Tweeting noise

Possibly a partially seized rear caliper, which is by no means uncommon.

Any 'anti squeal' grease been put between the piston and pad?

Morning Chris (I've been a silent fan of your VW guruness)

Not being to mechanically minded the caliper is the part of the brake system that pushes the piston out to push to brake pad to stop the car right. I did change the front disc and pads about 2 years ago so am a little familiar with the setup on the front, but the rears look a bit different with the handbrake cable bit. Looks like it all comes off the same though.

I was hoping it was just something to do with worns discs.

Is this a job I could do alone as I did do the fronts have all the tools even a rewind tool and a set if barely used axle stands :)

I guess my next question is how do I determine which caliper is partially seized. Is freeing a seized caliper a job of working something to and fro or is it new caliper time ?

If it is new caliper time does this mean I need to bleed the brakes after ...so I would need an ezibleed doodah

hmmm seems many questions but I would like to have a go at this myself so any help is always much appreciated.

When I had the wheel off I didn't see anything like cooper slip or anything clear like on it.

Thats your most likely squeek site then, the pads vibrate against the discs, but this is asbestos to metal so no noise, the bit that presses against the piston is metal, so metal to metal rings like a bell.

Of course this may be a red herring, could be a wheel bearing shuddering under braking.

I've had several instances, with various vehicles I've owned, where the pad becomes held firmly in it's recess by a combination of road dirt and rust, the symptoms of which have been christened by the family, "dicky bird wheel" - rather similar to your description of the problem you're experiencing.

Solution is to remove pads from recesses clean out rust from both recess and end of pad (without damaging piston seal, or removing metal from either component). I then apply a smear of grease to the recesses in the calliper, to give some protection against further build up rust - smear of grease only, leaving only a sheen on the metallic surface, not enough to melt and to come into contact with the disc or piston dirt seal.

If the piston is seized in the calliper, I've never had much luck with that scenario personally, as the piston is usually corroded externally, leaving pits, which rapidly rip the seal into ribbons as it is forced into retraction. In this case it's new calliper time.

My bet is the pads seized in the recesses. Don't bother too much which brake, if one is squealing, the other likely isn't too far behind.

The disc wear, whilst undesirable, as no doubt the MOT man will explain, isn't likely to be the cause of the noise. With the pad in constant contact with the disc they overheat and are forced more into contact by expansion and a vicious circle is set up - more pressure, more heat etc.............

Blimey. Wouldn't say I'm a guru, just interested and slightly mecahnically minded.

Oddly emough I've never had a set of rear calipers apart! I will doubtless have to soon with our Lupo. Anyway, it should all be similar to a front, with the exception of needing a rewind tool.

You should just get away with taking it off, cleaning up anyting that moves, and putting it back.

jack the back up and spin the wheels. You might feel one dragging. To be honst, it's best to do the pair.

If you did fit a new caliper, then a eezilbleed is strogly reccomended.

Oh, take some note of the post below by Rosie too.

Heavily worn discs do cause noise, the lip touches against the side of the pad.

:)

Aparantly after some research along with a rewind tool it is advised you undo a bleed nipple (never done this before) then use the rewind tool to not force brake fluid the wrong way up the abs pump... but many have said they didn;t and it went back fine.

Thats my first port of call on Wednesday when I have some free time. Got some nice buttery smelling cooper grease to use today :)

I was planning on changing the discs and pads whilst it all apart for good measure as the discs do need doing. I don't want to use the old pads even though they are only half worn I may aswell put a new set on with the new discs for good measure.

I'll pick up a eezibleed doodah if I need a new caliper. I'm optimistic that after a good cleanup of the hub and greasing of the hub and back of new pads and the fitting of new discs it all works out well. A little nervoud of touching this bleed nipple thing as scared of introducing air to the system. I'll get one of those brake flexi clamps if I need a new caliper.

Thanks for the input all.

Thanks alot for the post Rosie it was very helpful!!

Loving the term you've given it dickey bord wheel I'll remember that one :)

Thanks for the post and will post back results once I get it all stripped down.

If you're squeezing the cylinder back at the same time there's no chance of introducing air.

That's reccomended for ABS-equipped cars, and in the past I've always dome it. It's not much effort and it probably gives you extra peace of mind regarding the (expensive) ABS pump.

However....

If you read the official manual for our Lupo, when changing front brake pads it just says to push the piston back, so I just did that. It was fine.

Mind you, it's had a recent fluid change. The reason for undoing the bleed nipple is twofold: you keep old, potentially dirty fluid away from the pump, and you don't apply reverse pressure to it.