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Discussion Starter #1
Okay guys... First post, and really need some help.

My dad has recently purchased a 1987 300d turbo. Has ABS but not traction control. The brakes worked fine, but he decided to bleed the brakes as the fluid hasn't been changed in years. He found the rear caliper's locked up. So here's what he did:

Round 1:

New Pads. ~ Rear wheels
New calipers. ~ Rear wheels
New Rotors ~ Rear Wheels
New brake hoses~ Rear Wheels
Bled 2 containers of fluid through the lines. Doing it in the right order. No vacumm pump used.

The brakes were mushy. Tried rebleeding, no change.
I told him he probably blew his master cylinder seals.

Round 2:

New master cylinder. Rebleed brakes with vacumm pump for all 4 brakes. Made sure resevoir had fluid the whole time.

Still mushy feeling, and hard to stop. NO leaks. The resevior level has not dropped any. Have since ran a gallon of fluid through it to try and get all the air/algae out of the lines...

WHAT IS THERE LEFT TO DO?

I appreciate any help
 

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95 E320 Cabriolet, 140K
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1,332 Posts
Two thoughts...

Was the master cylinder bench-bled before installing in the car? I'm not sure about MB, but most manufacturers require bench-bleeding the master cylinder if it is removed, replaced, or ever ran dry.

You may simply be experiencing the normal softness of the brake pedal until the pads seat themselves to the rotors.
 

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Discussion Starter #3
Thanks for your response...

Yes the master was bench bleed, and the pads are not setting in at all.. They are barely rubbing on the rotor. It has been driven alot in an attempt to get the "pads to set in"

Do you think it could be a problem with the booster? Thats the only thing i haven't replaced...
 

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Depends on the day!
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13,337 Posts
booster is about all that's left.. You have done everything else that *could* remedy the problem. I would be astounded if the ABS pump was getting in the way.

Let me know if I can help!

Jonathan
 

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1987 300DT, 1995 C220 2007 GL320CDI
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I had the same problem with a Ford. Turned out I needed a "power bleed" done to clear all air from the master cylinder and ABS.
 

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Sounds familiar...

Make sure the rear calipers were not swapped when installed. They may look the same, and they may bolt up the same, but they're different (bleeder screw location). If you have them reversed, the bleeder screw may be below the cylinder level, and you'll never be able to get the air out...
 
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