Degreasing new brake discs - essential to use brake cleaner?
Discussion
Long story short, whilst changing the rear discs I just could not get the OSR disc off (summer car, minimal use so could have been on 15-20 years) - just corroded to the hub. Having successfully changed one side I temporarily reassembled the other and asked my local garage chap if he could remove the old disc which he kindly did.
Unfortunately he didn't have any brake cleaner so just reassembled the new one and said that the new pads would clean off the residue. Is that ok?
I have always used brake cleaner to clean down new discs, and indeed did on the NSR - they were Eicher discs with what seemed a more light waxy layer than the oily protection that I remember on previous discs.
Only a short drive home but the new pads will now presumably already have ingested any residue. Should I pop new pads in? Or are they likely to be perfectly fine? Or just watch for signs of uneven pad wear once the car has done some miles?
To me, cleaning liberally with brake cleaner is natural - but he seemed very relaxed and almost optional to use a cleaner. He did make an effort to keep oily fingers away from the surface.
Happy to be educated.
Unfortunately he didn't have any brake cleaner so just reassembled the new one and said that the new pads would clean off the residue. Is that ok?
I have always used brake cleaner to clean down new discs, and indeed did on the NSR - they were Eicher discs with what seemed a more light waxy layer than the oily protection that I remember on previous discs.
Only a short drive home but the new pads will now presumably already have ingested any residue. Should I pop new pads in? Or are they likely to be perfectly fine? Or just watch for signs of uneven pad wear once the car has done some miles?
To me, cleaning liberally with brake cleaner is natural - but he seemed very relaxed and almost optional to use a cleaner. He did make an effort to keep oily fingers away from the surface.
Happy to be educated.
I'd stick my neck out here and say they will be fine.
I wouldn't have done it myself, but I don't think it will have contaminated the pads to the extent that they need replacing - i'd expect heat to burn off any residue within a few hundred miles. I'd just keep an eye on the situation and whether or not you feel any 'imbalance' in braking performance, although being rears, that'll be negligible I'd imagine.
Ultimately though, what is the cost of a rear set of pads? And are you the sort of person that will be kept up at night thinking about this? I guess just weigh one against the other and make the call.
I wouldn't have done it myself, but I don't think it will have contaminated the pads to the extent that they need replacing - i'd expect heat to burn off any residue within a few hundred miles. I'd just keep an eye on the situation and whether or not you feel any 'imbalance' in braking performance, although being rears, that'll be negligible I'd imagine.
Ultimately though, what is the cost of a rear set of pads? And are you the sort of person that will be kept up at night thinking about this? I guess just weigh one against the other and make the call.
Edited by MattyD803 on Tuesday 4th January 15:12
I've always just popped them on and off I go (gently, until bedded in). I've had a mix of discs over the years with a mix of materials on them (and not, seems to depend on the manufacturer, I had one set with a silver paint like material on them) and never even given it a second thought about cleaning them, the pads'll do that job and it won't overly effect their performance.
Tyre Smoke said:
Never ever bothered. I think you are being overly fussy. Pads and discs will need to bed in. Whatever was there, including your brake cleaner is long gone.
Brake cleaner just cleans brake dust residue anyway. New brakes don't have any.
PAGID discs i've fitted in the past tend to come coated with an oily/protective residue. I think the OP is most concerned about that oil having 'contaminated' the pads.....Brake cleaner just cleans brake dust residue anyway. New brakes don't have any.
I use White Spirit / Meths typically....
Tyre Smoke said:
They're Eicher discs. Not Pagid. Even so, I've never had an issue with Pagid either. Take it very easy for a couple of miles and then brake gently for the next few miles. After that, good to go.
Make of discs is irrelevant, I only mentioned it as its another brand at the cheaper end of the scale that the likes of ECP sell....hence I imagine Eicher are the same. I've had Lucas & genuine factory discs coated just the same.Manufacturers' literature supplied with the discs typically recommends that you 'degrease' disc faces before fitting. It's 'good practice'....but I doubt has any long term impact on braking performance....
