Brake wear and maybe bearing issue?

[2226]

Something weird on my 2017 Cross Polo 1.2tsi. Or it might just be me.

Just over a week ago after a short trip from friend to home, <10km, I was greeted with a somewhat plastic-like burning smell with lots of pinking noises coming from the rear axle. A quick check revealed the rear right wheel putting out an enormous amount of heat. No glowing disc or pads, no crazy looking stress marks on the disc. It was however doing those overheated metal pinking noises.

I pulled the wheel a few days later to fix a flat and noticed the rear brake pads are way more worn down than the fronts.

The rear wheels also seen to carry a lot more brake dust than I'm used to on other cars.

Over the last couple of days I've noticed I don't really need to brake much either. Kinda just coast to a stop and I get that little jerk of weight transfer as you get when braking to a halt. And it doesn't roll back on slight inclines (hillstart assist isn't on when this happens), it just sits there.

Would a rear bearing really put out so much heat?
How long do these bearings usually last?

Is it normal for more rear pad wear on these cars? Or am I looking at a dealer con of simply replacing front pads and charging for all?

I'll pull the wheel and have a closer look later, but just curious if anyone had similar experience.

[2226]

I just jacked it up and checked. Handbrake released, wheel clear of the ground, and I can't spin the rear wheel freely by hand. Well I can turn it, but at that point I'm pushing the car forward.

38000km on it ... That doesn't seem like regular wear to me.

[2226]

Right rear parking brake mechanism was stuck. It's completely run down the pads. Don't know why VW funny change these at last service.

Well I suppose that's better than it being the bearing.

Should I just lubricate the mechanism?

[RUM4MO]

Bad news, all VW Group smaller cars can suffer from early life wheel bearing failure, but hopefully in your case, the bearing has survived getting heated up by the seizing brake calliper(s).

I'd be very cautious about just cleaning up and lubricating that/these callipers, I'd think replacing is now the only long term fix, along with pads and if really necessary discs - but you can easily check the discs for discolourisation, wear(thickness) and if they are still not warped - no or very little run-out.

Edit:- just for reference, I've just serviced the brakes on my wife's August 2015 Polo 1.2TSI 110PS and they rear discs are 8.5mm thick and the pad material is 8.0mm thick - that is at almost 3 years old and 31K miles/50K kms.

Another Edit:- maybe not too relevant, but as I've had that issue early in the lifetime of a 2002 9N Polo, instead of getting a new calliper fitted under warranty (the only fix that VW dealership would take), I cleaned everything up and fitted external "lever return springs" - and that sorted that out until we sold it at 13years and 105K miles. Having had that issue on that car, one of the first things that I did to her new Polo when she bought it in August 2015, was to order in and fit a set of lever return springs, now I think that the handbrake lever internal return spring is stronger on later cars, but I just wanted to stop this ever happening, and so at 31K miles and 5 years, the rear brakes are always free when the handbrake is off, so so far so good, plus every car needs its brakes serviced every two years, doing nothing and just waiting for a failure is a mugs game. In UK every VW Group dealership will only report on brakes during servicing and never perform any periodic maintenance on brakes - that is always an extra cost job and normally only reported when collecting the car after service, ie "book it back in as soon as possible" which is not what people want/need to do after having already lost their car for a day!
Typically it is the RHS calliper that seizes first, well for RHD cars anyway - as your is.

[2226]

Yeah, no, mine are not 8mm ... More like 2mm. I've been after some ebc pads and discs, so I think I'll check what they cost here. Probably a small fortune again, in which case I'll just have to give it to VW to sort out as there is still warranty.

Just not the biggest fan of dealership mechanics.

Until I can find a full day to be without a vehicle (MK1 is playing dead in the driveway) I think I'll loosen then up with lubricant for now. Once I'd released it it seems to be moving correctly, but it'll probably be stuck by the time I'm back home later.

Those return springs sound like a pretty good idea. Just have to see if there's anything like that available around here.

[RUM4MO]

I think that you will find that the piston needs fully retracting on that side, so remove the bolts lever the calliper out, probably need to lever the handbrake cable off first, or slacken the adjuster off quite a bit behind the handbrake "handle" first to get some free cable to let you remove the cable from the calliper lever. Then clean everything with brake cleaner, fully retract the piston using a calliper rewind tool, and take it from there - though buying and fitting a couple of external return springs and fitting them would win you more time.

LH Handbrake return spring 7M0 615 295 (from 1998 Sharan)
RH Handbrake return spring 7M0 615 296 (from 1998 Sharan)

Edit:- is the handbrake lever on the RHS not just "seized" because the piston has wound out and effectively applied the brake on that calliper?

[2226]

Yes, I'm thinking it was just wound out too far. It hasn't stuck today after releasing it.

Not too happy running with such low pads, but I'll only be able to sort out this Saturday. Should have springs by Thursday or Friday. Friend has a rewind tool. Just need to get some pads and rotors.

