Well, my front brakes are squealing again. I fought a long hard battle last year and thought I had defeated the demon, but its finally returned. Thankfully, it's not nearly as terrifyingly loud as it was last year...for now. Anyways, here's a rundown of what I've done/replaced:

-3 different sets/types of rotor/pad combinations, including ceramics and drilled/slotted
-Tried another used set of calipers
-New wheel hubs/bearings
-New Caliper brackets
-New Caliper slide pins
-New Caliper pistons/seals/boots
-Complete fluid flush with Pentosin Dot 4 LV Class 6
-Tried every kind of brake grease, CRC disc quiet goop, spray, etc, you can think of.
-Tried every type of breaking-in procedure you can think of.

So as you can see, I replaced practically everything and still the noise persisted. It wasn't until I finally installed OEM style Jurid pads (dirty as hell but excellent stopping power) and blank Brembo rotors that the noise was silenced. But even then, every once in a while there would still be a squeal here or there. But now its back on regular basis AT. EVERY. STOP.

I just finally got the engine running at its full potential again and these damn brakes make me want to throw the whole car away. What am I missing here? Surely with the forum's combined knowledge we can rid ourselves of this evil once and for all.

 

And yes, I have recently inspected the pads and rotors and everything seems fine with plenty of material left.

 

Nothing, huh?

 

Since the squeak has returned, have you tried applying grease/brake quiet on the back of the brake pads where the caliper pistons press against them? That is the most common fix for squeaking brakes and would be the first thing I would try. I know you said you applied the grease before and it didn't help, but it isn't clear if you have tried it in this instance since you changed the rotors and pads a year ago.

 

Can I make a suggestion which we used as a matter of course on rally cars. When you replace a set of pads go out and get them really smoking this brings all the glues and waxes out of the pads. When they have cooled down take them out and put them in a vice and attack them with a file till you have a very rough contact surface,( I have used a wood rasp)!!. This was always successful, if at sometime later they start to squeal again you are getting brake dust, and probably just wobbling around town ,rather than giving them a bit of a workout, or run a softer pad.

 

Yes, I did apply grease and the CRC goop again. They were quiet for about 2 and a half minutes. That stuff just doesn't go anything for me. Thanks for the suggestion, though.

I had tried something similar in the past and it would only work for half a day or so. I do believe this squealing is a product of my daily commute, during which I am forced to constantly drag my brakes (traffic is not quite full stop-n-go, but still too slow to just let the car coast without braking). However, I've had this same commute for nearly 10 years and the squealing has only become a problem within the past 2. Thanks for your suggestion and input.

 

Here's a question: as I mentioned in the first post, I rebuilt my calipers. Before that I had tried a different set of used calipers. Both sets still produced squealing. Am I wrong in assuming that the actual caliper bodies themselves don't get worn out, just the pistons/boots/seals/pins? Are the calipers themselves lifetime parts or should they be replaced eventually also?

 

Certainly is your slow speed issue. The other quick fix is to buy a sheet of Teflon Bar B Que paper the stuff they sell at home depot etc, cut that into a shape which will fit between the pad and the piston contact area, this will work like an insulator, you can still get the pads red hot and not damage the teflon. Squealing pads are caused by a resonance either from a shiny pad face or from transmission of very rapid vibration of pad on disc. But realistically the car is not being used as designed, Maybe buy a little runaround something for 1000$ to drive to work??? , c ,a, b,

 

I'll try out the Teflon paper, thanks.

If being in traffic is not using the car as designed, then Jaguars shouldn't be allowed anywhere in Los Angeles! The Jag is what makes the commute bearable. Besides, at its amount of mileage, the Jag isn't far from being a $1000 beater anyway.

I'm not so sure it's a glazing issue anymore because the squeal doesn't stop while hitting the brakes hard. Something about the positioning and alignment of the pads, rotors, and pistons isn't right and its causing excessive resonance. But everything is snug and tight upon inspection. I'm stumped.

I'm guessing from the lack of replies that no one has ever heard of the actual caliper bodies themselves degrading.

 

I do not drive some of my cars often. The Jag and Audi can sit for weeks.
Replaced Audi pads and rotors and had the light pedal pressure squealing. This was with Meyle Canadian pads. Replaced springs boots, pins, and backing, camferred the edge of the pads, roughed up the pads, and turned the rotors.
Finally through the Meyle semi-metallic pads away and replaced with TRW. No squeals.
The previous owner replaced pads and turned rotors on my XJR as a condition of sale. I asked what brand and either one of us cannot pronounce the name correctly, or I have never heard of them.
Replaced the rotors last year, they may have been original at 105,000. The pads he installed are dead quiet on original thin rotors and a fresh set of AC Delco elcheapo rotors.
I think another set of pads may fix your issue.

 

I've got Jurid pads up front and Pagids in the rear. They're very similar to TRW and I believe they have both been used as Jaguar OEM pads at some point. They both have a nice rubberized shim on the back. Like I said, they were fairly quiet since I installed them about a year ago. Only recently has the squeal returned. There's so much pad material left, I'd hate to just replace them. Even if new pads did the trick, there still must be some other issue causing premature squealing on these fairly new pads.

Thanks for your input, Panelhead. If I do end up switching pads again, I'll try the TRWs. Did you use semi-metallic or ceramic?.

I wish you could try out different pads and return them if you don't like them

 

I would suggest you dont use Ceramic, they need way heat to get them working ,otherwise you will had a "Dead" pedal, . TRW equipment has always been some of the best in the world, they may do an "Organic " pad which for your purpose would be fine, I would suggest.
My suggestion that the car is not designed to drive to work in , I really was inferring that the Jag was designed to do more!

 

Thanks, Barney. I'll definitely check out TRW should I go that route.

 

UPDATE.

I replaced my subframe bolts due to a loud knocking clunk I was getting at tight corners and grade changes. Not only did the new bolts solve my clunk, but it significantly diminished my brake squeal! I guess the additional vibrations from the loose subframe was agitating the harmonics in the brake system. Its not gone 100% but I'll take anything I can get.