I always clean them off but I suspect even if you lashed a load of grease on the disks they would still work as its a massively powerful vacuum assisted hydraulic system dissipating huge amounts of energy into a relatively small area.
Anything on there would initially lubricate but the lubrication wouldn't overwhelm the force for very long and whatever is there would be heated very quickly and just burn/evaporate off before biting as normal. Worst bit of a new brake pad and disk is the time for them to bed together and they often feel like wood for a few miles.
I doubt it would contaminate the pad, well not more than a few microns into what is a pretty dense friction material, brakes are pretty resilient and cope with extremes of temperatures, rapid quenching from water on the road being thrown up or wading, I think the contaminated bit would soon be worn away down to fresh material.
Not recommending greasing brake pads but I think you would be hard pushed to stop them working for very long doing that, never mind a bit of the protective stuff they spray on.
Anything on there would initially lubricate but the lubrication wouldn't overwhelm the force for very long and whatever is there would be heated very quickly and just burn/evaporate off before biting as normal. Worst bit of a new brake pad and disk is the time for them to bed together and they often feel like wood for a few miles.
I doubt it would contaminate the pad, well not more than a few microns into what is a pretty dense friction material, brakes are pretty resilient and cope with extremes of temperatures, rapid quenching from water on the road being thrown up or wading, I think the contaminated bit would soon be worn away down to fresh material.
Not recommending greasing brake pads but I think you would be hard pushed to stop them working for very long doing that, never mind a bit of the protective stuff they spray on.
I'm trying to picture even a bodgit and scarper mechanic not having something lurking about he could clean the light grease off a new brake disc with if he'd run out of brake cleaner, a drop of petrol on a rag would have done the business even a squirt of plus gas would have liquified the grease so it could be wiped off.
If it were my car i'd grab a can of brake cleaner and give the brake concerned a good soaking, concentrating on the pads.
If it were my car i'd grab a can of brake cleaner and give the brake concerned a good soaking, concentrating on the pads.
Smint said:
I'm trying to picture even a bodgit and scarper mechanic not having something lurking about he could clean the light grease off a new brake disc with if he'd run out of brake cleaner, a drop of petrol on a rag would have done the business even a squirt of plus gas would have liquified the grease so it could be wiped off.
If it were my car i'd grab a can of brake cleaner and give the brake concerned a good soaking, concentrating on the pads.
Yeah certainly sounds a little odd - surely every garage has a bottle of something lying around for such tasks.....probably rushing as it was a 'favour' job....If it were my car i'd grab a can of brake cleaner and give the brake concerned a good soaking, concentrating on the pads.
Like most, I always grab a can of brakecleaner and use it both to wash the dust off as well as clean the coating off the disc. I've always done it that way because it makes sense to me. However I've heard a lot of people say they don't bother and just rely on the brakes to clean themselves. In all my years of amateur spannering I've never, ever heard of anyone coming a cropper because they didn't degrease new discs.
I'd also suggest that the Chief of Disc Protective Coatings at a brake manufacturer carefully selects coatings that wouldn't cause brakes to succumb to failure and fiery death if not removed.
If you compare new brake discs with new tools, the coating is totally different. I'd say for discs it's more akin to the residue on items that have been wrapped in VCI paper, rather than heavy greasy stuff. With the V being for Volatile, I expect a good bit of heat will boil them off if they're still there.
OP, you'll be fine. Try getting the brakes nice and hot for some reassurance if you want... In a straight line, nowhere near a school/kitten factory/something that will hurt if you hit it, of course.
I'd also suggest that the Chief of Disc Protective Coatings at a brake manufacturer carefully selects coatings that wouldn't cause brakes to succumb to failure and fiery death if not removed.
If you compare new brake discs with new tools, the coating is totally different. I'd say for discs it's more akin to the residue on items that have been wrapped in VCI paper, rather than heavy greasy stuff. With the V being for Volatile, I expect a good bit of heat will boil them off if they're still there.
OP, you'll be fine. Try getting the brakes nice and hot for some reassurance if you want... In a straight line, nowhere near a school/kitten factory/something that will hurt if you hit it, of course.
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