Certainly can reference the service manual when the time comes, but was wondering if anyone knows of a "how to" on the procedure for removing/installing the "vacuum brake booster/servo"?

Removing boosters is usually a pretty easy affair of a couple bolts to the firewall and master cylinder, but the XJ booster looks a little more complicated in its connectivity to both brake and accelerator pedals, and the odd mounting in the engine bay.

I suspect it isn't too hard, but just wondered if a pictorial was already posted here or one of the other forums? A quick search didn't turn one up.

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Found it! "How To" from JagRepair.com.

Excellent:

http://jagrepair.com/images/AutoRepa...ster%20R&R.pdf


The only thing not included are torque values for the various fasteners involved.


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I know this is an old thread but I thought it was better to post here to keep the references to the brake booster in one place.

I had removed the pedal box and booster as described in the excellent how to article by D Jensen at JagRepair.com - Jaguar Repair Information Resource and noted his comment after reassembling in section 24 -
"For a reason I don't understand the brake pedal switch actuator no longer pushed the brake switch to the open position ......
because of this the brake lights were always on ...... I solved this by sliding a tie wrap over the switch actuator ...."


Brake switch location in pedal box

On reassembling I checked the operation of the brake switch before reinstalling the pedal box and also had the same problem - the switch was always on.
I couldn't understand why as there is no scope for adjustment when reinstalling the brake pedal and I had checked the correct operation of the switch before dismantling.
I removed the switch to investigate. It is mounted using a bolt at the top with a 8mm nut to the inside and a 7mm head on the outside.
The switch housing has a forked mount at the bottom that slides into a fixed bolt which is mostly inaccessible due to the brake pedal and does not need to be removed.

I discovered there is a ratchet type adjustment in the switch itself, and as the brake pedal puts up a good fight during removal it is likely that this ratchet is disturbed.
I adjusted the ratchet and after a few trial fittings got the switch to work as it should.
So this explains the mystery as to why the switch is always on when the whole thing is re-assembled and no tie-wrap required.

Look out for this if you dismantle the pedal box.


Brake switch adjustment ratchet mechanism