new brake lines, pedal super spongy?

[vinnY]

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]

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]

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]

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]

i shall say, your brake master cylinder is rooted

[yellow-dc2]

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

[destrukshn]

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]

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]

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]

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]

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]

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.

[aaronng]

1 man bleed kits are useless. You rely on a seal around the nipple, which is poor at best. Even if you have a good seal, air still gets into the caliper through the gap in between the threads of the bleed nipple and caliper.

Just get your family/friend to help you press the brake pedal and re-bleed all 4 brake calipers.

[yellow-dc2]

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


If it was the MC it would be showing more signs, like leaking through to cabin, leaking externally in engine bay (not common), and as he is loosing so much fluid it would be fairly noticeable, if it was all coming in the cabin.:)

[destrukshn]

If it was the MC it would be showing more signs, like leaking through to cabin, leaking externally in engine bay (not common), and as he is loosing so much fluid it would be fairly noticeable, if it was all coming in the cabin.:)
you would be more talking about the clutch master cylinder.
that would leak in the cabin.
the brake master would leak internally, through the primary and secondary piston/seals

[vinnY]

well i just gave it a test pump while off, pedal goes firm after about 2 pumps and when i hold it, it appears to stay solid so i guess that rules out the mc being gone?
also came back to see no puddles where the brake lines are and underneath the calipers so there doesn't seem to be much of a sign of leaking
i suppose i gotta bleed it properly with a 2-man team and see how i go, hopefully my second pair of hands get here soon to help me figure this out :( sucks not being able to go anywhere

[shadou]

sounds like the m.c may need replacement. My m/c is rooted but can only feel the effects once the weather hots up. Give the 2 man bleed a shot first

[Zdster]

you would be more talking about the clutch master cylinder.
that would leak in the cabin.
the brake master would leak internally, through the primary and secondary piston/seals

Exactly. I was a bit confused. It is not that uncommon to see the piston seals go.

[aaronng]

Since his brakes were working fine before changing the lines and trying to one-man bleed the system, I'd say his MC is still alright. Although, pressing hard on the MC when there is clearly hard resistance can cause leakages through the seal. Hopefully he wasn't pumping with all the strength of his right foot.

[shadou]

maybe the seals were already on there way out and with all the pedal pumpage you just helped it along? dunno just throwing something around

[aaronng]

maybe the seals were already on there way out and with all the pedal pumpage you just helped it along? dunno just throwing something around

I'm very sure it's the one-man kit's fault. I've used it and it was junk. $10 gone too... :(

[vinnY]

well i re-bled the system with a 2-man setup and its fully bled but the pedal is still super spongy and the pedal travels heaps
sure it stops but its pretty much either on or off now, no such thing as slowing down :(
threw on my cusco brace and tightened it up and still didn't do anything for the feel

hopefully when i put on the itr calipers and front braided lines it'll stiffen up more but at the moment its just scary to drive :(

[yellow-dc2]

now it sounds like MC or booster

[creativepunka]

If some how the M/C did suck in air when you were bleeding it can take up to 3 bottles to completly flush it out "sometimes". The pedal travel indicates it still has air in the system or the M/C is internally leaking back into the resovire. Im still thinking air in the system, how did you bleed it? try the clamping off of the rear lines then do the same to the front.

[tinkerbell]

well i re-bled the system with a 2-man setup and its fully bled but the pedal is still super spongy and the pedal travels heaps

have you tried bleeding with the engine running?

i found this helped me once on a DC2 that just wouldnt bleed right...

it felt hard whislt bleeding but once the engine was running it was spongy... doing teh 2 man bleeding with the engine running helped a lot...

(an no - i cant explain why it helped, it just did!)

[creativepunka]

If the booster was stuffed then you would have a hard pedal and it wouldnt be "either on or off" it would be on with two feet pushing lol.

[tinkerbell]

i doubt it is the booster.

it is definitly air.

[aaronng]

How many bottles did you use? To properly clear out the brake lines, you'll need a bit over 1 bottle. When I did it after installing braided lines (front and rear), it took 2 bottles.

