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k2fender
09-12-2006, 02:47 PM
My car had been sitting for a while, while I saved up money for an sr, and I finally got it in and running good the other day. Well the brakes were fairly locked up from sitting I guess. I re-bled them all. Did everything right. Took it out a few minutes ago and it's pretty much, just as bad. I have to push the pedal real hard to get it to stop and even then it stops real slow. I have a z32 4 piston caliper upgrade up front. The brakes worked fine before it had been sitting. Any ideas on how to fix this?

k2fender
09-13-2006, 11:27 AM
Anyone have an idea?

NemeGuero
09-13-2006, 11:32 AM
if you rebled properly..
my guess is seals are bad on the pistons

k2fender
09-14-2006, 09:30 AM
Yea rebled properly. I'm starting to think the seals may be bad but doesnt this sound more like a vacuum issue? Maybe a bad booster? Anyone else?

cgguy
09-14-2006, 11:26 AM
You re-bled but did you check to see if any of the calipers were seized? If it's been sitting for a while theres a good chance at least one or more of your pistons and/or (rear) sliders are seized up. I'd pull them all and make sure everythings moving freely before anything else.

NemeGuero
09-14-2006, 11:49 AM
You can check the booster with a vacuum gauge tester and an FSM.
The output piston will extend a certain amount.. pedal pressure should increase after you run the car off and pump the brakes.. stuff like that.
Check it out.

timtiminy
09-14-2006, 11:52 AM
yeah sounds like your booster isnt working man. pedal will be extremely hard if its not working. check that out along with making sure everything is moving freely.

Neejay
09-14-2006, 01:43 PM
According to the FSM you can test by:

- Press and hold brake pedal down
- cut car off
- if the pedal raises (forces your foot back up), you have a booster leak.

Dream240
09-14-2006, 02:57 PM
You re-bled but did you check to see if any of the calipers were seized? If it's been sitting for a while theres a good chance at least one or more of your pistons and/or (rear) sliders are seized up. I'd pull them all and make sure everythings moving freely before anything else.

Well that seems like alot of work. A caliper won't seize up from non-use unless there's no brake fluid in the system. Brake fluid is mineral oil basically so it's still acting like a lubricate to the metal parts. So even if the car sat for 5 years as long as the brake fluid stayed in the system and was never bled out or leaked out then the internals would stay clean. Sure the fluid would be bad but not the parts.

I'd say you definitely have a booster problem. Grab a working one here on Zilvia and off you go!! Oh and also if you had a bad bleed system you're pedal would be going to the floor with no brake power not the other way around.
Super hard pedal means no booster assistance.

Good Luck.

k2fender
09-14-2006, 10:45 PM
Yeah, im trying to track down one for a good price near me(richmond,VA). I checked the booster according to the fsm today, and it is failing. So hopefully i can track one day asap.

street_white180sx
09-14-2006, 10:57 PM
If your car sits up for a while there is rust built up possibly on your rotors this will cause tha type of braking. if the rotors are clean it sounds more like a booster issue check vaccum lines etc. but if the piston for the caliper was seized u wudnt have brakes period. think it out eliminate all possibilities. if u havent driven the car much take it for a lil drive and keep applyin the brakes at a good speed and tha will get rid of the rust build up if any. If u rule tha out check vaccum to the brake booster.

n2motorsports
09-14-2006, 10:57 PM
try car-parts.com or just get a reman one from autozone. my brakes were acting up and finally the booster failed on me while driving on a busy road, it locked up my brakes. pedal was super hard and brakes were fully engaged, needless to say it was very dangerous. get one soon.

k2fender
09-14-2006, 11:43 PM
I've been driving it around the neighborhood and got all the rust off. I don't have the money for a reman one right now. I'm just trying to get somthing used near me that I can afford.

zugoi
09-15-2006, 12:08 AM
According to the FSM you can test by:

- Press and hold brake pedal down
- cut car off
- if the pedal raises (forces your foot back up), you have a booster leak.

I think you got it mixed up. With the car off pump the brake pedal. Hold the pedal and if the pedal falls then you have a leak or a bad master cylinder.

