brake fluid Options

[kamax]

can our car use synthetic brake fluid?

i am asking because i put it in my bakes and it feels really light. i bleed the system and all.. but the first press feels really light, and the brake pedal goes right to the floor with lil resistance.

[Hanyo]

that sounds like there is an air bubble in the lines somewhere.

[LewFX]

use 2 ppl to bleed. start from passenger rear. driver rear, passenger front, driver front. pump pedal 2 times and hold it down...use your 8mm wrench and release the fluid and tighten the bolt. repeat until all air is gone. you can see the fluid with the clear hose. do to all 4.

http://www.drivewerks.com/tech/mult_bleed_brakes2.htm

This post has been edited by LewFX: Mar 21, 2007 - 9:30 PM

[jc47]

All brake fluid is synthetic. 'Synthetic' has become a marketing term, and it really doesn't have much meaning anymore. Just make sure you are not using DOT 5 silicone brake fluid. Like the other posts suggest, it sounds like air got into the brake lines when you exchanged the fluid.

[6gsillyca]

Doesnt an air bubble just make the pedal "mushy" (rather than being firm)? If it goes all the way to the floor with little resistance, pedal droping with constant pressure that sounds like a master cylinder (or in my case, rotten hard lines)
eg.
stopped on a hill you need to keep pressing the pedal further and further down to stay still

You should be albe to press the pedal down, it will get firm and you cant press it and further.


As for synthetic fluid it doesnt absorb water, which is bad. (hydroscopic) Regular fluid can absorb small amounts of water (reduces boiling point) but it keeps water from sitting in your lines and rusting them out.

[eggman40]

I use dot4 brake fluid becuase of its higher boiling point. I originaly had some cheap $2 bottle crap and after a few good stops the brakes would feel mushy. Now its gone, unless i do it for very prolonged periods of time. And like they said above dont use dot5 its bad for the system. If im not mistaken that for really hardcore race aps where you would need an even higher boiling point, but will change your fluid more consistently. If it sits for too long it will start to eat crap up.

[Bitter]

if the pedal is going all the way to the floor with no holding power then its a leak which can be internal (bad master cylinder seals) or external (hole or loose fitting).

however if you pump the pedal and it is able to hold the car then its probably trapped air in the system, however air doesnt just get in on its own.

[kamax]

it's holding power and everything, but just feel light. probably there's bubble still, in the process of bleeding, i did run out of brake fluid to bleed.

so i depress the pedal til there's a strong jet of fluid coming out right? and than tighten it to get rid of the air bubble?

oh and when i brake, i hear a hissing sound coming from the pass front side... could that be the problem? thanks for all your helps

[Bitter]

have a friend help you bleed, you push down, then he opens, you push the pedal to the floor and hold it till he closes it, then let up and do it till its all clean fluid coming out or until when its closed the pedal feels correct.


i'm not sure what the hissing is, have someone look while you pump the pedal.

[kamax]

yep got to feel pretty good now. i'll just need to get use to it i guess, since i have new rotors and brake pads installed also.

and I still dont know what the hissing sound is though.... it's near the front pass wheel but sounds like it's inside the engine bay towards the bottom. Pressing the pedal down caused the sound... anyone know what this might be?