Safe Speed Forums

Very decent article in this week's "Auto Express" which looks at thos e things which can go wrong and which DO INDEED CAUSE our nasties.

I do not see much wrong with the advice given and I think I shall rund through one or two. Some may well justify a thread all of their own for discussion

OK so top of the list is ..

THE BLOW OUT ON THE MOTORWAY.

More likely to occur if you ton up for a really long distance.

So what do you do?

For most.. I guess the first panic reaction is to hit the brakes - hard

Nope .. take a deep breath and try to keep the sterr staight whilst you slow gently and in a straight line. Be aware the blown tyre will affect the steer and braking performance but one you are in control - steer gently to the hard shoulder and call the AA/RAC etc for help = as it's not nice changing a tyre under those conditions.


Seems sound advice to me ..

The next item .. the FAILED BRAKES...



Obviously .. best tried and tested practice is to use the engine braking and gears to get speed down ... and then apply the handbrake method to stop the car.

But who can tell me what the "handbrake method" is - without reading the mag

What else in the car's braking system could help you - and regular guys and Wildy who know the answers.. I'd like mosis and/or the sensible majority to answer this second easy question.

By the way - I am not going to accept "driving at or below the speed limit or having a camera in the car as the right answer" as I want to know whether you understand basic car mechanics and not just a lollysign

If brakes fail - even at 20 mph - you have to know how to stop safely in a straight line without skidding into something or someone.


PS - no peeking on the shelves in the supermarket mag rack either.

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Kick myself for not noticing the warning signs. Most blow outs follow overheating caused by underinflation. Long before the blow out there may be signs - steering vibration, pulling to one side, 'loose' handling.

If you EVER feel these things unexpectedly pull over and check your tyres.

One of my favourite tips is to check tyre temperatures with your hand each time you stop during a high speed run. Any temperature differential across an axle is a strong warning sign.

Edited to add: An ounce of prevention is worth a pound of cure.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

OK, got to say that TOTAL brake failure is nigh impossible (like the Titanic was "unsinkable"!) on modern cars with dual circuit brakes but I don't suppose that's the spirit of the question is it?

3 kinds of brake failure (discounting "fade" due to giving it too much pain)!

1. Servo failure. Pretty scary, can feel just like you've lost the brakes on today's grossly over-servoed cars but you just need to press the pedal a lot harder. Brakes are all working fine, you've just lost the power assistance.

2. One circuit failure. Depends a lot on the car and how the circuits are split. Front/rear splits are rare these days but depending on which circuit has failed, the car might try to spin if you brake too hard. Presumably you only find out about brake failure when you actually NEED the brakes so it's a bit pointless telling people to brake very gently but obviously, as gently as the situation ahead will allow and start looking for "escape routes" and use gears to slow down as much as possible!

3. Both circuits failed simultaneously (or the only circuit on a single circuit system). Get as much as you can out of the brakes by pumping the pedal - even if there's a bit of air being compressed because all the fluid has gone, it will still give you a smidgin of retardation. As before, use gears as much as poss but beware in a rear wheel drive car on slippery surfaces - going down too many gears in one go and letting the clutch out hard can lock the back wheels!

4. Don't know what the "handbrake method" is - pulling it seems like a good start! Probably not worth doing it too early as (a) it might lock the rear wheels (if that's the end it works on) and (b) it might fade the brakes on which it is working. Best loose as much speed as possible with the gears first.

5. I suppose if you were a real smart arse, you might be able to yank the handbrake on and spin the car neatly to dissipate all that nasty kinetic energy but I probably could do it in a panic situation and cars are best at protecting you when you hit things head-on.

So much depends on the car and the circumstances. I have been in a low speed situation with a very old car that lost (most of) its brakes on a rural road going down a hill. Running it into the long grass in the verge was sufficient.

Haven't seen the mag!

I always thought over-inflation was a bigger cause of blow-outs? Am I being totally clueless

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Why can't we just use Common Sense?

If the problem is down to fluid loss, air or steam in the system, or forgetting to bring new pads up to the discs pumping the pedal may well restore (at least some) some braking action.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Mega overinflation could cause blow-outs, but I've never heard of that actually happening. With underinflation the tyre compound has to flex MUCH more and the internal friction causes huge temperatures leading to failure.

