THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

Work progresses ! callipers now out - not any easy job, as advised !
Will get checked/rebuilt professionally, as I don't mind going fast, but like to know I can stop !
Thanks all for your comments and tips/suggestions....look forward to having her on the road again !

The pistons should move far enough on both sides to pop out whilst the calipers are still in situ but you would have to remove the calipers and split them if you wanted to change the rubber seals. The idea is to remove the pistons before splitting the calipers otherwise there are too many holes to plug back up to get any pressure in the system to pop the piston out. I have in the past tried to remove pistons on the bench with large plumbers pliers and a vice after splitting the calipers but then ended up having to reassemble them all to pop the pistons out with either air or re-attaching it to the brake system so I can use the hydraulics. The calipers can be removed with two bolts holding each from the rear assembly after disconnecting the brake hose. It's quiet tight to get into the bolts and pipe connection but doable. Just have patience and a ramp, if not and you have the money I would give it to a garage to do. What might take you all weekend will take them a couple of hours with the right tools and a ramp.

Just confirming - I can get the pistons out without stripping the whole rear end ?
I've heard of using compressed air and note the comment re ensuring both pistons come out at the same time.

actually Nigel, I haven't ! That's a job I need to do again. Thanks for the advice.

"bleed the brake system which I did myself around 1998."

Jose please don't say you have not changed the fluid since! Brake fluid is hydroscopic so absorbs water, if you had to stop hard from speed this will turn to steam and lead to loss of braking power big time. As well as this, crud and corrosion will build up in the master cylinder and the callipers. Unless silicone fluid is used change the fluid every three years

yes, spot welding the nuts would need to be done with the cage off the car, and after you have marked the area that needs cutting with the cage in place, then cut the access opening with the cage off the car and the rest of the mod is done with the cage off the car as well.

I think this is a modification worth doing. If I get to the point where I need to drop the rear cage, I will get it done.

curiously, I have driven my 1984 XJ-6 since 1989 when I bought it, and in all these years, I have never had any issues with the rear brakes, not even changing pads. The only brake work that has been done to the car has been to drain, refill and bleed the brake system which I did myself around 1998.

I had thought of welding the nuts to the undeside for fixing the panel on but getting to the underside with a welder would be a problem with the subframe in place.

The rear brakes access panel should have been added when these cars were designed. After all, there are access panels on either side of the transmission tunnel. Unless there is an issue with the structural integrity of the body in that area.

if I were to fabricate a rear brakes access panel, i would cut the hole, fabricate a panel, then drill holes for bolts with nuts on the underside, then weld the nuts to the underside after tightening the panel bolts and nuts. Overkill maybe but i think it needs to be very sturdy.

The rear brakes access panel should have been added when these cars were designed. After all, there are access panels on either side of the transmission tunnel.

To push the pistons out you need to either attach a compressed air hose to the system to force them out. They tend to do this in the garages where they have a large compressor or as I have done I have a spare brake pedal assembly and master cylinder with a section of copper pipe attached which I can screw in to the caliper and depress the pedal so the pistons come out using the remaining fluid in the calipers. If you can't get hold of a spare pedal and master cylinder, wheel the axle back under the car and attach the flexi hose back up to the original copper pipe then press the foot pedal in the car. Same thing but be careful that both pistons are forced out at the same time. If one pops out before the other it is a bitch to get the last one out. They have to come out evenly by using a lever between the pistons holding one back whilst the other moves and vice versa.
I am going to go for the panel in the boot so yesterday I contacted my Jaguar breaker who is going to cut the rear tunnel roof out of the boot of a 420 he is breaking and send it to me. I can then make a hole in the boot over the top of the brake calipers and using the section from the 420 make two panels that are slightly bigger in size than the holes I will have cut and fix them in place using self tappers and a decent rubber seal. Once the carpet goes back in place it will never be seen. Not one perhaps for the purist but definitely one for the pragmatic.