Issues with brakes - can't find the fault

[TREMAiNE]

The track car a friend and I own has been off the road for a year now with a brakes issue we cannot resolve.
I have posted on here before for help and had some good suggestions but nothing has worked and we're struggling to diagnose what is causing the issue.

I was approaching Paddock Hill bend and hit the brakes and noticed they weren't "all there", it felt as if I only had half brakes, I took it easy and brought the car back in. The pedal was going fully to the floor with no resistance.

So far we, have:
-Replaced the master cylinder
-Manually bled the ABS and master cylinder from all connections to/from them (multiple times)
-Bled the brakes (multiple times)
-Used a pressurised brake bleeder to try and force the air out
-Tried emergency braking on gravel to try and activate the abs to remove any trapped air
-Completely stripped the brakes down and refurbished the callipers with new seals, pistons, guide pins and grease

But despite all that, the pedal is still going to the floor with almost no pressure.

We’re stumped at what else we can do to fix the issue.
Anything obvious we're missing?

[tight fart]

Expansion in a rubber hose?

[sherman]

Have you tried new brake pads?
Try a different brand.
Some just feel better under different conditions.

[Dynion Araf Uchaf]

Vacuum hose from inlet manifold to servo possibly split?

[Jazoli]

Have you connected the car to a diagnostic and bled the abs pump properly? That’s what I’d be trying next.

[CoolHands]

Maybe the abs pump / module. I have heard of the occasional one that has caused problems only solved once changed



Or see if you could get existing one tested by
https://www.ecutesting.com/common-faults/suzuki/su...

Edited by CoolHands on Sunday 16th February 22:23

[TREMAiNE]

CoolHands said:

Maybe the abs pump / module. I have heard of the occasional one that has caused problems only solved once changed



Or see if you could get existing one tested by
https://www.ecutesting.com/common-faults/suzuki/su...

Edited by CoolHands on Sunday 16th February 22:23

Thank you, we are starting to believe it could well be this and will look at refurbing our module.

[Richard-D]

This video is worth a watch (knowledgeable mechanic describing exactly your issue and how to diagnose/fix):-

https://www.youtube.com/watch?v=2uzMdKno4-c&t=...