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My cars not been used that much since I bought it last October due to working from home etc. Most journeys have been in the wet and with the car sitting unused a lot of the time the rear discs are rusty. Front are not so bad but still some rust.
I noticed they were rubbing yesterday while driving with the window down so took the car for a longer drive in the evening doing lots of heavy braking on an empty road. It did make a little difference but they still look dull and some surface rust.
Is the rust inevitable due to its use or a warranty job? Car is 1.5 years old. Or is it easy enough to clean off myself? Don't mind if it's an easy job. Back at work now so need the car.
Double post so it actually shows up.
Rust on discs is inevitable but doesn't accumulate unless unused. It's not a problem if it's uniform, but if it gets uneven, in bands, it abrades the pads unevenly, and that's a vicious circle as the worn areas of pad then don't take the rust off so well. Provided the discs and pads are at least the minimum thickness, and the wear isn't too uneven, they will work fine and will pass an MoT.
The cars only done 4k miles so hardly any wear at all. Both rear discs do look even in terms of the rust so not in patches. I can see very faint rings where the rust has worn off.
Is there anything I can do to get the rust to clear so they dont drag? I've read about using brake cleaner and a wire brush but don't know if it's worth it?
They should take care of themselves after a while.. Just keep an eye out for any pitting or unusual scoring
I had to replace my front recently due to uneven wear - the car was buried outside my house in a snowdrift for most of February and when I came to use it there was was sticking and grinding. They then started to squeal horribly - the rust had accumulated on the outside edge of the disc and so there was uneven wear between the pad and the disc. The brakes were fine but the squealing awful - it would go away, but if you turned a corner, it would start again.
It wouldn't be covered under warranty. You just need to make sure you do a few hard brakes on the first drive after the car has been sitting a while. Rear brakes don't get much use compared to the front so would take longer to clear from driving alone. I wouldn't worry too much as the effort of trying to clean it off both sides is not far off replacing the discs.
You could get the discs skimmed if you were really that bothered
Maybe I'll leave it a few weeks then. I'm back to driving to work every day. Short journey but its stop start driving. If the road is clear I'll do a few hard stops.
Try pulling the handbrake up whilst driving along for a bit, may do the trick.
Edit: Don't know if this will work if you have an electronic handbrake.
To add to above comment, try driving it with your handbrake on the first click providing its not electric. failing that, if you are confident enough in car brakes, remove the discs and give them a going over with a wire wheel in a drill
Try pulling the handbrake up whilst driving along for a bit, may do the trick.
Edit: Don’t know if this will work if you have an electronic handbrake.
Have an electronic handbrake so don't want to try that.
Handbrake is probably internal to the discs so not affected by the pads sticking to the disc. My Cupra does it really badly after rain or washing. 100mph/brake hard and repeat... 😀
Ideally you would wire brush the rust off so that you don't get it all embedded into the pads... However I can't imagine many people bother.
Surely if the problem with clearing it off is that rear brakes aren't as heavily loaded, the only responsible thing to do is heavy braking while driving flat out backwards?
Not all handbrakes apply on the brake surface anyway.
If it were me, I'd just drive it, soon comes off. That's probably the way most likely to cause unever wear, but, I don't think it's that likely in any case, certainly I don't worry about it enough to ever think I'd take the discs off.
If the rust hasn't come off I'd be asking whether the rear brakes are working at all.
Heavy braking is subjective. Try an empty road and a proper emergency stop from 60-70 mph.
Is the rust inevitable due to its use or a warranty job? Car is 1.5 years old.
Not a VW or Skoda perchance? Well known for rusty rear discs. I ended up replacing mine (Skoda Superb) at just under 3 years old and 26k miles. Prior to that I managed it by reversing down my slightly sloping st at 15-20mph and braking hard.
Plenty threads on Briskoda about it. Theory is poor quality steel on OE discs doesn't help. Any car can get rusty discs if parked up for a long time but VW/Skoda seem particularly prone. I had kept an eye on mine and had to replace when the pads now well worn lost a couple of chunks from the braking surface. Discs were now well lipped.
It's a Citroen. Rear brakes are working; I can see where the rust has started to wear off. But ghat was after several lots of heavy braking on a 60mph road last night. Might try dragging the brakes while no ones behind on a fast road.
Disc brake cleaner worth a try?
Nah disc brake cleaner is basically degreaser, won't touch rust.
Surface rust will appear on the disc brakes of laid-up cars. It will disappear once you start driving it again. If it doesn't then your problem isn't a requirement for brake cleaner, it's a requirement for working brakes.
I can see where the rust has started to wear off.
There you go then. Aside from the discs 'looking slightly orange' did it affect your braking performance?
