Has anyone tried the vented, drilled, zinc coated rotors with the
ceramic pads from E-Bay? They’re only $150 or so and free shipping,
for 2. I am thinking about going to these unless someone has tried
them and they are junk!
Thanks, Doug–
First ever Jag…1995 XJS 2+2 conv., 4.0
Elkton Md., United States
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digdoug2 wrote:
Has anyone tried the vented, drilled, zinc coated rotors…
Vented + drilled = junk. And I dunno why anyone would consider
coating a rotor with zinc.
– Kirbert
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In reply to a message from Kirbert sent Fri 5 Jun 2009:
I have on my 87’’ VDP with EBC Greenstuff pads and They work fine.
Lower dust than regular pads, I may go to redstuff…I hate brake
dust.–
87’ VDP (black), 86’ XJ-SC (grey), 86’ XJS (red),
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In reply to a message from Kirbert sent Fri 5 Jun 2009:
Zinc coating does nothing for the braking surface, as the
pads wear it off, but it does great hings for the rest of
the rotor. Zinc keeps the iron from rusting, up here in
salt country that is worth gold since rust does not
dissapate heat well.
So far as cross drilled, stay away unless this is a track
car. Cross drilled are extremely prone to cracking between
the drill holes (specifically in the presence of
water/snow). If you want that ‘‘sporty look’’ get slotted.
The problem with slotted (and cross drilled as well) is when
you change pads you have to throw the rotors away and buy
new ones, they can’t be turned and only a fool would put new
pads on a rotor that has been broke in without turning it.
No input as far as the specific EBay vendor/product you seek
info on (especially since you don’t say who/what
product/link to site). Best advise is to look at their
sales (power seller or not) and their feedback. I stay away
from any business that has less than 90% positive feedback,
more risk than I am willing to deal with otherwise.
Harold–
The original message included these comments:
Has anyone tried the vented, drilled, zinc coated rotors…
Vented + drilled = junk. And I dunno why anyone would consider
coating a rotor with zinc.
– Kirbert
–
'89 XJ-S US Spec 5.3HE (Lucas) Auto
MN, United States
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Hsmith wrote:
So far as cross drilled, stay away unless this is a track
car.
Stay away even if it IS a track car! Drilling vented rotors is
stupid, stupid, stupid.
– Kirbert
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In reply to a message from Kirbert sent Fri 5 Jun 2009:
I guess I am a fool. I have been replacing pads w/o rotor turning
for a very long time. Warped rotors is another thing.
Same for shoes in drums. I have replaced many a shoe in an unturned
drum.
My Old Ford pickup and IHC Scout had the same brake system. One
wrnech and ahammer and a chisel to remove them to change pads.
Also prone to grooving the rotor. No matter, new pads and they wore
in. Braking was just fie, thank you.
Same for the 88 T bird, I changed it;s pads several times duroing
it’s life with us. No turning, just new pads and once or twice rear
shoes and it braked just fine.
I like the Jaguar system. Nicely sized and vented rotors, simple
straight forward pad changing. Althugh I haven’t tried the rears
yet!!
Zinc sound ok. Not much point on the wear surface, but if it
retards rust, sure!!
Carl–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
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In reply to a message from cadjag sent Fri 5 Jun 2009:
Kirby, cross drilling increases the interface area between the
rotor and air, as well as allowing HOT pads to gas out through the
drill holes(both leading to increased brake performance under
extreme loads). On a race car where brakes are bed in properly,
not usually run in the wet and inspected thoughly and regurarly
drilled is an ok compromise for most.
Carl, please advise me in advance if you ever plan to drive in
upper Minnesota so I can put all the cars in the garage and stay
off the roads. Pad slaps are dangerous as the new flat pad rides
only on the highest ridge until it wears a groove into the pad, a
severly smaller effective pad serface, increased heat (although
possibly not any more total heat than with good brakes, the heat is
much more localized and causes higher friction temps.) If memory
serves me correctly a rotors ability to dissapate heat is inversly
portotional to the amount of heat it is required to dissapate.
using randon and generic numbers that in no way actually reflect
real world brake temps/times if you have 100 deg it takes 1 sec to
dissapate that heat, but 2.5 sec to dissapate 200 deg, but even if
i am incorrect it still takes longer to dissapate more heat no
matter how you do the math. The localized hot spots on the rotor
are much hotter that the same given area of a properly working
brake. Not trying to slam you or put you down, just brakes are a
huge pet peve of mine. Most want a car that can go fast, I prefer
one that stops fast. Maybe we have a brake engineer here somewhere
who could explain this better than I.