[yellow-dc2]

(an no - i cant explain why it helped, it just did!)

Power Assisted brakes???

[tinkerbell]

well, all brakes are vacuum assisted these days, but not sure WHY this would affect it...

but in this case - it might be worth a try?

someone tried to tell me it had soemthing to do with ABS, but i didnt really understand why...

[creativepunka]

ABS can be a prick to bleed if you get air in the system, some manufactures like holden do an abs bleed with a scan tool and your right foot while someones underneath undoing the bleeds screws. ( that wont help but its interesting)

[shadou]

one man bleed kits aren't all bad, although I prefer the 2 people bleed method over it. Depends how you use it and of course the little rubber seal on the nipple, every mech workshop has at least one and I've used it from rebuilding m.c. to those crappy time consuming prelude brake line recalls, never has it resulted in spongy pedal afterwards.

[fatboyz39]

have you tried bleeding with the engine running?

i found this helped me once on a DC2 that just wouldnt bleed right...

it felt hard whislt bleeding but once the engine was running it was spongy... doing teh 2 man bleeding with the engine running helped a lot...

(an no - i cant explain why it helped, it just did!)

Will try that next time when bleeding brakes:thumbsup:

[dsp26]

have you tried bleeding with the engine running?

i found this helped me once on a DC2 that just wouldnt bleed right...

it felt hard whislt bleeding but once the engine was running it was spongy... doing teh 2 man bleeding with the engine running helped a lot...

(an no - i cant explain why it helped, it just did!)

i'm not disputing that this does not work as this was the only way i knew before... HOWEVER, can someone explain to me why everyone else tells me not to do it.

it's obvious why the brake booster helps in squeezing every bit of air out... but what is the supposed DANGER in doing it with the engine running???

[aaronng]

it's obvious why the brake booster helps in squeezing every bit of air out... but what is the supposed DANGER in doing it with the engine running???
I guess the brake fluid would be sprayed out at high pressure. Make sure you hold the hose down properly and be ready to close the bleeder nipple quickly.

[dsp26]

I guess the brake fluid would be sprayed out at high pressure. Make sure you hold the hose down properly and be ready to close the bleeder nipple quickly.

good point, so we can logically assume then that poses a danger also to every seal in the system during bleeding because of the unnecessary additional pressure?

[tinkerbell]

it's obvious why the brake booster helps in squeezing every bit of air out... but what is the supposed DANGER in doing it with the engine running???

the only danger i noticed was carbon monoxide poisoning doing the rear calipers... :eek:

(however - there might be other mechanical ones)

[shadou]

having the engine running while bleeding ain't gonna make it squirt out like a geyser! Just make sure the hose/rubber grommet attached onto the nipple is firm.

[Limbo]

wait i think we are going about this all wrong. Let me ask a question.
Is your front brakes still hooked up? cos if not then the front brakes are not bitting into anything thus the spongyness! You cannot bleed the brakes without all the brakes installed.(correct me if i'm wrong).
I don't think anything is wrong at all. COnnect the front brakes before you bleed the rear.

P.S. I just changed to ITR calipers also. You need to machine 2.5mm from teh caliper make it fit. for some reason the ITR rotor is 2.5mm closer to your hub. Other option is to run a 3mm spacer but someone will need to machine it for you also.

[vinnY]

at the moment running stock calipers all round, just waiting for the weekend to throw on the itr caliper and new rotors/pads

was going to do all the lines but realised i need to cut the brake dust shield before the new bigger rotors would go on so i was left with just the rears being braided while the fronts are stock lines

bled the lines and should have gotten all the air out of the lines, but the pedal remains spongy for now
its as if the first 2 inches you push down do next to nothing and it'll just suddenly bite while the pedals about an inch from the floor

threw on my cusco brake stopper and it did squat for brake feel unlike when i had my stock brake booster/MC on which i found really odd

[aaronng]

His front brakes are hooked up. He didn't change the front lines.

vinnY, I hope you bleeded all 4 corners again using the 2 person approach.

