Help - brake fluid leak??

[JVkouki]

edit: (Mods, please move to 240sx tech instead?)

I somehow ran out of brake fluid in the master reservoir tonight.

2 weeks ago I had a really spongy brake pedal after installing my front pads so I had to bleed my brakes.

I successfully bled all four of my brakes (RR,LR,RF,LF order) and topped it off with fluid in the master. Double checked everything and tightened ALL the bleeder bolts and depressed the brake pedal and watched if fluid leaked from the bolts. No leakage.

Brakes felt MFing amazing after I bled all four (R33 Calipers <IMG NAME="icon" SRC="http://images.nicoclub.com/forums/image ... huckle.gif" BORDER="0">).

Anyway, After driving for about 2 weeks (with no problems), my brake pedals now feels soft and spongy again, and fluid in the master is gone. I took a look at my front brakes, and it looks like fluid is slowly leaking from it... How is this possible?? Does this mean I have to bleed them again?? HELP!
Modified by JVkouki at 8:38 AM 9/2/2009

[goldeneye9mm]

ok i'm gonna ask you a question and give you my diagnosis. did you put a new master cylinder on it? if not you may have torn or pulled a seal while bleeding your brakes. believe it or not that rubber seal in your master cylinder wears a groove at it's normal limit of function when most people bleed brakes they push the pedal all the way to the floor which pushes it past that groove and can pull the rubber seal out of place. sorry for the windy explination but i hope to help more than just you w /this. when you bleed the brake only use the normal range of pedal motion or vacume bleed them unless you have a brande new master cylinder. if you have a small amount of fluid coming from the caliper that is probly not helping the situation but i doubt it's your whole problem. pullthe master cylinder away from the booster and i gurentee fluid pours out.
Modified by goldeneye9mm at 10:56 PM 3/22/2008

[Xdisaster240sX]

never mind i read this wrong...

[240life]

did you remove any of the lines to the caliper and forgot to replace the crush washers....maybe your bleeder screws are not functioning correctlyand allowing fluid to slowly pass through them...those are 2 simple solutions...i have never had an issue with the above mentioned seal tearing, i'm not saying it isn't a possibility just pretty uncommon

[JVkouki]

BUMP

hmm, yea my car had a new 300zx master cylinder installed with stainless brakes lines. And no, I didnt remove any lines, I put them back where It was. If anything i'm just gonna have to take another look at it today...

And when I pumped the brake pedal, I did it so it didnt touch the ground... so i dont think I tore up any seals in the new master cylinder. I'm just wondering how the brake fluid is leaking when I already tightened up the bleeder bolts.... ahhhhhhhhh

[sjbsuperman1425]

man i am probably gonna get bitched at for this lol but i just want to try and finish up the thread i guess.

they might be leaking from the screws if they are not "Seating" right. it happened to me the other day. and then i lost ALL fluid DIRECTLY from the Master cylinder from a torn seal. i pushed the pedal down all the way lol anyway..thats my story. i'd try new bleeder screws maybe, and check seals just to be sure.

[sjbsuperman1425]

well heres a resurrection! lol

i fixed the master cylinder seal that was leaking on my car. I thought that solved the problem, but it turns out the passenger rear assembly is leaking, enough to where i haven't drove it and all the fluid is out of the master cylinder. the bleeder screw doesn't work for that brake, but i found another way to bleed it (dont ask..). Could the piston just need to be pushed back into the caliper, or what could the problem be?

like said, i haven't drove it in over 3 months and its just gone. Any help would be appreciated. Thanks.

[Papi Chulo]

Leaking from where?

That caliper probably needs to be replaced/rebuilt.

Bleeding without bleeder? Explain.

[sjbsuperman1425]

Leaking from where?

That caliper probably needs to be replaced/rebuilt.