Harold–
'89 XJ-S US Spec 5.3HE (Lucas) Auto
MN, United States
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In reply to a message from Hsmith sent Sat 6 Jun 2009:
Harold:
No worry. I have no plans to go to your beautiful country. I see
the guys on Hometime, working in the winter.
And, I have not used grooved rotors for over ten years, It was just
frustrationa my Scout and then my pickup eating pads and rotors
for breakfast. Actually, as I now recall, the last brake job on the
Ford included bearings and races and ‘‘loaded’’ calipers and new
rotors. Then, sold not too long after? I hope the new guy didn’t
have any trouble with that cumbersome system. Crude. Undo a 9/16
lock bolt. Knock out a loaded wedge with a drift and hammer, lift
off caliper and change pads. Removing the hubs meant dealing with
the locking system for the front drive axle. The Scout was easy.
The Ford ahd some interesting split rings to prize ut and a special
hub wrench to reach in the cavity.
And, every time you turn a drum or rotor, you loose important metal.
I suspect most rotors or drums will take one turn only before
becoming just too thin. Shops are linmited as to how much they are
allowed to remove and with good reason. Warpoing drums and rotors
are not good.
It’s been a veeeery long time that I drove cars with next to non
existant brakes. In my teens, I am approaching 80!!
Carl–
The original message included these comments:
Carl, please advise me in advance if you ever plan to drive in
upper Minnesota so I can put all the cars in the garage and stay
off the roads. Pad slaps are dangerous as the new flat pad rides
only on the highest ridge until it wears a groove into the pad, a
severly smaller effective pad serface, increased heat (although
possibly not any more total heat than with good brakes, the heat is
much more localized and causes higher friction temps.) If memory
serves me correctly a rotors ability to dissapate heat is inversly
portotional to the amount of heat it is required to dissapate.
using randon and generic numbers that in no way actually reflect
real world brake temps/times if you have 100 deg it takes 1 sec to
–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
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Hsmith wrote:
Kirby, cross drilling increases the interface area between the
rotor and air, as well as allowing HOT pads to gas out through the
drill holes(both leading to increased brake performance under extreme
loads).
All of which is manure spread widely to sell drilled rotors.
– Kirbert
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cadjag wrote:
And, I have not used grooved rotors for over ten years, It was just
frustrationa my Scout and then my pickup eating pads and rotors for
breakfast.
Hey, I used to replace pads and/or shoes without turning the rotors
and drums all the time. If you run organic pads, sometimes it’s hard
to see any good reason to turn the rotors; the things don’t wear the
rotors at all, they’re just nicely polished. Of course, what I gave
up long ago was using organic pads, since they are dangerous. Using
semi-metallics for safety, yeah, you’d need to turn them every time
if not replace them altogether.
In my younger days I was even known to just install new pads over
lightly grooved rotors. Didn’t make any significant difference to
the braking performance that I could tell. In short order the new
pads would be seated in to the same shape as the grooves anyway.
Probably not the best thing for pad life, but pads are cheap.
Of course, turning rotors is cheap, too. On rice burners, even
buying new rotors is cheap!
– Kirbert
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In reply to a message from digdoug2 sent Fri 5 Jun 2009:
I am with Carl on this one. I have replaced many a pad without
turning the rotors, as long as the rotors are not heavily grooved.
I have noted no ill effects, even on my cars that are used at road
racing tracks. If we change pads at the track we do not change or
turn the rotors while doing so. It takes a short time to seat the
new pads to the surface of the rotor so the early braking is
slightly lessened but after seating the brake performance is normal.
I have used organic, semi-metallic, and ceramic pads in these
changes, with no obvious differences in reaction of the different
materials.
Removal or rotor material by grinding also removes a portion of the
heat sink capability of the rotors and makes them more prone to
warping if they become quite hot, as on the track. I have had
rotors turned in the past to correct warping and it was not too
long afterward that they were warped again and I just ended up
replacing them.
