Sudden long brake pedal travel

I had a sudden brake lock up when not pressing the pedal not to hard. Since this the pedal goes virtually straight to the floor before it goes hard and I get some brakes so not really driveable. No sign of any leaks and reservoirs are normal full level. Handbrake is fine as normal. Has anybody had similar and knows what to look at?

I’m not that familiar with the S2 but at a guess, the master cylinder could be knackered. Either fluid leaking past the seals internally or it’s somehow drawn air into the system?

Good suggestion on the master cylinder. Now the bad news. S2 can be a pain to bleed after working as you need to set the ABS into a mode using a scan tool.

Thanks for the suggestion. I thought master cylinder but it seems like I still have brakes, just that I have almost full pedal travel before It goes hard which doesn’t sound like a master cylinder seal - or does it?

Thanks for the tip ref the ABS, does this make it a specialist item to fix?

I managed to bleed my S2 brakes once with no problems and another time it was a nightmare which took several attempts. In the end Gav at Unit 4 in Burton did them. That’s why urged caution.

I’ve had similar problems when leaving calipers disconnected over winter, the abs plumbing slowly drains out and that’s where the problems come.

My only DIY fix is to simply bleed it best I can, take it out and try my best to lock the brakes up a couple of times, then back to garage to rebleed and just repeat till it’s done. I read something somewhere about having the car running while bleeding too, I don’t know if there’s any science in it but I do it anyway…

If you’re just doing a standard bleed, air in the abs shouldn’t really be a problem.


That’s right. Just a fluid change is no problem, it’s when you have let air into the system that problems arise.

Thanks for the tips, I’ll have a think as to how to tackle this and see if it sorts it.

Just to let you know, a full brake bleed sorted the problem. Thanks for the suggestions. :slightly_smiling_face:

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