Splitting the calipers
 

Hi all,
ive been looking around on this forum and cant find any info on splitting the calipers, maybe im not looking hard enough?

anyway personally i wasnt going to split them but then my jaguar specialist i buy parts from said there is no problem as long as you replace the seals (which he has in stock).
the internet has two very different opinion. one bloke says that they are stretch bolts and they will never hold tension again, some say it was only because people wouldnt replace the seals between the halves.

so who has done it and who knows the reason jaguar say not to. i haven't found a instance where it has ended in anything bad, just allot of people saying it will lol. im wondering what the real experiences are.
thanks,
jay

Mmmmm, being ex Jaguar, I have never sold the seals, so if he has them, GOOD, and the bolts.

I have never split the front ones, ever, saw no need. The pistons etc are easily removed as are the o/rings and dust boots. OK, cleaning can be difficult, so what, and honing is a no-no.

I have known of some that have done it, and always have had that dampness around the joint, never fixed as far as I know.

im beginning to go back to my initial plan of leaving them and just soaking them in metho or something then blowing the crud out that way?
only reason i would consider splitting them is becuase there was a fair bit of muck in there.

so the suggesting is dont split them. what was jaguars reason for this tho?

thanks,
jay

No matter what you do, there will always be crud in there. Brake pad dust and stuff. They are designed to run in that environment. So as long as the boots are GOOD, and the fluid is changed annually, there will never be an issue with them.

The idea is NOT Jaguar, nearly all multi piston calipers are like that, and when you look carefully at it, our "new" Aussie stuff only has 4 piston as an "option", mmmm. Then add to that, Jaguar did not make them, they were made by a brake supplier, Jaguar just decided to use them waaaaaaaay back to give the XJ superior braking, then and now.

Our S2 XJ12, is still as it left the UK, and at 500000km is doing quite well, but it does get maintenence without question. The calipers have never been rebuilt, a set of boots 12 years ago, thats it.

What are "the seals between the halves"?

apparently there is some square o-rings between them and thats all that they seal with.

your seriously not joking there. even with leaking seals and a pedal that went half way to the floor my XJ6 still stopped much better then my 2011 xr6, which is a thousand times lighter and faster.
even the handbrake on the jaguar has more stopping power then my mums 67 impala which has 4 spot callipers on the front.

its amazing how much better to drive those cars must have been in there day. the impala is like a truck and wanders everywhere but the jag you can easily do 100kmh on rubbish dirt roads no problems when the modern crap you struggle at 80. i suppose its the weight and independent suspension that does the trick.

These square passages don't have brake fluid going through them, do they? I was under the impression that the the crossover tubes took the pressurized brake fluid from one side to the other. The calipers on both the front and rear of my SIII have them.

as far as i know all series 3 front callipers had internal passages? and by square i meant profile, not shape. should have made that clear i suppose lol

Oh I see. I guess the the fronts do have internal passages with no crossover tubes. I know the rear ones have crossover tubes, I suppose instead of passages.

The four-piston front calipers can generate huge separation forces in emergency braking, so the bolts holding the two halves together are special one-use-only bolts. Caliper refurbishing firms will use new bolts. The seal on the fluid passage is really just there to eliminate seapage as no gasket goo is used when bolting the two halves together. I believe they were made by Girling.

Rears are like the originals, with a pipe coupling the two cylinders together.

I just got a set of reman'd rear brake calipers for my SIII XJ6 from Centric and the bolts holding the two halves together are actually 3/8-24 bolts. They are marked 10.9 as if they're metric, but they're actually SAE. I guess the 10.9 specifies the strength of the bolt and is not limited to metric fasteners. Generally, grade-8 bolts are roughly equivalent to 10.9 bolts, so you can probably replace with garde-8 if necessary.