What causes warped brake discs? (Octavia)

warren

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Evening,

When I bought my Octavia it had a warped front brake disc/discs, these were replaced with new pagid discs and pads, issue went away completely for about a year, but its just been slowly creeping back now to the point where its very annoying again. Its worst under moderate braking, when you start to brake harder it smooths out.

The two brakes have different wear patterns, but both were installed at the same time, both seem clean, can't see any dirt or objects that shouldn't be there. One disc is perfectly smooth, the other is scored and pitted (obviously the suspect for the problem).

Neither calliper feels seized, both wheels turn about the same, hard to tell with the transmission drag how free they are. When I was last out I measured the temp of the discs and both were sitting around the 45deg mark when I got home so it doesn't appear one is more seized than the other.

I'm just wondering if anyone has anything I can do or check before I replace them again, as the underlying issue is clearly still there. Car is a daily driver, has a very easy life.

IMG_20200924_120903.jpg

IMG_20200924_120913.jpg
 

purplea4T

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Any damage to the actual hub? Was the mounting face cleaned when the discs were put on? Definitely looks like pad deposits on the bottom disc too. Sliders clean and free moving? Looks like quite the lip on the discs too.
 

Apis

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Have a read up on "disc thickness variation". It can start when the pads are bedding in and you dont notice it, but then it snowballs over time, getting worse and worse.
This is far more likely than warping.
 

warren

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warren
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They have been on for well over a year now of perfectly smooth operation.

The hubs were cleaned reasonably well when they were installed, I'll certainly pull the disc off again and give it a proper going over though if it could help!

Is it reccomended they go ontop the hub completely dry? No copper grease etc?

That sounds like some good solid reading for work tomorrow @Apis

@stevieturbo maybe.... I did buy ones from a reputable manufacturer hoping id have no issues, I'd like to think they should last more than a year!
 

stevieturbo

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@stevieturbo maybe.... I did buy ones from a reputable manufacturer hoping id have no issues, I'd like to think they should last more than a year!

All these brand names may claim OEM this and that.

I've never come across any actually the same or as good as OEM. They're just different.

Even on my crappy van for years I'd always used OEM, and then they stopped doing packages on them with PSA took over so I opted for a full Brembo setup instead, full F/R discs/pads. Plus I wasnt using it as often by that stage anyway
It was utter rubbish compared to the OEM Vauxhall discs/pads. Most notably low speed braking. Just felt dull and crap.

IMO if you've had problems and seem difficult to resolve...I'd go OEM. Let's face it, they always work well on new cars, often for many years without issue.
 

Mark_C

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Almost certainly they won't be warped. The standard 'diagnostic' is to measure run out. At the front (ie on a single) face. If you measure the rear and the front face simultaneously you more than likely won't find an inverse reading at the same time.
 

warren

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Thats a brilliant read @markmeus . It actually has me thinking that when I replaced these I remember there was a while that the pad was only rubbing on about half of the normal disc face, at the time I just thought they took a while to bed in etc. Does that mean however that my caliper is off axis with the disc/wheel assembly.....

I really wish the car was worth more so that I could justify putting more time and money into it. Its cost me a fortune already this year.
 

roverspeed

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As above, I would say in road use its very hard to warp discs on a modern car (modern is anything after 2000 for me)

You could buy yourself a cheapy dial gauge and holder of amazon and check (with some degree of accuracy) runout on the discs.

I personally can't see it being in the hubs etc, surely it would be evident regardless of new or worn discs? Discs will never been 100% flat, and the new braking surface on yours pads is never 100% flat when fitted, so I wouldn't worry about feeling in resistance whilst turning by hand on a car. (please anyone correct me if I am wrong, I am not a mechanic! Just speaking from experience)

You do look to have a fair lip on it, very hard to tell in a picture though. Also, its hard to tell but also some pitting?

I genuinely have warped discs in the past and didn't experience judder, its more like having out of balance tyres but only whilst braking.

I agree with the sentiment above on brands of discs, I would only ever get Brembo, Zimmermann and whatever OEM may be, even on my Insignia with is worth F all squared. Though being totally honest, I would go to other brands for rear discs if there is a big price difference as they get a lot less punishment.

Credentials - I have covered about 450,000 miles in the last 10 years and have been through quite a sets of discs and pads. And I always do my own brakes for the last 6 years
 

warren

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Yeah warp is the wrong word, I was unaware of all the other things it could be until I started this thread!

Thats what that last article was saying could be an issue just, that something is off axis and the pads arent sitting straight on the disc face, which got me thinking it was only rubbing on half of the face for a while when they were new.

I know they arent Brembo but Pagid are also a very reputable company, so I dont think its a disc quality issue as such. Ive changed many sets of discs and pads over the years, often with much cheaper stuff and never had any real problems!

Its the fact that the discs were shaking when I bought the car and it got gradually worse, replaced, were perfect for a year and have started to go downhill again that makes me suspect theres something else at play here. Id almost put money on it happening again if I was to replace them!
 

roverspeed

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Ah I see, you are probably correct. Yes Pagid are decent

The problem you face is measuring variance in the parts that could be causing it and knowing what the acceptable variance is for those parts.

The other way to do it is to throw the most obvious parts at it first. Its a hard call :-(
 

ChrisL

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Wouldnt really agree with the just buying OEM and leave other brands comment lol

Ive used Pagid on my M3 and then used Godspeed ones on my Scoob and all were just as good as OEM if not better quality. Used non OEM discs on my Cupra, Hemi, Jag .... list goes on. Obviously if you arent buying them off a lorry straight in from Taiwan id say you should be fine.

