Charged up the battery over night and retested. It took 41 seconds to pressurize the accumulator and 42 pumps of the brake pedal for resistance to drop. The fluid reservoir doesn't look stained and the wire leads look almost new.
Based on your rating above it doesn't look like replacement is an immediate need. Thanks for the info!
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"Although there is a sale on now. Where master assy are only about $1K."
No! I would not replace just yet!
The only reason we have no brakes, is no hydraulic pressure. As long as fluid is in system and booster motor/pump working. We have pressure and so we have brakes.
But I would dig deeper on the 41 second and 42 pumps.
It's important for a good timing test. That ~12.5 volts gets to booster pump motor. We sometime have a drop in voltage after battery post. Number one cause is oxidation or some substance between battery post and clamp, inhibiting the current flow. I check voltage with multimeter on battery post first, then on battery cable clamps, then from positive post & then clamp to a ground on body, then ground on engine. All should read the same volts. We can also check at master, but usually I don't need too.
When flushing, we also flush the accumulator. I do this by drawing (out a rear bleeder) fluid down, until reservoir almost empty. The turn IG key off and pump pedal 40 times, evacuating accumulator into reservoir. Add equal amount of fresh fluid to reservoir, as what remains after evacuating accumulator. I repeat 5 times. Then fill reservoir and move on to flushing and bleeding all lines/calipers, make sure fluid stays above low line in reservoir. If replacing brake pad at same time. I then compress caliper pistons, with its bleeder open. Making sure, I do not get air in, and or rebleed that caliper.
The FSM tells us to re-bleed, if more than 40 seconds. As the test is to determine if air in system.
I've also found:
If other than Toyota brake fluid in system, I may get higher times.
It can also be indication booster assembly weak. As a whole assembly or just one component of it like accumulator, which they do weaken with time as nitrogen depletes.
Motor also weakens with use over time, an it may spin a bit slower. It will, without a doubt, spin slower the lower the voltage.
Also can indicate a leak.
Also can indicate a weak internal seals in master. Mainly, ones we can't replace.
A new master assembly takes 25 to 28 pump, before pedal pressure drops.
More pump can be one or a combination of issues.
The two that may contribute the most, seem to be:
1) Accumulator, which its nitrogen depletes with time.
2) Also the master cylinder plunger assembly, seal weakens.
Other seals, in the master, may also be a factor. But they can't be replaced. It's one of these seals failing, that result in high pressure lose (dying seagull sound)
The pumps it take on pedal, mostly deals with the master. We may also get a small effect from: Flex lines, flex more with age. But this has only a very small effect as does caliper minor leaks, on pumps of pedal.
Screeching, AKA Dying Seagull sound. Is fluid under high pressure passing a non replaceable seal. This worsen in cold weather and with time. Resulting in booster motor running excessive long, working hard to keep pressure up. Which motor is only designed, to run very short duration often. Running longer than 2 minutes, is advised against in the FSM. It will lead to premature wear on motor brushes and commutator (motor failure). The seal can affect both run time and pumps on pedal.
This is only a very short duration, of fluid under high pressure passing a damaged seal "dying seagull sound". If longer duration, we'd be able to see bubbles coming up front of reservoir, associated with sound.
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