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Original 305 calipers on original mounts, but with new 325 rotors, will not fit.
AFAIK, new 325 calipers on new 325 rotors will, provided you have suitable wheels and very deep piles of cash. Found no reports from anyone who has done so.
There are backets available that move the caliper out so it can go on a 325 disc . The discs and brackets are about £120 in total. If I am going to change the discs I might as well go large for the price. Caliper Carrier
I have 18 in wheels and there is loads of clearance even the backing plate is 20mm bigger than the existing discs. like you say if you are changing the discs you might as well do the mod.
I have 18 in wheels and there is loads of clearance . . .
My XK8 already has the 325 rotors but behind 20" BBS Detroit wheels. I agree; even mine still has tons of clearance.
But your proposal has me thinking of my S-Type which has only 305 rotors behind 18" Mercury wheels.
That's why I am interested in supplier of those replacement carriers matched to larger rotors etc.
Look Here From what I can tell the early cars had "progressive" brakes ie not too good so the brake booster was changed .Going to 325 will only give you 7% better brakes and the feel will be the same.
I've got a 52 plate XKR with the Brembo brakes, which are supposedly the best brake option Jaguar offered. They are still not good enough in my opinion.
You have to apply quite a lot of pressure to the pedal to get decent stopping strength.
I've got a 52 plate XKR with the Brembo brakes, which are supposedly the best brake option Jaguar offered. They are still not good enough in my opinion.
You have to apply quite a lot of pressure to the pedal to get decent stopping strength.
the type and size of booster used is primarily responsible for the amount of pedal effort.
On power assisted brake systems, the master cylinder bore size, calipers design, and pad composition do impact stopping distance of course, but, those items contribute less to the pedal effort required than does the booster size.
Since experimentation with different booster units is not practical, I’d suggest changing the pads out for a
set that are more efficient.
Using the ebc redstuff pads has worked for me to improve stopping distances, and they also serve to reduce the pedal effort somewhat vs OEM pads on both the ATE & Brembo systems.
Surprisingly, the redstuff pads are pretty easy on the rotors
OE Brembo brakes stop the car very fast and quickly in my experience.
Hmmm, maybe there is something not working as it should then.
Maybe I just have different expectations. I drive my XE over 100 miles a day so am very used to it. When I jump in the XKR I always feel like the pedal needs to be pressed a lot further before the brakes respond. Then if I switch back to the XE I find myself hitting the brakes too hard 😄
I always put it down to a difference of 15+ years of progression in braking technology and the XE being a lighter car.
I have put new (oem) rear pads on since I have had the car so I will do the front ones when I get round to it and see if that makes any difference.
Hmmm, maybe there is something not working as it should then…….”
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that was my guess.
Originally Posted by XK Owen
“……..I have put new (oem) rear pads on since I have had the car so I will do the front ones when I get round to it and see if that makes any difference.
to experience the most benefit from better pads, be sure to have the rotors turned (aka: skimmed or machined) by a competent brake shop so they are perfectly flat before installing the pads.
The cost is next to nothing and many places will do it while you wait. Both front rotors can be done in about 30 minutes .
Of course, new reproduction rotors from Barratt are about $55 each, really inexpensive. Something to consider.
When I jump in the XKR I always feel like the pedal needs to be pressed a lot further before the brakes respond.
I'd start looking into bleeding the system in case there are air bubbles trapped in there. If you are like most of us, you are likely overdue for a brake fluid flush anyway. Remember that somehow, the Jaguar factory procedure calls for bleeding the calipers by _increasing_ distance to the booster. Most of us seem to have picked up that starting with the furthest away was the way to go, so go figure.
It has also been mentioned that under some circumstances (ABS module work, etc.) some air can be introduced into the master cylinder, and it appears it cannot easily be flushed out the normal way. The master cylinder has to be "bench bled" instead. Folks have mentioned this procedure has restored much of a factory feel to their braking system.
FWIW, I recently installed the quad piston Brembo setup on my own car (front only) and it makes a pretty phenomenal difference.
Change discs from 305 to 325 ..Good move ??
