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Thu 1 Mar 2018 13:36

Ford StreetKa - Ford StreetKA brake pedal goes to floor - Elliott1993

Hi guys, I’m new on this forum and would appreciate all your help!

My sisters streetka failed it’s MOT on various bits and bobs, most important being that the brake pedal creeps to the floor under pressure.

I started with the obvious and used my eezibleed kit to bleed the brakes, no air came out whatsoever and fluid looked like new. My next step was to get a second hand master cylinder online, I noticed when I bench bled the new(ish) master cylinder that once is topped up the reservoir it started coming out both brake line holes almost immediately, as if I didn’t need to bleed it at all. Is this normal or do you reckon I’ve been sold a dud?

Either way I put the new master cylinder on, bled the brakes again and went for a test drive. The brakes are much more responsive and it doesn’t feel like the pedal creeps half as quickly however I still have the same problem. If I press the brake (with engine running) twice the pedal sits firm about half way, however just once and the pedal creeps down.

I assume the brake booster is fine as when I take the hose off I can here a rush of air.

Could it be ABS module?

Any help would be greatly appreciated! Thanks

Forgot to add, no fluid loss from the master cylinder and can’t see any leaks!

Edited by Elliott1993 on 01/03/2018 at 13:42

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Thu 1 Mar 2018 14:09

Ford StreetKa - Ford StreetKA brake pedal goes to floor - bathtub tom

Why on earth would you want to change a possibly faulty master cylinder with one that you have no idea of its condition.

If you think you've a faulty master cylinder, for heavens sake fit a NEW one.

My daughter's Verso suffers from brake pedal 'sink', but only when stationary. You'd never apply that much pressure under normal braking conditions. It's never failed an MOT as a result.

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Thu 1 Mar 2018 17:23

Ford StreetKa - Ford StreetKA brake pedal goes to floor - Elliott1993

Thanks for the reply, yeah I should’ve bought a new one but I was trying to save her money! Plus the old one had only done 30 odd thousand miles so I assumed it would be fine. I’ve pulled the old master cylinder apart, and the seals look fine, no damage on the inside of the barrel. Any ideas?

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Thu 1 Mar 2018 20:23

Ford StreetKa - Ford StreetKA brake pedal goes to floor - Bolt

Thanks for the reply, yeah I should’ve bought a new one but I was trying to save her money! Plus the old one had only done 30 odd thousand miles so I assumed it would be fine. I’ve pulled the old master cylinder apart, and the seals look fine, no damage on the inside of the barrel. Any ideas?

its possible and more likely the seals are turning back on themselves causing the fluid to pass, used to happen a lot on fords in the 80s 90s, but never fit an old second hand one as that may have the same problem/ and usually do!

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Fri 2 Mar 2018 10:28

Ford StreetKa - Ford StreetKA brake pedal goes to floor - edlithgow

Thanks for the reply, yeah I should’ve bought a new one but I was trying to save her money! Plus the old one had only done 30 odd thousand miles so I assumed it would be fine. I’ve pulled the old master cylinder apart, and the seals look fine, no damage on the inside of the barrel. Any ideas?

its possible and more likely the seals are turning back on themselves causing the fluid to pass, used to happen a lot on fords in the 80s 90s, but never fit an old second hand one as that may have the same problem/ and usually do!

"Usually do" sounds a bit of a stretch. MOST scrap KA's have faulty master cylinders?

Seems statistically VERY improbable.

To be true, either most KA's have faulty master cylinders in service at the time of scrapping, (which suggests a lot of people scrap KA's due to faulty master cylinders) or they'd have to fail while passive in the scrapyard due to, say, corrosion.

Neither hypothesis seems very likely, especially if it looks OK when stripped.

Seems a reasonable gamble to me, (depending on the price difference) so the OP either got unlucky (which of course could happen) or something else is going on here.

Worth chucking a seal kit on it?

Edited by edlithgow on 02/03/2018 at 10:30

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Fri 2 Mar 2018 11:26

Ford StreetKa - Ford StreetKA brake pedal goes to floor - Bolt

especially if it looks OK when stripped.

Looking ok does not mean they are serviceable, but your point of using a seal kit was something I neglected to mention, bearing in mind not all M/c had repair kits, nor can I answer that question

I said may have that problem NOT do, not all scrap yards know why a car is scrapped.but in the past I have had master cylinders with worn bores, so fitting replacement seals is a waste of time, thats why I always recommend a new one not secondhand

Its up to the OP as to what they do, but I don`t recommend second hand !

