2009 XF non s/c
55k milies on it currently
had new pads and rotors installed 11k miles ago.

went to a non dealership many recommend in NY.
He said "all good" u she change yr front pads but the rotors are fine.

Now when coming to stop signs- lights etc - squeaks squeaks making me nuts.
I called him said "are u SURE THESE PADS ARE OEM JAG" he says yes.
another place says one set of rotors she cover 2 sets of replacement pads.

should he have "turned" the rotors- or used some type of grease on back pad?
He is supposedly a wizard on jags on this board in ny area.

Jaguar has changed JUST pads and no squeak…

any ideas?

 

jwmciti, you will get lots of varying ideas on this subject. So, this is my thought process on things and you can take it for what it is worth. If you brake and the steering wheel does not wobble back and forth, then turning the rotors is not required as they are straight (ie, not warped). A lot of shops will recommend turning the rotors regardless because turning rotors removes the most amount of metal of anything that you will do to the car and that means they will be replacing the rotors sooner, making them more money in the end. The exception I have to not turning the rotors is if you can run your finger nail from the center to the outside edge and feel your finger nail catching on the rotor (ie, over a 1/32" ridge). But then, ridges should only be formed when you drive for too long on the pads and you reach a point where the rivets in the pads come in contact with the rotor.

As for squeaking, I have a product that I recommend to you. IT is called "Stop Squeak". You can pick it up at any auto parts store. It comes in a 4 ounce bottle and is a pink high temp adhesive. To use, you will end up removing the pads from your car and then compressing the piston(s) some and then on the edge of the piston(s), put a bead of this adhesive there. Put another little bit of adhesive on the outside edge where the pad touches the caliper (all spots). Re-install the pads and as soon as you can, step on the brakes to firmly push the pads against the rotor. This will squeeze out all extra adhesive, leaving a very thin layer between the pad and the caliper parts.

What this does is keeps the pads firmly in touch with the caliper and because you have a thin rubber layer, when you brake, the pad will not bounce any more. The bouncing pad what is leading to your squeaking.

Getting back to turning rotors, I haven't had the rotors turned on my truck in the 15 years that I have owned the truck. LIke was mentioned, as long as you don't have grooves or a wobble in the steering under braking, no real need to turn the rotors.

 

I'm not a great fan of turning rotors and also expect a lot more than a set to last two sets of pads! As Chris says, there's varying ideas on the subject.

Let's look at what you've done to the vehicle so far.

1. new pads AND rotors installed 11K miles ago - no squeak
2. new pads fitted now with 11K old rotors - squeak

The difference between (1) and (2) - with new pads and new rotors, both the pad surface and the rotor surface are perfectly flat and contact across the full area.

Now with your new pads and used rotors, the rotors will be a bit uneven or slightly grooved. The pads won't contact the full rotor surface area until they are bedded in and the pads wear down slightly to match the surface of the rotor.

Unless a caliper is sticking, the squeak should go as the pads bed in.

Graham

 

I agree with the guys.

Never in my automotive life have I turned the rotors.

Intrigued as to why you needed to at only 11k.

Check that they used anti squeal shims if appropriate and or some anti squeal on the pads.

Best way, to bed things in, drive a little with your other foot on the brake pedal.

Pads and disks will soon have an intimate relationship.

Just don't set things on fire, I know, it is not good!

 

I'll bet you never changed the oil at 3K either!

 

+1 on all the comments against turning rotors. 99% of the time it's not needed or of benefit and the other 1% is misguided attempts to fix unrelated issues.

You might be in that 1%. The pads are the issue- and OEM Jag pads can squeak. Thermo is on the right path with finding a way to dampen high frequency vibrations (squeak/squeal).

 

Did you bed the pads in?

I agree, don't turn rotors. I did it once and never again. The rotors become very wobbly.

 

The no wear ridge appears on all rotors. It has nothing to do with pad wear. It is simply the edge of the rotor where no pad touches. The latest thing is wavy edge rotors which develop no "no wear ridge" because the pad is always reaching the very edge of the rotor at the "dips" in the wavy edge. The peaks of the wavy edge still won't wear. All modern brake pads are bonded not riveted. When the pad material wears out you get full metal to metal contact between the pad backing plate and the rotor. I guarantee you won't drive three blocks if that happens!

