every 2 weeks i get the brake fluid light coming up so i put 300mls of liquid to bring it up to level.
but after another 2 weeks as passed i needed to had the same again this is the 4th time can any help me on this matter.
where is it going ?

ALL THE BEST MATTHEW

2003 XJ350

 

ouch! That is not good, you need to get it looked at and fixed.
It's a sealed hydraulic system, so either it's leaking from a brake line, one of the calipers, or the master cylinder in all likelihood.

You can look for wetness on the calipers or lines, easiest if the car is up on a rack. Or it can be the engine bay around the master cylinder. Likely you'll find your leak.

I've seen a few where a master cylinder leaked into the interior of the car, fluid was soaked up by the carpet so it was hard to spot but that's an outlier.

 

I believe there is also a brake line junction block at or near the rear axle and it's covered so you will not see it without removing some insulation/heat shields.

 

My money is on the brake fluid being sucked into the engine via the power (vacuum) brake booster.
You have a fluid leak from the back of the master cylinder that drains into the brake booster.
Do you have white smoke puff on first start up in the am?

 

Exactly what I was thinking !

 

I keep finding little drops of fluid on the spokes of my front wheels, but I don't see any brake fluid being lost. That's the only fluid I could see possibly appearing on the front wheels under any circumstances. Could it be such a small amount that it doesn't deplete the reservoir?

 

I doubt that the booster could suck in brake fluid, if it could, it would cause a vacuum leak in the intake. The more likely scenario is that there is a loose or dodgy washer between the brake hose and the caliper.

 

Sorry Oldmots, You are in error.


I tried to post a long winded post on the hows and whys but lost it in a computer glitch. Dang.


So you will just have to look it up yourself. Sorry.

 

good news we are closer to fix the leek...........

I have attached a photo of the caliper rear right hand side drivers side after looking for the price on uk jaguar £320 later but before i go down this route i would like to know if i can just change the seals which is where the leek is coming from, dripping from the spring just behind the piston.

thank you and every one that helps me get to the bottom of this.........

matthew barden
XJ 350 2004 3.0L amazing car

 

i think you are right i have taken a picture of the leek and hope you can help me all the best matthew

 

" i would like to know if i can just change the seals which is where the leek is coming from, dripping from the spring just behind the piston."

Used callipers are avilable on E bay

 

You can also buy rebuilt calipers at most auto parts stores; at least here in the states. they basically clean them up and put new seals in; much cheaper than buying from Jaguar.

 

Also I can fly stuff from England so just the delivery cost which still works out much cheaper than France...

 

Seal kit:

Jaguar XJ Type X350 Front Brake Caliper Repair KIT 3856 | eBay


Just checked and you need rear seals but I am sure vendors can help.