vincej

My 2000 Max was outside all day at work (a cold 15 degrees outside). Started car and backed out. Brakes worked fine. Shifted into drive. Got to end of parking lot and proceeded down a hill towards entrance. Stepped on brake. Pedal was hard and would not depress. Car would not stop and I ended up plowing through the stop sign. Luckily there was not another car around or I would have been in an accident. Kept depressing the pedal and it finally came back to normal. Has not happened since.

A couple of times over the last week I noticed that the brake pedal was spongy especially when I applied the brake lightly but maybe this is normal.

I am thinking that the power booster is bad and possibly the master cylinder is leaking. Car has around 45k. I just bought it from a dealer and am under their 60 day warrenty so I am bringing it in tormorrow. Any ideas?

Progress

iTrader: (26)

What kind of damage did you receive from hitting the stop sign. I would be pissed if that happened to me and I would file a complaint or something at the dealership. Good thing you didn't get hurt/killed, good luck on getting to the dealer safely. I hope it doesn't happen again to you.

LA02MAX

iTrader: (3)

what he meant was that he ran the stop sign...he didnt phyically run into it!

LA02MAX

iTrader: (3)

sorry, this computer is being stupid and i couldnt continue my post for some reason....anyways, i would definitely take it back and get those checked...thats not a good experiance to have when you first buy a car....if they give you trouble about it, just cause a scene, and there will be about 5 people around you trying to help

Progress

iTrader: (26)

Gotcha, my bad!

Charliejag

Spongy pedal means leaky master cylinder. I've had that before, not on the max though. When it happened my brakes still worked, but I bet the same thing would have happened to me if I was going down a hill. Did you get ANY braking action AT ALL?

Jeff92se

iTrader: (82)

Or faulty abs system. Or moisture in the brake lines froze (since you can bet it's the original brake fluid)

Doom878

I think I just read somewhere that the booster is bad when the brake goes down all the way to the floor.

Jeff92se

iTrader: (82)

You might want to check on that.

irish44j

iTrader: (38)

moisture in the brake lines...frozen. Also you probably have some air in the lines (causing spongy pedal)....have the brake fluid changed and re-bleed everything before you go spend more $$ on brake boosters or master cylinders...

97Se5spd

I have a 2000 GXE, 51000 miles, just bought it and my pedal is ALWAYS changing firmness, sometimes its really hard, and then its really soft, i had it serveiced at the dealer and they said the ebrake was locked up, it was better for a little while but its happening again. Wat is going on here? Thanks

vincej

I started this thread - thanks for the suggestions. I brought it to the NISSAN dealer Friday and I am not too happy. They said they checked all brake components and found no problems so they did nothing, not even replace brake fluid! By the time I got there the service manager had left so I did not get any where by complaining. Friday night I left the car outside (below zero temps). This morning I started the car, backed it up, brakes worked fine. Then I drove to the end of the driveway. Again the brakes failed. The pedal would not depress – the pedal was very hard (similar to how it feels when the engine is shut down after pumping it a few times). I pumped the pedal a few times – it did nothing. After holding my foot on the pedal a few seconds it finally depressed and went back to normal operation. I was just rolling at this time but it did seem that there was just a little bit of braking action even with the hard pedal but not enough to stop the car while rolling. I pulled back in the driveway and shut it down. I let it sit for awhile (Its about 5 degrees out). I took it out a couple of hours latter and the brakes were normal. It seems to me to be something with the power booster. The fact that the brakes work fine for the first couple of pushes on the pedal and do not fail till I drive for a few seconds shows that it probably is not water in the brake lines freezing doesn’t it? I need some more ideas when I call Monday to talk with the service manager. By the way doing a goggle search I found at least one person that had the exact same issue with the same year (2000) Maxima.

E55AMG2

iTrader: (4)

moisture in the brake fluid is the culprit here

vincej

The story continues. I see a posting about someone having the same exact problem with the same car (2000 Max). They respond and tell me it was the booster check valve and give me a part number – 47474-2Y900 Hose-Booster. Sounds reasonable. I check my Nissan repair manual and it discusses how to test the check valve. I call the dealer and give him this information. They claim that there is no check valve on the car and that the part number I gave them is just a hose with no valve inside it. So does any one know where the brake booster check valve is on a 2000 Max?

Charliejag

Whenever I get an answer I don't really like from a dealer, I just call around the country for another one. If its late in the day and theyre closed, I call Hawaii. Try calling around and see if everybody says the same thing, they normally don't.

imjd

The booster check valve sounds like it makes sense.
Rather than moisture in the brake lines, you probably have moisture in the check valve. Here's the theory. When the engine is shut off, the check valve closes to maintain vacuum in the booster. And it freezes that way, so even after you restart the engine the booster chamber is still sealed off from the intake manifold. When you start the engine you get one or two pumps with boost, then it's unboosted - until engine heat defrosts the valve.

Claim that there is no check valve is ridiculous. The check valve might be in-line in the hose or it might be integrated with the booster dome but it has to be there, if you have vacuum-boosted brakes.

A good question would be how water got into it.