This saga goes back a few months. But I will cut to the chase. New front brake pads, discs, hydraulic hoses(flexies) and reconditioned calipers fitted by myself. I could not get a hard pedal and had very poor brakes. Foot to the floor stuff. Not at all good. After a near disaster with the car rolling off the ramps and pushing me and the hydraulic jack I was using down my drive, I took the car very slowly to my local highly regarded garage. They liked my work but could not get a hard brake pedal. I then took the car to another classic car specialist a little further away, who understood the Jaguar system with ABS. They could not get a hard brake pedal either. They did say that if they locked off the flexies then a good pedal could be obtained. Releasing the rear flexies maintained the hard pedal, but releasing the front flexies resulted in no pedal again. This showed the problem to be associated with the front calipers! So, I returned the calipers to the parts dealer for testing. Eventually, the calipers were returned with "no fault found". Last week-end was The Jaguar Enthusiasts Club's 30th Birthday bash. Bob Bate - a well known Jaguar expert was there. He offered me advice. In essence, you must fit the brake bleed tube to the bleed nipple, direct it vertically for six inches, before feeding it into the fluid catching bottle. Now open the bleed nipple, very slowly push the pedal to the floor, wait a few seconds, lock off the nipple release the pedal, wait. Repeat process as much as you like until all air is expelled. Repeat on the other wheel. Result - I HAVE THE BEST BRAKES IN TOWN!! I have been doing my own maintenance on cars and rebuilt cars for many years but have never had brake bleed problems before. Thus, is this technique the answer to our X300 soft brake feel - or were the remanufactured calipers defective before my returning them for investigation? Is that a touch cynical?

 

I have seen a post either here or on the XJ8 forum with the same issue. Some one suggested what I think was a similar procedure with the explanation that the caliper design allowed some air to remain trapped unless that procedure was followed. I use a pressure bleed pump and have not had a problem.

 

Very interesting.

I'm wondering why what happens *outside* of the bleeder nipple would make a difference, though ? I mean, if the hose was up, down, or straight, why would it matter? Maybe some air bubbles travel back into the caliper unless the hose is pointed upward?

I'm not arguing with success, though!

Cheers
DD

 

Many years ago I rebuilt the brakes on my MGB Roadster. I had exactly the same issue with getting any brake pedal pressure. I spent all day trying various techniques, pressure bleeder, fast, slow but nothing helped.

I had more or less given up and was sitting staring at one of the calipers while drinking tea. It occurred to me that it was strange that the bleed nipple was on the bottom of the caliper.

Strange indeed. I had fitted the front calipers on the opposite sides and they were therefore upside down.

Stupid mistake I know but in the heat of the battle these things can happen. I don't even know if it's possible to do the same thing on the X300 - but it might be?

 

I agree Doug, can't see how anything outside the bleed nipple would matter but then again I've heard/seen stranger things!

 

I performed this and it's true it works. Funny, maybe a pressure thing.