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Fri 2 Mar 2018 22:58

Ford StreetKa - Ford StreetKA brake pedal goes to floor - edlithgow

I said may have that problem NOT do,

“The Moving Finger writes; and, having writ,
Moves on: nor all thy Piety nor Wit
Shall lure it back to cancel half a Line,
Nor all thy Tears wash out a Word of it.”

:Unless you're pretty quick with the edit button, of course :)

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Fri 2 Mar 2018 23:00

Ford StreetKa - Ford StreetKA brake pedal goes to floor - KJP 123

"Usually do" sounds a bit of a stretch. MOST scrap KA's have faulty master cylinders?

Seems statistically VERY improbable.

Not talking about KAs but if a car has a known problem or weakness the chances of the scrap one having it too would seem to be quite high.

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Fri 2 Mar 2018 23:58

Ford StreetKa - Ford StreetKA brake pedal goes to floor - edlithgow

"Usually do" sounds a bit of a stretch. MOST scrap KA's have faulty master cylinders?

Seems statistically VERY improbable.

Not talking about KAs but if a car has a known problem or weakness the chances of the scrap one having it too would seem to be quite high.

Well, "quite high" is rather vague.

"Usually do" = "MOST" is still a bit vague, but it has to be more than 50% and probably in the 70 - 90% area, which doesn't sound very likely to me.

A scrap part is always a gamble, so its a numbers game,

I seriously doubt the numbers are as bad as suggested above.

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Sun 4 Mar 2018 09:44

Ford StreetKa - Ford StreetKA brake pedal goes to floor - Bolt

"Usually do" sounds a bit of a stretch. MOST scrap KA's have faulty master cylinders?

Seems statistically VERY improbable.

Not talking about KAs but if a car has a known problem or weakness the chances of the scrap one having it too would seem to be quite high.

I gave up buying from scrap yards 20 years ago for bangers as the parts bought were allways as bad as the part removed, its annoying if its a hard to get to part, as you have to do it more than once.

by the time you have made several trips to the yard, your better off buying a new part, obviuosly if the car is that old you have to put up with what you can get, in which case not a lot you can do.

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Fri 2 Mar 2018 12:41

Ford StreetKa - Ford StreetKA brake pedal goes to floor - edlithgow

Could it be ABS module?

I've got no experience of ABS, and don't much want any, but a bit of Googling suggests that perhaps it could.

Have a look at this thread

mechanics.stackexchange.com/questions/7819/brake-p...d

First incident seems to have just been air in the system, but the discussion describes how similar symptoms could apparently be ABS generated. One suggestion/example is that a failure of the valves that normally isolate the brake pedal during an ABS event could allow pedal-generated brake pressure to bleed off fluid into the ABS accumulator reservoir.

This guy

www.youtube.com/watch?v=ceN0a-nPUZw

tried everything and then installed a used ABS module from a scrapyard (THE HORROR) and it fixed his problem.

(He could have described it in a sentence but he preferred to make a tedious Youtube video. Americans, y'know?)

Is there any way you could isolate the ABS system, for diagnostic purposes?

(Fuze removal is mentioned in the above discussion, which would be nice and simple if it works, though it seems to assume correct failsafe operation.

Physical isolation/disconnection would be pretty unambiguous)

Edited by edlithgow on 02/03/2018 at 13:10

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Fri 2 Mar 2018 17:41

Ford StreetKa - Ford StreetKA brake pedal goes to floor - Elliott1993

Thanks for all your replies guys. Today I took the master cylinder off, re bled it, re bled the brakes (no air again) and took it for a spin. Brakes now seem to drop to the floor very quickly and then apply the brakes when it gets to the bottom, almost like there’s air in the system.

Took your advice on the ABS module and looked up how to bleed without a scan tool. With all the ice and snow I took it down the road and did about 20 emergency stops where the ABS kicked in, re bled the lines and still no change. I’m starting to think it’s faulty ABS module! Going to have a look online for one.

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Fri 2 Mar 2018 22:47

Ford StreetKa - Ford StreetKA brake pedal goes to floor - edlithgow

I’m starting to think it’s faulty ABS module! Going to have a look online for one.

The example in that discussion I linked to was fixed by replacing a couple of O rings, so you might not need the whole thing.

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