Brakes - SOS !

[bpossel]

  Update....
It was the rear rubber hoses.  I guess this means that I have only been driving on the front brakes.  Once I removed the hoses and cleaned them out, the fluid now runs nice and clean.

Thanks all for the comments and direction!
Bob
------------------------------------------

Hi All,

 :evil: I received my power bleeder and tried it out this evening.

I started by removing the screen and the black rubber flow divider...  and then sucked out all of the fluid from the 2 reservoirs with my wife’s turkey baster.  Worked good…  I guess she’ll have to get a new one for turkey day…

Anyway, connected the power bleeder, pumped it up to 15psi and started with the passenger side rear (furthest nipple from the master cylinder).  It started to release the darker (old) fluid but only “trickled” out..  very little pressure.  The fluid stopped running out and even tough I screwed the nipple back in and out, thinking the nipple was plugged, nothing was coming out.

I then tighten the nipple and went to the drivers side rear and the same thing happened.  A small amount of dark, old fluid came out and then…  nothing…

So, tighten this nipple, checked the power bleeder pressure and it was still at ~15psi.  Pumped up a bit more (still under 20psi) and went to the passenger side front.  This worked great!  Open the nipple and a strong flow of dark, old fluid came out and when it was clear, with new fluid, I closed the nipple.

Went to the driver’s side and repeated the process.  Same results, dark flow was strong and when it ran clear, I closed the nipple.

I then thought that having the parking break engaged was the problem for the rear.  So I released the parking break and started the car.  Pumped the brakes, they did feel “mushy”.  When they seemed to be a bit tighter, I turned off the car and tried one of the rear’s again.  Same issue….  No flow of either fluid or air.

What could be wrong?

Help!

Bob


bpossel
Memphis, TN.
1971 280SL
1997 E320

[hauser]

Not too long ago I had remove excess brake fluid and used a cough syrup syringe.  Worked pretty good!

1969 280sl 5 spd        1999 ML320          Gainesville,Fl.

[ja17]

Hello Bob,
Sounds like you have a rear rubber brake hose plugged. These old cars without ABS should br easy to bleed even without a power bleeder.

Joe Alexander
Blacklick, Ohio

[erickmarciano]

change all the rubbber hoses that go to the calipers they are probably disintegrated from the inside

1971 280sl
1962 VW
1954 Allstate vespa
1958 gs150 vespa
1962 gs160 vespa

[bpossel]

Since there is no fluid or air on either rear's, I read that there might be air in the master cyl.  I will start there and ensure no air and that fuild comes out of the master at the rear line connection and work my way back to the rear, removing the brake line at the rear of the calipers.  Will keep you posted.
This was supposed to be easy!  The fronts were a breeze!  Once this works, will be able to power bleed 1x/year and keep the brakes tuned...
I wonder if the wife will let me buy a power lift?  Would make working on this baby easier...

B.

quote:Originally posted by ja17

Hello Bob,
Sounds like you have a rear rubber brake hose plugged. These old cars without ABS should br easy to bleed even without a power bleeder.

Joe Alexander
Blacklick, Ohio

bpossel
Memphis, TN.
1971 280SL
1997 E320

[ja17]

Hello Bob,
Yes, the brake masters should  always bench bled before installation.  However I would guess that a power bleeder would overcome an air lock but it is worth a try.

Joe Alexander
Blacklick, Ohio

[A Dalton]

As pointed out , the rear hoses are suspect.
 A test for this will be to see if fluid comes out a rear bleeder when pushing on the brake pedal. This gets high pressure to the lines , whereas , your bleeder tool is a low pressure system and can not pass swollen lines..
 There could also be a problem with the rear regulator.
 You can also crack the line connector at the regulator and check for fluid flow at that point .. [ this would be the feed line from
 the master]

[Benz Dr.]

ABS brakes are bled in the same way as regular brakes. I've done enough of them to know this.
 ABS is a wheel speed sensitive system which acts upon a pressure limiting device in the engine bay. Normal bleeding methods work just fine.

Sounds like brakes hoses - pretty common actually. Brake pressure regulator is less suspect as it works at high pressure and limits the brake force to the rear wheels during panic stopping. Rear wheel lock up is the major cause of loosing control of your car at speed.

Drum brake cars don't have this device and the brake cylinders are sized to prevent this as much as possible. The larger the brake cylinder the more the force.

Daniel G Caron

[A Dalton]

<<Update....
It was the rear rubber hoses. I guess this means that I have only been driving on the front brakes. Once I removed the hoses and cleaned them out, the fluid now runs nice and clean.>>

 Great ..
 You are going to replace them ??
 The hoses are done for once they show any signs of internal collapsing/swelling...
Cleaning them out has diagnosed the problem, but will not remedy it.

[bpossel]

Hello A Dalton,

I agree! I did put the old ones back on after cleaning them.  I'll order new ones ones on Monday.  I heard that they run ~$25/each.

Why do you think they were plugged?  Former owner didnt do regular maintenance?  I hope that if I flush 1x per year that they wont clog anymore...

Bob

quote:Originally posted by A Dalton

<<Update....
It was the rear rubber hoses. I guess this means that I have only been driving on the front brakes. Once I removed the hoses and cleaned them out, the fluid now runs nice and clean.>>

 Great ..
 You are going to replace them ??
 The hoses are done for once they show any signs of internal collapsing/swelling...
Cleaning them out has diagnosed the problem, but will not remedy it.

bpossel
Memphis, TN.
1971 280SL
1997 E320

[A Dalton]

Just age .. they all do it ...

 The newer materials are prolly better and may last longer  , but , who know what Evil lurks in the fate of Time..