MK4 golf 1.6s 2001

Within the last week after driving for about 10/15 minutes when I apply the
brakes there is a what I can best describe as a tweeting noise fairly loud
and noticeable. It sounds as though it is coming from the rear of the
vehicle.

I took the rear wheels off the pads have had quite even wear on both sides
and about 50% used both sides.

The discs on both rears looks quite worn and have a lip on them.

Could it be the discs causing this auwful noise ?

Advice welcomed :-)

David wrote:

David wrote:

"Chris Bartram" <news (AT) delete-me (DOT) piglet-net.net> wrote

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.

"Blah" <blah (AT) hotmail (DOT) com> wrote

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

David wrote:
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.

"David" <none (AT) host (DOT) com> wrote

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.............

David wrote:

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.

Chris Bartram wrote:

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