Odd brake fluid leak - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Flicktitty · 06-14-2012, 12:21 PM

I installed some Q45 front calipers/rotors/lines a couple weeks ago. bleed the brakes filled the master cylinder. pedal was ok, then i noticed the fluid level went down. I found the caliper was leaking bought a new one. and it was fine, I went ahead and re-bleed all the brakes pedal was fine. went out had lunch came back and the reservoir was about half empty. brake pedal was still firm. Then i refilled it and it hasen't gone down at all.

*NOTE - I HAVEN'T DRIVEN THE CAR* it's just leaked when it sits in the garage. No fluid on the wheels, or calipers. no leaks on the hard lines. the rear lines are dry. and the new front stainless lines are dry. all the calipers check out good.

there was a LITTLE fluid under the master cylinder and the frame rail but not much, no where near as much fluid as was lost. Just wondering what else to check? I ordered a new master cyl. and reservoir but just looking for other thoughts.

Thanks, Nick

jr_ss · 06-14-2012, 12:34 PM

Possibly leaking out of the back of the MC. Did you tighten up the lines from the MC? it has to be going somewhere, it doesn't just disappear. Notice any fluid on the bottom of the booster?

Flicktitty · 06-14-2012, 12:49 PM

Quote:

Originally Posted by jr_ss

Possibly leaking out of the back of the MC. Did you tighten up the lines from the MC? it has to be going somewhere, it doesn't just disappear. Notice any fluid on the bottom of the booster?

there is very little. but i couldn't tell if thats from spilling the fluid or not. i have since wiped it off and nothing has been back. Would it leak out the back of the MC without the brake pedal being pressed?

jr_ss · 06-14-2012, 03:40 PM

Quote:

Originally Posted by Flicktitty

there is very little. but i couldn't tell if thats from spilling the fluid or not. i have since wiped it off and nothing has been back. Would it leak out the back of the MC without the brake pedal being pressed?

If the internal seals are bad enough, yes it can seep out. I have a similiar issue, however, I have a completely different setup than you. Wilwood 4pot Superlites and Z32 rears. I noticed my fluid running skinny in the resevoir a few times. I found a small leak at one of the rear calipers, however I think it only leaks when pressure is applied to the system(inbetween caliper halves).

Brake fluid is very corrosive, if it's not cleaned off a painted surface fast enough it will eat down to bare metal. Keep that in mind, unless you don't care too much how your engine bay looks.

project-c2 · 06-15-2012, 06:36 PM

Back of the master leaking into the booster?

06-14-2012, 12:21 PM	#1
Flicktitty Post Whore! Join Date: Apr 2007 Location: Wisconsin Age: 34 Posts: 3,685 Trader Rating: (13) Feedback Score: 13 reviews	Odd brake fluid leak I installed some Q45 front calipers/rotors/lines a couple weeks ago. bleed the brakes filled the master cylinder. pedal was ok, then i noticed the fluid level went down. I found the caliper was leaking bought a new one. and it was fine, I went ahead and re-bleed all the brakes pedal was fine. went out had lunch came back and the reservoir was about half empty. brake pedal was still firm. Then i refilled it and it hasen't gone down at all. NOTE - I HAVEN'T DRIVEN THE CAR it's just leaked when it sits in the garage. No fluid on the wheels, or calipers. no leaks on the hard lines. the rear lines are dry. and the new front stainless lines are dry. all the calipers check out good. there was a LITTLE fluid under the master cylinder and the frame rail but not much, no where near as much fluid as was lost. Just wondering what else to check? I ordered a new master cyl. and reservoir but just looking for other thoughts. Thanks, Nick __________________ 2JZ-GTE Swapped S13 Coupe - 1994 Supra Turbo

06-14-2012, 12:34 PM	#2
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,052 Trader Rating: (34) Feedback Score: 34 reviews	Possibly leaking out of the back of the MC. Did you tighten up the lines from the MC? it has to be going somewhere, it doesn't just disappear. Notice any fluid on the bottom of the booster? __________________ My SR20VET

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06-15-2012, 06:36 PM	#5
project-c2 Leaky Injector Join Date: Jan 2012 Location: Honolulu, HI Age: 39 Posts: 76 Trader Rating: (4) Feedback Score: 4 reviews	Back of the master leaking into the booster?