General Whistling brake - anything look wrong?

[larkim]

Drivers side rear brake is whistling / screeching after about 10 miles of driving. Its definitely the brake as applying the handbrake (gently) whilst driving causes the whistling to stop.

I've taken off the tyre and rotated the wheel and it feels like the pad is rubbing when the disc is in a certain position, so presumably the disc is slightly out of alignment? Or would this indicate a further problem? There didn't seem to be any play in the wheel at all.

Photos attached - anything look obviously wrong (apart from the fact they are filthy and apparently unloved!)

Thanks!

Matt

 

[wish mine was orange]

Had that prob on front pads. Friend told me to shamfer the front and rear edge with file. Worked, quiet brakes at least.

 

[MattB2k]

I have this problem today newish pads front and rear. Expect it will go eventually, on the plus side today I had roof off for the first time this year and that was wonderful.

 

[afroking]

I think your rear nearside disc is warped. It looks as though it has a fair bit of wear anyway judging by that lip.

 

[topher]

I have had a lot of problems with the brakes on my MG screeching, so I have done a fair bit of reading. If your brakes are killing your ears slowly then try the following:

If they are new, drive gently for 200 / 300 miles (obviously if you get in and do 300 miles on a motorway then they are not bedded in, do some more miles in town!), when you change pads, it is quite common for them to squeal at first but careful bedding in will mean this squeal will go away.

Back of pad - thin smear of copper slip - I use Mintex brake lube - also use on the sides of the pads where the retaining clips sit

Chamfer the edges of the pad - as already suggested

Remove material from pad surface - if the brakes are new and you dont bed them in properly, ie cook them striaght away, the glue migrates to the top surface of the pad - this is the shinny surface you sometimes see. Take some fairly rough paper and take 0.5-1mm of material from the pad surface until the shinny finish is gone

worn pistons - on older higher mileage cars, the piston can move from side to side as the seals etc wear. This can cause the ear killing noise, solution is to get some pad backing tape, its about 1.5mm thick and sticks to the back of the pad, the piston eventually cuts into the tape, thus the tape holds the piston in the same position on the back of the pad, stopping it moving

When putting the brakes back together, cleanliness is your best ally, get some brake cleaner spray, some fine wire wool and a bit of time and clean up all the pad retaining clips - use the wire wool (use as fine stuff as you can get)

For Mr Larkin, yep, sounds like you have a warped disc, it is worth checking that the rear brake isnt binding and causing excessive heat, discs can also warm when they are heavily worn.

Regards

Chris

 

[docorangepeel]

Take out the pads and clean the caliper and back of the pads first, next as Topher said above "A thin smear of copper slip on the back of the pad"

Also do two hundred lines on:

I should never let my Barchetta get so dirty, it's all my fault.

 

[topher]

I should never let my Barchetta get so dirty, it's all my fault.

Oh dear, I best not put up photos of mine, i will be doing lines for the rest of my life! I remember at school when I failed my French "Writing the time test", the teacher made me write out "The time is 5 minutes past one in the afternoon" but in French - and then again and again but in five minute intervals for 24 hours! It took me ages to do but I was great at the time after that - well not so good now, it did happen about 17 years ago now!!

Regards

Chris

 

[HP]

With the state of those rear discs, I'd put new discs and pads on with the copper slip as mentioned. They aren't expensive.

 

[docorangepeel]

We have standards you know !!

And before you say it I know I dont drive my Barchetta everyday and it sleeps on a bed of fresh silk in a climate controlled environment and all that heehhe but dirt is dirt hehehe

 

[afroking]

There's always one!

 

[larkim]

For Mr Larkin, yep, sounds like you have a warped disc, it is worth checking that the rear brake isnt binding and causing excessive heat, discs can also warm when they are heavily worn.

Regards

Chris

Thanks for the steer - interesting, as the discs / pads were new about 12 months ago (Fiat fitted too). What might cause warping? Excessive heat in the brakes I presume, but that's one hell of a lot of heat to warp a piece of metal that size. I guess they do get hot though.....

Anyway, thanks - at least I can sound remotely knowledgeable when I take it to the garage.

And my head is hung in shame for the dirty quality of the brakes - mind you, you should see the rest of B - with 4 kids under 10, no time at weekends, and using the B as a daily driver I'm afraid she doesn't get the TLC that others are able to lavish on theirs!

Matt

 

[topher]

larkim,

It could also be that the disc has a slight "high spot" due to corrosion, my daily drive often sits for a few weeks when I go away, when I come back the disc corrodes a little causing hogh spots. When i first drive it and push the pedal, i can feel the judder. It is always worse after salt has been down as it causes quicker corrosion. If you havent used it a lot, it is worth going for a good drive, and use the brakes a fair bit, get them nice and warm. If you are confident (or crazy!), get up to about 30mph and pull the handbrake (about half of what you would when you park it up) and leave it for 5-10 seconds, drive for another minute and do it again, careful not to lock the back brakes as you are not doing any good then, just being dangerous and scrubbing your tyres. Then the pads will just give the disc a good clean and remove any surface corrosion.

Chris

 

[Mad Matt]

I've only had a warped disc once and not on the Barchetta. I was told that there are two common causes:

1. Something which causes the brake to get too hot, like binding or in one case a fire caused by a binding and a broken brake line squirting brake fluid on to the already hot disc.

2. Lots of heavy braking and no lifting off the brakes. So, you charge up to the lights and hit the brakes at the last moment and keep your foot there so the pads keep the heat in.

OK, I'll be honest, the first one wasn't told to me it actually happened to me

 

[afroking]

Either the garage didn't wind the piston into the caliper enough and it is causing the brakes to bind, or the piston has seized in the caliper and will not return past a certain point.

 

[larkim]

B has been off the road for a few weeks whilst some corrosion ( ) work was done to get through the MOT (don't ask why it took a few weeks, crap mechanic!)

I still haven't sorted the whistling brake (will do this week), but I did come across a post which suggested that parking the car up on a slope with the handbrake on after warming the brakes up could cause the disc to warp slightly. (I don't get any judder through the pedals, so I don't think they are badly warped) I park the car on a slope diagonally with front driver's side at the highest point and rear passenger side at the lowest point. Intuitively (to me) this would put the most braking strain on the rear driver's side brake, which is the one which is whistling.

Is it really adviseable not to use the handbrake on warm brakes? I only ask so that I don't screw another disc / pad combination!

Matt

 

[afroking]

Cars have been designed to meet everyday requirements from its user, if you drive it like a road car then there won't be any problems. Like I said, it will be a problem with with either a seized caliper or the piston not being wound fully 'home'.

 

[doolahrock]

on the plus side today I had roof off for the first time this year and that was wonderful.

Amen to that. Went for a short drive and ended up having to fill up the tank.........twice

 

[alexces]

Hello,

I wrote on different threads and none responded me.

I have problems with the back caliper . The "hand brake" it's not working cause the lever which is actioned by the cable is blocked (see the pic).

The wheel it's not getting hot, and it's braking well.
What should i do to resolve the problem?

Thanks for your answer

 

[afroking]

You need to free up the lever some how, possibly a few taps with a hammer and some penetrating oil will do the trick?

 

[alexces]

You need to free up the lever some how, possibly a few taps with a hammer and some penetrating oil will do the trick?

Hello,

I'll try to unblock or move it with the car lifter and i'll see what else i'll destroy

Thanks anyway.