Just leave it alone and stop fretting, you don't need any "brake cleaner" because there's nowt wrong with it. This is a non-problem, it's simply how iron works.
Leave it in gear with the handbrake off if leaving it for a while. Assuming you can do that safely and an electronic handbrake allows it.
Prior to that I managed it by reversing down my slightly sloping st at 15-20mph and braking hard.
Surely reversing doesn't change the brake balance?
Surely reversing doesn’t change the brake balance?
I wondered this and don't know the answer. I guess if the ABS is independent per wheel, forwards and reverse might be different.
I wouldn’t worry, I do very little mileage my rear discs are always rusty, the car is 8 years old now, I had the discs/pads replaced last year as the garage advice was there close to knackered and had warped, a few months later new discs showing signs of rust. If i get 8 years out of these then I will be happy enough.
Surely reversing doesn’t change the brake balance?
Weighting and momentum of vehicle has changed......
I can't talk for modern nonsense but with both my older vehicles the brake bias is highly dependant on the weight and momentum. The bias valve would not close off the rear brakes if momentum was going to the back
Was out this afternoon and while no one was on the road behind I tried dragging the brakes for about 10 seconds at a time. This seemed to make the rubbing stop but it came back again. Could be just heating up and expanding of parts.
I'll try to find a safe place to roll backwards and brake a few times. Not sure where though.
Over the course of a year you’re not going to get anything other than surface rust and brake pads wear through surface rust the same as metal so uneven wear is not due to the rust. Maybe a sticky calliper or handbrake mechanism which can also be affected by being left unused for a while. If you’re concerned do a few hard braking cycles, in a safe manner of course. If you’re really concerned you can get your discs skimmed cheaply enough.
JUST
DRIVE
IT.
Regarding using an electronic handbrake while driving: I once picked up a car at Malaga airport. The way out is a narrow elevated twisty road with concrete walls either side. As I was getting used to a new LHD car, bright sunshine and intense heat, Mrs BigJohn was searching for the air conditioning and pressed the handbrake button. After a bit of skidding up the road I then enjoyed a 20 minute telling off for shouting.
It might be that your rear calliper pistons are not moving as freely as they should. This could be due to seals or corrosion.
It might be that your rear calliper pistons are not moving as freely as they should. This could be due to seals or corrosion.
Even at only 1 year old?
The best way to clean the rust with braking is to drag the brake, not to brake hard. If you brake hard, the momentum of the car pitches the weight onto the front wheels and the balance valve detects the rear suspension lifting and stops any braking effort going to the back - because the back wheels will skid with full braking and no weight on them. Hence the suggestion above to brake hard in reverse.
I would just drive it and not worry, but if you're bothered, put some sandbags or something heavy in the boot and then brake moderately.
Just drive the car and stop worrying!
Exposed heated steelwork subject to a corrosion warrenty.,....... Good luck with that.
Granted you may not be au fait with materials but suffice it your brakes didn't corrode such as they do....you would not like the price of your brake disks.
JUST
DRIVE
IT.
This.
Just drive the car and stop worrying!
And this.
Why are you asking questions if you're going to ignore answers?
What are the symptoms of this "rubbing" you're experiencing?
Applying a modern handbrake while moving will generally just destroys the little shoes mounted inside the disc - they don't use the calipers
The slide puns may need lubrication - if they are a bit sticky from sitting, the pads won't be moving smoothly. May not contact the disc evenly or enough.
Just give it an Italian tune-up. Find a nice windy, hilly bit of road and thrash the snot out of it for half an hour with lots of hard braking. Assuming it has anti-lock, just stamp on the brakes as hard as you can so you can hear and feel the anti-lock kicking in. Or just play boy racers round town for a while. Steel brake discs will get surface corrosion, but it's not harmful. You just need to give them a good workout - they should smell hot when you're finished. Pottering around town like an old woman will not do the job.
Applying a modern handbrake while moving will generally just destroys the little shoes mounted inside the disc – they don’t use the calipers
Some do, some don't. Most normal mainstream cars tend to have the rear calliper dong the handbrake too and does away with the expense of a separate handbrake mechanism. More high performance cars with fancy rear calipers might have a second smaller calliper for the handbrake or shoes built into the hub. Buiding shoes in the hub means you can't make the rear hub mechanism as stiff or strong so a big no no in such a high performance car.
Exposed heated steelwork subject to a corrosion warrenty.,……. Good luck with that.
Yep. Warranties always exclude normal wear and tear parts - excuses, brake linings and discs and some other things, unless it due to manufacturing defect and surface rust isn't a manufacturing defect - just a fact of life. If its a sticky calliper or handbrake mechanism you'll probably be OK claiming under warranty. Like I said earlier, uneven brake wear wont be due to surface rust on your disks.
