My two year old Stilo has had persistent brake problems for the last year or so. At times the pedal feels hard to press, as though the servo unit has gone. Causes a panic at road junctions and decending steep hills.

Sitting at lights with foot on the brake pedal the pedal occasionally drops about 2 cms for no apparent reason.

At other times the pedal is so sensitive and light that the passengers start complaining about the jerky ride.

The ABS system cuts in unexpectedly, even with light braking.

Servo has been changed, ABS sensors checked and defective one replace, last week new disks and pads replaced as well as other, unspecified, poations of the braking system.

Any one seen anything like this?

This is just one of a catalogue of faults on this car. I like the car, shame about the faults.

What fault codes were obtained by the garage?

Fault codes? This car doesn't record fault codes!

I have been getting false (hopefully) ABS and EBD errors on the display from month 1 but the log is always empty (apart from once).

Forgive my ignorance but what should be going into the log?

The error displays and failure to log are on my list of outstanding problems given to the dealer and Fiat(UK). (There are many others)

Fiat dealership here changed from a small shop which you knew that if they fixed it it stayed fixed to a larger group whose idea of a good service was to clean the car well to another larger group who seem to be even worse.

Shame 'cause I've had Fiats for 20+ years without major problems.

My two year old Stilo has had persistent brake problems for the last year or so. At times the pedal feels hard to press, as though the servo unit has gone. Causes a panic at road junctions and decending steep hills.
Servo not working properly

Sitting at lights with foot on the brake pedal the pedal occasionally drops about 2 cms for no apparent reason.
Servo suddenly working

At other times the pedal is so sensitive and light that the passengers start complaining about the jerky ride.
Servo working again

The ABS system cuts in unexpectedly, even with light braking.
Probably related to the servo over powering

The fact you've had the servo changed doesn't change the symptoms that the servo isn't working right. Servo vaccuum feed, non return valves can all cause stuff like this

Simple servo test. With engine off, pump out the brakes until they go rock hard. Keep your foot on the brake and start the engine. Pedal should almost immmediately go down. If that's the same sensation as you describe above when you're stationary in traffic then there's your baby! Intermittent servo problem.

Test 2 Turn the engine off. Wait for a while, maybe a minute, then try the brakes. See if the servo is holding pressure before they go rock hard again

There's not much else can give the same symptoms as you describe

Thanks for the response. I agree with your conclusions entirely. I specifically asked them about valves in the servo unit area when I gave them the car last week for further work. But then I'm only an ignorant customer who knows nothing, despite having spent the last 40 years in problem diagnosis of computers. Of course there is always the possibility that the replacement servo unit was also faulty.

I tried your suggestion of engine off etc. Yes, the pedal does go down as the engine starts, but rather more slowly than when it drops in traffic.

The problem seems to occur more frequently (but not uniquely) after a long run downhill and applying the brakes at the bottom (can be real scary!). My thought was that there was an over vacuum valve (?) somewhere that was releasing and not seating back down quick enough. I also had one day of hard pulls to the left as I braked. Could that be EBD in error? My normal place of abode is rather flat but the problem still occurs there.

Must get back to my writing to the MD of the group complaing about the sill damage that occured, right next to the jacking points.

Stone me! You've really got to get this fixed.

Heading downhilll with no throttle produces high vaccuum but it'll depend whether you're using the brakes on the way down as to what's happening. For instance, if you were using the brakes on and off a lot on the way down then you could run out of vaccuum if there was a leak in the system, just like turning the engine off.


Pulling to one side wouldn't normally be caused by the servo, that could be ANYTHING that's reducing brake force on one side. ABS sensor failure would be a possibility

I've been trying for a year to get this fixed!!!

Using the brakes on and off down a hill seems to reduce the vacuum enough that the vacuum does not get too great and everything works, which is why I think it is a valve type problem.

Trouble is that when the pedal goes hard I have to press hard to stop and then the servo comes in, braking gets severe and the ABS kicks in. I have two type of ABS action on the this car, severe so that it really is noticed and a little excuse for ABS that just slightly rattles the brake pedal.

For one of the tests it was reported that the vacuum was droppping, but later I was told that it was a fault on the test equiopment.

