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  #1  
Old 07-29-2013, 12:11 AM
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Replaced front calipers on '85 300TD- trouble bleeding

The rear bleeders were a snap. Fronts are giving me fits. Mity vac won't pull fluid through and my kids have cramps from pumping the pedal for me.

I read someplace that said you need to have the motor running in order have pressure to bleed the fronts.

Can anybody verify that little gem of a secret before I limp out to find a mechanic who might have a power bleeder?

Thanks!

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  #2  
Old 07-29-2013, 01:03 AM
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Are both halves of the reserviour full?

Did you bench bleed the Master Cylinder?
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  #3  
Old 07-29-2013, 01:14 AM
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The reason to have the Motor running was so that when some one stepped on the Brake Pedal during the Bleeding Process the Piston in the Master Cylinder moved only the normal amount. That keeps the Master Cylinder Piston Seals from moving into areas where the Gunk or Rust Pits have built up and messing with the Seals.

However, not starting the Engine won't keep you from bleeding the brakes.

Could it be that the Bleeder Screw passages in the screw or the Caliper are blocked with Rust?
Could it be that the Brake Lines are messed up inside and not allowing the Fluid to reach the Calipers?
There is 2 ports in the Master Cylinder If they get Plugged Fluid will not be sucked into the Master Cylinder. I would try Bleeding the Master Cylinder first to see if anything comes out of it.

Do you have ABS Brakes?

I know when I was a Kid pressing the Pedal I sometimes got My Fathers Instructions reversed and it sucked Air into the Lines.

.
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  #4  
Old 07-29-2013, 01:32 AM
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I think, anyone owning a Mercedes should either make a pressure bleeder or invest in one from Motive. Its one thing I am going to do...makes bleeding and flush so simple..

http://www.youtube.com/watch?v=Mdcn1USVQ-w
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  #5  
Old 07-29-2013, 10:50 AM
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Quote:
Originally Posted by Diesel911 View Post
The reason to have the Motor running was so that when some one stepped on the Brake Pedal during the Bleeding Process the Piston in the Master Cylinder moved only the normal amount. That keeps the Master Cylinder Piston Seals from moving into areas where the Gunk or Rust Pits have built up and messing with the Seals.

However, not starting the Engine won't keep you from bleeding the brakes.

Could it be that the Bleeder Screw passages in the screw or the Caliper are blocked with Rust?
Could it be that the Brake Lines are messed up inside and not allowing the Fluid to reach the Calipers?
There is 2 ports in the Master Cylinder If they get Plugged Fluid will not be sucked into the Master Cylinder. I would try Bleeding the Master Cylinder first to see if anything comes out of it.

Do you have ABS Brakes?

I know when I was a Kid pressing the Pedal I sometimes got My Fathers Instructions reversed and it sucked Air into the Lines.

.
No ABS. For whatever reason, I was not able to get a fluid push out of the bleeder (on caliper) until I left the engine running. I do see how the master cylinder levels are deceiving if you just go by the visual markings on the outside of the reservoir. I initially had replaced the brake hose as well, but put the old one back on to backpedal to narrow down the problem.

My Mighty vac seems useless for this work. Sounds like the power bleeder is a must. One side done, guess I may pop for the power bleeder to tackle the other side. Would this unit be adequate: Brake Fluid Bleeder

Appreciate the help!
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  #6  
Old 07-29-2013, 01:29 PM
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Hi Pin,

Our host sells the one you want, which is this model.

Pelican Parts.com - Black Label European Power Bleeder Kit

It has a swivel head which makes screwing the bleeder cap onto the master cylinder reservoir much easier.

If you go cheap and get the one without the swivel adapter, you will have to spin the pump bottle to keep the pressure hose from getting knotted up. That is, if you have three hands. And do it again when you're done.
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  #7  
Old 07-29-2013, 06:01 PM
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Quote:
Originally Posted by Ol' Yeller View Post
Hi Pin,

Our host sells the one you want, which is this model.

Pelican Parts.com - Black Label European Power Bleeder Kit

It has a swivel head which makes screwing the bleeder cap onto the master cylinder reservoir much easier.

If you go cheap and get the one without the swivel adapter, you will have to spin the pump bottle to keep the pressure hose from getting knotted up. That is, if you have three hands. And do it again when you're done.
yup, that's the one I got for my shop, great setup.

if you decide to build your own, you don't need to destroy an MB cap, GM screw on caps are the same thread...

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