Squeaking pads is often a result of failure to bed the new pads in properly. If you change pad type (different brand) then often the new pad material is not compatible with the previous pad material. As the new pad beds in it starts vibrating when the old pad material grabs the new. It is the harmonic vibration of the edges of the pads amplified through the calipers and rotors that causes audible squealing. "Adhesive" or lubricant on the backs of the pads breaks up the transmission of the vibration so it can't be amplified.

 

A wobbly rotor post-cut would be indicative of poor technique. A well machined rotor should be perfectly flat and carry surfaces perpendicular to the spindle axis.

Turning rotors might not be necessary in many cases, but a light skim cut can be beneficial.

The problem is that in most circumstances turning rotors is a piece work job where the operator does not get paid more for a better job.

 

The main reason to skim rotors is to take off the old pad material. Warped rotors are extremely rare, and ventilated rotors can't warp, physically impossible. Uneven deposition of pad material causes symptoms frequently and incorrectly described as "warped". A good thrashing of new pads is all that is required to bed in new brakes.

 

I believe OP is saying "new pads from Jag" = no squeak.

 

Check the below link. Bedding in new brake pads is crucial - especially when you are using new pads on old rotors. Everyone has their own method - but best to follow what the manufacturer recommends.

Brake Tech - Brake Pad and Rotor Bed-In Procedures

 

I understand logic- new pad new rotor correct "bedding"
but these rotors are 11k used miles-

i was always told 1 set of new rotors should cover 2 sets of pads..
and in the past when jag dealer changed ONLY pad no squeaks.

 

Jaguar recommends fitting new rotors whenever the rear pads are replaced. The old ones will wear out before the pads do. Don't know about the wear rate on front rotors. However, modern pads are very abrasive and rotors are now disposable items. Certainly, the old rotors will be worn out after two sets of pads.

Brake squeal due to inadequate brake pad break in can show up many miles after installation. Rotor wear does not cause brake squeal. Uneven deposition of pad material onto the rotor surface will. Fitting different a brand of pads onto old rotors without skimming the old pad material off can also cause this.

 

Can you point to a credible resource that confirms this?

 

OK HELP!!!
continuance of "the squeak" that is not unbearable when slowing down.
I brought is to local shop- he looked through rim and said there is your problem-the outer most portion of the rotor has a LIP around it.

then brought it to another shop had the tire removed - the rotor is smooth but there is a perfect lip around the outer circumference.

my question:
is this normal????

and being jag installed the rotors is their any warranty?
can front rotors "go" in 11k miles???????? I am not too rough on these at all

rotor- I'm to describe what the guy showed me-
a flat plate - the outer edge of circumference of plate had a lip around the entire plate both sides

 

Answered quite well by jagular in post #8 above. It's normal.

 

Me

Or

mossmotors.com/SiteGraphics/Pages/brake_discs.html

Or

http://en.wikipedia.org/wiki/Disc_brake

Or

http://www.stoptech.com/technical-su...nd-other-myths

Should I go on or is this enough to be going on with.

Fact is brake discs don't warp. The myth is perpetuated by the mechanics "proving" the disc face is not flat and then "fixing" it by machining the "bulges" off. In reality, those bulges are just uneven pad deposition usually caused by incorrect bedding in of new pads.

 

making myself nuts- all 2 shops pointed out the lip around the perimeter?
I live in a condo-like 300 cars
I went to 10 cars- with flashlight and hand
Mercedes - Toyota- Lexus-
totally flat no ridge on robots
3 jags
all ridges on perimeter
some more pronounced than others

 

The lip is irrelevant except the new pads may be a bit rumbly until bedded in around those lips.

What matters is the thickness remaining where the disc is shiny. If more than half the allowable wear has occurred just fit new discs. If less than half then don't machine them, tell the brake shop to just put new pads on.