Well, I guess the reality is, there are those that know and those that don’t. If you know then you do what’s been since forever on many makes and models, cinch it up and back off a bit until you feel it free up, then tighten it down. If you don’t know, use the dial gauge. If you are anal, you use the dial gauge and set it squarely in the middle of the spec.
But what you shouldn’t do is let it go unchecked indefinitely, because these cars tend to loose tolerance over time. If periodically checked and repacked there’s no real reason why they should last a very long time.
That has more to with the fact that rotors start out just above the minimum thickness, and if you turn them, they tend to warp faster.
Even new, Id check them with a dial indicator.
I just had shudder when braking on my xk8. I bought new rotors for both sides figuring the old ones were probably original. I swapped them as a pair and no more shake on braking. Just looking at the rotors you couldn’t see anything. Absolutely was the problem though
Paul, have you seen quality of lowest-range products recently? Those are perfectly straight, with immaculate runout. This changes radically with firts strong braking.
Rotors goes bad when overheated. The overheat treshold usually goes up with the price…
It’s not expensive to turn the rotor casting, but to make the casting from specific, pure material, with specific heat treatment to follow.
You won’t get runout of brake discs these days. IATF and PPAPs are stating brake systems as critical. That makes statistical process control unapplicable to rotors itself. Those are 100% in-process checked (unless falsified).
Not sure about US but in UK - car workshops are absolute joke and mistake. Still, rich parasites with delusion of humanity are leaving their cars in ‘prestige’ places (or buying cars from those) - where the ongoin rip-off on car service is beyond IQ level of their owners. All you need to do - is to place Union Jack next to the entrance. Then you can put the cheapest chinese products in, without any concerns from the owner’s side…
Yes… just recently.
Got a new pair of rotors for my Hyundai, and under normal, light use, warped into square waves, within 1000 kms…
Returned them for a credit, and put my old ones back on, which were only slightly warped.
Even back in the day, I checked all with a dial indicator. Trust but verify.
Aaargghhhh!!! XJS owner driving Hyundai hedge-trimmer.
Moderators! Quick!! Block him!!! Before it spreads!!! He shall not be allowed!!!
Yup, MOT check every year, which is only a couple of thousand miles for “my” cars in the garage. Her Subaru does more miles, and is difficult to check statically because of the AWD system. My alternative method is a pair of long sweeping corners between two sections of dual carriage way. Drive really fast and listen/feel for the noise of a bad bearing on the left, then right side. I probably only need to do this every 6 months. But I do it every time on that section of road, just in case.
When I said mine shuddered violently it was when braking., probably set off by uneven rotors…if you look at the steering rack and the hanger rubber bushings are oily or loose… that will do it…I could move mine back and forth by hand about half an inch each way…put on the polyurethane ones… voila! No more problem.
1 Like
Too late… not going away.
In any case, I like my DD to be nearly faultless!
1 Like
Yeah, my lower back gives me fits now. 
1 Like
Decent rotors are critical too. I never go cheap on rotors, nor pads. I am also using ceramic pads when i can.
The go to rotors i like are Brembo, never had an issue.
Pads i like are Akebono, wish they made them for the XJS.
You and me both. Have them on my other cars. Great performance and very low dust.
1 Like
Tech Buds and Pep Boys…eventually you will see that you get what you pay for.
I think you owe it to yourself to find a shop in Dallas, one that does honest work, and have them do the work, and do it right.
I think you’ve spent more time going back and forth between this forum, the tech bud and the cheapest shops in town to have paid the dealer three times over to fix these issues.
2 Likes
Have you checked caliper pistons are not seized
That makes sense. But how can you tell a good quality rotor or pad from a cheapo rotor or pad that the seller has just decided to overcharge you for?
2 Likes
“This is the first time NALUTZ43 has posted — let’s welcome them to our community!”
Welcome to jag-lovers, Mr. Lutz! 
2 Likes
Or collapsed brake hoses that prevent the caliper from fully releasing…
I shop around online and can find at least five different vendors, and so get a sense of high cost/low cost rotors.
Zimmermann “Z” coated rotors are very good, as is Brembo and Pagid. Generally, really cheap, crap rotors are uncoated, and upmarket rotors are coated.
Sorry, VK (ltns, btw) but I’m afraid (and have posted before) we have no such creature in the Dallas area in regard to the XJS, at least that I know of. 
Here is a little recap for ya (and everyone else)
1- “John’s Cars” - the huge Jaguar salvage yard here, appropriately located on “Jaguar Lane” near the Fairgrounds/Fair Park. Although John and his crew used to also service Jags at their facility for a long time, they stopped doing so many years ago and only sell parts out of the yard now, no explanation given. He’s also still big, of course, on selling those custom engine/transmission lumping kits of his for Jag owners who wish to swap things out for American-made engines in their cars.
2 - The Jaguar dealerships - I had approached them some time back about working on my XJSes, and was rebuffed, claiming they do not service “vintage Jaguars”. 
btw, we have gone through some of those of late, with shuffling around and a new location recently opening up in the DFW area. These are ones that are “officially” associated with the Jaguar co. (Tata Motors). We have one “dealership” here that is apparently no longer officially associated with Tata, but still claims to be a Jaguar dealer. Go figure. 
3 - Motorcars Ltd. (based in Houston). When ML - one of our usual new/rebuilt/used parts suspects - was at their peak many years ago, they decided to open branch service shops in Austin and in Dallas (actually, IIRC, it was in Addison or Carrolton), as well as a a couple of locations in their native Houston. However, as apparently parts sales slacked off (lack of Jaguar popularity + online competition) their income waned and they began laying off parts sales person and their tech people (service techs). I’m sure some of you remember Phil Prince, probably their top tech guy and the host of ML’s own online Jaguar forum - kind of a mini-version of JL’ers, back in the day. 
Eventually, adios went the forums AND Phil. 
More importantly as far as getting our Jags worked on, ML cut things back further by shutting down their Austin service location and then their Dallas (Addison?) location. 
I remember calling the Dallas location one day, intending to drive one of my XJSes over there for some work, and got a “this # is disconnected” message instead, to my total shock.
4- “Jag Mac”. Jag Mac is probably the last of the “Jag only” private service facilities left in Dallas (again, that i know of). The place is owned and ran (I think alone?) but an “older” gent out of Scotland, IIRC (might be Ireland? 
). It has also been in biz a long time in the Dallas area. However, when I rang him up a few years ago, again to have one of my XJSes worked on, he informed me, much to my amazement, “I don’t work on those older Jags anymore”.
So, there you have it … At one time I believe I talked to our Motorcarman about possibly me flat-bedding my XJS(s) out to his place to be worked on, but can’t remember how that turned out (maybe he said he only worked on his own Jags anymore ?). He does live though out in the country, on the opposite side of the DFW Metroplex from me (I’m on the very east edge, he is NW of Ft. Worth), about 60 miles from my place.
Seems like the only thing an XJS owner in Dallas like me can do is, either (1) get it fixed himself (2) drive/flatbed it to ML’s home location in Houston - 250+ miles away or (3) get rid of my “older” “vintage” etc. models and trade up to a “newer” model Jag … (unless of course one of you gents would like to invest 
in a new private Jag service biz in the DFW area that is not afraid to tackle the “older”, “vintage”, etc. models, assuming it would be any more successful than the other bizes were. 
Unfortunately, ,as the marque is continuing to wane in popularity - with no more “XJ line” at all, going to electric cars only, etc. - the situation is only going to get worse all over, as time goes by, it appears … 