Noise from rear when turning left

GTE

Howdy,

Shall try to keep it brief. 00 Golf. I was told that the rear brakes seem to stick but that it was nothing serious.

A few thousand miles later, I am getting a tone like sound from the rear left when turning left on a motorway. Applying the handbrake gently makes it go away and I sense that there is small amount of handbrake lever travel where there is a "snag" or extra resistance.

I'm going to take a look with the wheel off tonight or tomorrow but I'm just looking for pointers on how to fix a sticking brake or diagnose any other causes.

Thanks!

YbFocus

Brakes sticking is always serious BBK, huge heat build up over time even with the smallest amounts of friction.

Usually in these scenarios you will have cooked the wheel bearing.

That's what it sounds like here, it should show itself as a noise that raises in pitch with speed and can come and go as you load and unload that wheel (Turn left and right).

I would be almost completely certain that the bearing is gone. If you jack the car up this evening or whatever, just grab the wheel and see can you shake it.
If there is any play, even miniscule, your bearing has been burnt out by this excessive heat.

With sticky brakes you can warp discs, glaze your pads and destroy the piston in your caliper. Never leave anything wrong with your brakes go on the long finger

Not sure whether your car will have rear drums or discs but check for excessive pad wear right and left to see which caliper/cylinder isn't releasing.

Most of the time with sticking brakes you need a new caliper or cylinder to fix it as the moving parts have become rusted over time from the seals going.

Anyways,

The humming noise will be your wheel bearing and it'll likely be a sticky caliper causing your problem.

GTE

Thanks for the reply.

It hasn't made the noise since during test drives and the tone definitely didn't raise or lower in pitch which would make sense if its a rubbing of the disc. Discs at the back. No play when jacked.

Peaking through the wheel hub, there is 1 or 2 mm of rust on the outer edge of the disc face.

Good advice which should be heeded regarding not putting brake work on the long finger but at least for me the issue popped up towards the end of the last required journey for a while.

YbFocus

bbk wrote: »

Thanks for the reply.

It hasn't made the noise since during test drives and the tone definitely didn't raise or lower in pitch which would make sense if its a rubbing of the disc. Discs at the back. No play when jacked.

Peaking through the wheel hub, there is 1 or 2 mm of rust on the outer edge of the disc face.

Good advice which should be heeded regarding not putting brake work on the long finger but at least for me the issue popped up towards the end of the last required journey for a while.

If you're seeing rust around the disc edge just have a feel and see is it developing a lip. If so then your getting near the end of the discs life.

You'd know if it was a wheel bearing as it's a prominent noise so I think take off the caliper and look at the condition of the sliders and the piston.
See if the sliders are clean and not rusty looking. Check does the piston turn back ok (rear pistons must be turned while being pressed in, not sure if you know that).

If there is a lot of force against you while turning back the piston then you probably need a rebuild kit or the easier option, just get a caliper.

GTE

Without knowing the lingo, there are two bolts on the rear callipers which act on each end of the two pads. The sliders mentioned above? The bottom bolts on each of the rear brakes were rusty and dirty internally and not freely moving so the pads were always in contact with the disc. It was extremely difficult to take the pads off too, down to dirt and rust. Also, the rear left piston was stuck but thankfully, with some messing around it was freed up.

I got a mechanic friend of mine to do them, while I watched and I learned a lot. We had the help of an air assisted winder for the pistons and judging by how stuck the rear left was, I would never have been able to manually free it up. I was told that it may have stuck because the piston very rarely travels that far and there was nearly nothing left on the pads.

Looks like it just needed TLC after 14 years of life I can take extra care to look out for the issues if I ever have to delve down there again. The back plates are also not looking too good so we will see what the NCT says about them.

GTE

To recap my waffle from before, the pads were changed and on the rear left the calliper piston took an extreme amount of effort (with the help of a persuading bar) to wind back. Once it got going, it was moving smoothly. It had been stuck as the pads were worn right down.

Brake sticks again
After a short to medium drive, enough to get things heated up again, I checked the rear and the rear left was very hot so it looks like the calliper has stuck again.

Am I right to guess that the calliper needs fixing/replacing or are there other things I should check? I have already been tinkering with that brake as the new pads were fairly tight and stiff so I did some thorough cleaning and they slide in and out well now.

There was no noticeable heat from the right rear and I helped install those pads myself so I know they were not too tight a fit.

New or used
It is a project I am chomping at the bit to do now, so I am wondering if breakers yard callipers from a newer MK4 Golf/Bora would be recommended or not. Local factors are quoting 130 for a new unit, which I do not mind paying but I could really use with keeping things cheap. This ties in with the next point about the initial cause of the issue so maybe I do not need any new bits or a used bit would not be too much of an issue.

Handbrake
It seems odd to me that both back brakes had gone through pads extremely quickly. Would I be right in saying that rather than both callipers giving trouble that the handbrake is too tight? Pad rubbing resulted which cooked a calliper. The sliders were fairly stiff on both sides though.

Brake Bleeding
If a new calliper is required, any advice on bleeding the brakes? I was thinking of clamping the brake line if there is a rubber section and then bleeding the brakes. Would there only be the air at the section of the pipe and new calliper that I would have to worry about? Is there a specific kind of brake bleeding kit I need for my Golf? A mechanic before messed a brake fluid change and blamed it on some quirk of the MK4 Golf. Suppose a vacuum based bleeder would be very handy for a one person DIYer.