Brake failure

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Snapcap

Member
Posts
21
Location
Near Manchester
I recently experienced severe brake failure whilst travelling at high speed dolwn a steep gradient.I suspect the cause to be old brake fluid,Having had the vehicle for only a couple of months i was cauhgt completely unawares,however on checking the service history, the last time it appears to have been changed is 2007. I'm hoping this will resolve the issue but i will also be checking for sub standard pads. Is this acommon problem with this car.
 
And how did the brakes fail? Working fine then next push nothing? Slow fade to nothing, pedal travel slowly/quickly increased? We'll need more information to go on. Once we have this we can advise further. There are known parts that can fail on RRs, each with their own characteristics, as with any make of car, assuming you are refering to a Range Rover........
 
Sorry guys , it's a RR 4.4 petrol 2004. The brakes initially engaged and the RR started to slow down , there was no excessive travel on the pedal but complete fading of stopping power.Once i let the system cool down(and chaged my pants) everything seemed normal.
 
So, high speed, steep gradient, then fading of stopping power. Once cooled off, back to normal. Sounds like classic brake fade, caused either by brake pads overheating and/or brake fluid boiling in the calipers. Won't hurt to change the brake fluid and pads anyway, but problem was most probably driver error? The 4.4 RR is almost 3 tons, with any heavy vehicle this situation could have occured, use the gears to slow/limit speed when decending hills. Rely on the brakes alone and you now know what can happen.
 
Yes a definite Gypsys warning and not one to be repeated, i got away with it this time, with a damaged tyre when i hit the roundabout at the bottom and went straight over the top of it. Fortunately it was early morning with nothing on the road.Lesson learnt.
 
Surely a properly functioning braking system on any modern car should be able to cope with at least a few hard braking stops from speed without fading, yet alone failing completely? We are talking about just one hard braking attempt here, aren't we??

Even allowing for the hill, there must be something wrong IMO, get it diagnosed and fixed asap!

Cheers,

Jerry

ps wouldn't boiling fluid cause the pedal to go to the floor? I don't think old fluid can be the cause of this problem...
 
Brake Fluid is Hydroscopic (LOVES water)

So old fluid will be saturated with water molecules and this is what causes the brake fluid to boil....

So old Fluid will cause brake fade due to the amount of suspended water molecules in it...
 
It's going in this week for a thorough brake inspection and overhaul so hopefully any problems will be sorted out.I think the water absorbtion theory is odds on favourite. Still thanks for all your advice and i'll keep you posted with the outcome next week.
Kind regards Snapcap.
 
The newish type wont have this problem,4. whatever its synthetic and wont attract water, a little more £ but a lot less hassle I hear you don't have to change it, don't know if that's true or not and can be mixed with older types, but check first i could be full of **** on this one, and I don't want you coming to me complaining that your dead
 
Yes, the problem is the water in the fluid boils creating gas and that makes the brake pedal spongy (you are now compressing gas rather than displacing fluid) and, if enough of the water boils, the pedal could hit the floor and the brakes stop working.

But the OP clearly states that there was no excessive travel on the pedal.

Which is why I don't think brake fluid is the issue here....

I suspect dodgy aftermarket pads. Let's see what the OP's diagnosis throws up!

Cheers,

Jerry
 
Ok the outcome of the brake investigation that has been carried out today confirm that my suspicions were correct.Woefully cheap and nasty pads,discs would see out another set of pads but are showing a lip on the outer edge.
So a brake fluid change with new discs and top quality pads being fitted should resolve the problem . Once again thanks for all your input

Kind regards Snapcap.
 
You should not be paying more thank £50 if you have your brake fluid changed in the whole of the system, that's what I was quoted and National Tyres, and they price matched this at a Vauxhall dealership and that was for DOT 5.1 (they used over 2lt of the stuff, so it doesn't really pay you to DIY it, cheaper and less hassle letting someone else to do it for that price
 
Dopey said:
The newish type wont have this problem,4. whatever its synthetic and wont attract water,
Click to expand...

Oh yes it will, all non-silicone brake fluid is hygroscopic whether it's DOT 1,2,3,4 or 5.1. DOT 5 (silicone fluid) on the other hand doesn't absorb water but that leads to worse problems, moisture pools in the lowest point of the system - usually the brake calipers, this water becomes very acidic and attacks the brake pistons, being pure water rather than being absorbed into the fluid (giving you plenty of warning that bleeding is required) means it boils at just 100C, so you hit the brakes hard the pressure stops the water boiling, then you let the brake off, the water immediately boils turning to steam - expanding faster than the tiny air hole on the master cylinder can cope with, your brakes lock solid and you crash! Brake fluid absorbing moisture from the system is a good thing.
 
It makes you really wonder about people who won't pay a few extra pounds for life critical components. Cheap pads. Should be a law against them. Decent pads are not expensive anyway, Island 4x4 have just supplied a set of Mintex pads for my P38 for £18.49 inc VAT. These were only a couple of quid more than an unbranded set of pads.

As to brake fade, I have only once experienced it, in my Freelander TD4. It had fairly fresh brake fluid and was fitted with known brand pads. I was driving very spiritedly along some country lanes, using the tiptronic box and late, hard braking. After 4 miles, approaching a roundabout I had sudden and almost total brake failure, the pedal travel increased a bit, but that could have just been me pushing ever harder. Bit of an eek moment, but no traffic and the roundabout was taken far too fast, but unscathed. Slow driving and no brake application for next half mile and all was back to normal, and no problems since. I can only surmise the pads went over their operational temperature. I now drive it less spiritedly.
 
Alan C said:
It makes you really wonder about people who won't pay a few extra pounds for life critical components. Cheap pads. Should be a law against them. Decent pads are not expensive anyway, Island 4x4 have just supplied a set of Mintex pads for my P38 for £18.49 inc VAT. These were only a couple of quid more than an unbranded set of pads.

As to brake fade, I have only once experienced it, in my Freelander TD4. It had fairly fresh brake fluid and was fitted with known brand pads. I was driving very spiritedly along some country lanes, using the tiptronic box and late, hard braking. After 4 miles, approaching a roundabout I had sudden and almost total brake failure, the pedal travel increased a bit, but that could have just been me pushing ever harder. Bit of an eek moment, but no traffic and the roundabout was taken far too fast, but unscathed. Slow driving and no brake application for next half mile and all was back to normal, and no problems since. I can only surmise the pads went over their operational temperature. I now drive it less spiritedly.
Click to expand...

Almost identical incident to mine in my Jag XJR, racing a TVR for a few miles I braked from 150mph into a roundabout and ran out of brakes - total fade. Fluid and (o/e) pads were fresh. Got round - just, and waved the TVR jockey by! :doh:
 
you're both idiots. and if someone driving like you on the public road were to say run it to my kid and her mum i will hunt you down and roast your balls and feed them to you without first detaching them from your body.
 
rasheed said:
you're both idiots. and if someone driving like you on the public road were to say run it to my kid and her mum i will hunt you down and roast your balls and feed them to you without first detaching them from your body.
Click to expand...

I agree, we've all done daft things occasionally, this was at 4 O'clock in the morning on a near deserted A-road. But still, naughty I know. I don't speed in urban areas where there will be kids about, never have done, never will do.
 
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