I ordered the 295A and the 296 listed for the Polo. Only about 7 GBP for the pair.

[RUM4MO]

Just one thing, these springs were never intended by VW Group to get fitted to any of these small VW Group cars, like Skoda Fabia, VW Polo, SEAT Ibiza or Audi A2 or Audi A1, so I would not have expected any VW Group dealership parts department to refer to them as being for a Polo, not as far as any Polos sold into European markets.

There were two versions of these springs that lots of people bought for this task on Fabia, Polo, Ibiza etc, and they were springs that were fitted to Ford Galaxy, VW Sharon and similar SEAT MPV, they fitted best, and there was the version fitted to VW Vento/Jetta notchbacks, they did not fit as well in my experience - I bought both versions to find which was best.

When you quoted the part number 295A and 296 it sounds like you have bought the Vento/Jetta version. I'm sure that you fully understand the way that VW Group give numbers to parts for their fleet - 295 and 296 only means that they are rear calliper return springs, the "odd" number meaning the LHS one and the "even" number the RHS one, it is the first 3 letters-numbers that fix which version they are.

[2226]

Yes, aware of VW part numbering.
Picked the numbers off ETKA.
That's before I spotted your numbers.

If I went and ordered the wrong ones then I'll order the numbers you gave. At these prices it's not a train smash error I've made. I'll still get the pads and discs replaced this weekend and then fit the springs when they arrive.

[2226]

Got the rear brakes done on Saturday. Longest rear pad replacement yet. Took over 2 hours. I battled a bit trying to pry the calipers off the carriers as they were just wedged up against the pads.

Copper greased the mating surfaces, brake cleaned as much as I could, and decided to try out Ate plastilube on the pad backs and the pad guides. Will see how that works out. Never used it before as I usually just run a little copper grease on them.

Picked up the springs from VW today and just fitted them. Went in without an issue. I was concerned about your 7M0 part compared to the 7H0 I ordered, but looking at the following page they look like the correct thing:

http://www.users.on.net/~graeme86/handb ... brake.html

They fit snuggly into the cutouts. Can't quite tell what the difference is. Will find out when they fall out.

Everything is bedding in nicely at the moment. No more dragging.

I completely forgot to run a little lubricant under the seals though. The right rear piston let out a little pop when I started to wind it back, but beyond that point it went in smoothly.

The rear right bearing, however, feels like it doesn't roll as freely as the left. Damage done from the heat I guess. A job for another time.

And what's with the 8mm Allen socket back there? I'm accustomed to getting out the 6mm and 7mm, so it took a good 20 minutes finding a 8mm in my "organised" garage.

[RUM4MO]

8mm Allen key, I'm guessing that you were meaning the rear calliper carrier to hub fixing bolts, I've not needed to take them out of a 6C Polo yet, but I would have expected them to be maybe M8 Spline, as that is what they have always been in earlier VW Group cars.

I'm glad that the alternative springs are working, now that you have said that they just slipped in, maybe that was why I avoided the Golf/Jetta/Vento ones and opted for the slightly "tighter" MK1 Sharan ones, but if they do the job required, good enough.

My older daughter's late 2009 SEAT Ibiza SC, which is a very close relation to these Polos, had a horrible sounding rear bearing - I only discovered it while cleaning out the rear brakes, it sounded like a ball bearing was missing, the UK MOT yearly test never commented on it, and when I cleaned its brake up maybe 6 months before she sold it in 2019, I'm not sure that that bearing was still "sounding bad" - self healing bearings, if only!

[2226]

I don't mind the Allen bolt. I'd have called it quits of it was an odd spline drive in there.

Well, when I said slipped into placed I meant they fitted into the cutouts as expected. I used a bit of rope to pull it into place on the right side (had to use my left hand) and then a went by hand on the left, but it took a bit of force to compress at that angle as I just crawled between the car and garage door to get access.

I suppose I didn't need to remove the carrier, but I did anyway to give it a good clean.

Guess I'll do the front next. I noticed they have a lip to them. I'm sure VW will have words when the next service comes round.

Still don't trust the caliper though so I'll keep an eye on it.

[RUM4MO]

Good, if I'm honest I have forgotten if the Golf/Jetta/Vento - Boro(?) version was stronger or slightly weaker than the preferred Sharan ones, it is a slightly curious that there is the ability to fit external lever return springs, but they are not fitted, I ended up guessing that for these shorter cars, VW Group thought/hoped that there would be less drag in the handbrake cables so left them out.

I'm surprised that the discs,front and rear, (and pads wear) in my wife's 34(?)K miles 2015 Polo are still in such good condition as rock salt is used on the roads in winter - I'm think that the brakes on that car will easily survive another 2 winters in UK before I replace them. It is normally heavy rusting up of the swept area on the inner faces of the rear discs that forces replacing them - though UK annual testing, ie MOT normally does not fail them as rear braking effort requirements are so low.