I am old school and back in the day, if the brake pedal sinks to the floor, the master cylinder is bad, or the brake line is leaking, or a caliper is leaking.
Since there is no leak anywhere, I was sure it was the master cylinder.

I changed the master cylinder and it still does the exact same thing. Pedal to the floor. What baffles me is that even when the engine is not running, the brake pedal still goes to the floor.
I heard if you bleed the brakes, some cars need to be in ABS brake bleed mode. Can someone explain how in the world the valves in the ABS module can allow the brake pedal sink to the floor?

The fact that the pedal isn't going high-and-hard with the engine off means there could be some sort of problem with the actuator shaft inside the booster. Some of those are muti-piece assemblies (I don't know about the gen1 Rogue in particular) and it could be telescoping. It could also mean a complete lack of resistance in the hydraulics. The high-hard pedal results from loss of vacuum on the engine side of the diaphragm, so it won't happen if there's a ton of air in the hydraulic part of the system. The ABS itself can't bypass, it has no path to do so like the master cylinder bypassing back into the reservoir. It isn't necessary to bleed by powering the ABS actuators, but bleeding in the wrong order can cause trapped air in the ABS valving to be incompletely purged. That varies from car to car depending on the design of the system. The '09 Rogue has dual-diagonal passages internally and the order is rear right → front left → rear left → front right. One thing you can do to see if the problem is upstream or downstream is to use brake line plugs to cap off first the master and then the ABS outlets, and if that hardens the pedal then pinch off the flex lines at the wheels. If that still hardens the pedal, take the pinches loose one at a time to see which caliper is causing the problem.

Sounds like the brake line plugs idea will help isolate the issue.
Will give that a try!

Thanks again for the help!

You're most welcome. Post back on what you find!

Strange. We removed the brake lines from the Master Cylinder and plugged them with 2 bolts ( bolts were taped with teflon tape).
The pedal was solid.

So we are looking at excessive air somewhere or it is a funky ABS module.

Next step is to do the same with all 4 ports on the ABS. If it's still solid then you know the issue is in one of the lines or wheels.

DANG IT!!
LOL, we already took the ABS out and are thinking about sending it in for repair.
The reason we went this route is because there are no visible leaks and we see no swelling on the flexible lines when pushing the brakes.

Live and learn!

Rockhoundrob wrote: ↑

Mon May 23, 2022 7:19 am

DANG IT!!
LOL, we already took the ABS out and are thinking about sending it in for repair.
The reason we went this route is because there are no visible leaks and we see no swelling on the flexible lines when pushing the brakes.

Live and learn!

Did replacing the ABS module fix the problem? Where did you send yours out for repair? I've got he same issue on a 05 G35.

Yea, sorry I did not come back with the update.
We put the repaired module back in. Bled the brakes, then did a auto brake bleed using a Autel MK808.
It did not work the first time, so we waited til the next day.

We did auto bleed again and the brakes were better. We did it a 3rd time and the brake pedal was up to par.
We sent the ABS module/pump to https://repairlaboratory.com/,
It took about 3-4 days send and get it back. If you send on Monday, you are likely to get it back on thurs/friday.

Advice. if your pedal is going to the floor, make sure the master cylinder is good.
Any vehicle after 10 years is likely to have a bad master cylinder. Remove the brake line from the master cylinder and plug it with 2 bolts wrapped with teflon tape.
If the brake pedal still goes to the floor, then your master cylinder is bad.
If the brake pedal is solid, then the problem is air in the brake line, bad ABS module/pump, or a brake line is leaking.

Rockhoundrob wrote: ↑

Sat Aug 27, 2022 5:38 pm

Yea, sorry I did not come back with the update.
We put the repaired module back in. Bled the brakes, then did a auto brake bleed using a Autel MK808.
It did not work the first time, so we waited til the next day.

We did auto bleed again and the brakes were better. We did it a 3rd time and the brake pedal was up to par.
We sent the ABS module/pump to https://repairlaboratory.com/,
It took about 3-4 days send and get it back. If you send on Monday, you are likely to get it back on thurs/friday.

Advice. if your pedal is going to the floor, make sure the master cylinder is good.
Any vehicle after 10 years is likely to have a bad master cylinder. Remove the brake line from the master cylinder and plug it with 2 bolts wrapped with teflon tape.
If the brake pedal still goes to the floor, then your master cylinder is bad.
If the brake pedal is solid, then the problem is air in the brake line, bad ABS module/pump, or a brake line is leaking.

Thanks for the infomation.
Replaced my MC 2x. 99.9% sure my MC is good. 3 new calipers and all new brakes all around. Brakes were locked up at one time. That cleared up during the bleeding process. My first couple of bleeds I didn't use the factory recommednataion and did not disconnect the battery or use the proper sequence LR, LF, RR, RF. I'm not sure if that fubared the control module or it was already fubared. I'm going to talk to the repair laboratory folks and see what they say but I'm betting on the module being toast.

According to repair labs I'll need a scanner to bleed the ABS module after repairs. Probably going order just one. At least I can check it and try to bleed the system before I go get another abs module.

Yep...

I got the Autel MK808 specifically to do this. We ordered it while the part was shipped for repair.
NOTE: the scanner will work on MANY cars, so you could help family and friends.

You could give it a try and bleed it with the scanner first and see what happens.

Oh I'm definitely going to try to bleed it before I purchase a new control module for $1k or even get a used one.

What?? why not take the WHOLE ABS system out and send it in for repair? AND get the SAME module back.
If I remember right it cost like $375.

Well I mean sure... bleed it first, but if that doesn't work, then take out the module and send it in for repair.

RL said they cannot always be repaired. I'll cross that bridge when I get there.

I re-read what you wrote. You said you replaced the Master cylinder, but you also said you "may get another ABS module".

I am thinking, if you replaced the MC and ABS module, you might get lucky with the auto-bleeding.

Yep, I'll run it through the scanner and cross my fingers and go from there. The module may have gone belly up.

Picked up the MK808, unfortunately it would not allow for brake bleed. I had conflicting info on whether it would or not. Looks like the MX808 should do it. We'll see. I did get some DTC's but no issues with the ABS. I could cycle solenoids and get a hard pedal but after releasing them it's back to no pedal.

Finally figured out why I could not get air out of the system. It was my f'up. I installed the front calipers upside down or left on the right side. Bleed screw is on the bottom.
DOH!!
E brake adjustement and seating the pads and I'm done.

Your screen name kinda describes what happened when you attempted this repair.

It must have been frustrating and satisfying at the same time knowing it was a easy fix in the end.

I feel your pain, been there, done that.

casperfun wrote: ↑

Mon Sep 05, 2022 2:42 pm

Your screen name kinda describes what happened when you attempted this repair.

It must have been frustrating and satisfying at the same time knowing it was a easy fix in the end.

I feel your pain, been there, done that.

Lmao yeah this was one of the more painful repairs. Jacked up my back in the beginning of the year and it was really feeling good. Definetly took a few steps back doing this repair, I never figured it going on as long as it did. But I'm thrilled it's fixed. Well almost fixed. One of the rear calipers is hanging up. It's much hotter than the other side. can't catch a break.