Hi,
My tyre disintegrated the other day (either driving with a puncture or with too little air pressure) and my brakes failed causing me to freewheel at 60mph.

I pumped the brakes but they were rock hard (a symptom of ABS falure), then after a hundred yards or so and all of a sudden my brake pedal hit the floor but without affecting the brakes. I came to rest with my handbrake on.

I understand the reason why the ABS system failed, with one wheel reving at a different speed to the others but I don't understand why the normal braking system didn't take over.

My mechanic suggested that it was a freak incident that probably won't be repeated. I've driven since Monday without a problem but this has knocked my faith in the car.

I'll get a diagnostic report on Monday. Meanwhile I wonder if anyone has any experience of this or an idea why this would have occured.

Regards,
Steve Jones

Personally, I'd be thankful to survive a blow-out without a scratch to the car.

Assuming this is on the front then I'd try to come to a stop with minimal use of the brakes as the last thing you want is that front rim to dig in

Does seem odd I agree but I'd just reassure myself by going down some quite roads and checking just how fast you can stop (after all blow-outs aren't that common)

I had a very similar thing happen on my old granni many years back, what had happened in my case was the tire disintergrated lodging a piece of the tire debris or a stone in the brakes some how thus causing the breaks to be hard and ineffective (this is what i suspect), it eventually shifted and the brakes went to the floor (probo because i was pushing with all my might).
I suspect something similar has happend to you. The brakes are purely mechanical when the abs is out so i doubt a diagnostics check would actually do anything. You should have still had your handbrake working to stop you (eventually). Its probo worth while inspecting the side that had the problem. There could be something adrift or wrong that is apparent under normal usage.
roy

Argonought said:

Personally, I'd be thankful to survive a blow-out without a scratch to the car.

Assuming this is on the front then I'd try to come to a stop with minimal use of the brakes as the last thing you want is that front rim to dig in

Does seem odd I agree but I'd just reassure myself by going down some quite roads and checking just how fast you can stop (after all blow-outs aren't that common)

Click to expand...

Yes, I was pleased the way the car handled itself, except for the slightly disturbing matter of the brakes.

The blowout was on the back right tyre.

Maybe they're not common but it'd be a freaky situation if you're approaching a junction or traffic jam or whatever,...
Better to have use of the brakes in case they're needed and hope that good judgment prevails in the heat of the moment!

Cheers,
Steve

roy lovelock said:

I had a very similar thing happen on my old granni many years back, what had happened in my case was the tire disintergrated lodging a piece of the tire debris or a stone in the brakes some how thus causing the breaks to be hard and ineffective (this is what i suspect), it eventually shifted and the brakes went to the floor (probo because i was pushing with all my might).
I suspect something similar has happend to you. The brakes are purely mechanical when the abs is out so i doubt a diagnostics check would actually do anything. You should have still had your handbrake working to stop you (eventually). Its probo worth while inspecting the side that had the problem. There could be something adrift or wrong that is apparent under normal usage.
roy

Click to expand...

Could be the case! Is there a way to disable ABS to perform a check on the car?
I'll take it to the garage on monday and suggest that we try to do that. Thanks Roy.
Steve

Steve

hywyn said:

Yes, I was pleased the way the car handled itself

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Hmmm - make it a front tyre, add a corner, and then the handling does degrade a little.....

https://www.fiatforum.com/stilo/108616-stilo-cull-continues.html

or motorway at any speed allowed on motorway......

its tilit, game over.

Big Black Stilo said:

or motorway at any speed allowed on motorway......

its tilit, game over

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Actually, apart from being stationary , then the motorway is the best place to have a blow-out.

No sharp curves, no junctions or roundabouts to worry about, plenty of lanes to regain control, no oncoming traffic but best of all a hard shoulder to aim for.

The key advice is go really really easy on the brakes and just concentrate on keeping the car stable whilst the tyre disintegrates (as if you just found yourself on ice ). The car will soon roll off its speed

Argonought said:

Actually, apart from being stationary , then the motorway is the best place to have a blow-out.

No sharp curves, no junctions or roundabouts to worry about, plenty of lanes to regain control, no oncoming traffic but best of all a hard shoulder to aim for.

The key advice is go really really easy on the brakes and just concentrate on keeping the car stable whilst the tyre disintegrates (as if you just found yourself on ice ). The car will soon roll off its speed

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I concur with that, absolutely except why go easy on the brakes, - is it in case the inbalance would send the car lurching to the side where the blowout occured?

Steve

hywyn said:

I concur with that, absolutely except why go easy on the brakes, - is it in case the inbalance would send the car lurching to the side where the blowout occured?

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Quite so Steve; the worst blowout you can get is on the front. If you hit the brakes then most of the cars weight will be transfered to the front driving the damaged wheel into the tarmac with potentially lethal consequences .

