HELP! Power Bleeder problems - no fluid coming from caliper bleeder screw/valve!

[HuskyMan]

So, I take a turkey baster and vacuum out some of the brake fluid out of the girling master brake fluid reservoir on the 1991 560SEL. I then place one quart of new DOT4 synthetic brake fluid into my pressure bleeder, then attach the cap to the reservoir, then pump up to 10 PSI.

Fluid begins to spurt around the cap so I check the fittings and retighten to stop the leaks, then wipe up the slight fluid spill. It appears that the new fluid has entered the brake master cylinder causing the fluid level to rise.

I then go to the right rear caliper and open the bleeder screw. NO FLUID COMES OUT!!! WHAT AM I DOING WRONG?

Pictures enclosed:

[ThatOne]

Originally Posted by HuskyMan

So, I take a turkey baster and vacuum out some of the brake fluid out of the girling master brake fluid reservoir on the 1991 560SEL. I then place one quart of new DOT4 synthetic brake fluid into my pressure bleeder, then attach the cap to the reservoir, then pump up to 10 PSI.

Fluid begins to spurt around the cap so I check the fittings and retighten to stop the leaks, then wipe up the slight fluid spill. It appears that the new fluid has entered the brake master cylinder causing the fluid level to rise.

I then go to the right rear caliper and open the bleeder screw. NO FLUID COMES OUT!!! WHAT AM I DOING WRONG?

Pictures enclosed:

When you opened the bleeder screw, nothing came out? Did any air pressure escape? If so:

You have to be certain that the rear section of the reservoir is filled to capacity before attempting any bleeding, if not you're only pushing air through.

On second thought after looking at your pictures it seems like you had fluid in the rear section of the reservoir, from what I can see of it.

[HuskyMan]

I was just reading my instructions for pressure bleeding:

"If you can not get fluid to move out of the lbeeder fitting (with the system pressurized) there are a couple things that could be causing the problem (especially on cars that have not run for a long time or are over 20 years old). First, try slowly pumping the brake pedal. Do not pump all the way to the floor or you may damage your master clyinder seals. The seals inside may be sticking or gummed up.

By gently pumping while pressurizing the system, you might be able to get the fluid moving by using this technique. If this does not work, release the pressure from the tank and remove the bleeder fitting to make sure it is not plugged. Next, replace the rubber flexible brake hose if it is over 15 years old. If you still can not get fluid to move through the caliper you may have to replace the master cylinder/caliper or both."

So......I guess I should try S-L-O-W-L-Y pumping the brake peddle. If that doesn't work, I'll try removing the bleeder fitting to make sure it is not plugged. I've replaced the brake hoses with new hoses so they should be OK.

Any and all ideas/input is appreciated!!

[engatwork]

Remove the bleeder screw all the way and see if you get anything out. If you don't take a straight metal pick and stick down in there to see if you can get flow. If no flow then start looking closely at the hoses then the calipers.

[HuskyMan]

So, I pumped the pressure bleeder to 10 PSI. I then get in the car and pump the pedal slowly four to six times until the pedal became solid. I then went to the right rear caliper and opened it. No fluid flowed. I then released all the pressure from the pressure bleeder then went back to the right caliper and REMOVED the bleeder screw. Still no flow.

So.....I pump up the pressure bleeder back to 10 PSI, then slowly pump the brake pedal three or four times. This time it doesn't pump up to a solid pedal. I then go to the right rear caliper and loosen the bleeder screw. Still no flow. I don't want to pump the brake pedal too much, I'm taking it about half way to the floor. Should I pump it gently ten or more times?

[HuskyMan]

Had a friend come over and pump the pedal slowly while I monitored the bleeder screw. Still no joy; I'm thinking this may indicate a bad brake master cylinder or bad caliper? Is there anyway to test either a brake master cylinder or brake caliper to know if they are bad?

[engatwork]

If you get flow to either of the two rear calipers then you should be fine in regards to the master cylinder. Somewhere going to the back is a tee where it splits off and goes to each side. Find it and loosen the inlet to the tee. If you are getting fluid to there then again, this should indicate a good master cylinder.

Another thing to try would be to loosen up the brake hose where the hard line ends at the wheel well. If you get flow then I would suspect the hose is bad.

[HuskyMan]

I'm thinking the back portion of the brake fluid reservoir is not full; how do I tell if it is full?