedal feel. Let the road shake out the last bit of air and move it to the bleeder.

      - - - Updated - - -

      I was able to use a vaccum pump with a nozzle end in the master cylinder to get the last bit of air out of mine. I know it should have gotten out during master bleeding, but it's an idea.

      Are you able to drive the car? If so, I usually like to go for a drive once I have a decent/reliable pedal feel. Let the road shake out the last bit of air and move it to the bleeder.
      1972 Plymouth 'Cuda - Not LS-swapped, 5.7L Hemi [MS3 Gold Box], T56 Magnum 6-speed - 'Cuda Build Page
      1976 Dodge D100 - Warlock
      2016 Subaru WRX - E30 Tune

    12. #12
      Join Date
      May 2020
      Posts
      52
      Quote Originally Posted by GoodysGotaCuda View Post
      I was able to use a vaccum pump with a nozzle end in the master cylinder to get the last bit of air out of mine. I know it should have gotten out during master bleeding, but it's an idea.

      Are you able to drive the car? If so, I usually like to go for a drive once I have a decent/reliable pedal feel. Let the road shake out the last bit of air and move it to the bleeder.

      - - - Updated - - -

      I was able to use a vaccum pump with a nozzle end in the master cylinder to get the last bit of air out of mine. I know it should have gotten out during master bleeding, but it's an idea.

      Are you able to drive the car? If so, I usually like to go for a drive once I have a decent/reliable pedal feel. Let the road shake out the last bit of air and move it to the bleeder.
      Yep the car is driveable, and stops fine once you pump the pedal. If you hit the pedal repeatedly every 30 seconds or so it stops fine on the first press, but if you wait any longer then you have to pump it once before it has a hard pedal feel.

    13. #13
      Join Date
      May 2014
      Location
      Stanislaus County Ca.
      Posts
      176
      Country Flag: United States
      Is it spongy when your just parked in the garage, or only when you drive it ?

      I ask because it could be related to pad knock if you have a wobbly rotor.

    14. #14
      Join Date
      May 2020
      Posts
      52
      Hello Everyone! just wanted to post a quick update. I took out the master and bled it the way suggested by jetmech442, and upon re bleeding the entire system I have a firm pedal on the first press! Thanks everyone for your help in diagnosing this issue. I have been chasing it for a while and am very glad to have finally solved it!

    15. #15
      Join Date
      Jun 2012
      Location
      Chicago burbs
      Posts
      247
      Country Flag: United States
      I've been having a pretty crappy week with work, but hearing that you got your brakes right made me happier than it probly should have.
      Keep up the good work and post some pics or something, always good to see another Olds out there.

      1969 442 6.0L LQ9 T56
      Fab9 w/ custom 3 Link conversion
      FAYS2 Watts link
      Thanks to Mark at SC&C for his honesty and passion for the sport, and Ron Sutton for the wealth of knowledge that has helped shape so many of the cars on this site.

    16. #16
      Join Date
      Jul 2016
      Location
      Phoenix, AZ
      Posts
      3
      Country Flag: United States

      Having same issue, thanks for all the help guys

      I was just about to post on this and was able to read all the comments. I have a Hydratech booster with a wildwood tandem master. The system is sealed, the ps pump is primed, no froth and no matter how many times I bleed the system it's a total sponge. I will try re-bench bleeding and blocking off the outlets and try moving it around shake air out. Thanks!

    17. #17
      Join Date
      Jul 2016
      Location
      Phoenix, AZ
      Posts
      3
      Country Flag: United States

      Success!

      JetMech I had to remove the master 2 times and bench bleed it. You are correct, those little plastic screw-ins they give you to connect to the clear tubes for bleeding cause more problems than help. I ended up flaring up short pieces of tubing, bending them upwards and connecting the clear recirculating tubing to that. A solid tight connection allowed me to get a good bleed on that puppy. Then I made two more flared tubes and bent the end over 2 times onto itself and smashed it with a hammer. Now I have solid plugs to transport the full master back and forth from bench to car. I should mention that I am running a Wilwood in-line hydro brake for the rear calipers. That thing needed a proper bleeding as well and there's a sequence to bleeding two masters in series.

    18. #18
      Join Date
      Dec 2004
      Posts
      15

      No More Spongy Pedal!

      Quote Originally Posted by jetmech442 View Post
      Brake can be frustrating, but it seems like you've got a good handle on troublshooting. As far as bench bleeding, I can say this...
      bleeding with the tubes that loop around and push fluid/air bubbles back into the top of the master do not work. There is no indication that you have all the air out of the master. you can cycle the piston for half an hour, and visually there may be no air. but that doesn't mean that there isn't a pocket hiding somewhere.

      Plugging both ports and cycling the piston is the only way I've been able to have success. I get out all the obvious air, then tilt it up and cycle. tilt it down, sideways. Give it little taps with a screwdriver handle(actually knocks some of the tiny guys loose from the bore to escape). You can see the tiny air bubbles escaping back through the ports through the reservoir. I know I'm done when the piston doesn't move at all--like...not even half a freakin mm.

      The plastic plugs that shipped with my rockauto MC worked great. If you don't have those, you can cut a short piece of tubing, fold it over on itself several times and bash it shut with Mjolnir.

      I really hope this helps man, good luck this weekend.
      Big Thanks to @jetmech442. I was having so much trouble getting a firm pedal no matter what I tried. I used my reverse brake tool to bleed my MC because of your tip to ditch the tubes. I now have brakes. Thank You!

    19. #19
      Join Date
      Jun 2012
      Location
      Chicago burbs
      Posts
      247
      Country Flag: United States
      Quote Originally Posted by ubac View Post
      Big Thanks to @jetmech442. I was having so much trouble getting a firm pedal no matter what I tried. I used my reverse brake tool to bleed my MC because of your tip to ditch the tubes. I now have brakes. Thank You!
      hearing yall got solid brakes makes me happier than it probly should. Thanks for letting me know. you guys should be good to go when Spring hits!

      1969 442 6.0L LQ9 T56
      Fab9 w/ custom 3 Link conversion
      FAYS2 Watts link
      Thanks to Mark at SC&C for his honesty and passion for the sport, and Ron Sutton for the wealth of knowledge that has helped shape so many of the cars on this site.





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