309 front brake squeal

[Gsbx1220]

Ok,

I have persistent brake squeal on our 309 DTurbo. This only occurs on very light braking.

To rewind a bit we replaced front pads and discs mainly because the front right pad set had significantly more wear than the left. The calliper sliders on right were binding.

Car uses Girling callipers

On fitting the parts, I freed up (or I thought I had) the sliders. After the first test drive the front right wheel was considerably hotter than the left by a good bit, and it had that horrible acrid brake smell. I stupidly thought that the pads were just bedding in, and drove it to work the following day, 20 mile return. Brakes were squealing slightly at this point on right wheel and squealed more depending on steering angle. Brake smell was still present, but not as strong.

Still the same, so took everything apart and as suspected the slider was still binding. Decision was made to fit new aftermarket callipers.

Callipers fitted & brakes feel so much better than before, but the squeal was there under light braking.

Pads are Febi ones https://www.gsfcarparts.com/products/feb16242 they have a rubberised backing. No anti squeal shims were on the original pads.

The pads are fitted correctly with the anti knock springs on the inner part of the calliper piston side with the anti knock spring hooked over the lower retaining pin as per Haynes manual. The retaining pins have also been changed out for new ones.

I have taken it all apart, re-greased with ceramic grease, still same, so tried old fashioned copper grease, that did not work so I took the pads out and chamfered the edges using a file to brake the hard edge on the friction material.

Only thing I can think of now is to try a different brand of pads.

This is driving me up the wall!

Any Ideas ??

Cheers


Richard.

[mickthemaverick]

Did you clean the new discs thoroughly with brake cleaner before you fitted them?

[PaulC5]

Did it squeal on the old pads ? Were the discs a good make ? If you did not get the noise before then it is likely the pads. A search on Febi pads comes up with a few topics on Febi pads and noise so maybe it is the material they use. It also looks as if a piston might have been seized on the old calipers.

[Rp0thejester]

Adding to what has already been said, have you fitted anything to the wheels, like anti dust guards to stop the alloys getting dirty or put hub plates on etc....

[Gsbx1220]

Hi.

To answer all questions,

The discs were thoroughly cleaned using brake cleaner, the old pads did not squeal in the original callipers, but the new pads did squeal in the brief time when fitted in the original callipers. I put that down to the sliders on the calliper being not particularly free. No dust guards etc have been used.

Pads and discs I fitted are if Febi brand.

The original callipers were not that great. The left one had the bleed screw snapped off, and someone in the past had put a screw in its place, which the head had snapped off flush with the calliper body, so impossible for me to bleed.

We bought the car in November, and the owners had the car in a garage on October to address binding on the right. The invoice states that the calliper was stripped & rebuilt. No way that this happened! That’s why we fitted new callipers.

[mickthemaverick]

You said you tried copper grease. Did you apply it to the tips of the pads where they rest in the calipers and onto the back of the pads where the pistons make contact?

[Sloppysod]

I assume you have put them the right way, the low pad warning wire usually goes inboard? And is it both sides or just one that squeals?
Also, how is the right wheel bearing?

[Gsbx1220]

Hi,

Yes. The pads were greased on backs & contact edges. I originally used ceratec ceramic brake grease on them, but wondered for some reason that grease wasn't good enough. I use that on the moderns with no issue and on my BX & GS OK. Stopped using copper grease on brakes years ago, but gave it another go here.

Pads have been fitted correctly as per the Haynes manual. There was an up-date to the pad fitting procedure at some point in the past & new pads incorporate anti knock springs which are fitted on the inner, piston side & these springs hook over the pad retaining pins. The pad with the wear indicator wire is now fitted on the outer. Again, this is documented in Haynes as a revision. The anti knock springs were at one point sold separate & could be fitted to earlier pads, but like I said are now part of the pad.

Wheel bearing is OK Went through MOT last week & feels fine.

What is at the back of my mind is that the new pads on right got over heated with the bind & are now cooked. I know it was only a couple of short drives, 40 miles max.

Picture of pad fitting below

[mickthemaverick]

In view of the info re the springs, did you grease them where they hook over the pins?

[Gsbx1220]

Yes, All metal-to-metal contact points have been greased

[Sloppysod]

If pads could have possibly been 'cooked', recut the surfaces with a rough grit paper, possibly do same with the rota/disc, to remove the glaze.

[PaulC5]

If pads could have possibly been 'cooked', recut the surfaces with a rough grit paper, possibly do same with the rota/disc, to remove the glaze.

I use 180 grit emery paper on the discs and pad friction material to clean them up and on the pads use a file around the edges of the friction material to take off the sharp edge. The pads should be able to slide into the caliper without being a tight fit so if needed I run a file around the metal to remove any sharp bits

[Gsbx1220]

The car has done a good couple of hundred miles since the overheat with the original callipers & the fitting of the new.
Surely any glazing of the pads would have been removed by now.

I think that I may have given them a quick going over with some sandpaper when I broke the sharp edges on the pads with a file, but I can’t remember.

In the back of my mind, I am still sort of tempted to just cut my losses and buy a new set of pads. It was mentioned above that the Febi pads are reported to be noisy in reviews. I have since read the same, so with that coupled with the possibility that the pads may have been cooked, I am tempted.