I will agree that new rotors or newly turned rotors is the ideal
situation when changing pads but feel very strongly that it is not
necessary in many cases. The typical repair shop will always
suggest turning or replacement for two reasons: 1. They make more
money on the job. 2. They do not want comebacks.
Since I do all my own brake work, these reasons are not relevant to
me.
Harold, if you are going to park your cars in the garage if either
Carl or I come to your area, that is wonderful! There will be less
cars with which we have to share the road and fewer traffic
jams. 
I do believe that you are being overly conservative in your
opinion, however, and I am speaking as an automotive engineer with
about 45 years experience in the OEM, aftermarket, and competition
arenas.
Just my $ .04 (After inflation).
Kern Fischer–
91 Classic Collection Convt. (NCHNTRS)
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In reply to a message from Kern sent Sat 6 Jun 2009:
Hello !
Well, I think both of you are right, but on one point : puting
rotors on a lathe is ok is they are are a little warped, but for
small grooves you should use special grinding machines designed to
work with the rotor on the car. With these, you get a nice smooth
surface on each side of the rotor in a few minutes and only few
metal is removed at rather low temperature- ears protection is
must, the noise during the process is like hell !
Just my $ 0.05 (inflation and �/$ rate
All the best !–
The original message included these comments:
I am with Carl on this one. I have replaced many a pad without
turning the rotors, as long as the rotors are not heavily grooved.
Removal or rotor material by grinding also removes a portion of the
heat sink capability of the rotors and makes them more prone to
warping if they become quite hot, as on the track. I have had
–
Philippe, XJSC 87 Strasbourg
STRASBOURG, France
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In reply to a message from Klebs sent Sun 7 Jun 2009:
Yes, turning the rotors on car is the best way to go. The shop I
ran three years ago had purchased a unit that allowed the rotors to
be resurfaced on car. Huge time saver on heavy duty vehicles where
they do not have modular/composite rotors, removing and repacking
the bearings at every brake change is a labour intensive process.
In Alaska, where that shop was located, the mechanic physically
doing the repair as well as the shop in which hte repair was done
are both civily and criminaly liable for any safety related work
performed (brakes obviously qualify). Under this system, I as a
mechanic would rather tell a customer that I flat refuse to put new
pads on worn rotors (weather smooth or grooved) as the penalties
are far to great to risk such a cheap procedure. The loss of one
customer is well worth the respect of the rest, quality first, deal
with the rest later.
Harold–
'89 XJ-S US Spec 5.3HE (Lucas) Auto
MN, United States
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The downside is that wheel bearings, also a safety item, don’t get cleaned
and repacked often enough as it is !
Cheers
Doug Dwyer
Longview Washington USA
1995 XJR
:
Huge time saver on heavy duty vehicles where
they do not have modular/composite rotors, removing and repacking
the bearings at every brake change is a labour intensive process.
// please trim quoted text to context onlyFrom: “Hsmith” super60daytona@yahoo.com
This debate has been going on for decades with loads of contradictory
information.
I’m sure most of us would prefer new rotors at every pad change. Who
wouldn’t? I’m also sure that a great many of us have installed new pads on
lightly worn/grooved rotors and never had a problem.
Some car manufacturers specifically point out that rotor
replacement/resurfacing is not required at every pad change. The Jaguar ROM
doesn’t go that far, but it doesn’t mention it as a requirement by virtue of
the fact that it isn’t mentioned at all
On inboard rear brakes replacing or resurfacing rotors at every pad change
is a pretty tall order. A show of hands, please, of all those who do so at
every pad change. Aha, just as I thought
One thing to consider if you’re in the “resurface every time” group is how
thin your rotors are getting…and thinner is not better.
Since Jag rotors are fairly inexpensive…perhaps not like a Honda but
still reasonably affordable…I just replace 'em.
I’ll add the the Akebono ceramics I am using these days don’t seem to groove
the rotors.
Cheers
Doug Dwyer
Longview Washington USA
1995 XJR
Hey, I used to replace pads and/or shoes without turning the rotors
and drums all the time. If you run organic pads, sometimes it’s hard
to see any good reason to turn the rotors;
In my younger days I was even known to just install new pads over
lightly grooved rotors. Didn’t make any significant difference to
the braking performance that I could tell.
