right i have had this problem since i own the car, it is basically intermittent dodgy brakes, at times the brakes would be perfect, feel right and stop in good distances. and at other times the brakes are very stiff, very little movement in the pedal and poor stopping distances. now ive researched into the threads and the cause was thought to be the ABS but this also seems to be dismissed. now ill just explain symptoms: first of no fault codes. brakes intermittent, when good no problems, when dodgy, very little movement in pedal, very hard, poor stopping distances, can feel ABS kick in extensivly, generally if this happens then the brakes feel a bit better after, also if sitting at traffic lights and have foot on brake, this can al of a sudden drop down another inch as if the biting point has totally changed. now the pads and discs are fine, good wear left in them. ive replaced the light switch as ive had this as an error code so its been replaced. the only thing i can see if that i checked the brake fluid container and the level was above the MAX line (i didnt do this) so im wondering if that could have an effect or if anyone has any ideas on where the problem might lie?

Sounds like a brake servo vacuum fault.
This is a Petrol Stilo right?

yes, apoligies for any sign of stupidity but i havent a clue about engine bays and the vacuum servo any ideas on how to solve this? il have a quick search as well :devil:

Changed a caliper on mine recently and had the same symptoms as you. bled the brake system and all is fine again

This is exactly the symptoms I have with my car, and it is still not fixed after 4 years, even after investigation by Fiat(UK). Theory is that it is the EBD (part of the ABS) system causing the problem but NO FIX. Everything (almost) in the braking system has been changed. Search the forums using my username and you will find some more details.

I have contact names in Fiat(UK) and VOSA that will be more than interested in this problem. I don't think it is unique, several seem to be suffering from it. Please contact me using the email address "car AT ostell.co.uk" (usual substitutions) for more detail.

Mine seems to happen when going over an uneven section of road. Does this match?

Well a cheap and cheerful item to replace would be the brake servo one way valve. this keeps the vacuum tight and if it's leaking on occasions then you'd lose the vacuum which would give your symptoms of an ineffective servo

It's only a cheap plastic valve and simply pulls out so you wouldn't need engineering skills to replace it. Check the pipe leading to it for cracks or leaks

Next time you get in the car, don't start it, just pump the brakes until the pedal goes rock hard. Now keep pushing on the pedal and start the engine. Feel it surge down? Does that feel like your symptoms when it happens?

yes ive read your thread several times and unfortuantly mine is out of warranty so i knew all these lines of action were not an option, email on its way
cheers decks for the info and image, speaks a thousand words, lol. just a few questions though before i dive in, if it was leaking would my fluid level not be lower than what it is considering its quite high? also if i disconnect this valve and i going to have brake fluid running out so im guessing i will need to bleed it? thx

No the vacuum system won't have any effect on the hydraulic level. The vacuum line purely gives the vacuum air pressure power for brake effort assistance. When you pull it out there's just an empty cavity inside, it'll be quite an anticlimax if you were expecting something dramatic behind there

You just pull it out, change it and pop it back in again, just like a cork in an empty wine bottle

thats dead on, will i need to bleed the system to get rid of any trapped air or will this eventually find its way to the valve and disperse itself
nah i like it handy like that saves a lot of hassle and gets the job done and you know a garage would try and charge you an arm and a leg for it, lol
looks like another trip to the local dealer :devil:

No you won't need to bleed anything to fit the one way valve. It just stop air getting into the vacuum side of the servo and holds the vacuum or is supposed to.

If that doesn't work then you may be into bleeding the hydraulics but that's a different story

J0nny, did you get my emails?

