Hot brakes

Wellington

Wellington

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Carthago Compact 138
It sounds like a cocktail! However, not so much fun.

Yesterday we drove into the Tuscan hills on a single track hair pin road, and then down a stony hill to a very lovely Ranch Sosta (which has sadly closed). As we got there the brakes (I think) started to smell very hot! We stopped for a bit, but obviously couldn’t stay long, as they don't take campers any more. I’m still getting whiffs of hot brakes, even though we’ve been parked up overnight (it is 32 °C here. Nothing is cooling very efficiently!)

Should I worry, or is it just one of those things that engines do to keep you on your toes?
 
Brakes get hot in normal use - especially if used a lot down a steep hill. The smell (and powdery residue) of hot braking can last a while - a bit like when you’ve been heavy on the clutch. I assume you’re sure it is a brake smell and not engine or clutch?

First test is to check they work ok, aren’t making a screeching/binding noise and there’s no vibration through the steering wheel.

If all is well, drive carefully for a while and reassess the smell.

Hope this is helpful,

Robin
 
Smells like brakes, and I didn’t use engine braking at all, because we were running on fumes at that point. However, the fiscal crisis has somewhat abated so I can stop being Scroogey over fuel now.

It doesn’t smell nearly as bad as the clutch did when I reversed the caravan up a grassy hill, and Mr AA said that it would be fine (it was too) I just didn’t fancy a conversation with an Italian mechanic about it if it was normal. Bloody mountains!

ETA they work fine, and we’re in no hurry, so will take it easy.
 
If it's in gear and you've not got your foot on the accelerator, it's probably not using any fuel at all. Certainty less than if you were coasting with the clutch down because then some fuel is required to keep it ticking over.

When going down steep hills, stay in a lower gear. Don't trail the brake for long periods. Instead it's better to brake stiffly to bring your speed down in bursts, but not all in one go just before the apex! Most of all, descend slowly. You're giving your brakes more time to dissipate the energy. And if they do overheat, you'll be going at a safer speed.

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On long hills use your gears to increase engine braking as stated above but also use your brakes intermittently rather than trailing them all the way down this will give them little rests to cool a bit resulting in overall lower temperature.

Martin

Or as Guigsy said coz he had faster fingers than me.
 
Quite normal to get the brakes hot with a heavy motorhome on big hills, just try to stay off them as much as possible and use the gearbox to stay at lower speeds. When you get to the bottom don't come to a complete stop and stay on the brake pedal or the hotspot created will tend to warp the discs (juddering when apply the brakes) just drive steady and allow them to cool off naturally.
 
If you get them so hot they start to "feel funny" STOP (otherwise you wont be able to), park up and let them cool down
 
We nearly did, there were some
hilldweller said:
Burn your brakes out and you'll really know the meaning of fiscal crisis.

Remember all that engine labouring up a hill turns into heat in your brakes on the way down.
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See, it’s never worth scrimping, I’ve always said so.

Hill driving training completed, I shall be more careful next time. I wasn’t actually planning on any mountain driving (although I was toying with going back over the alps instead of through the tunnel. My cousin did it to avoid the queues, with a caravan, so it can’t have been that bad. Not if shot brakes are the price, though)

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We had smoking breaks a few years ago in Italy after my navigator sent us over the wrong route in the mountains. I just pulled over at the bottom and had a cuppa, waited about an hour then traveled on. On my next service I asked them to check the breaks and they told me all was OK. As others have said try to use your gears more than breaking, sounds easier said than done. Happy travels.
 
Even in my relatively light van, the engine doesn't help with braking much once you get to properly steep hills. 2nd gear and 3500rpm doesn't sound kind to the poor thing! Just keep firmly braking every so often (and well before the corners).

I've been down long descents coming off the Alps and used the throttle so little for such a long period that the temperature gauge dropped right down.
 
Sounds like you've had a very lucky escape with your braking method.
When using only brakes going downhill your brake fluid boils, now the physics bit, brake fluid cannot be compressed but, when it boils & turns to steam it then becomes compressible, the next thing that happens is your brake pedal disappears to the floor & no amount of effort will ever bring it back.
Brake fluid is hygroscopic, this means that it can & will be taking on water, so the older your brake fluid, the more likely it is to boil as water boils a lot easier than brake fluid.
A lot of folks that service their own vehicles simply do not change the fluid at the proper intervals, personally I wouldn't drive a vehicle with brake fluid which is over three years old.

The smell you've described from the brakes means they've probably become red hot & almost certainly been a whisker away from failing!

My recommendation is that you buy a lottery tick as you sound like a very luck gambler.
 