This is one of many faults that are manifesting themselves on this car, a lot of them electronic. For instance, apart from the messages that appear from time to time (nothing in the log) I've had the security LED in the drivers door flashing with the doors unlocked, keys in the ignition, engine running and car moving

I think you're very much on the right track. Sounds like when the vaccuum gets to a certain high vaccuum point it leaks air in. Servo usually has a check (non return ) valve in the air pipe leading to the servo. First port of call for testing I would have thought

The door leds are a mystery to us all. I think it's something to do with the Pope. Do you have the autolock with speed feature on or off?

Autolock is off. I've tried autolock on and this works but the led doesn't turn on when it activates. Anyway, the doors were still unlocked with the LED flashing.

As I said I did ask about valve in the vacuum circuits but was probably ignored. Could also be a collapsing pipe in the vacuum line (wrong pipe fitted). I'll let you know if they find it.

This car must have been a Friday afternoon and Monday morning car.

This morning the Sales Director should get an email copy of the fax I sent so hopefuly (though I doubt it) I may get a response today.

recently i have had rear brake problems, it was making a loud high pitch noise, fiat said nothing at it's 24k service, as the sound had got louder (at 26k) i had the brakes checked by a local garage, they found the rear left caliper had siezed causing the inner brake pads to wear out. after freeing up the caliper and refitting the pads, plus bleeding the brakes, the car now brakes 100% better!

Just so you have correct information, diesels dont use manifold vacuum at all for brakes, they use vacuum pumps. Vacuum pumps spin at engine revs, so vacuum is reduced at lower engine speeds. Personally I would try going down the hill with the engine revving at say 2000 revs (use left foot braking). If the brakes are improved you know the vacuum is increasing and a faulty pump could be the cause.

Mine occasionally does the hard brake pedal thing (probably once a fortnight) which is then fixed by lifting off and reapplying the brakes.
It's been mentioned to the garage but they say they've checked and found nothing wrong
It is Arnold Clarks though

Problem has manifested itself going down hill using the engine for braking down the hill so the engine was still turning at a reasonable rate. Brakes went hard at the bottom of the hill when I had to stop at the main road!

Other times it just comes and goes.

The brakes always work even when the pedal is hard, power assist kicks in again and then the braking is severe and ABS kicks in. Disconcerting.

Looks like the vacuum pump is another item that could have problems. Wonder if that has been changed? Almost every other item seems to have been.

timr69: Could you persuade them to report it to Fiat (UK)? Perhaps several with the same problem could persuade them to investigate a little harder.

I don't think I've ever triggered the ABS on mine apart from in snow.

Didn't even manage it in the demo car on the test drive despite stepping on the middle pedal VERY hard to see what it was like.
Got strained tendons in the back of my eye balls from that one though

Finally got a result (I hope). Talked with the technician rather than the monkeys on the desk and it came down to ABS/ECU unit faulty. Fiat rep had to visit to give the OK but now waiting for replacement unit.

Turned out there is a technical bulletin describing the problem. I was not allowed to see it because "It was not for my eyes" but I believe it was issued early this year.

Why has it taken them so long to find the bulletin?

I like Fiat cars, had them for the last 20 years but this car and this dealer give Fiat a real bad name.

No left foot braking

NumanR said:

Personally I would try going down the hill with the engine revving at say 2000 revs (use left foot braking).

Click to expand...

Ahhh, but then you hit an ECU "spy" - had it explained to me at my local Fiat dealer that left foot braking in the Stilo is out as the ECU gets all confused when you have accelerator and braking inputs at the same time

Effectively it has a "wibble" moment as it, apparently, doesn't like both inputs as it can't figure out what you're trying to do A major hassle for me as my winter driving style includes left foot braking
I'm advised (but someone may know better?) that extended or regular use of left foot braking will lead to more errors flashing on the system :bang:

So conventional braking it is :idea:

Re: No left foot braking

I agree about the ECU confusion - this is why a sticking brake light switch causes so much problems, and not just with anybody trying to follow you - I got constant ASR/ESP failures, because it was sensing braking/acceleration at the same time, and can't cope....

ostell said:

Turned out there is a technical bulletin describing the problem. I was not allowed to see it because "It was not for my eyes" but I believe it was issued early this year.

Click to expand...

I don't suppose you or anyone else knows the bulletin number as I was going to try and get this sorted while the car is in for its next service?

New ABS unit and ECU (supposedly come as one unit) fixed the problem. At last I have brakes that behave consistently, though I occasionally suspect that a small vestige of the old problem is still there.

Sorry, can't give any details about the tech bulletin.