Replaced master, bled, still poor brake pedal
 

1997 3.0CL 183k miles.

Started out with my brakes getting bad over time. They got mushy, and would go to the floor if I pressed hard.

I figured the master cylinder was bad. So I bought a new one (not remanufactured).

I also bought a nice pressure bleeder, the kind you fill up with fluid, attach to reservoir, pump it up, and bleed. Nice.

Anyway I bench bled the master, then bled at wheels. Ran about 2 quarts though whole system. Verified NO leaks anywhere, etc.

No change in brake performance.

I took it to a shop, let them have at it. They says they "bled the **** out of it", but no change. So they said the new master cylinder must be bad.

I warrantied it and replaced it and bled again.

Still no change.

I tried bleeding the abs bleeder per https://www.hondaaccordforum.com/for...systems-31228/. No air ever came out, just fluid.

What else is there to do?


The guy at the shop said the ABS may need bled with a special scanner tool, to fire the pistons manually.


Any thoughts?

So is the pedal still going to the floor or is it just "mushy?

It's mushy, and will go to the floor if I press hard enough. If I apply just SOME pressure, it'll will stay. It doesn't go to the floor "by itself" under my foot.

When the car's not running, the pedal is very firm, but with a lot of effort it will still go to the floor.

If I'm driving and I have to suddenly stop, there's no way it would lock the tires.

do you have rear discs or drums? if you have rear drums youll need to adjust them.
usual culprit for a mushy pedal.
as for bleeding the ABS dont bother, the "guy" at the shop is talking out his butt.
you can also have low pads, pistons being at the end of their stroke which will give you mushy pedal.
as for the master cylinder i doubt that was ever the source of your problem.

Well, the rear brakes are disc. All 4 rotors and brake pads are new. (Less than 1000 miles.)
Also, I replaced all the hoses, and the 2 hard lines in the back. I did all this when I did the master.

So unless there's something going on in the ABS I don't know about (if that's even possible), I'm starting to believe a: My old master was bad, and b: NAPA has a batch of defective masters for this car.

Before I took off the first NEW master to warranty it, I had my wife press down the pedal while I watched the fluid in the reservoir. The fluid would rise and fall. That's a bad master right?

ive gotten runs of bad parts, everything is made in China these days.
the masters youve gotten did they come with plugs or fittings with hoses to bench bleed? i dont recommend the plug process ever, it doesnt work. even if you dont bench bleed the air shouldve escaped running the fluid youve ran through the system. try another master, i know its a PITA and getting costly, if they wont give you another master for free, cut your losses and go to another parts store.

Are the bleeder bolts on the calipers on the top or the bottom of the calipers?

All the bleeders are up top.

The reason I asked is because you could switch the driver and passenger side up front. Then no air would bleed from the system.

The way I would bleed the system is to push in the piston at each with the bleeder valve open. This will push all the air/fluid out of the caliper. Now most of the fluid is in the lines and you are dealing with less volume of fluid in the system.

I open the bleeder valve, then have an assistant push on the brake pedal. When the fluid stops flowing, then I close the valve. Repeat until the fluid is clear.

Repeat at each caliper. The order is passenger rear, driver rear, passenger front, driver front.

EDIT: When you are finished, have your assistant slowly push down the brake pedal. The fluid in the reservoir will drop, so be ready to add fluid, so you don't pull air back into the system.

Thanks for the tips.
I installed a third master cylinder, and being that I have a LOT on my plate right now, I took it directly to the shop and let them bleed it.
He said he had to get the Acura dealer to fax him whatever special procedure
was needed to bleed the system. (The theory being there's air in the ABS). So after they bled the hell out of the lines, and spent lots of time bleeding the ABS with this special procedure, the brakes are a better. But not 100%. They will lock the wheels just barely, but you're foot's on the floor maxed out when they do. It's safe enough to drive. He wouldn't let me have a copy of the "procedure", I imagine its in the Acura manual. I have an Acura manual but its the 3.0 supplement, I need the 2.2 manual for this info. Can anyone post it? I'm curious.