Lastbutfirst

I'll try and only put necessary info…

2000 se manual

Brakes used to seize up at 4 corners …badly

Mechanic thought it was cause the calipers were bad, changed the fronts only as the back ones had been changed like 3 months ago

Ride back home… they seize up again

Trail it back to garage, after a couple of days of me looking into it, I find out that it might be the brake booster (mechanic had no idea)

Get one from the scrap yard, they change it – along with cleaning out the master cylinder and bleeding the brakes

and it rides ok for a month or so and in the last two weeks this is the issue:

brake pedal with almost no pressure when I start the car and hit the first stop. As the ride gets longer than 10-15 minutes, pedal gets harder and the brakes will start to seize up again.

It’s not as bad as before the booster was changed but it’s still bad.

My question is.. what now? Is it a mix of another old booster + bad master cylinder? Is it only the booster? Do I buy a remanufactured booster (200+ $CAD) or a master cylinder ?

I tried a couple of simple brake tests for the booster and they all responded positively.

Im truly puzzeled

DennisMik

iTrader: (2)

I don't what checks you have done, but here is a link to the Nissan service manual for the brakes. Page 21 is the start of the vacuum booster checks. I wonder id the vary last check is where you problem may be.

http://boredmder.com/FSMs/Nissan/Maxima/2000.5/BR.pdf

FanaticMadMax

just one question, since I had that experience with my ex's Mitsu, by any chance, slightest chance you might have pour power steering fluid in brake master cyl by accident. because my ex did that, and few months later, the brakes locked up because slight drop of fluid other than DOT 3 or 4 brake fluid will ruin the whole system. That's the only resasonable explanation I had customer did that, and really messed up big time. If that's the case, then the bad news, you have to replace the master cy, calipers and fluid and flush it out.

Lastbutfirst

I tried the tests..They all pass.

And I doubt there was any steering fluid in there.

Still not sure what to do.. how safe is to to ride like this? Which the brakes locking up a little and heating up the rotors after 15 minutes... they will wear out quicker obviously but is it dangerous?

DennisMik

iTrader: (2)

It can be dangerous in 2 ways. If the brakes lock up and the car stops suddenly, someone could hit you. The other thing is that if the rotors are hot, they are less able to stop the car if you step on the brakes hard.

I wonder if the ABS unit could be messing up? There is a self diagnostic that you can run. Using the same link I posted, page 49 is the start of how to do the diagnostic. The diagnostic makes the ABS light in the instrument cluster blink a combination of long and short pulses that you count. Then go to page 63 to find out what the code means and what page to go to for repair info.

But at the bottom of the chart on page 63 are 2 things that might apply to you: Unexpected pedal action and ABS works frequently

Lastbutfirst

Really short on ideas here... Is getting a new brake booster worth it on a 15+ year car?

Can i get it shipped from the US cheaper (re: exchange rate)

Try another used one? Refurb one (Still 150$)

DennisMik

iTrader: (2)

Is it worth fixing a 15 year old car? I think so, unless the car has a boat load of other problems. $150 for a rebuilt booster or $???? for another car.

I really don't know what the cause of your problem is. Trying to go on logic with this.

In your original post you said that you had replaced the booster and it worked for a while. Since the booster came from the scrap yard, it is entirely possible that it failed.

Two other possibilities come to mind. Brake boosters have a check valve in the vacuum line from the engine to the booster. If this check valve were to fail I don't Know what the symptoms would be.

Then there is the master cylinder. If the piston in the master cylinder were to be binding in its bore and not retracting, this would keep the brakes applied.

But you changed the booster and you problem went away for a month. If you had a check valve problem or a master cylinder problem, those are the same parts all along and I don't think changing the booster would have caused them to stop malfunction for a month.

I'm guessing that your scrap yard booster is bad. I would go with a refurb on this part.

Derrick2k2SE

iTrader: (3)

I really doubt it's the booster.
I'm guessing it's the master cylinder. It seems like it's not letting the fluid expand back into the reservoir as it heats up. The only other place it can expand to is the calipers where it creates pressure. That would explain why all 4 are locking up.

You may also have a kinked or clogged line between the master and the ABS unit right below it. That could cause pressure to build up between the master and the calipers. The pressure coming from by the master is far more than the pressure flowing back to it so you could apply the brakes but not let the pressure off.

I believe the problem has to be somewhere near the master/ ABS splitter. After that, the lines split and each caliper has it's own line. Any problems past the ABS splitter would only affect individual calipers.

DennisMik

iTrader: (2)

Since Derrick2k2SE brings up the ABS, why don't you run the self diagnostic in it?

See page 49 in this link - http://boredmder.com/FSMs/Nissan/Maxima/2000.5/BR.pdf

The self diagnostic makes the ABS (or SLIP if you have traction control) light blink. The chart to decode the blinks is on page 63.

The procedure says to ground pin 9 in the "Data link connector". This is the connector where an OBD code reader plugs into.