94 honda civic cx
d16a vtec
t3/t4 turbo w/ front mount intercooler

before whenever i would brake sometime(like on warmer days or freeway trips or i'm carrying a few people) the brake pedal would start to sink slowly. i change the master cylinder and now the sinking stops, but the break is really low to the ground now. i have to step on it and it would drop to a little over halfway before you can feel it bite. is there a way to fix this? i bleed it lots of time already. i dont know if doing it wrong but here are my bleeding technique.

have someone in car pump 5 times, hold, i go and bleed each wheel, i start from the passenger rear, driver front, driver rear, passenger front.

thanks for any inputs because this is driving me crazy.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lv6l &raquo;</TD></TR><TR><TD CLASS="quote">94 honda civic cx
d16a vtec
t3/t4 turbo w/ front mount intercooler

before whenever i would brake sometime(like on warmer days or freeway trips or i'm carrying a few people) the brake pedal would start to sink slowly. i change the master cylinder and now the sinking stops, but the break is really low to the ground now. i have to step on it and it would drop to a little over halfway before you can feel it bite. is there a way to fix this? i bleed it lots of time already. i dont know if doing it wrong but here are my bleeding technique.

have someone in car pump 5 times, hold, i go and bleed each wheel, i start from the passenger rear, driver front, driver rear, passenger front.

thanks for any inputs because this is driving me crazy.</TD></TR></TABLE>

should have changed the booster as well. when the M/C goes out fluid leaks every where. is this what happened to you? also, the booster and M/C go hand and hand.
it's like the clutch cylinder, when you change that out, you might as well change the slave cylinder too.

 

well i did not have fluid going everywhere. nothing was leaking at all really. i just had bad cases of sinking....strange, now what

well here's something that might help. when i pull out the mc to change, there is a strong suction. was there suppose to be a special way to put the other mc back in? i read in the honda service manual and they didn't say much so i'm afraid i might of did something wrong.

 

you are bleeding the brakes several times per wheel until you have no air in the fluid and it come out clean? Also are you making sure the M/C is always kept full of fluid? You have the right order it just sounds like you still have air in the system

Edit: I have never heard of a brake booster causing a soft pedal when they go bad you can't push the pedal

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lv6l &raquo;</TD></TR><TR><TD CLASS="quote">well i did not have fluid going everywhere. nothing was leaking at all really. i just had bad cases of sinking....strange, now what</TD></TR></TABLE>

i would first inspect all your brake lines and calipers. make sure you don't have some sort of pin hole leak or bad piston seals. second, i would try bleeding the brakes again and making sure you are using the proper brake fluid for your application. third, if all else fails you might want to invest in buying a new booster and changing it out.

 

ok let me try bleeding again, but to make sure so i wont run into any problems later on, wheni bleed it, i will have my buddy pump the pedals several times and hold, while i loosen the nipple and have it come out. i will then move on to the next wheel or continue to bleed that one until i see no bubbles.

also how should it look like or sound when ti comes out, is it suppose to come out smooth stream because i can remember there's a couple times i had one wheel(passenger front) it would shoot out kind of irractically. how long should i loosen the nipple each time before closing and pumping again.

and yes i made sure the resevior is always full and i'm using vavoline full synthetic dot 4 brake fluids. before i had in valuecraft dot3/dot4. could the switch to full synthetic cause anything?

thanks.

EDIT: i check all hose and pistons, everything seem to be looking and working like they should, no leaks no pin hole leaks. fluid has always been full. once in a while my clutch master cylinder would be a bit empty, does the clutch and brake lines connect in any way?

 

did you prime the M/C before you installed it? if you didnt you have air in the system up near the M/C that will cause soft brakes and/or low pedal.

 

maybe this is my answer here. no i didnt. how do i prime it? is it already too late to prime it?

 

Bench bleeding or "Priming" the m/c just reduces the time it takes to bleed the brakes. It's not like if you don't bench bleed the m/c it will never be right - it just takes a lot longer to bleed all of the air of of the system.

I have a feeling you have double gasketed the master cylinder where the shaft of it goes into the booster.

Leave the brake lines hooked up (so you don't have to rebleed as much) and remove the two nuts that hold the m/c to the booster, then pull the m/c off of the booster and make sure only ONE of those thick rubber washers/gaskets are on the shaft of the m/c.

A lot of times the new m/c comes with a new gasket, but the one from the old m/c sticks inside of the booster.

Check this before you rebleed the system for the 12th time.

 

alright. i'll double check that. i see a hex nut on the mc, can i bleed this part of it as well?

and my question earlier, when bleeding how do i know when there is no more air in the lines, is it suppose to flow out very smoothly, sometime i get a big squirt of fluid, is that the air? and do i keep bleeding a wheel until fluid comes out smoothly before moving onto the next one, or i rotate even if there's still air.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lv6l &raquo;</TD></TR><TR><TD CLASS="quote">alright. i'll double check that. i see a hex nut on the mc, can i bleed this part of it as well? </TD></TR></TABLE>

No.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">and my question earlier, when bleeding how do i know when there is no more air in the lines, is it suppose to flow out very smoothly, sometime i get a big squirt of fluid, is that the air? and do i keep bleeding a wheel until fluid comes out smoothly before moving onto the next one, or i rotate even if there's still air.</TD></TR></TABLE>

As long as solid fluid comes out with no air bubbles you're good. Make sure your buddy isn't jamming the pdeal as hard as he can when you open up the bleeder though - that will make it squirt out every time!

 

ok. i open up the mc and check to make sure i didn't double gasket and i found only 1 gasket in there. i put everything back. bleed it in the order honda sugested and stop when solid fluid came out, made sure resevoir is always full. put everything back. it seem like it help, but just very little. i mean this is the third or fouth time i bleed it after installing the mc and i would like to know how long or many times does it normally take to fully bleed a brake system.

thanks in advance.

 

are the brakes old, possibly laminated rotors, rotors heat cracked. metal on metal. slides locked up on caliper. maybe just check the basics.

 

i'll give that a check. worth a try. wish me luck.