Neejay
09-15-2006, 08:57 AM
I think you got it mixed up. With the car off pump the brake pedal. Hold the pedal and if the pedal falls then you have a leak or a bad master cylinder.
That's actually kind of the first part of the test:

Dream240
09-15-2006, 11:13 AM
If your car sits up for a while there is rust built up possibly on your rotors this will cause tha type of braking. if the rotors are clean it sounds more like a booster issue check vaccum lines etc. but if the piston for the caliper was seized u wudnt have brakes period. think it out eliminate all possibilities. if u havent driven the car much take it for a lil drive and keep applyin the brakes at a good speed and tha will get rid of the rust build up if any. If u rule tha out check vaccum to the brake booster.

Let me just correct some mis-information. Rust on the rotors will not cause anything but a squeal and possibly a shimmy to your braking power for about 5 seconds upon initial braking. Rusty rotors does absolutely nothing else to the car's braking system. You get rust on your rotors all the time: in the early morning when is damp, after an overnight rain storm, after washing your car and letting it sit. It's no big deal.
Also if the brake caliper seized up, depending on when it seized, you would either have constant application or no application at all. Plus you have to remember that if one piston seizes in the un-applied position on a 300zx front setup, you will still have 3 pistons in that caliper that are probably working normally, you won't notice a real difference in the braking, only upon inspection of the brake pads, uneven wear on the failed piston side.

Hope this helps, sorry for the novel.

NemeGuero
09-15-2006, 03:12 PM
I like how everyone chimes in AFTER he's figured his shit out..

timtiminy
09-15-2006, 08:19 PM
So, have you gotten a new booster yet?? tell us how it worked out for you man. oh and another way to see if your booster is working is to step on the brake pedal and start the car at the same time, if its good you should feel the brake pedal being pushed back up. if its bad there shouldnt be anything that happens.

k2fender
09-15-2006, 10:31 PM
I like how everyone chimes in AFTER he's figured his shit out..
Haha I know. Still haven't picked up a new one yet. Trying to get some money together/find one within an hour and a half from me in richmond, va.

NemeGuero
09-16-2006, 04:11 AM
Cool, let me know how it turns out.
-Evan

driftracer
09-20-2006, 10:27 AM
I feel like i'm having the same issue has k2fender...

After my SR swap was done...the car has been sitting in the garage for a few months now and the pedal is stiff as a board...it barely goes down and when pushed down all the way the car doesnt stop very well.

I'm guessing the brake booster is a easy fix...all i have to do is remove fluid from the MC...disconnect the brake lines..remove the MC..then remove the brake booster from floorboard where the pedal attaches..right? Any other tips would be appreciated.

Dream240
09-20-2006, 01:26 PM
I feel like i'm having the same issue has k2fender...

After my SR swap was done...the car has been sitting in the garage for a few months now and the pedal is stiff as a board...it barely goes down and when pushed down all the way the car doesnt stop very well.

I'm guessing the brake booster is a easy fix...all i have to do is remove fluid from the MC...disconnect the brake lines..remove the MC..then remove the brake booster from floorboard where the pedal attaches..right? Any other tips would be appreciated.

You are also going to want to drain ALL the brake fluid from the entire system BEFORE you perform this job. Then after you are done, refill the fluid and thouroughly bleed the lines. You might also do a bench bleed on the M/C before reinstalling it just to make your bleeding job easier.

ondatdryftonyte
09-20-2006, 02:15 PM
http://www.zeroyon.com/index/content/section/6/47/ i believe the fsm is in here.

k2fender
09-23-2006, 11:00 AM
ok so i put in a new brake booster. Didnt help a bit. Brakes are still really stiff. I can hear the back brakes kinda scraping when i start moving. Maybe a piston on the rear caliper is stuck? But would that cause slow braking all the way around and an extremely stiff pedal. I can't figure it out, and I need help fast.

kandyflip445
09-23-2006, 11:27 AM
Inspect all the lines and make sure that none of them are kinked. Is the car pulling at all under braking?

k2fender
09-24-2006, 09:51 PM
Lines are all good. Correction on the scraping sound during driving though, there isn't any of that. I was wrong. I have no fucking clue what the problem is. I have to apply a lot of pressure to get the car to brake and even then it does it slowly. Anyone?

k2fender
09-25-2006, 09:58 PM
Anyone at all???

NemeGuero
09-26-2006, 01:30 AM
Swap 'em out.. just eliminate one variable at a time till you get down to the answer..

I had a similar issue, replaced everything but the booster. Guess what was wrong with it?

kandyflip445
09-26-2006, 01:56 AM
Did you check the hose going to the booster to make sure it wasn't leaking? Did you check the brake booster check valve?