Hey guys,
I have determined that my master cylinder has gone bad, as my brakes work fine for the most part, but if you apply pressure to them while stopped, the pedal will slowly sink and loose pressure. This really causes issues while stopped on hills so I have to use the e-brake.

Anyway, my question is how difficult is this to replace? I've never bled brakes except for on a motorcycle and I understand the procedure. But the ABS has its own reservoir and brake lines, but does that mean each caliper has two brake lines going to it, or do they converge? I just want to be able to do a simple bleed in my driveway and not have to worry about pointless **** like that. I pulled the ABS relay since it's screwed anyway so I'm not worried about losing it. So is it as easy as doing a bench bleed, installing, and then bleeding at each wheel?

Thanks

 

Basically yes.
bleed in this order: RR - FL - RL - FR

 

Are you basing it solely on the fact that you lose pressure, or do you have a leak down the front of the booster, or possibly at another junction?

 

 

The brake lines for the ABS reservoir converge with the ones from the MC at the ABS module. It's just one line going to each wheel.

Also, while the car relies on the ABS module to provide brake proportioning for the rear brakes, it doesn't use the fluid from the second reservoir until the ABS kicks in. So as SnlpeR said, it's a regular bench bleed, install, then bleed at calipers.

 

 

You can bleed it WAY faster without even taking the wheels off and it works every time if done properly.

What you have to remember is that the component you're replacing is at the top of the system and air being a gas is going to stay at the top. I've done this countless times over the years working as a dealer tech especially with the recall for the Odyssey master cylinder plunger seal problem causing a soft pedal. This is the procedure that you'd perform and you have to make certain you don't pump the pedal with the lines closed like you normally would otherwise it's likely the air will be forced down stream then lifting the car and bleeding the wheels is your only option.

Step 1: Replace master cylinder
Step 2: Fill with new brake fluid to the top
Step 3: Loosen both lines at the master cylinder, place an absorbent spill mat or anything you may have to catch the fluid
Step 4: Let fluid run out for about 5-10 mins, this will get most of the air out.
Step 5: Close lines
Step 6: IMPORTANT! With an assistant, loosen the 2 lines on the MC a turn or so, and have them SLOWLY push the pedal to the floor WITHOUT pumping like you normally would, you'll see bubbles exiting the fittings
Step 7: With assistant HOLDING the pedal to the floor, tighten the lines (don't go crazy cause you'll do this a few times) and once they are tight have them release the pedal
Step 8: Repeat step 6 and 7 about 5 or so times until you get a firm pedal
Step 9: Test drive and you're done

This method will keep from from even having to lift the car, if done properly it never fails and saves a lot of time. If you have a fluid evacuator you may also want to be certain the seal on the plunger hasn't allowed a leak into the brake booster as it can ruin the diaphragm.

 

This is very helpful. I have one question, won't there be air in the end of the brake lines when I reinstall them, meaning the air will be pushed through the system, even if it is just a small amount?

Also, do you refill the reservoir after Step 5, or have no fluid the whole time?

 

Yes, constantly check the reservoir and add fluid as you go.

The air will come out of the loosened lines at the MC, air will always take the path of least resistance to escape. As long as the person helping doesn't let off the pedal with the lines open or push the pedal down when they are closed the air will stay right there at the top until it's forced out.

I've done this more times than I can count, it always works if done properly.