The cheapest way to get the problem solved is via a recall for those affected.

hey sorry yea got your emails but laptop broke so had to buy a new one and im currently trying to downgrade to xp so was a bit skint and busy, replied and all!

right this has got really bad now
im afraid of knocking someone down tbh
so me and a mechanic friend of mine are going to have a proper going over it the end of this week, onli time were both free
so i was wondering what can i do or look for

firstly im going up 2 belfast on monday so ill call into either europarts or the fiat dealer and get a brake servo valve and sort that out
ostell was saying that it may be due to ebd sensors in the wheels so we were thinking that one of the sensors may be defective so it there any way to test the resistance of the sensors or anything like that and see if they are all operating the same

i was also gona bleed the brakes and ill check out the pads and discs just incase, i cant imagine theyre done as the pads were new a year ago and the discs had v little wear but im just looking ways to improve this. i know it may not be totally curable but anything to help me reduce stopping distance would be greatly appreciated! :worship:

Just a thought but have you kept to the service routine as far as changing brake fluid. Just drive into a brake specialist centre - only cost me £25 a year or so back.

i didnt service the brakes myself

i have no idea of the service history of the car, i had nothing from the previous owners, so when i first got the car i left it into a very good mechanic and told him i wanted everything done, so typical done, filters, oil, brakes checked and springs done etc etc. so i presume he would have this done this as it cost me shy of 500 quid

ill have a browse in the yellow pages and see if i can find any brake centre near

EDIT: right i found one, I C A Brake & Clutch Specialist which is in belfast as well, ill talk to them about it and see what they say

still all the same any tips or advice would be welcome

:bang: sucha mood

i had fun going between fiat, euro car parts, ICA brake specialist and halfords to see if any one knew what the servo one way (non-return) valve was, and did they have off

first off fiat, the two guys in fiat parts, i havent dealt with arrogance and stupidty like that in years, i dont know how they are still employed

i got quoted £140 for the valve!!!!!!!!!!!!!!!!!!!!!!!!!!!
i questioned if he had the right part, he said yep, checked again
i said i didnt need the entire servo just the valve, same quote
so i got a printed quote:

77362099: Master Cylinder £140.41

which to me looks like the entire thing, ICA brake specialists sell pads, thats about the extent of it, halfords knew wat i was on about but they cant get it. euro car parts were very helpful but couldnt get up what i was looking for so im hoping someone can get me a part number so i can get it off either fiat or them please :worship:

Brake pedal suddenly going high and hard sounds like a brake servo fault

Start your engine and pump the pedal, now turn the engine off and pump the pedal. It will suddenly go hard and high. Is that exactly the same as experience? Take out the non return valve and see if it's got any cntamination, test if it's only allowing air one way

Have a look here as it shows the one way valve
http://www.buckeyetriumphs.org/technical/Brakes/Servo/Servo.htm

BUT I'm not suggesting you take the servo apart like this guy did. There is a lethal strength spring in there and you 'd need a good workshop and very clean environment. You can't get replacement internal parts so it would be pointless. But it does show how the servo works

It could also be an ABS fault as your ABS is triggering when you have problems. This could be a full bleed being required using Examiner as they need to electrically open and close valves in sequence in the ABS unit

My brakes feel hard when im driving yea, i can just sense it now while driving, when i slam on the brakes theyre hard and the wheels skid slightly with abs kicking in, i reckon if the travel on the brake pedal was correct then the abs wouldnt need to kick in

the pedal goes hard when engine is off, i havent tested this while stationary but in movement yea its pretty much the same thing

so i normal bleed from a mechanic wouldnt do the job? as i was planning on getting that done this weekend after i got the valve, which i cant is there any chance you could get a part no. for the part on the diagram you were showing me?

Test the non return valve yourself to see if it's allowing air in one direction only simply by blowing through

I doubt Fiat sell the valve separately as it's an all or nothing replacement

Try ePer for parts up above, it's not working for me right now

For a thorough bleed and release untrapped air you'd need to have it done at Fiat for the reasons above

An intermittent brake fault is decidedly nasty and you need to have it looked at professionally

kk, well ill let the mechanic mate test it because looking at the diagram i couldnt find it myself

yea it seems that way i dont have 150 quid tho, and the bit that gets me is that it might not fix it.

ePer wouldnt work for me there, il try it again in a bit. so even if i do get the system bled by a mechanic there still possibly going to be some air trapped inside anyway? im guessing as soon as the examiner is involved the price goes up quite rapidy

also i presume the servo is different for each car but would the valve remain the same as i know of a salvage yard stilo with a bit of front damage