new brake lines, pedal super spongy?

**vinnY** · 04-12-2007 10:38 AM

so i bought myself some new braided brake lines, thought i'd install the rears first since somethings a bit funky with my new rotors on the front so i can't fit them and the calipers yet

got the old rear lines off and installed the new ones on no problems, time to bleed all 4 corners no problems, bled with the one-man-bleed-kit and no signs of air after about 10-15 pumps per corner
get around to all 4 and seem to be bleeding fine, tighten all the nipples test the pedal again. solid, sweet!

think maybe i'll take it out for a test drive, so i start the car and pump the pedal a few times to get fluids going and make sure the brakes actually work.
now here's the kicker, pedal sinks in til its about 1.5 inches from the floor then slowly sinks to the bottom eventually.

okay fair enough might be more air in there that i didn't bleed out properly.
so i bleed the brakes again and check again that all my bolts and connectors are tight and aren't leaking fluids, all check.
finish the bleed on all 4's and drop it down again and start it up, same thing.

am i doing something wrong here? running all stock ek4 calipers at the moment with a itr booster/master cylinder
with the stock lines pedal pressure and braking were fine, with just the rears having the braided hose it would just sink to the floor
didn't have time to fit the old ones back on since it was 4;30am already
is there a special procedure i'm missing? am i approaching this totally wrong? i would have thought it would be a straight swap of lines and a bleed but apparently its just not enough

**yellow-dc2** · 04-12-2007 12:46 PM

You either have a leaking line or the extra stress you have put on your Brake MC by bleeding them has caused a seal to fail check under the pedal for leaking fluid and under your car for the same thing

**destrukshn** · 04-12-2007 02:25 PM

did you ever let the fluid go dry in the reservoir?
when bleeding?
a thing that can happen as well, is when you change your brake fluid, soemtimes, your master cylinder tends to go with it as well, esp if you haven't done a flush for a while.

**vinnY** · 04-12-2007 02:31 PM

nope never dry, top up every 10 pumps
i just installed a 1" itr MC and booster, it was fine for a the few days before i changed to the rear braided lines, its after that lines which it wouldn't hold
bench bled the MC before installation and it was fine with the stock ek4 brake setup, bled and off i went

**destrukshn** · 04-12-2007 02:36 PM

i shall say, your brake master cylinder is rooted

**yellow-dc2** · 04-12-2007 02:39 PM

also check the bias valve (if its separate from the MC) its rear for these to go but it does happen.

**destrukshn** · 04-12-2007 02:43 PM

the porportional valve you mean?
the one located on the firewall?
i would somewhat highlighly doubt it.
but in some cases yes, it would happen, but you should see fluid leaking out, and by that time, you would of noticed it.

**creativepunka** · 04-12-2007 02:58 PM

get some brake hose clamps or vise grips and clamp off the rear lines. if it still sinks its before the caliper if not its after. I doubt its a rooted M/C. do a two person bleed.

**yellow-dc2** · 04-12-2007 03:06 PM

destrukshn correction noted

(its the Americanization in me)

I would have to agree with creativepunka about the 2 person bleed, its the only way to do it 100%

**vinnY** · 04-12-2007 04:12 PM

thanks for your help fellas
yep will do a 2-man bleed tonight and hopefully it'll work
will report back later if it fixed it

also with changing brake lines, is there a special procedure i'm supposed to follow? i.e. take off caliper and make sure the nipple/brake line is facing up before unbolting everything etc? do i take off the brake line off the caliper or the hardline first?

**yellow-dc2** · 04-12-2007 04:15 PM

Originally Posted by vinnY

thanks for your help fellas
yep will do a 2-man bleed tonight and hopefully it'll work
will report back later if it fixed it

also with changing brake lines, is there a special procedure i'm supposed to follow? i.e. take off caliper and make sure the nipple/brake line is facing up before unbolting everything etc? do i take off the brake line off the caliper or the hardline first?

I think it just depends on which one you think will make less of a mess

**Zdster** · 04-12-2007 04:39 PM

Originally Posted by creativepunka

get some brake hose clamps or vise grips and clamp off the rear lines. if it still sinks its before the caliper if not its after. I doubt its a rooted M/C. do a two person bleed.

I am curious as to why you dont think it could be the MC? It is not uncommon for them to go.