Bleeding without bleeder? Explain.

i never saw it leak, but i saw fluid on the inner side of the rim..a friend had the same problem on his Subaru and it was just the piston needed pushing back in.

i was thinking the same things, a rebuild kit for the one caliper is like $5 so i might go ahead and do that.

what i did was take the bleeder all the way out, have a friend push the pedal, wait for fluid to start coming out, screw it in quickly! lol im buying a new bleeder too so lol

[sjbsuperman1425]

http://www.partsamerica.com/Pr...Set=A

^i think this is the right thing to buy if one of my calipers is leaking, right?

also, im replacing all rotors and pads just incase.

[94_240sx]

Sounds like piston seal to me. Not the ouside one. The one you can get to after you remove the piston. Check 240sx Tech article that I wrote. I have some extras.

[sjbsuperman1425]

Sounds like piston seal to me. Not the ouside one. The one you can get to after you remove the piston. Check 240sx Tech article that I wrote. I have some extras.

yea thats what im thinking too. isn't the piston seal included in the link i provided above? i've never done a caliper rebuild before so im not sure.

[sjbsuperman1425]

http://shop.advanceautoparts.c...32___

just looking for confrimation that this is what i need to replace the piston seal and boot on my non-abs S13? i plan on buying it today so i just want to be sure..are the calipers on abs and non-abs 240's the same as for rebuilding?

[Stripes]

My bmc is leaking like a mofo too man. I think mine is from pressing the pedal to far down when I bled them. Would I be able to get a rebuild kit and fix this or do I need a whole new master cylinder? Also, can I use a z32 BMC on stock brakes?

[sjbsuperman1425]

My bmc is leaking like a mofo too man. I think mine is from pressing the pedal to far down when I bled them. Would I be able to get a rebuild kit and fix this or do I need a whole new master cylinder? Also, can I use a z32 BMC on stock brakes?

go to the dealership and ask for BMC resevoir seals..i had to replace one and it was like $12. and you can use the Z32 BMC on stock brakes IIRC.

as for my caliper problem, im going to see if the piston is just popped out first and then if it still leaks after pushing it in and new pads/rotors, i'll rebuild it

[Stripes]

go to the dealership and ask for BMC resevoir seals..i had to replace one and it was like $12. and you can use the Z32 BMC on stock brakes IIRC.

as for my caliper problem, im going to see if the piston is just popped out first and then if it still leaks after pushing it in and new pads/rotors, i'll rebuild it

Awesome, I'll have to look into that seal.About the Z BMC, someone told me the front brakes might lock up to fast, thats why I was wondering.

[sjbsuperman1425]

it shouldn't lock up to quick i wouldn't think..but your stopping power will be badass n1ggggaaa!

[94_240sx]

yea thats what im thinking too. isn't the piston seal included in the link i provided above? i've never done a caliper rebuild before so im not sure.

Yeah upper left corner. That's piston seal. It's easy to rebuild. I had never done it before too, but had no problem doing it.

http://www.nicoclub.com/articles.php?id=215854

[s13gebala]

i had to redo my brake lines and screwed one into the caliper line crooked, it made tons of headache problems and i ended up having to switch the ends from us to euro (i had abs)..

hopefully you dont have to do that because brake fluid is a little b**** to deal with and so is the high pressure brake system

find the leak and fix it.. hopefully your threads are not fkd up

[JVkouki]

(Mods, please move to 240sx tech instead?)

I just finished rebuilding my R33 Front calipers with new seals, O rings, clips, etc (thanks to 94_240sx ) BUT I didnt bleed them yet, so brakes feel airy and spongy. I didnt care though, I just wanted to drive around the block to check if the master cylinder was still depleting brake fluid when I step the brake pedal.

still, brake fluid is still getting low in the master and its leaking....somewhere.

This time....from what I can tell, it doesn't seem like its coming from the caliper though (didnt notice any leaks from there...but I didnt drive around that long) I dont know where else to look? ....

EDIT: I jumped the gun I shoulda bled the brakes before I did anything else. Just bled all four brakes after the rebuild and now the brakes feel GREAT. No more leaks...! If anyone has this problem I recommend rebuilding the calipers

Resources:http://www.nicoclub.com/articles.php?id=215854 http://240sxforums.com/forums/....html
Modified by JVkouki at 7:21 PM 9/4/2009