soft brakes after pad change
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    1. #1
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      Question soft brakes after pad change

      I changed my front pads and now have spongy brakes. No, I did not leave the cap on when pushing the caliper pistons back in for either side. Simple pad change is something I have done on many cars over the last 30 years and have done this at least 4 times on this 2006 T5 V50.

      I bought a brand new master cylinder, bench bled it then we bled all of the wheels in order of Rear passenger, rear drivers, then Front passenger and finally front driver's. It seemed nice and firm but went soft as soon as the car was started. I noticed I failed to
      put the MC o-ring gasket on, so had to remove the new MC and reinstall with the O-ring on it this time. We re-bled the system as before and now Same result, soft pedal when car is running. This has never happened to me before.

      I noticed the vacuum pump for the booster was not working so replaced it ( used one ), rebled system this time but this time with ignition on and in the run position, still soft brakes but better. I could now drive vehicle around the block but pedal goes to the floor, pumping helps. Before I had zero stopping power! I ordered a new pump, since the used one I bought runs hot and is very loud. I believe its going to die soon.

      This still does not address the original problem of a soft spongy pedal with after simple pad change. I never touched anything that involved letting air in the system. Is there anyone who can tell me why this is happening? I am almost ready to rool this car in front of a MACK truck or train or down a cliff side. Is there a solution?

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    3. #2
      Junior Member LittleRedRidingHood's Avatar
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      Happened to see this the other day: https://www.youtube.com/watch?v=Tde6xd8ezr4

      There is an adjustment you can make on the master cylinder to take up the slack in the pedal which should be done when installing a new master cylinder. Not sure if this is your issue, just thought it might help.
      2007 Volvo V50 T5 AWD M66 - Passion Red
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    4. #3
      Junior Member Jirv0id's Avatar
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      Are they good quality pads? The ones I took out were horrible I couldn't even get ABS to kick on in the rain just completely useless.
      2007 V50 T5 AWD M66 ~ Custom machined weighted shiftknob powdercoated wrinkle polstarblue, Custom pod filter intake, Muffler delete, 18" Pegasus IPD Reps, EBC redstuff pads, EBC blank rotors.

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    6. #4
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      Why did you change the master cylinder? Were you doing preventative maintenance? Or did you already notice a problem? Also, what brand master cylinder did you buy?
      From your description, I'd say you have air in the lines or a failing master cylinder. Pumping the brakes to get even a bit of braking back is a classic description of a master cylinder failure.
      If you're absolutely certain there's no air in the lines, maybe try putting your original master back on. Just to see if anything changes.

    7. #5
      Global Moderator tmtalpey's Avatar
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      After touching the master cylinder, you have to be super-patient with bleeding. Air at the top of the system, and especially in the ABS unit, can be quite a chore to get out. Do you have a pressure bleed unit? You may need one.
      2005 V50 T5 AWD 6MT w/Heico tune, Heico exhaust, Bell intercooler, IPD TCV, Viva Forge CBV, Elevate rear swaybar and torque mount, Snabb shift kit, etc.
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    8. #6
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      I agree with those who say you still have air in the lines.

      From time to time, I've had soft brake pedal issues after replacing something in the hydraulic brake system even after pressure bleeding multiple times. I usually would finally get it resolved by doing the 2-man brake bleed.
      2007 S40 T5

    9. #7
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      https://forums.swedespeed.com/showthread.php?172638 If you look at this sticky at the top post #24 you will see that the recomended bleeding sequence is different than you listed. Not sure if that will help though. I had an issue with air in the lines and could not bleed it out, tried for days. Dealer did fix it for me. Also I really doubt that vacuum pump is going to do anything for you. It should only turn on for power assist when vacuum is low. Like when your cars stalls. Should rarely ever even turn on for more than a few seconds unless you have a vacuum leak. Greg

    10. #8
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      Did you bleed before or after changing the pads? It's possible to push crud back up the lines unless you are careful.

    11. #9
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      Quote Originally Posted by c30c30 View Post
      Did you bleed before or after changing the pads? It's possible to push crud back up the lines unless you are careful.
      +1 I always crack open the bleeder when pushing the pistons in. That way I can catch the crud and not have it flow to the MC.

      What I would try in this scenario is to loosen the hard lines at the MC (one at a time) and pump the pedal, so as to bleed the upper end of the piping. I recently replaced a MC using this bleeding method, and it came out perfect.
      Last edited by FritzM; 09-17-2018 at 01:52 PM.

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