Binding rear disc: Fix with a clean up?

[VAG-Abound]

Afternoon all, diving straight in with the first post...

When I changed the rear pads a couple of weeks ago I saw that the OSR was quite a bit more worn that the NSR. I didn't have time to do much about it then, but have kept an eye on it and noticed that it is grinding a bit and getting quite hot.

AFAIK all the parts have done the full 130k miles that the car has, so are perhaps a bit 'sticky'. I'm hoping to fix it up without a full refurb / replacement of the caliper, and that a good clean / lube of the guide pins and pad retainers (that I should probably have planned for when doing the pads ) will get things working again.

The piston winds back easily during the pad change, so I'm assuming it isn't in bad shape itself. If it's easy to wiggle then I'll maybe push the piston out a bit by working the handbrake mechanism, and clean that up as well. But maybe not...

All I'm expecting to use is wire brush and emery paper to clean up removed pins and extractor, and a bit of Ceratec lubricant on each of those to try and keep things moving nicely afterwards.

Can anyone think of anything else I'd do well to have to hand to make it go smoothly? Cleaner / degreaser maybe?

[VAG-Abound]

Although I was expecting to do this on Sat it was a nice enough evening to get it done already . Not sure I made much of a difference though .

The pads were wedged in very tight. After using a screwdriver to ease the outer pad away from the disc a spanner slipped in flat between pad / disc to continue nudging the pad out felt like it might snap! Inner pad was a lot easier, but still very snug.

Some crud certainly came off of things after removing the pad retainers, and after reassembling with a bit of Ceratec on the retainer tracks the pads slipped in and out a bit easier - but still tight.

The guide pins boots were intact with a smear of lube all around the pin, but I put a bit more Ceratec in anyway. One thing I did think was a bit odd was that there was more push / recover in the top pin - the lower one didn't have much 'bounce'.

Since the pad retainers were so tight I'm placing my bets on them being the problem, so I didn't bother doing anything with the caliper this time.

But after reassembly and a ten minute spirited drive up / down the road that tell-tale odour reappeared . Maybe just bedding back in?

[VAG-Abound]

But after reassembly and a ten minute spirited drive up / down the road that tell-tale odour reappeared . Maybe just bedding back in?

Actually seems a lot better today. Both rear wheels have similar warm rather than hot temp after 30 mile dual carriageway run.

Bit of a 'rumble' from somewhere though. Cooked bearing?

[discobarry]

I had replied to this with a nice post but i clicked the orange 'reply to thread' button! Anyway you figured it out pretty much yourself, we usually clean pad carriers up with the shims removed with a file. Clean them back to good metal and get rid of the build up which occurs over time. If the calliper piston winds back easily and pumps back out fine you don't need to worry about it being faulty as it won't be.

[VAG-Abound]

I had replied to this with a nice post but i clicked the orange 'reply to thread' button! Anyway you figured it out pretty much yourself, we usually clean pad carriers up with the shims removed with a file. Clean them back to good metal and get rid of the build up which occurs over time. If the calliper piston winds back easily and pumps back out fine you don't need to worry about it being faulty as it won't be.

Thanks for that. Good to know I'm on the right track.

I'm still sensing a bit of a rumble from somewhere, but having driven around with the rear window down for a while am less convinced that it is that bearing. Ah well, at least one problem seems to be solved.

[Teflon]

Look up "saw tooth wear" on this forum. It sounds for all he world like a bearing, but it's very common on Passats.

You might get away with four wheel alignment (my local Just Car Clinic uses a Hunter machine and charges £46, which is a steal). Swapping tyres around may also help, but on my Passat it made the dull rumble into a very noticable throb when the fronts went on the back.

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[VAG-Abound]

Look up "saw tooth wear" on this forum. It sounds for all he world like a bearing, but it's very common on Passats.

You might get away with four wheel alignment (my local Just Car Clinic uses a Hunter machine and charges £46, which is a steal). Swapping tyres around may also help, but on my Passat it made the dull rumble into a very noticable throb when the fronts went on the back.

That's interesting. Never heard of 'saw tooth' before. But it makes a lot of sense with what I'm hearing.

It's currently sitting on Bridgestone A001 all season tyres which were new last December. Would it have much effect after ~3-4k miles? Those tyres do have the 'spaced' design mentioned on this page about saw tooth wear, and a few of those other factors may have come into play as well ...

Getting summer tyres on was one of the jobs to do after getting the binding sorted, so that's be about now then . I'll be interested to see if it that changes things at all.

[VAG-Abound]

Quick follow up on this...

The above didn't fix it. Those pads wore unevenly and the OSR was gone very quickly .

I had been using reasonable quality ones from the local factor, but they were just pads and bolts - no new shims. Next time I got pads from VAG that had new shims and although it was hard work getting the new one into that OSR carrier (making me thing it was out of shape from corrosion or something) once everything was in the problem does seem to have been fixed. Those pads are wearing evenly and lasting longer .