[vinnY]

sure did, PR.DR.PF.DF
braking is okay but i just miss the solid feel it has previously, i'd only need to push it down about an inch to get the same stopping feeling

heel and toe is a bit difficult when the pedal sinks in that much further than the throttle :(

[aaronng]

How many bottles of brake fluid did you use to bleed the lines the 1st, 2nd and 3rd time?

[vinnY]

when i first installed the booster/MC i used a bottle after i bench bled the MC

when i changed the rear lines i ended up going through 2 bottles
only needed about 3/4 of a bottle tonight when i bled out all the air that we could

i'm just disappointed now that the pedal feel has gone so soft, braking is fine for now however

[aaronng]

Did you tighten up the banjo bolt properly?

[tinkerbell]

so there was air when you bleed to night?

maybe you damaged/lost a banjo washer?

[vinnY]

benjo bolts seem fine, no leaking from them
crush washers appear to be doing their jobs, yes i have 2 on each banjo bolt
tiny bit of air but it came out fine
will try bleeding the brakes in a couple days time and probably will install the itr caliers on the weekend and see if its any different

[aaronng]

good point, so we can logically assume then that poses a danger also to every seal in the system during bleeding because of the unnecessary additional pressure?

Nah, the components after the booster are designed to handle the high pressure. The only things after the booster that can't handle high pressure are the clear hose that you are using, the paint and your face.

[vinnY]

will probably try to bleed my brakes while the car is on next time to see if it helps.
so how can i avoid copping a face full of fluid? make sure i'm holding the plastic hose firmly against the bleed nipple and open and close the bleed nipple quickly?

[shadou]

like said, it won't exert an enormous amount of pressure so a firm hold on the grommet or tube end to the nipple and do a normal brake flush, just keep topping up after each corner.

[Samo]

just try gravity bleed

with the car off ... pump the pedal a few times and crack open a nipple (one at a time like u would with other ways)
and just let it drip and if there is air in dat corner u should see it bubbling out ... and wait until its just fluid coming out close the nipple and pump the pedal a few times and do it again ... should do it abt 3 times per corner

we do dat in the workshop when we change brake lines or calipers

and good thing is it doesnt take much fluid ...
tip is to put a rag under the nipple to absord the flui running off

[Limbo]

Try bleeding the front first and then the rear. ANd use a 2 man team.
In relation to the dusk covers, don't grind them off just bend them back and they will fit. You might need to bend them once or twice once you go for a drive. I had to do that also

[Paul1985]

Don't do the front first then the rear. The reason being is you bleed the farthest from the master cylinder first is AIR if you do the closest to the front first there will still be trapped air that can then escape to the rear, if you do the rear first you remove that trapped air then move to the front eliminating the air so it can't escape to the rear.

Thats correct.
Depending on the vehicles braking setup the farthest point can be different aswell, don't just assume the rear left is the furthest point (although usually is).
If your unsure check the workshop manual.

Pretty sure this guy knows what he's doing with the bleeding process now :thumbsup:

[vinnY]

yeah i've experimented with the PR.DR.PF.DF and also the cross method PR.DF.PF.DR and both seemed to have the same result and no loss in pedal feel
braking is okay for now but the pedal is still very spongy, much like stepping on dense foam instead of stepping on a rock
checked for leaks again and it appears that its fine, fluid hasn't moved from the max position
is there anything i should have done to the booster before installation? i sort of just unbolted the MC and bolted it back into where the old booster was

with the gravity bleed, how does that work when nothings forcing the air out of the calipers? the bleed nipple isn't at the top of the caliper so how do the air bubbles escape with gravity alone?

[destrukshn]

by anychance do you head a air leak from the booster?
air could be leaking inbetween the booster and the cylinder.
if that's the case it's a seal inbetween it.

[vinnY]

how do i check for internal leaks?
while the car is off and i pump the pedal, it goes hard and doesn't sink
while the car is on the pedal travels down quite a bit and is spongy to step on but doesn't ever really touch the floor nor sink down there eventually, maybe i should change the thread title

[destrukshn]

with the car on, go to the brake booster, and see if you can hear any leaks, air leaks that is.