Of course, turning rotors is cheap, too. On rice burners, even
buying new rotors is cheap!
// please trim quoted text to context onlyFrom: “Kirbert” palmk@nettally.com
In reply to a message from Doug Dwyer sent Sun 7 Jun 2009:
well, it seems as tho,Ferrari, Porsche, some Mercedes, and
other engineers dont know what there doing.
some come from factory with Drilled or slotted rotors!–
The original message included these comments:
information.
the rotors.
–
Ronbros
daytona fl. / Austin TX., United States
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In reply to a message from Kern sent Sat 6 Jun 2009:
I agree with every word Kern.
It is, being polite, ridiculous to insist that every new set of
pads HAS to be accompanied by a turned/regund or new disc. Yes, in
the ideal world it would be nice but please don’t try to tell me
the life of a disc surface is inevitably the same as the life of a
pad.
What a pro might need to feel they’ve covered their backside
against avaricious lawyers is not the same as what’s needed for
effective and safe brake operation. Nervousness on one person’s
part does not constitute negligence on another’s.
Pete–
The original message included these comments:
I am with Carl on this one. I have replaced many a pad without
turning the rotors, as long as the rotors are not heavily grooved.
I have noted no ill effects, even on my cars that are used at road
racing tracks. If we change pads at the track we do not change or
–
68 E-type OTS, 96 X305 XJ12
Cambridge, United Kingdom
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In reply to a message from PeterCrespin sent Sun 7 Jun 2009:
Pete:
Yes, for the pro, it is definitely a PIYA against come backs or
lawyers.
But, for the rest of us, Good judgement and experience will carry
the day.
I bet the pros don’t turn or replace rotors every time they change
pads on thir poersonal cars.–
The original message included these comments:
What a pro might need to feel they’ve covered their backside
against avaricious lawyers is not the same as what’s needed for
effective and safe brake operation. Nervousness on one person’s
part does not constitute negligence on another’s.
–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
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It used to be that shops over-repaired cars out of good old fashion greed
and dishonesty.
Now they do it to cover their butts. Lord knows how much the customers have
paid on account of consumerism and lawsuits.
Cheers
Doug Dwyer
Longview Washington USA
1995 XJR
What a pro might need to feel they’ve covered their backside
against avaricious lawyers is not the same as what’s needed for
effective and safe brake operation. Nervousness on one person’s
part does not constitute negligence on another’s.
// please trim quoted text to context onlyFrom: “PeterCrespin” jag@thewritersbureau.com
It is hard to imagine a fact scenario where failure to turn or replace
brake discs when replacing pads would give rise to a lawsuit where the
plaintiff would prevail against the mechanic/shop. To be liable, there
would have to be a showing that a reasonable man would have replaced
the discs (negligence), and that negligence caused or contributed to
cause an accident or mechanical failure.
Unless (1) the disc were so worn that it was less than the specified
minimum thickness (or could be proven to have had some other obvious
defect when the mechanic worked on the car), and (2) that condition
somehow caused brake or other mechanical failure, the plaintiff could
not prevail. The proof of those two factors would be very difficult,
and the burden of proof is on the plaintiff to show that each of those
factors occurred, more likely than not. Unless the disc broke or
otherwise failed mechanically, it is difficult to see how it could
cause brake failure. The law is based on common sense and logic
(regardless of impressions created by television or movies).
Based on that, I would would go with your “greed & dishonesty”
postulate, perhaps adding “ignorance” (both the customer’s ignorance of
anything mechanical and the shop’s ignorance of the law 
George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP
It used to be=2
0that shops over-repaired cars out of good old fashion
greed and dishonesty.
Now they do it to cover their butts. Lord knows how much the customers
have paid on account of consumerism and lawsuits.
Cheers
Doug Dwyer
What a pro might need to feel they’ve covered their backside
against avaricious lawyers is not the same as what’s needed for
effective and safe brake operation. Nervousness on one person’s
part does not constitute negligence on another’s.
// please trim quoted text to context only-----Original Message-----
From: Doug Dwyer dougdwyer1@comcast.net
From: “PeterCrespin” jag@thewritersbureau.com