Symptoms Of A Weak Accumulator, But...?

[Elessee]

i have no answers but might offer some food for thought.

first off, i mistakenly identified the second hose coming off the reservoir. It is a "return line" according to the manual.

Perhaps that return line could be properly "bled" by pumping the pedal while alternating between allowing and blocking fluid flowing through that line, like at a wheel caliper. (You may have mentioned your previously doing exactly that.. if so ignore this.)

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secondly, the manual states that a pressure bleed is required when replacing the pump. I'm not sure if this protects the new pump by forcing (lubricating) brake fluid through it lest it's allowed to run without any lube, or because some air cannot be evacuated from some parts of the system by any other method.

Pressure bleed is basically applying about 35 PSI of air to the reservoir's filler hole. Fluid is pushed through the system by nothing but air pressure.

 

[ridindirrty]

I Have The Answer

Did some online research, took me about 2 minutes to find the answer. To bleed the master cylinder in the car you have to disconnect the brake lines, screw in some fittings with nipples on them, connect some tubing and route it back up into the reservoir. Pump the pedal until the bubbles stop. reconnect the brake lines and bleed the calipers. There are actual kits available to do this very thing.
No need for that though, just get the thread spec on the brake lines, pick up the appropriate fittings and some tubing.
I could not have bench bled mine when it was out of the car because I left the ABS valve block behind and would have had no way to attatch fittings to the fluid outlets. There are only machined bosses with o-rings sealing the valve block to the master. No threads.
Long story short, those lines have to be cracked in order to proceed. It's nearly friggin impossible to get a wrench, let alone your hand in there and ford thoughtfully placed the outlets on the BOTTOM of the master making it that much more of a bastard to work with.
The car i was looking at online was a mazda something-or-other and the outlets exit the TOP of the ABS unit and are nicely spaced and easy to access.
What a pain .

 

[Elessee]

I also did some online searching and saw the kits.. one guy made his own since he couldn't find one (for a bench bleed and non-ABS)

so... you got some nipples in the holes and your done bleeding. Then what?

You have to unscrew the nipples and remove them.. then mess with reattaching the lines. Is that not a fine opportunity for fluid to leak out? Will leaked fluid be replaced by air? Maybe not. Maybe fluid will stream in from the reservoir and fill empty space if it can..

When R+R-ing various parts of the master cylinder assembly, the manual only says to plug the holes in the valve block to avoid fluid loss, but that's followed by a bleed as a last step..

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I bought a set of tube-wrenches special made for the tube-nut gizmos .. they are like a closed end wrench but they have a gap for the tubing. Strong and easy to use and add a measure of confidence when wrenching those things.

I've done a lot of stuff on my Mark, like new radiator, replaced brake lines and shocks and things where rusty, seized or frozen nuts and bolts might be expected, but haven't come across any so far. On these cars, Lincoln used good parts and put lots of thought into engineering.

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Maybe consider a ride to a brake shop.. explain the situation (or just tell them you want a complete brake bleed including the MC), say that you're price shopping, and see if you can find out how they plan to proceed...

 

[ridindirrty]

You have to unscrew the nipples and remove them.. then mess with reattaching the lines. Is that not a fine opportunity for fluid to leak out? Will leaked fluid be replaced by air? Maybe not. Maybe fluid will stream in from the reservoir and fill empty space if it can..

Shouldn't be a big problem if you are careful. Have the pedal held down, i would expect some fluid to drip out, only to be replaced by more from the reservoir or,
if there is no connection to the reservoir with the pedal on the mat, you may lose NO fluid at all due to atmospheric pressure.
Think about what happens when you dip a straw in some water, cover the top end with your finger and pull the straw out of the water. The water is held in the straw by atmospheric pressure and vacum.
Dig?
Just do one line at a time. Remove the hose and fitting, replace the hard line and so on and so forth.

I bought a set of tube-wrenches special made for the tube-nut gizmos ..

Yup. Flare-nut wrenches. Grab the hex on 5 sides.

Maybe consider a ride to a brake shop.. explain the situation (or just tell them you want a complete brake bleed including the MC), say that you're price shopping, and see if you can find out how they plan to proceed...

We'll see. The procedure it self makes total sense, doesn't stress me out one bit. It's just the awkward positioning of everything and the thought of demo-ing one of those lines.

As usual, thank you for your efforts .