I just turned the front rotors in my '96 XJS.
They ended up at 24mm thick.

The Jaguar manual says:
Minimum Refinish Thickness
Front ........................................ 27mm

The Centric Spec for a new front is rotor 24mm

I'm confused. Am I missing something?

 

Typically the rotor itself is stamped with a minimum thickness spec. Do yours have such stampings? If so, that's what I would go with.

cheers
DD

 

The local NAPA rep had a good simple answer.
"The minimum thickness is dependent on the rotor spec. Not the vehicle spec. So go by what's stamped on the rotor."

 

petemohr,

Whereabouts in the manual did you read the figure of 27mm? In the General Spec section, it quotes front disc thickness of 24.13mm.

Paul

 

You sir, are correct. My info came from Mitchell Repair Information Company. See the attached pdf.

 

rotors,rotors, i simply bought new ones , made for performance work, slotted and dimpled, cost was cheap! and gold anodized coated(dust dont stick easily).

 

Not sure we have the same definition of "cheap".
EBC gold anodized rotors are $300 each. Did you find some cheaper?
Brembo's from Coventry West are $37 each.

 

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i paid $195. shipped to the door, pair of EBC Gold, slotted and dimpled.

1978 Jaguar XJS ,fronts!

i dont know about Genuine Brembos for $37. each.

heck , just throw a set of pads on it,forget the resurfacing, save money!

 

I'm with that.


Rotors only need turning if they have an issue. Usually,
not, unless the pads were run down to the metal. and, then the gauges might be so bad as to make turning useless.


Scuff off any glaze if one wishes, make one feel useful. Actually,
not really, it will be right back on a bit of use.


Swapped out the pads on the front of my XJ wuzza six a few years ago. A bit prematurely. But, better than too late!!! Rotors decent, left them in. Braked just fine.


A bit later, oh, oh, losing fluid. drops under the rear!!! Yup, back calipers oozing...


Farmed out that job. Loaded rebuilt calipers via Rock Auto. Rotors good, still there. braking better, yet....


Way back when, my IHC Scout II and 85 Ford F150 used the same braking system. Each ate one pad per side and grooved the rotors.
I lived with it for a while. I could knock in fresh set of pads quickly.


But, then broke down and refreshed them, rotors, calipers and pads.
No discernible difference in braking????


Carl

 

Sorry for the hijack, but what bushings are those? I would like to know so I can steer away from them, since they are coming apart in chunks.

thanks

 

Most people with a new-to-them XJS probably have somewhat out of shape rotors that don't feel to noticeable, but given their age provide a little bit of oscillation under braking.

Replacing pads,rotors, calipers, etc is probably never going to be noticeable in normal traffic, except some warped rotors. The rest of the increased performance is picked up under hard braking and continued use, where less fade is apparent. So unless you slam the brakes enough to remember the difference, you aren't aware by the seat of the pants the smaller stopping distance from speed. Although I am personally a fan of brake checks to make myself aware of my own stopping distance. Nothing like hitting the floor once in a blue moon, only to find you keep going much further than expected!

I would also expect both of those vehicles to have garbage braking performance anyway, so even "up to spec" still means sub-optimal.

 

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i posted on another thread some pix, you are right cheap polyurathane bushes, changed to quality ploy-rubber , much better.

 

I don't get what you mean by garbage stopping power. I just saw a video of Xjs performance testing from the 80's Motor Week. The stock Xjs stopped from 60mph. in 110 ft. That's pretty good. As long as the stock brakes are properly maintained they should be fine. Upgraded pads, rotors, and especially modern slightly larger tires should improve on the stock performance. If the rotors are not turned or replaced you will not get that smooth braking feel back.