Do I need new brake disks?

gilbert_and_sullivan

Squealing is often the result of very high frequency vibration between the pad backing plate and the piston, a wipe of coppaslip on the backplate can often cure it.
Also caused when that similar vibration rubs the edge of the pad backing plate against the guide edges of the caliper body, you can sometimes see the results of this if yoy remove squealing pads, if there'e a shiny point on the edge of the backing plate thats sometimes where the noise is coming from.

Did you push the push the pistons out and push them back a few times to make sure the pistons arn't seizing, and did you clean and lubricate the sliding mechanism if the design has one?...another source of squeal.

londonTiger

I actually didn't do anything to do with the calipers. I was going to change them, but after seeing there was plenty left, I just let thyem as is.

Though I sprayed penetrating oil through the wheel onto the bleed valve - although I was super careful to not get any penetrating oil anywhere near and doubt any penetrating oil dripped down (it was a spray can penetrating oil).

So don't know why the noise has gone???

gilbert_and_sullivan

londonTiger wrote: »

I actually didn't do anything to do with the calipers. I was going to change them, but after seeing there was plenty left, I just let thyem as is.

Though I sprayed penetrating oil through the wheel onto the bleed valve - although I was super careful to not get any penetrating oil anywhere near and doubt any penetrating oil dripped down (it was a spray can penetrating oil).

So don't know why the noise has gone???

Braking systems are often neglected which is ironic as it is the most important part of a vehicle barr tyres, and subject to the most horrendous abuse.
From being battered in debris, wet for much of the year, bathed in salt which is left to cake on for months on end, when used in anger there is enough heat generated to boil saucepans of water and those boiling hot discs can be plunged into a flowing ford of water for instant cooling, miraculous just how resilient the system are.

Despite all this, the modern technicians idea of a brake service is to peer through or from behind the wheel at the fraction of pad thats visible in a small section of profile, squirt with brake cleaner, and pronouce all is well for another year or two of the above abuse, neglect no other word for it.

You cannot judge what condition brake friction materials are in unless you remove the things and examine them properly, that goes for every one, i've seen friction material fall off when pads have been removed due to excessive corrosion between friction material and backing plate, only the close tolerences in use prevented the things from disintegrating in use.

In many cases its very difficult to see the rear of the brake disc with pads fitted if it has a rear dust cover, time to check the disc rear surface is whilst pads are out in such cases.

You cannot judge whether the system is working correctly unless dismantled, a caliper slider could be seized and every application of the brake forces the disc over instead of pinching it with equal force from both sides.

Whilst pads are out, the pistons should be pumped out a little way (careful, leave something like a pad backing plate in situ to prevent the piston popping out too far) and if possible a small amount of correct brake grease applied as necessary to the visible piston before pushing home, the effort required to push them home should be minimal and all pistons require similar effort, anything requiring excessive force needs investigation.

Any caliper sliders should be cleaned and lubricated properly at the same time.

Reassemble with any new parts as needed applying a drop of Coppaslip to the backing plate if fibre type pads are not already bonded to the backing plate, also making sure the retaining pins/clips are in good condition .

Now's the time to bleed the system if needed.

The prudent owner also cleans and examins the brake flexible hoses and brake pipes for perishing corrosion and damage, and applies some grease to the exposed brake pipes before putting the wheels back.

eddie864

My experience tells me to not scrimp on pads. Go for a decent brand, clean up discs and piston surfaces as best you can. Same with brake fluid, you don't use much so buy a top brand of at least the correct grade or better. After the eezi bleed get the missus to pump and hold and go through again manually.

Westmead_Fan

best thing with brakes do not go for aftermarket brands, i go for Pagid pads & always use cera tec never copper grease i have never had brakes squeak but with copper grease they can squeal. if people know how to fix things like this & do it properly you will save alot of money on your vehicle & for me i enjoy fixing my vehicle & to learn on how it works.