Yes. There’s a difference between a bit of a hot smell after some downhill braking and impending catastrophe. One is pretty normal and one isn’t. From the OP’s description it sounds like the former.
 
I never planned to be on such a hill in the first place, I wish satnav had contour lines on.
 
Wellington said:
Ah well, we live and Learn. Boiling brake crisis averted, and hopefully someone else will read this and learn from my mistakes, which is always nice.
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The main thing is that your alright & we've all learned a wee lesson, every day is a school day. :)(y)

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HandyAndy said:
that post is a little dramatic
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Perhaps my post was a tad dramatic but then I've had a career where I met a ridiculous amount of people on the steep hills around my home that it all went wrong for.
Furthermore, the way I learned this lesson was the hard way, my friends AUDI 100 (remember them) suffered from boiling fluid when he'd ridden the brakes for too long, not a mistake either of us would like to repeat.
 
I hope you never find this advice useful, but here it is anyway. If a truck has failed brakes on a long steep hill, there is often a thing called an 'escape lane'. It's basically a kind of layby, but it's really a long trench full of loose gravel. It will bring a runaway vehicle to a stop. Even a heavy truck. As I say, hope you never need one, but it's as well to know about them.
 
Ivory55 said:
When driving in hilly places you have to use the gears more for engine braking and not so much brakes or they overheat
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Not part of the uk driving lessons now I am told.

I was taught to gear down in my lessons in a mini!.

My neighbour passed her driving test, first time.

Lessons were all on the flat around town.

When she went out to the hills for the first time, she came to me for help when she got back.

“Something wrong with my car” she said.

I said what ?

“ when I go uphill, it vibrates, slows down and then stalls”. “ I have to turn the engine off every time and start off again”. Each time, when I am near the top of the hill, it slows and stalls again”.

When I asked if she geared down?. She had no idea what I was talking about.

She then got an automatic, first day out she kept pressing the brake thinking it was some kind of “big combined clutch/brake pedal”.

1st day, kept slamming on in-front of drivers. Until someone pulled her over to educate her.

FECKING SCARY WHO DRIVES ONE TON-PLUS OF METAL AROUND THESE DAYS
 
Having your brakes on all the way down a steep hill will get the brakes hotter and hotter. Change down to a lower gear to hold you back, and use your brakes on and off, giving them a rest briefly to cool down. If you are in the correct gear, it won't run away.

Craig

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ambulancekidd said:
Sounds like you've had a very lucky escape with your braking method.
When using only brakes going downhill your brake fluid boils, now the physics bit, brake fluid cannot be compressed but, when it boils & turns to steam it then becomes compressible, the next thing that happens is your brake pedal disappears to the floor & no amount of effort will ever bring it back.
Brake fluid is hygroscopic, this means that it can & will be taking on water, so the older your brake fluid, the more likely it is to boil as water boils a lot easier than brake fluid.
A lot of folks that service their own vehicles simply do not change the fluid at the proper intervals, personally I wouldn't drive a vehicle with brake fluid which is over three years old.

The smell you've described from the brakes means they've probably become red hot & almost certainly been a whisker away from failing!

My recommendation is that you buy a lottery tick as you sound like a very luck gambler.
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What he said
 
Apologies to Funsters who have the Comfortmatic and already know this, but most of this thread assumes you have a manual gearbox.

In Auto mode the Comfortmatic gearbox is programmed to change down and give you engine braking when you drive down a hill. It does this when you start to brake.

If you have pressed the "Up" button, Comfortmatic changes down another another gear or two for extra engine braking. It can be startling until you get used to it because you may get the impression that the engine is revving too high. It can get a bit noisy. Still, it is a reassuring kind of noise.

For extra braking, in effect the engine is used as an air pump, compressing more air at higher revs, without adding any fuel. Compressed air gets very hot so the engine cooling system will still be working quite hard even though your foot isn't on the loud pedal.

I agree completely about using the foot brakes in short bursts at intervals, allowing the brake system to dissipate heat better during descents. Trail braking is more instinctive but best avoided.

I wouldn't pull over and stop at the bottom of a steep descent unless I have to, because of the "heat soak" effect. The mechanical bits are likely to be very hot by the time you get to the bottom so best carry on driving a little longer at 30-50 but not booting it, so the airflow cools everything including the brakes and gearbox more effectively.
 
Yorick said:
Engine braking uses less fuel than free wheeling.
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In fact engine braking uses zero fuel on any modern engine. Fuelling only restarts at engine rpm just above idling speed. Allowing the engine to spin at up to 4000rpm to utilise engine braking is also harmless. It'll just cool down quickly :) .

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