Lip seems fairly big in those images bud, best to get them changed. Cant go wrong with Pagid, Brembo etc
 
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Woodcutter

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I think people forget that car manufacturers don't make brake discs or pads, the so called 'aftermarket' companies tender for them, then make them and stick the manufacturer logo on them. All made in the same factories, just different batches for OE and Aftermarket.

Ferodo are one of the biggest suppliers of OE braking products for European cars, most of which are available in the aftermarket. Likewise Brembo, Textar, ATE, Jurid etc etc.
 

ChrisL

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I think people forget that car manufacturers don't make brake discs or pads, the so called 'aftermarket' companies tender for them, then make them and stick the manufacturer logo on them. All made in the same factories, just different batches for OE and Aftermarket.

Ferodo are one of the biggest suppliers of OE braking products for European cars, most of which are available in the aftermarket. Likewise Brembo, Textar, ATE, Jurid etc etc.

Ferodo that was the other brand I couldnt think of. Used them on all my 200sx's and 350z. Great quality.
 

warren

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@ChrisL I think its a bad angle Ive taken the photos, the edge of the disc tapers away from you, there is a tiny lip, but not much. They are probably only about 12k miles of pretty easy use old. Im just very reluctant to replace again as Im fairly confident in another year they are going to be the same again. If I can get to the root of the problem first id have no issue.

If I replace the wheel hub/bearing, caliper carrier, caliper, caliper pins, discs and pads one of those things is bound to fix my problem :laughing:

Just need one of those money trees now.
 

Jrooney06

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They have been on for well over a year now of perfectly smooth operation.

The hubs were cleaned reasonably well when they were installed, I'll certainly pull the disc off again and give it a proper going over though if it could help!

Is it reccomended they go ontop the hub completely dry? No copper grease etc?

That sounds like some good solid reading for work tomorrow @Apis

@stevieturbo maybe.... I did buy ones from a reputable manufacturer hoping id have no issues, I'd like to think they should last more than a year!
I know it’s a bit of an investment but get yourself a runout kit so when you fit them you can be sure the disc is perfectly square otherwise it’s a bit of a guessing game down the line. If you get judder you then know it’s pad deposit.
I think people forget that car manufacturers don't make brake discs or pads, the so called 'aftermarket' companies tender for them, then make them and stick the manufacturer logo on them. All made in the same factories, just different batches for OE and Aftermarket.

Ferodo are one of the biggest suppliers of OE braking products for European cars, most of which are available in the aftermarket. Likewise Brembo, Textar, ATE, Jurid etc etc.
Going to play devils advocate here but are the pads supplied to say BMW the same as the pads supplied when you go to Eurocarparts or wherever. Is the brake material the same? Logic would say yes but my experience says I’m not 100% sure.
 

dross432

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Is it an auto or a manuel?
Reason being on for example the X5 being an auto braking from speed to a stop causes alot of heat. And as its auto you sit with you foot on the brake to hold it from creeping.
Manuels are more like to ease off the brake or hover clutch/ use handbrake.
 

Apis

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Consider also the counterfeit car parts market, filters and brake pads being among the most common. And they are more likely to be counterfeiting the big name brands than the brands no one has heard of.
 

_James_

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Going to play devils advocate here but are the pads supplied to say BMW the same as the pads supplied when you go to Eurocarparts or wherever. Is the brake material the same? Logic would say yes but my experience says I’m not 100% sure.

Nope, they are definitely not.

It’s definitely not a definitely not but a more than likely not.

I have seen, physically handled and compared parts from OE manufacturers that are completely different depending on where you buy them but are touted as being just as good as genuine which they are not.

I forget who makes our brake pads but the genuine OE pad had chamfered edges and a sacrificial softer initial compound to aid pad/disc run-in and a cooling channel to help with heat transfer. The OE variant you buy in the motorfactors that comes from the exact same factory floor and touted as being as good as genuine has none of these features, uses a completely different compound, causes premature wear of discs, longer stopping distances and last around 30,000km less than genuine.

Sach make our clutches, we tore down a genuine, an OE spec and a remanufactured clutch kit, again all out of the same factory but supplied to either dealer or motorfactor. What was found.
OE spec, pressure plate springs not the correct rating required for the gearbox. More of a jack of all trade rating to fit multiple box configuration
OE spec also did not have a bearing designed to reduce vibration caused in the automated variant of the gearbox.
Remanufactured kits were pot luck on the bearing and spring rating as it all depended on what they were manufactured from.
OE and Remanufactured both used different clutch plate compounds and thicknesses compared to genuine.

Ball joints where another great one to tear down, not all ball joints are created equal.

Shocks, as above.

Suspension arms and bushes though, you are pretty much getting the same thing with OE variants.
 

NI_Volvo_Nut

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The main cause is sitting with your foot on the brake after stopping, especially after a harsh stop, the pad creates hot spots on the disc. Octavia's are also prone to calipers sticking which heats the disc up also causing hot spots when stopped.
 

warren

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How do I avoid using the brakes after I stop.... even if I handbrake thats just using the rears but same priciple!

Calipers dont seem sticky, both are the same temperature after a drive.

I know the damage is already done but I'm going to pull the suspect looking disc off and make sure everything is clean and tidy with the caliper and disc mounting.
 

gary1365

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Great news
Rears don’t heat up near as much as the fronts that’s why the rears don’t warp.
 

robert106

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as others have said the actual disc is unlikely to be warped, as i understand it its more likely to be pad deposits building up on the surface of the discs in an uneven pattern, often caused by sticking caliper, but also sitting at a stop with the brake on etc etc,

you could try doing a re bedding in, ie numerous repeated stops form 70 - 30 , to try and clean the surface of the disc, but when i had similar a number of years back it was the caliper at fault (corroded and therefore sticking piston) and ultimately a refurbed one fixed the issue. (along with discs and pads. )
 
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