I have a 1994 jaguar xjs and I am having an issue with the brakes not releasing on front and rear. Have replaced hoses and on all four and replaced the calipers on the front. My problem is when ordering the calipers for the rear, i recieved a dual piston calper with mounting area for an external parking brake hook up. My 1994 xjs has a single piston caliper on the rear. I would like to use the dual piston versions but they appear to use an external emergency brake system (that I don't have the hardware for) and mine uses an emergency brake system that mounts inside the rotor. my emergency brake cables are different and i do not have the cross over brake tube to go from the front of the caliper to the back side; My calipers look closer to the ones used on the `1995/96 xjs so I ordered them only to find out that although they look the same; the brake line fitting is threaded as a M10 1.0 thread and the 1995 calipers are threaded M10 1.5. My brake line is a fine thread fitting and the caliper is a coarse thread. Is there a way to determine the actual calipers I have by using the casting numbers? Does the 1995 rear brake line have M10 1.5 on caliper side and M10 1.0 on the brake line side? My 1994 rear brake lines have M10 1.0 on both ends. Threads are longer on the line side and shorter on the caliper side. How do I determine if I have some sort of Franken-jag on the brake system? Any help and thoughts on this will be greatly appreciated. my caliper looks exactly like the single piston 1995 version other than my brake line goes into the back into an angled boss and is fine thread. The 1995 brake line goes straight in to the back and does not have the angled boss and is threaded coarse.

 

You need to use the calipers for the unvented outboard brake disc's for your 94. The first ones you got were for the early inboard brake disc cars. The ones for the 96 were for vented outboard rear brakes. The late 95 andv96 cars used them. If you live in the US, you can get rebuilds from Rock Auto for your 94.

 

the original ones I ordered for the 1994 xjs

This is the type I originally ordered for the 1994 xjs. it has double pistons and parking brake mounts on the two threaded boses on the edge.

 

the ones i orderd for a 1995

1995 version which looked like mine but has a different thread on the brake line

 

Thanks for the info. It appears that what I have is the same one used on the xj6 and xj40 91-94.