With a rear blowout it would be quite different as braking would remove weight from the damaged wheel and could therefore actually help the situation.

Here's the nub though. In those few seconds when it happens how certain can you be which tyre has just blown. Get it wrong, and that wheel digs in, and you could find yourself cartwheeling or spinning

When I say go real easy on the brakes I'm assuming there's plenty of tarmac in front of you but then that's where the hard shoulder comes in

Argonought said:

Quite so Steve; the worst blowout you can get is on the front. If you hit the brakes then most of the cars weight will be transfered to the front driving the damaged wheel into the tarmac with potentially lethal consequences

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Damn right - I didn't even have time to brake when my front o/s tyre failed at around 60, with trailing throttle in a gentle right-hand curve.

The first clue was when the the car drifted a little towards the centre line, which I incorrectly interpreted as a transient bumpsteer effect. Because there was oncoming traffic I courteously nudged the steering wheel leftwards, which would normally have moved the car's road position by a foot or so.

But by then the tyre had completed it's deflation. My steering adjustment loaded the front o/s, and the rim bit the tarmac with a little bit of left turn on it. This caused retardation, which increased the load, which increased the retardation, which increased the load, which increased the retardation, which increased the load.....

The rear end instantly swung round at fairground waltzer speed, allowing no possibility of a happy ending. I threw max right lock on the steering wheel, but this was a narrow road and there wasn't a hope. Hit the nearside embankment traveling nearly sideways, and went crop-spraying.

The police were very polite, but I could tell they thought I'd overcooked it with lift-off oversteer. Fortunately the fresh crescent gouge in the tarmac, and the witnesses in oncoming cars, were sufficient to show I'd spun anti-clockwise in a clockwise corner.

As an experienced and swift driver, with several seasons of building and competing in motorsport, I honestly don't think I stood a chance. I've replayed it in my mind a thousand, thousand times, and every permutation comes up messy.

So I'm with Argonought 100% - front-end blowout in a corner is a very nasty place to be....

Have your brake system bled. I had a similar problem slowing down coming off aa motorway. Onto slip road at 70, junction ahead, brakes on, brakes on, brakes on.....nothing:bang: straight through the junction onto rounabout (very fortunate nothing was coming as I'd have taken us both out). off of roundabout pulled over with light braking they were fine again, long straight built up speed, brakes hard - nothing. Aware of problem took it easy driving in to work the following morning, took it to tyre dealer and asked them to bleed system completely including ABS following a brake test that they said passed. Picked it up drove to lights and nearly went through screen such was the difference, I guess there are tell tale signs but over a period of time you don't notice

wing1200a said:

Have your brake system bled. I had a similar problem slowing down coming off aa motorway. Onto slip road at 70, junction ahead, brakes on, brakes on, brakes on.....nothing:bang: straight through the junction onto rounabout (very fortunate nothing was coming as I'd have taken us both out). off of roundabout pulled over with light braking they were fine again, long straight built up speed, brakes hard - nothing. Aware of problem took it easy driving in to work the following morning, took it to tyre dealer and asked them to bleed system completely including ABS following a brake test that they said passed. Picked it up drove to lights and nearly went through screen such was the difference, I guess there are tell tale signs but over a period of time you don't notice

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so what were the tell tale signs, prior to you leaving the slip road like a scud missile?
I'd hope you had some sort of prior issues, any recent brake work?

That is a very scary thought to think that the brakes might just stop working.
When you said brakes on, etc, etc nothing, was it a rock hard peddle or foot to the floor and nothing?

Foot to the floor, nothing!! And again when I tried from speed. It was ok to stop from 30 with no issues, as per the test at the tyre centre (which incidentally would have passed the MOT), but nothing from speed and had the test centre quite baffled. Asked them to bleed the system as I had` had similar problems with older bikes braking ok when slow but rubbish when a bit of heat was put through the disks from higher speed braking.

Felt like a scud though. Now in need of new seat (charcoal one if anyone can help) as i dropped my bloody fag in the panic aftermath.:bang:

Oooops, no previous issues. Although always felt the brakes in the 1.6 better than the Abarth, but put it down to weight differences

Don't forget guys, brake fluid should be changed every 2 years (or every 36k if you do heavy mileage).

Only about £25 from many brake centres

A good point, and why not upgrade to 5.1DOT at the same time

wing1200a said:

Foot to the floor, nothing!! And again when I tried from speed.

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Mine was rock hard at first, then after paniced pumping the foot hit the floor,...nothing during both scenarios!

Thanks for the brake fluid tip. Worth the effort i'd say.

I have the extra load bearing Good Years on the front. No idea if that will help, but worth a go?!!

Steve