[vinnY]

just had a thought, two actually
was i supposed to adjust the pushrod before i installed the brake booster?
and since i had to disconnect the booster initially, and since it works on a vacuum, do i need someone to step on the brake pedal while i connect up the vacuum hose for the booster?

[aaronng]

Don't do the front first then the rear. The reason being is you bleed the farthest from the master cylinder first is AIR if you do the closest to the front first there will still be trapped air that can then escape to the rear, if you do the rear first you remove that trapped air then move to the front eliminating the air so it can't escape to the rear.

But if you bleed the front first, the air that escapes to the rear is then removed when you bleed the rear after that, right?

[creativepunka]

It all depends on what sort of vehicle it is. The bleed the rear most caliper came about when we were running a single piston M/C where all the brake lines get there pressure from one piston. They were made illegal because if a line punctures you have no brakes at all. and now we have two piston M/C that run two separate circuits so that if a brake line ruptures you still have two working brakes. RWD cars are usually split front to rear (different circuits) and FWD are usually diagonally split. If it was a front two rear it wouldnt really mater which end you started with as long as you do the furthest one from the m/c in that circuit.

[Bludger]

probably nothing related to your situation, but I've had a pedal sink to the floor on me.

pedal feel was normal, braking power was normal, just once you stop, pedal will slowly sink to the floor.

turned out to be the MC, seals

[vinnY]

okay reading a bit more about pedal free-play and such



After the usual checks all around to make sure everything was tight and leak-free, and all hoses put back where they should have been, I checked the freeplay at the pedal. And promptly ran into a problem. Pedal freeplay is best felt with your fingers, with a very light push. There ought to be a tiny bit of fairly easy movement before you feel the pedal hit hard against something. What's happening at the hard spot is that the pushrod has contacted the rear of the MC plunger.

There must be some clearance between the pushrod and the MC plunger, otherwise your brakes may lock on as you drive. If there is too much clearance, the pedal will feel soft and will have excessive travel. I ended up with the latter. The manual specifies 1 to 5mm clearance. I had 10mm. I did not think to check the clearance before I started, so I don't know what it originally was. The pedal definitely felt looser than before though, in spite of a very thorough bleeding session.


now when the car is off and there is no vacuum the pedal 'freeplay' seems to be within the 5mm spec
with the car on, pedal sinks about 1.5inches before i feel any braking power at all
have already bled lines and made sure theres no air in the lines and no leaks from newly installed lines
pedal doesn't sink when stationary and held in place so the MC is okay, booster isn't leaking since it seems to be holding vacuum okay

anyone want to suggest how i may tackle the problem of a unadjusted brake booster?

also noticed while looking at my stock booster and the one i have installed
http://img480.imageshack.us/img480/1215/ek4boosterlr4.th.jpg (http://img480.imageshack.us/my.php?image=ek4boosterlr4.jpg)
ek4 booster rear
http://img413.imageshack.us/img413/70/itrboosterdy4.th.jpg (http://img413.imageshack.us/my.php?image=itrboosterdy4.jpg)
new booster, dust cover?

[zco]

i installed new itr brake booster master cylinder today

did rear first. then front. then rear again.. when i went back to the rear the 2nd time there was still air in the system.. might wanna try doing that buddy

[vinnY]

bled about 3 times already dude :( will probably try again and see if it helps

[aaronng]

bled about 3 times already dude :( will probably try again and see if it helps

If you are going to bleed again, try the bleeding order in the service manual for the newer hondas. Front driver, front passenger, rear driver, rear passenger. Bleed 1 resevoir's worth of fluid for each corner.

[Limbo]

i got an easier solution take it to a mechanic. THe issues may be more than what you are describing and without really looking at it now its gonna be hard to know if we are recommending the right thing now. You've tried everything else. Now i think its time to see professional help!

[zco]

bled about 3 times already dude :( will probably try again and see if it helps

did u do rear, front then rear again ? try cahnging back to your old lines and see if anything happens

[tinkerbell]

ive never seen a 'dust cover' like that before?

please remind me where you got it from?