Moderate overinflation is a 'stable' condition, and although grip will be reduced there's no 'runaway' effect as there is with underinflation.

Cars on skid pans often run 70psi to reduce grip.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

I've had a front wheel blow out in an old Citroen DS on the motorway. In that situation, the answer is that you carry on feeling incredibly smug at having bought an old Citroen and pull up on the hard should when convenient (ideally before the sparks from the wheel rim damage your paintwork)! Honestly, it was absolutely uncanny how good it was! Other than the bang, which gave me a bit of a shock, therre was no question of panic - a very mild pulling to one side and a lot of vibration but no hint of a loss of control.

Most modern cars have "negative scrub" steering geometry which makes a loss of control much less likely. Agree though, braking hard really only makes things worse.

Had a rear (can't really call it a "blow out") but fairly rapid deflation a few months ago in a Peugeot 807 on the motorway. Noticed that the car felt a bit unstable but put it down to the cross wind that night. It got worse in a few hundred yards and I lifted off the throttle, then a few hundred yards after that, the road noise changed but by then the indicator was on and I was heading for the hard shoulder. Again not a terrifying experience. It was an offside tyre though and changing it on the hard shoulder at night was MUCH more scary!

Can't really see a properly inflated tyre of the correct load and speed rating blowing out after a prolonged thrash though. They're tested to well in excess of their rating.

I remember my Dad's old Citroen CX - a car that would counter-balance so that you could safely drive it on 3 wheels for prolonged distances. Good job, as apparently one of the wheels had a habit of falling off whilst driving, no matter how well bolted on it was For years I've had images of driving along in this car and then happening to notice a wheel that had fallen off rolling along the road beside you . Was only 7-8 years old at the time so cannot really verify these claims.

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Why can't we just use Common Sense?

Handbrake method - if I recall correctly has two schools of thought:- Firstly, pull up on handbrake until firm resistance is felt (not enough to lock wheels) for about five seconds, release to allow brakes to cool for about two seconds and re-apply. Continue, with appropriate down-shifts until vehicle is at rest or, secondly:- Apply handbrake in a series of rapid, hard pulls (a la cadence braking) to partially lock rear wheels - not to be attempted in front-wheel handbrake vehicles...

Or do what many would do - push dead pedal to floor, grip steering wheel as if it was Brunstrom's windpipe and scream "SH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!T"

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Aquila



Licat volare si super tergum aquila volat...

It's all happened to me.
I've had blowouts, a brake failure, even a bonnet flying open on me.
It's scary, but you can handle it, as long as you keep your wits about you and don't panic.
One tip though, if you're going to have a blowout, have it in a car with alloy wheels. There's no deep well for the tyre to fold up into, so it stays on the rim. You get a hell of a noise and vibration, but it doesn't throw you all over the road. I know, having experienced both.
The brake failure, BTW, was caused by a bottle rolling underneath the brake pedal - moral: keep your car tidy

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

Oh yes. I reckon in an emergency the bottle would shatter - not nice, but the brakes immediately start working again. I guess it depends how you react, and to a lesser extent how strong the bottle is.

If you have the 'standard' human reaction of pressing the pedal harder and harder, I think the bottle would run out of strength before you did!

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

The bottle stayed intact, but perhaps because I didn't just attempt to press ever harder on the pedal. I very quickly realised that I would be fighting a losing battle with the pedal, and stopped with a combination of gearchanges, handbrake and steering towards and onto the hard shoulder.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

On the topic of failed brakes - if the seal in master cylinder is faulty , allowing fluid to seep past, little at a time, partial or total failure is possible,depending on where the leak is. During normal driving, apart from the fluid level dropping, little is noticed and even the drop can be so little as to be almost not noticed, untill braking problems occur. ( put hand on heart and say how many, apart from on this site, check fluid levels)
The only sympton is white smoke from the exhaust, and only after a lot of braking. (Brake fluid burns white, like redex ) .

Only had it once in several cars, but it's not nice to trace.

