Can't Cure Soft Brake Pedal Problem...

[den0va]

Hey all,

So a little while ago I installed new slotted and drilled rotors for all four hubs, New EBC Reds all around and HEL Steel Braided Brake Lines (All bought from CamSkill) Along with this mild brake upgrade I also rebuilt all 4 calipers with new seals, dust boots, silicon paste lubing slide pins etc. My GPX does NOT have ABS and I have been using DOT 4 brake fluid. And as per title I can't cure my soft pedal after bleeding about 5 times using various methods. I have been following the correct pattern for brake bleeding as per workshop manual (Left rear, Right front, Right rear, left front)...

I've tried using the one man method (using a soft drink bottle cutting a hole into the top and using plastic/rubber tubing submerged in brake fluid) still soft pedal, I've tried using a one man pressure bleeder (the one that is like a spray bottle hooked up to plastic/rubber tubing which sends fluid back up to the master cylinder and back into the reservoir) still soft, I've tried using the two man method (pumping the brakes a few times, holding down then releasing the bleeder screw and quickly tightening before the pedal hits the floor again) was better than the others but was still soft. Before the upgrades etc my brakes were completely fine, rock solid...

Thinking of taking it to a shop and getting them to pressure bleed it but am a bit low on funds as I've just come off from 3 weeks holiday with last week being unpaid leave. If there is something I am missing please help me, this is driving me insane.

Thanks in advance... >_<

[Astron_Boy]

Losing fluid at all?
Brake reservoir diaphragm could have gone... or on the way out.
Happened with Lawso I think...

[den0va]

Don't think I'm losing any fluid, filled to the max line and was the same level today. I haven't let the reservoir run dry during bleeding either...

[Astron_Boy]

Brand new fluid?

[Vectose]

Best way I have found to bleed the lines is using a vacuum pump. Either hand or power operated.

One man job as well.

Simply hook it up to the bleed valve and start pumping.

Did you bleed until no bubbles at all were coming out of the lines?

[Shane001]

I've long suspected that I lost a bit of brake pedal feel when I put the HEL brake lines on the racecar, but never got around to swapping them back out to test. Maybe try putting the factory brake lines back on, re bleed and test. Let me know if this solves the problem

[silverGPX]

Lol what a sh*t c**t to have to take all the lines off and put factory ones on. How much play do u have in the pedal, try adjusting the pedal position.

[Shane001]

Lol what a sh*t c**t to have to take all the lines off and put factory ones on. How much play do u have in the pedal, try adjusting the pedal position.

If it fixes the problem then it's worth considering. Adjusting the pedal position aint going to do sh*t for a soft pedal

[Shane001]

By the way, I use a pressure bleeder on the race car. Pedal always came up pretty good but never really rock solid. But would require re bleeding after a couple of sessions on track. But remember I'm pushing these brakes to the absolute limit.

The other thing I suspected was maybe a tired brake booster. After bleeding the brakes the pedal was rock hard until starting the engine. Yes I know that's mostly normal but was a bit more than what I'd consider normal.

[Bennoz]

Check the rubber hose going from the booster to the intake. It has a pcv valve moulded into it. You can test it by pulling it off and trying to blow through it, from the intake end of it.

[Jase726]

I'm having the same problem. Dba's and red stuff pads I've still got the factory lines and am getting a soft pedal. Haven't bled the brakes yet but that was my plan of attack.

[Astron_Boy]

Haven't bled the brakes yet but that was my plan of attack.

[Shane001]

Haven't bled the brakes yet but that was my plan of attack.

[Jase726]

Sorry but you're going to have to enlighten me?

[Astron_Boy]

You posted about advice on a problem, whilst acknowledging a resolve that you have yet to try, and see if it will fix your problem.


I can't fragment that sentence, and I find your post very funny and whimsical.

[Jase726]

Meaning that I have similar symptoms that I haven't yet started narrowing down. Think of it as thinking of aloud. My soft pedal came post upgrade. To me even with limited mechanical knowledge it seems odd. I'll be sure to structure my late night ramblings so they make more sense in the future. Thank you for pointing out the error of my ways.

[Sahin]

Meaning that I have similar symptoms that I haven't yet started narrowing down. Think of it as thinking of aloud. My soft pedal came post upgrade. To me even with limited mechanical knowledge it seems odd. I'll be sure to structure my late night ramblings so they make more sense in the future. Thank you for pointing out the error of my ways.

Dude, if you undone the brake line. you have to bleed the brakes
when you upgraded your brakes, you would have undone the brake lines
That's why they are laughing at you because you missed the most crucial step.. unless of course you didn't do it... by reading your first post you sound like the biggest noob lol
/endjoke

[Astron_Boy]

Meaning that I have similar symptoms that I haven't yet started narrowing down. Think of it as thinking of aloud. My soft pedal came post upgrade. To me even with limited mechanical knowledge it seems odd. I'll be sure to structure my late night ramblings so they make more sense in the future. Thank you for pointing out the error of my ways.

lol, sorry dude, don't take it to heart.
I just found it funny is all, you know what needs to be done, so you're on the right path.

I dare say once you bleed the lines, your problem will be solved.

99% of the time, it's simply a fluid factor with brakes.

[Jase726]

I don't take the lines off the calipers to change the pads or rotors. If I did I'd bleed the brakes... Hence my curiuosness at having not touched the hydraulic side of the brakes. But yeah I'll bleed the brakes and post my results.

[silverGPX]

Would of been pretty hard to push the pistons back in lol