DaveUK

This is probably due to my lack of experience with sports cars (s2000 is my first, closest thing to a sports car before this was a mini cooper s), but I'm not sure what the brake pedal should actually feel like.

Am I right in thinking the brakes, once pads have made contact, should be like pushing your foot against a concrete floor?

With my brake pedal, there's some travel before contact, then once contact is made, the pedal keeps moving up to a point (not the stopper), so much so that when braking pretty hard, it's difficult to blip the throttle for down changes because my foot has travelled too far.

Things I've done to try to remedy this:
HEL braided lines
Brake master cylinder brace
Refurbished calipers all round
Countless bleeds. Quite a few ABS stops before 4 bleeds, some on gravel at 10 mph, some on tarmac from 60 mph.
Reversed the brake fluid up through the system by pushing in the pistons. For this I had to remove the pads, push the pedal a few times gently and the pushed the piston back in. I did this one caliper at a time.
I tried Billmans method of putting a big concrete block pressing hard on the pedal overnight. Maybe I should try this again because I did that a while ago after I installed the braided lines, so I definitely had air in the system back then. (the brakes feel a lot better than just after I installed the lines, but all I've done is got them back to how they were before).

Nothing has changed how they feel. My pads are EBC Redstuff. They've got loads of thickness left. I can stop on a dime if needed as well, so in that sense I'm very impressed with the brakes, just not the pedal travel.

Also, sometimes, there's two stages to braking. I brake, it starts stopping, then for a split second the braking force dissapears and then comes back. It's annoying. Is it gas from the pads? I have ebc redstuff, so I thought they didn't produce gas. It doesn't have to be hard braking for this to happen. It's very occasional, and not if I've put heat into the brakes. I first noticed this in the winter, and a friend said it might be water escaping from the pad as it gets heated up. There are a few things this friend had said/done for me to not trust his opinion though. Could this be down to a failing booster? Could that explain the pedal travel as well?

I've checked everywhere for leaks. All the nipples, the banjo bolts, the connections between hard lines and flexy lines, plus around the master cylinder and in the footwell.

I guess my main question is am I chasing a non-existent problem? Is the brake pedal not supposed to feel like you're pushing against something solid after the initial travel to make contact between pads and disc?

Thanks for any help.
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RESOLVED!!!

Thanks everyone for your help! I've finally got a firm pedal!

Here's what I had to do.

Replaced my brake master cylinder.
To do that I had to bench bleed it before putting it in the car, then once installed, I bled it again using Robinette's master cylinder bleeding method (https://www.robrobinette.com/bleedin...r_cylinder.htm). Then I bled all the calipers (air still came out). The pedal was much better, not perfect though. ~1 week later I bled again, this time with ATE TYP200 fluid instead of cheap stuff. A tiny amount of air came out, and my pedal is finally firm!

If you have a similar problem, this may not be your solution. Hopefully, you just need to bleed some more. I had already bled so many times it was driving me crazy. The brake master cylinder is expensive, I don't want people buying one if it's not necessary.

BenRNBP

My pedal will travel a small amount before the pads engage then bite nicely with a progressive feel all the way to lock up - bottom line is they should give you confidence and if they feel wrong they probably are.

Worth giving something like this a go - https://robrobinette.com/bleeding_th...r_cylinder.htm you may have air in your M/C which is difficult to get out - but you might actually have a master cylinder seal problem

GreenmanS2000

You are probably used to over servoed brakes

When was the fluid last changed
What pads are you using?
How worn are the pads?

DaveUK

The fluid was last changed 2 weeks ago.
Pads are ebc redstuff.
Not very worn at all.

Is the brake pedal supposed to carry on moving after the pads make contact? If brake fluid isn't compressible, I wouldn't have thought they should. Or is it slightly compressible?

It's not that I want to do emergency stops with not much pedal force, but the pedal shouldn't move. Or should it? That's my problem, I don't know what it should be like, I just know I don't like it. Also, my first S2000 I remember liking the brake feel. This one, not so much.

Nottm_S2

Red stuff do need to be warm but your description sounds odd

There's def no leak? The 2 phases thing sounds like you're losing pressure

I find the brakes in the S nice. Not over assisted, good feel.

DaveUK

I can't find any fluid leaking out of anywhere. I've checked all the nipples, the banjo bolts, the connections between hard lines and flexy lines, plus around the master cylinder and in the footwell.

The two stages thing doesn't happen all the time and not after I've put heat into the brakes. In fact it's very occassional, maybe 3% of the time.

Am I right in thinking the brakes, once pads have made contact, should be like pushing your foot against the floor?

In terms of stopping power, they're great I should add.

I think I'll update the first post because I made it on my phone so it's a bit mish mash and I've left some info out.

RobAp1

When the pads have made contact, the pedal won't be totally solid, but it should be very firm. As Ben said, it sounds like you might have leaky master cylinder seals allowing internal fluid bypass. If you crawl up in the footwell, is there any evidence of leakage from the BMC?

DaveUK

I've just had a thorough look in my footwell and a feel, and it's totally dry. In the engine bay around the master cylinder it's also bone dry.

I'm going to check the booster isn't faulty by following this: http://www.ebay.co.uk/gds/How-to-Dia...8571669/g.html

If it turns out OK according to the test, maybe I'll unplug the booster so I can see if the pedal still travels too far. *future update*: I rear-ended a car. LOL. Imagine.

DaveUK

Ok. I've been out to do the test on the booster. According to the test, the booster is fine. I also took two videos to show how much the pedal moves. One with engine on, one with it off.

On top of that, with the engine on, I pushed the pedal as far it it would go (with my foot, not my hand as in the videos), and I DID reach the stopper. Either this is worse than before (as recent as last night), or I'm just being more sensitive to it now, but it was definitely the stopper. Because of that, I didn't bother taking off the pipe to the booster.

Engine off:
https://youtu.be/jW1VIbHQbN4

Engine on:
https://youtu.be/xf4don8ySBU

Looking at this, it actually does look pretty spongy. The only place there could be air is in the ABS module, if any. I've bled the car maybe 10 times, aggressively and softly. I've even taken off the calipers and twisted them about whilst bleeding to make sure any air bubbles aren't trapped.

There's no leaking outside of the master cylinder, but could an internal seal be damaged, causing this?

Should I give in and get a dealer to do a proper bleed where they run the abs pump using their computer? They can do that, right?

Thanks for everyone's help so far. I really appreciate it.

Dembo

at the videos of you using your hand to press the brake pedal.

You've changed everything but the one thing you probably needed to change: the pads. Get something like Ferodos and it'll be much firmer.

I think I got air stuck in the ABS once but it was really horrible and sometimes needed to pump the pedal several times to get the brakes to work. Yours doesn't sound anything like that.