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

I have had an apparent total footbrake failure. I'm trying to remember the exact details, and I'm pretty sure it was because I hadn't fully closed a bleed nipple (I know it was my own fault after working on the brakes). I was 17.

The second time I tried to apply the brakes the pedal went to the floor. Unfortuntately I was approaching Streatham High Road from a side road heading downhill, but only at about 15mph (guess). I yanked on the handbrake and stopped about 10 feet over the give way line. Streatham High Road is (was?) a 6 lane dual carriageway at this point, and I've stopped across L1. Fortunately there's nothing coming in L1...

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Far more common than the (thankfully) extremely rare total brake failure is when the brake servo stops working. This can easily happen, due to something like a broken belt, vacuum pipe coming adrift or even a stalled engine.
The symptoms of this are a very solid brake pedal, and a great reluctance on the part of the car to slow down.
when this happens, the thing to remember is that the brakes do still work, and you can still stop quickly - it's just that you have to apply very much more pressure to the pedal.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

My blowout - don't remember much about it except trying to keep vannette straight , trying not to hit the brakes .It was on a Nissan 1800, similar to the Patrol, but a smallere version, with adjustable suspension which had been raised to allow for it to be a 4X4 and with one rear tyre flat the rear end was at a disturbing angle.

Only other nasty i've had was on a Peugot with McPherson type front suspension.
Top plates had been replaced .As i bounced along a sand dust track, somehow the top bolts had come loose/ came off, and the LH front wheel took on a mind of its own. As soon as i touched brakes it tried to pull off to the left. Only other option was to loose speed through the gears /handbrake.

_________________
lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

I've had two steer axle blowouts(total destructive) on an artic.
First one was coming down the A19 from Middlesborough, scared the living **** out of me, offside tyre had gone. No warning signs at all.
I veered towards the central reservation and lwo slung car height armco, and all I could see was me going over the armco.
I made the mistake of hitting the brakes.

I managed to control it enough to get over to the left lane and to a stop.

The scariest part was the cars coming down the road nad trying to take themselves out on the back of the trailer.
The police came along and put warning signs out and cones at the back of the truck, and one car took it so close that he took one of the cones with him past me.

One week later, along the M62, the nearside blew out, this was despite a check at the weekend by a tyre man.
Managed that one a lot better, but I still needed a change of underwear.
Amazing the damage that a blowout can do to a truck.

I've also had a blowout on a fully laden trailer, that was on bonfire night, and I had the time to think, That was a big firework, before I felt the real problem.

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These days, master cylinders have two seals - one for each circuit and both independent of each other. Also, legally, they need to have a brake fluid level warning light (well, effectively they do!) to warn the driver of the gradual fluid loss that you describe. The white smoke bit is interesting. I've seen it happen only once and it was because the diaphragm inside the servo had a hole in it AND there was a brake fluid leak. Engine vacuum would occasionally suck a bit of brake fluid in and burn it.

Interesting! Did it have alloy wheels? I had a CX with alloy wheels many years ago and they were secured with peculiar shouldered bolts with integral washers. After a long run once, I heard a slight knocking on full lock and thought I had a CV joint on the way out. It turned out to be loose wheel nuts! I kicked myself a bit because I could have sworn they were tight and re-tightened them. On the way back, the same thing happened!

For ages, I thought the being able to run on 3 wheels thing was due to the clever suspension but in fact, it's just because the old big Citroens were so incredibly nose-heavy they could manage without a back wheel! If you took a front wheel off, they'd fall over just like any other car!

[quote="Mole]

These days, master cylinders have two seals - one for each circuit and both independent of each other. Also, legally, they need to have a brake fluid level warning light (well, effectively they do!) to warn the driver of the gradual fluid loss that you describe. The white smoke bit is interesting. I've seen it happen only once and it was because the diaphragm inside the servo had a hole in it AND there was a brake fluid leak. Engine vacuum would occasionally suck a bit of brake fluid in and burn it.[/quote]

This was donkeys ago - servo's were a luxury, never mind warning lights, and dual circuit braking - unheard of. But when you hit the brakes - clouds of white smoke, via servo to engine.

_________________
lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on