1994 Dodge Ram air bubbles in master cylinder and soft brak

1994 DODGE RAM
160,000 MILES • V8 • 2WD • AUTOMATIC
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RESPONES
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have had to replace almost every part of brakes from master cylinder to brake lines to rear cylinders to rotors.started to bleed at right rear to left rear to right front to left front. bleeding with truck not running. brakes peddle is hard at frist but then I start truck and they go to floor and soft. also master cylinder has tiny air bubbles in it after running truck and pumping brakes
Aug 15, 2010 at 9:04 AM
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MMPRINCE4000
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If there are no leaks in system, then booster may be bad.

Remove MC and look for brake fluid in booster diaphram.

It is also VERY important to bench bleed MC before install, did you bench bleed it?
Aug 15, 2010 at 9:18 AM
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RESPONES
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I did bleed master cylinder before installling. when I installed master cylinder did not see any brake fluid in booster diaphram.
Aug 15, 2010 at 1:30 PM
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MMPRINCE4000
  • ✓ASE Certified Mechanic
  • 8,548 POSTS
  • ASE Certified Mechanic
If there are no leaks in system. Then you may have a bad MC. It happens.

The reason I mentioned the bench bleed is that if you install a MC dry and use pedal to pump up, you will ruin the piston seal in MC.
Aug 16, 2010 at 8:53 AM
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