I have the Brembo brakes on my XKR and there is a hideous high pitched squeak when stopping, especially slow stopping. There seems to be plenty of life left on the pads and I have tried to re-bed them multiple times, squeak stops for a bit then comes back, mainly from the rear. Just curious, is the squeak coming from the pad, rotor, or both? I've read up on this a bit and do not know if all the bolts were replaced when brakes were done, to be honest don't know if the brakes were ever done, car has 55K on the odometer.

 

All brake squeak, squeals, howls, etc are caused by vibration. Pull the pads, sand the face, apply anti squeal compound to backing plate, reinstall pads, then burnish the pads by accelerating on a quiet road to approx 50 mph then medium brake down to approx 20 mph, then back to up 50 mph, and brake again etc 15-20 times. Be careful not to overheat the brakes, a light heat haze from the brakes would be normal when burnishing is completed.
Squeal, squeak should be gone.
Regards,

 

Ahh, you brought up something I had not thought of, vibration....My rear shocks are 120%+ shot, have a new set ready to install just have not had the time. Perhaps, this is causing vibration causing the brakes to squeak. Sound plausible?

 

Carefully check disc faces (inner & outer) in case one is not shiny bright metal. In that case you have a sticking caliper piston(s).

 

My 2006 XK8 started doing this in the endless stop start traffic on the border crossing from Spain to Gibraltar. At the time I thought it was just the unaccustomed heat but it persisted intermittently on the 1800 mile journey home to England.

I found two contributing causes:

1. pad back plates binding on the chrome 'slippers'.
2. distorted pad retaining pins

Unlike cast iron calipers, the aluminium Brembo calipers have chromed 'slippers' where the pad back plates sit (one side arrowed in red in the photo of my front RH Brembo caliper).



If the steel brake pad back plate was directly onto the aluminium caliper it would soon wear it away.

The brake pads must move laterally without binding. Check if the 'slippers' need cleaning or polishing. Jaguar recommends application of Molikote 7439 copper grease to the shoulders of the brake pad backplate:



I was used to the strong pins fitted to cast iron calipers but the Brembo pins are very thin by comparison and can bend. Two of mine were distorted so I replaced the complete vehicle set.

The squealing disappeared and never returned before I sold the vehicle a year later.

Graham

 

Looks just like mine (*). Good pics & info. I never knew a name for them.

(*) er, except the pins look thinner than on mine (odd)

Probably worth taking pads out and gently cleaning off any build up of (muck - brake dust plus grease plus who knows what) in the caliper (esp. those slippers) then small amount of copper grease. Clean the clips & pins as well.

 

Have you got OE Brembo pins fitted? The replacements for mine were a truly terrifying cost.



I could see no logical reason for them being machined to a smaller diameter in the centre and at the inner end. It just weakens the structure and makes it more prone to distortion.

Graham

 

On newer cars it looks like Brembo did away with the thin area. My 2013 Mustang Brembos have a near constant diameter pin that doesn't try to center the spring...at least I don't remember a thin area when I recently swapped pads. The new pins have a head and knurl to retain them in the body and the spring floats on the pin, rather than the pin floating in the body.

The one thing you have to love about Brembos is the speed that pads can be swapped.

At a recent autrocross school I attended, there was a Brembo equipped Mustang with HORRIBLE brake squeal. 1/4 mile away you could hear him braking for a corner. If they squeal, its loud.

 

GGG,
Your own drawing makes it clear why the pin is machined narrow at that point. Spring clip #2 fits into the narrow section effectively locking it into place, not allowing it to move in or out. If I remember correctly there is also a small shepards crook style retaining clip (Jesus clip) is also used, but it is not shown on your drawing. Italian version of belt and braces (suspenders)?
Regards,

 

I believe I have. I had to replace (or rebuild) a front caliper and found I could not shift one of the pins on my bad caliper so got a used caliper off ebay. Same pins etc.

Are the STR calipers & pins the same or just very similar? Maybe bigger.

Is the middle thinner to seat the spring clip?

The pins in the photo look much longer than mine - mine don't stick out much at all. Mine look rather like the schematic, i.e. very short and not much thinner end part.

Just went and grabbed a spare pin from the bad caliper. It does NOT look like the ones in the photo (the one with the red arrows). Shorter, hardly sticks out, and fatter. Has the narrower middle. The end without the spring clip is slightly tapered for 3-4mm (and bashed a bit due to my struggle to remove the pin).

You can just about see the pins in this ebay listing and they look like mine (in shape, can't say actual size) FIAT COUPE 20V TURBO BREMBO CALIPERS BRACKETS AND PINS | eBay

The attached is close, not sure identical.

 

"a truly terrifying cost", could you quantify this, just curious.

I am going to fiddle with the brakes next weekend, getting ready to head outside and replace the auxiliary intercooler pump.