MaximA VlaD

iTrader: (7)

I've been having a problem with my braking. This problem is completely random. Once in a great while, i would say every 4 or 5 weeks, my brake pedal would suddenly lose almost all back pressure during driving. The car starts fine, i drive for about an hour, then when i least expect it the pedal goes to the floor almost freely. If i push the pedal down slowly there is enough pressure to give me effective breaking power in order to avoid a car in front of me. But if i step on it quickly, there is that initial breaking power, and as the pedal goes all the way down the breaking disappears. Basically, i have to pump it repeatedly in order to actually slow down at a reasonable rate. It seems it could be a valve in the master cylinder. When the car is parked and idling, after stepping on the brake pedal i can hear a faint rattling for about a second, if i push the pedal further the rattling happens again for a second, if i let go same thing happens... thats why i think it is a valve.

has anyone else had this problem? what did you do?

i've been also thinking about larger rotors and different calipers.. some do the gen 5 larger calipers/rotors conversion. some do the 300zx... can anyone direct me where to look for DIY info on this, and which one should i do?

thanks guys, really appreciate any help.

MDeezy

iTrader: (27)

I would inspect brake lines for leaks as well as the master cyclinder. How are your pads?

I plan on getting the Z calipers with cobra rotors, but later this year. for now I will go with J30 calipers (or q45 calipers would work) and Z rotors (milled down to fit). This is an even cheaper version of the Z+cobra BBK, it costs less, and wont require you to get new wheels or worry about clearance.

there is a thread about it in the general section.

MaximA VlaD

iTrader: (7)

the pads are only 4,000 old in the front and i am going to check the rear again. they were fine when i replaced the fronts. break lines do not look like they are leaking, but i will take a closer look tomorrow. i will try to bleed the brake lines too.

i have 18" ADR stage ii rims, i think they will clear. my winter wheels are from a 300ZX - 16"... i think they will clear because the guy before me had them on a 2002 or 03 - whenever they came out with the larger calipers.

some do skyline calipers... how are those.?

MDeezy

iTrader: (27)

skyline calipers are the same aluminum 4 piston calipers that the Z has.

A Bleed would definately help.

jvienneau

Sounds like your M/C is failing.

MaximaSE96

iTrader: (8)

actually they are bigger...not much i think 32 or 34mm compared to 30mm Z calipers..people always advertise as the same but they're not

i opted for the BlehmCO (Matt93SE) mattblehm.com 300zx calipers with 04/05 maxima rotors...http://mattblehm.com/300ZX_brakes.htm

UncleMax98

Most likely the master cylinder, esp. if you don't lose brake fluid.

tbergma1

Definatly Master cylinder, definatly

Preet S 22

Like most of them said it's gotta be the master cylinder. Happened in my friends integra. Changed the cylinder braking as good as new. Good Luck...Definitly check everything..........I think brake are the MOST important thing on a car.

MaximA VlaD

iTrader: (7)

yeah, i will try bleeding the brakes first and then check the system completely. thanks for the help tho. i will keep u updated if it turnes out to be something unusual.

marco polo

check the hose at the brake booster could be leaking depending if its a cold or hot day, check for any hissing when applying the brakes

Maxgig

iTrader: (5)

If the problem is random, (every 4 or 5 weeks) I vote for a failing booster or master cylinder.

MaximA VlaD

iTrader: (7)

turned out that rear caliper was frozen...

avocent

Hmm Similar problem Im having, I was thinking MC but ill look into this