I tried an Italian tune which made a little difference but there is still some rubbing. The rubbing sounds rough and goes while braking.
I think the comments about hard braking only affecting the front brakes might be right. It sounds logical.
On my way to work this morning I tried dragging the brakes a few times with my left foot. It's only a 10 min journey but the rubbing did improve a bit. Maybe it's heat related? The calipers look clean and corrosion free but I might get the wheel off to have a proper look this evening.
I'm only ignoring comments like "just drive it". I am driving it but want to make the rubbing stop and was worried about the rust. There's been a lot of good advice from most people which I'm using.
I think the comments about hard braking only affecting the front brakes might be right. It sounds logical.
They're not. Mashing the brake pedal to the floor should lock all four wheels subject to the interruption of ABS etc.
They’re not. Mashing the brake pedal to the floor should lock all four wheels subject to the interruption of ABS etc.
This. ABS and EBD are fitted to most cars now and controls the brake force applied to all 4 wheels with any potential locks detected and controlled by electronics.
"Balance Valves" sounds like how things were before the introduction of ABS and EBD.
Although under heavy braking there is obviously a bias to the front wheels as they have the most traction, the rear will also have maximum force applied with any lock-ups monitored and controlled via the ABS.
Sometimes rust builds up on the edge of the disc. You can knock it off with a hammer or similar, but only if the wheel is off.
Sometimes rust builds up on the edge of the disc. You can knock it off with a hammer or similar, but only if the wheel is off.
This - I was just coming in to add an almost identical post. There is likely a lip/ridge of rust around the outside edge of the disk. The pads can't wear this bit off and it'll be causing the noise. Tap (maybe quite enthusiastically) the around this and it'll flake off. You'll be good to go.
Sometimes rust builds up on the edge of the disc. You can knock it off with a hammer or similar, but only if the wheel is off.
I think I'll try that next. I'll pick up a wire brush on my way home too and give that a go.
I'm happy to jack the car up and remove the wheel to get to the disc but don't want to remove the brake caliper. Not on a new car anyway.
There's probably a dust shield on the inner side of the disc which might make access a little tricky.
This is usually the worse affected side.
There’s probably a dust shield on the inner side of the disc which might make access a little tricky.
Yeah there is on this car. Hopefully I'll be able to see/ hear where the rubbing is and go from there.
Sometimes rust builds up on the edge of the disc
Yes, on a 5 year old car where the discs have worn a bit. But not a one year old car with low mileage.
I’m only ignoring comments like “just drive it”. I am driving it but want to make the rubbing stop and was worried about the rust. There’s been a lot of good advice from most people which I’m using.
You're following the advice that reinforces what you're already thinking.
You can knock it off with a hammer or similar
What Could Possibly Go Wrong.
If it's com in Ng back when you corner I'd be more concerned abot wheel bearings than rusty disks
I’m only ignoring comments like “just drive it”. I am driving it but want to make the rubbing stop and was worried about the rust. There’s been a lot of good advice from most people which I’m using.
Ok, I'll turn my advice level up a notch.
Stop fannying about......and just drive it.
On my way home this evening I found an empty dead end road and did a few reverse to 20mph and brake hard. It definitely got the rear brakes working more tjan going forwards as I could hear a rougher sound from the rusty surface and the rear discs had a few new faint rings in them.
Got home and checked the rear brakes. Both rub and passenger side makes a louder rubbing noise. There's a little more rust on this one. Took the wheel off and gave it a good brush with a new wire brush. The rust is pretty solid on there with only a few bits wearing down a bit but managed to make it slightly smoother.
Also checked for any movement of the wheel bearing but they seemed fine.
Totally agree with cougar and RNP. Drive it. Drive it fast. You could probably trigger the EBD to trail a rear calliper a bit by braking at high speed on a bend, but really? No. It’s rust, it’s less hard than the pad material and will go away. Brakes on the Giulia and the Van rust up in about ten minutes after a wash. Quick scoot ‘round the block with some and the “graunch-graunch-graunch” goes away.
Also it’s a Citroen: high likelihood that the handbrake acts on the front discs, possibly through a line lock (though those TRW combined calipers with servo motor handbrake are everywhere as they’re cheap-cheap).
Honestly fella, what you are experiencing is mechanically a non issue. It won't impair braking performance now or in future, it won't damage the pads and the noise will sort itself out over time.
But if you really want to make it an issue and clear the discs, fill your boots. Crack on with the wire brush, make sure you do both sides of the discs and have a good look at the edges. Due to the lack of use you won't have a lip on the edges that has corroded more, so probably best stay away from the hammer.
Personally I would just drive it.
You might now have some debris between the pad and disc. Try flushing it with a pressure washer/hose.
If you're in doubt an MOT test station can check the performance of the rear brakes.