Hi, I was changing my brake fluid today with my GF and she was pumping the pedal on the first wheel as I was checking the fluid level, but it seems that once you get at the low mark, the fluid only goes down at the rear part of the container, so unless you are really checking the rear part, you dont see it going down anymore. So basically, I started hearing her pumping air.

So I re-filled the container, and she pumped the brakes until the fluid going out of the caliper was bubble free and the pedal was firm again, then I did the other 3 wheels without getting air in.

When the engine is off, the pedal is really firm and doesnt feel spongy. When I turn the car on, I can lower the pedal all the way and it feels like a sponge and I hear woosh woosh in the pedal (but maybe it was like that before and it's like that on maximas?).

Braking feels normal on the road. A bit spongy but maybe just like it was before. IMO the max brakes feel spongy.

The old fluid was probably 4 years old and really brown. I though I'd be unable to unscrew the bleeder screws because of salt and rust, but I wirebrushed them clean and they just all easily popped open.

So my question is, is there a place on the ABS actuator or master cylinder where I'd have to bleed air, or if I refilled, then drained all the air through the lines, then bled all wheels, I'm fine?


Thanks

 

take it to a shop with a power bleeder and have them do it. its basically a pump you hook on the reservoir and pumps fluid into the system at about 15 PSI and all you have to do it crack the bleeder screws open and wait till the air is out and the fluid is coming out clear

 

In the nissan service manual, they say that you can empty the lines, and then just refill the master cylinder and pump until there is no air, like I did.

So basically, is there really a need for a power bleeder? Maybe I just got all the air out? If there was air left, the pedal would feel mushy with the car off would it?

Because 15 psi or not, it's still just going to push the fluid through the lines, just like you do with the pedal, imo, right?

 

bump for some more info, im dealing with the same thing. only difference is that i changed out to ss brake lines.

power bleeder makes the job easier and faster but you are fine doing it that way. pump up the pedal 5-10 times and hold; open then close the bleeder valve and repeat.

 

Bleeding Brake System EFS004D3
CAUTION:

Carefully monitor brake fluid level at master cylinder during bleeding operation.

Fill reservoir with new brake fluid MA-10, "RECOMMENDED FLUIDS AND LUBRICANTS" . Make
sure it is full at all times while bleeding air out of system.

Place a container under master cylinder to avoid spillage of brake fluid.

Do not loosen the connecting portion of the actuator during air bleeding.
1. Turn ignition switch OFF and disconnect ABS actuator and control unit connector or battery ground cable.
2. Connect a transparent vinyl tube and container to air bleeder valve.
3. Fully depress brake pedal several times.
4. With brake pedal depressed, open air bleeder valve to release
air.
5. Close air bleeder valve.
6. Release brake pedal slowly.
7. Tighten air bleeder valve to specification.
8. Repeat steps 2. through 7. until no more air bubbles come out of
air bleeder valve.
9. Bleed the brake hydraulic system air bleeder valves in the following order:
Right rear brake → Left front brake → Left rear brake → Right front brake

 

.....

 

can someone explain the abs part. Ive read around at different sites about the same thing but no explanation why.

 

No clue, I just kept the ignition off, and didnt hear anything ABS during the bleed....

 

To the guy with a softer brake pedal during running, compared to not running, I would tell ya I havnt seen a car yet that dont do that. But the guys are right if your a perfectionist and want all the air out ya lines it needs to be done professionally. I have been bleeding brakes for years on many different cars and have never had a need for any other procedure other than just the good ole buddy system, pump,loosen,hold down,tighten on corner to corner. But I am just a halfa-- shadetree mech. maxman7

 

There is a Dual proportioning valve that may need purged if ya cant get fluid back to that line. If ya let to much fluid escape and air enter the line. (D.P.V.) will close off that line from the rest of the system to avoid polluting air into other lines, It is impossible to get any fluid back to the closed line without first purging the (D.P.V.) It is located on passenger side firewall about one foot or so down. Is hard to see, It is a little block with four lines coming from it. Each line is one of your calipers feed line.To bleed loosen brake line where (rubber caliper line joins (metal) main feed line, leave loose. Go to (D.P.V.) and open that line You will here the air escaping as you do. I am pretty sure each of the outer lines are for front wheels and middle two are for back wheels, left outer will be left front, right middle is right rear and so on. I know the thread wasnt about this problem but any brake thread I find I list this cause it is very hard to diagnos without knowing this device exists. 90 percent of the time if You are careful Ya wont get enuff air in the system to activate the dual proportioning valve but if Ya do Your gonna have to get familiar with it. And the service manual for maxima,s dont go into much detail about this part. I just hope this thread helps someone to know what they have done in the event this happens. maxman7