Brake Accumulator, Pump, and loud alarm

[Goldish]

My ABS pump on my 2004 has been squealing for a while. The pump would run and end with a squeal. I figured it was the ABS pump motor wearing out due to a leaking accumulator. Eventually, the pump gave out all together. This was accompanied by the high pitched brake warning alarm.

I swapped out the pump and accumulator, and the alarm is still on. Techstream shows that the accumulator is not building pressure. The pump just runs and runs. My question is, could air trapped in the lines be causing this? I did a round of brake bleeding using techstream, but the high pitched alarm was driving us crazy, even with ear protection. If we just need to keep on bleeding then no worries, but would this cause the pump to keep running?

Is there anything else to check? There is a spring and pin that goes in the housing where the accumulator mounts, and visually these seemed ok. Could they be the culprit? Could the new accumulator be faulty?

 

[Bossman]

Maybe some info in these threads:

Help: VSC/TRAC/ABS/BRAKE lights on plus loud, continuous alarm?

WARNING! Brakes, ABS, loud annoying warning noise....

Brakes went out this morning! HELP!

2003 v8 4runner ABS Pump Problem! Any Solutions?

Brake Actuator failure

2003 v8 brake booster pump diy fix

 

[Goldish]

Thanks, I've had tabs open on most of those and I went through the ones I hadn't read yet. That's what led me to believe in the new pump and accumulator.

 

[Goldish]

I bled the heck out of the brakes. The alarm quit for a while during the process (and no codes picked up by techstream). The pump never turned off. Alarm turned on again before I finished. Same codes saying the accumulator isn't building up pressure. Any ideas are welcome, but at this point it looks like I wasted my money replacing the pump and accumulator, and should have gone with a whole master cylinder unit. I suppose it's possible that the new accumulator is bad, but that seems unlikely and I don't know of any way to test that without throwing another accumulator at it. I don't fully understand the way this system works, but I am wondering if my problem is internal to the accumulator/pump housing, or the master cylinder.

 

[Goldish]

I have kept going with the bleeding using techstream. Mostly air is coming out. I tried with the car on and holding the pedal down to let the pump work the air out of the rears. Pretty much a solid stream of VERY aerated brake fluid, like foam. I read another thread where someone said they had to flush $100 of fluid before they got rid of all the air and foamy fluid. I guess I will just keep going. My worry is that air is getting into the system somehow and I'm wasting my time and money on fluid. I can't find any leaks that indicate this is happening. Throughout all of this, the pump runs about 3 seconds on, 3 seconds off. The high pitched alarm remains on. Only updating in case someone has some wisdom or something else to try.

 

[earthrealm]

I have kept going with the bleeding using techstream. Mostly air is coming out. I tried with the car on and holding the pedal down to let the pump work the air out of the rears. Pretty much a solid stream of VERY aerated brake fluid, like foam. I read another thread where someone said they had to flush $100 of fluid before they got rid of all the air and foamy fluid. I guess I will just keep going. My worry is that air is getting into the system somehow and I'm wasting my time and money on fluid. I can't find any leaks that indicate this is happening. Throughout all of this, the pump runs about 3 seconds on, 3 seconds off. The high pitched alarm remains on. Only updating in case someone has some wisdom or something else to try.

replace the piston assy in the MC

2008 4runner Master Cylinder piston, I found the part # and fixed it!!!

 

[rdruss]

I have kept going with the bleeding using techstream. Mostly air is coming out. I tried with the car on and holding the pedal down to let the pump work the air out of the rears. Pretty much a solid stream of VERY aerated brake fluid, like foam. I read another thread where someone said they had to flush $100 of fluid before they got rid of all the air and foamy fluid. I guess I will just keep going. My worry is that air is getting into the system somehow and I'm wasting my time and money on fluid. I can't find any leaks that indicate this is happening. Throughout all of this, the pump runs about 3 seconds on, 3 seconds off. The high pitched alarm remains on. Only updating in case someone has some wisdom or something else to try.

Be nice to know if/how you solved your problem.

 

[shoopdagoose]

Brake Fluid leak and loud alarm

I have encountered the dashboard lights (e-brake, VSC OFF, ABS, VSC TRAC) and the loud continuous alarm inside the cabin, which will turn on for a while and come back on even after turning the car off then back on, as well as after disconnecting the battery. The lights and alarm have turned themselves off each time while driving, and I have not been able to get my car scanned while they are on.

I also have a slow brake fluid leak from somewhere around the HBB or Master Cylinder. Brake fluid levels have remained within range because I top it off every so often. The brakes and brake pedal have seemed normal, allowing me to stop as expected, but my fear keeps growing that I will lose that ability.

When turning the car to on (not started) the pump motor runs for a bit then stops. If I press the brake pedal it will only turn on briefly, then back off.

I have found results explaining the lights and noise could range from a missing screw causing the wiring system to lose it's ground...all the way up to a $3-4k replacement of the entire HBB/Master Cylinder assembly.

I need help.
How can I locate the leak?
What do the lights and alarm mean?

 

[mkscrewy]

I'm not sure where to start with the leaks, but I had the same lights/alarm when my accumulator went bad. It is possible to only buy the accumulator and have that replaced, as most of my research (on this site) showed that the accumulator is the part that most often goes bad. You may not have to shell out the $2100 for the whole brake booster assembly. I first bought a reman'd booster motor and accumulator, but that quickly proved to be faulty as well. I went back and picked up this part new:
#47070-30060 2003-2009 Toyota 4Runner - Power Brake Booster $689.38