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190E, SLK350
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Discussion Starter #1
Brakes that is!
I replaced the rear driver side bake caliper then I bled it. For good measure, I bled the whole system. Started from the rear passenger caliper, rear driver side, front passenger side and finally the driver side. In all steps I used a power bleeder and closed the bleeder screw when no bubbles where seen.
The final result is horrible! The brake pedal feels mushy and I get that uncertain feeling that the car will not stop where I need it.
I tried the whole process again but this time with the engine ON. Same result! I even tried it one more time while asking my wife to pump the brake pedal with the engine is on. No luck!
I used a Motive power bleeder and I set the pressure to 15psi. I have gone through two large bottles of brake fluid so far. Technically this is a flush by now.

Any ideas? What is it I am doing wrong?
 

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1987 420SEL
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The last time that happened to me, I had to dis-assemble a master-cylinder and then I just ended up rebuilding it and assembling it with varying methods of sucking brake fluid through it.

This was on a 1955 Jeep though; the basic of the basics.

I have absolutely no idea how to do this on a W126, sorry, nor would I even have the courage to try messing with the master. Hopefully someone else who's had this happen can chime in.
 

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MB calls for 30psi, 15 won't do it.

pump the pedal up before using the power bleeder. I like to run a full L plus through my system when I do a flush.

Jonathan
 

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'86 E300 Diesel '82 300 SD '87 560 SEL
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You made me look...
Are the brakes good enough to go drive it and make the ABS kick-in? Apply the brakes so the ABS runs a few times. It might take care of the problem.
 

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190E, SLK350
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Discussion Starter #8
I tried a sudden stop to engage the ABS, that didn't make a difference.
 

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yup.

engaging the ABS won't do it. 30psi...

Jonathan
 

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190E, SLK350
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Discussion Starter #11
30psi didn't make a difference!
I am at a loss here, I saw no bubbles, dirt or discolored fluid come out, just plain clean fluid. I used up FIVE large bottles of brake fluid today alone.
I tried this with engine off and engine on, pump the brakes, press the brakes; no difference whatever the method!
 

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That being the case, sounds like your master is shot.

Jonathan
 

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Discussion Starter #13
How did that happen? It was fine right before I installed the brake caliper. Did I kill it?
 

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You may have had one push to the floor, and if the bore of the master was a bit eaten up that could do the seal in...EASY to do.

W/ a pressure bleeder you won't have to bench bleed your master btw:)

Jonathan
 

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190E, SLK350
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Discussion Starter #15
I was aware of that push to the floor of death so I really tried to avoid it. Maybe my wife did it, I need someone to blame...
I guess off to the junkyard I go unless this part is readily available and reasonable.
 

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expect to pay around 200-ish for new.

The wife always works..now worries your secret is safe w/ us!

Jono
 

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190E, SLK350
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Discussion Starter #17
damit, I tried to do one more thing this afternoon after I got a PM that I should only turn the key in the ON position then bleed but the main hose for the Motive Power Bleeder sprung a leak through a pin hole and shot my wife right in the face. It was kind of a naughty thought but then again that shit is corrosive, so no playing around.
Now I am stuck and will have to wait and see if I can get that hose separate because that whole power bleeder ain't cheap considering that I only use it once a year.
 

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where did it spring a leak? If it's close to the base I'd just cut it back some.. I don't think the hose is anything spectacular..home despot etc should likely have something that would do..

And yes, brake fluid any where close to one's face it a BAD thing..it does a # on one's eye's right quick!!!!!

Jonathan
 
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