Hello experts,
I have recently had some problem with the brakes, all with the grace of moron mechs here in this part of the world, who are simple labors/helpers turned or self-qualified as mechanics.
The pads were changed and the rotors polished around 15 months back and the car driven for not more than 7k miles after that. This year the car went for annual inspection for the purpose of registration, and they found some sort of irreversible fault with the left front side. I took the car to the same mech who had done the previous job of the pads and the rotor polish. He simply [without any logic] assumed that it could be a problem with the BMC, and had also opened it. Meanwhile, at the same time, (as I had consulted with another expert forum member), he suggested that since there was a problem in just 1 wheel, it could be just that wheel alone, and not the BMC. I passed on the same message to the mech and he kept silent and fixed the BMC back. Later it was found that the caliper was little sliced from 1 corner and hence the piston kit replacement would also not work. I got the caliper replaced, but the car still did not show satisfactory results. On applying brakes, it used to produce screeching, scraping and loud scrubbing sound that would last for couple of miles after that.. This led me to find another good mech, (and I was lucky to get 1 who was qualified and genuinely experienced with jaguar repairs). On inspection of the brakes, he noticed the left front pads and rotors were completely worn off. He strongly advised to change the rotors, the pads and the piston kit too, to make sure that no used part wears off the other new parts. And to keep the entire front balanced, should change both the sides of the front. Once that is done only then the BMC can be tested for its proper functioning

My question is, 1) am I going in the right direction now ? 2. Can anyone advice what are the brake OEM for pads, rotors, and the piston kits? The local dealer here has got the HELLA brake pads, and the original piston kits. But the rotors are simply qualified as UK made, without any name, and guarantees for a minimum life of 30k miles. Is it advisable to go for this [unbranded] UK made rotors? 3. What is the average life of the original rotors, given the normal comfortable driving condition ? Any other advices that I may have to ask ?

Waiting for experts.
Thanks in advance.

 

A few thoughts:
1) Since it was both pads worn down, assuming they really had been changed out, it would suggest the caliper is functioning OK. And that wheel brake was continuously applied. DSC would show on the dash if the ABS was activating it.
2) To be continuously being applied pressure must be staying in the caliper - surprised you did not smell over heated brake pad!
3) One failure that will stop the pressure venting back is when the flex hose collapses internally. They progressively get worse until they will not release at all. Had that happen twice while on vacation in the USA. Smoke was billowing out from the front wheel, while at a stop light - cars all around, no one seemed to notice!

 

Hello Grasshopper
It would be nice if you could put your country in your signature. If it's UAE at a guess, then camels don't have brakes.

We have "moron mechs" here too, by the way. I take my XJ to a recognised "Indy". The local mech will do for my "lesser cars".

As an expert (Thank You!), I can reveal that "screeching, scraping and loud scrubbing sound" is not normal. And neither is "left front pads and rotors were completely worn off".

 

Thanks Edward,

Just remembered to add on the missed out points.
After replacing the caliper, the brakes pedal was a little spongy, and had to be pressed more to apply proper brakes. Informing about this to the mech, he did the bleed on all four sides again and it all seemed perfect immediately and for the next 2 3 days, after which it began to get little spongy again, and gradually within a week, the pedal went fully in to apply the brakes (and dangerously like no brakes).

What does this suggest should be wrong ? The mech or the brake ?

Please advice.

 

Hello ChrisMills,
I like that. But luckily, I dont drive a camel, hence I am a member of this forum.

Unfortunately, there is nothing like a recognized indy here in this world of camels. They are only camels. 🐪
Please make me an expert by advising what would be wrong here. And what should be the next logical step.

 

With engine not running, does pressing the brake peddle slowly sink to floor? So far with the additional info it sounds like bad seal in the master cylinder.

 

No. the pedal sinks only with engine running.

 

Can anyone advice what are the OEM names of brake parts that Jaguar uses ? I was doing some Google on the parts and got info that bosch and textar are good OEM. Can anyone advice what is the compatible BOSCH part number for this jaguar, as that may be available locally, and make this easier.

Also is Britishparts.co.uk a reliable source for jaguar parts ?

 

If it feels hard - not springy - with the engine not running - but goes down while running, the mechanical bits are probably not the problem. My bet would be air in the ABS unit. It is sometimes hard to get rid of that. I think there is a special sequence for that, in the workshop manual or TSB, and also one for bleeding a new caliper as opposed to a used one that has fluid already in it.

 

It sounds to me like air in the system also I bet those pads were not changed.

 

I have ordered new set of pads and the discs from britishparts.co.uk. Should be arriving here in the next few days. I will know the the existing pads when I take the the car to the repair shop for the change.

Regarding the air, something strange happening now. The mech blead the system again to tighten the brakes, and it remains fine for a test drive of 1 or 2 kms. When I drive back home, it suddenly goes spongy (fully pressed) after driving for around 12-15 kms. I slow down the speed and keep distance. But suddenly, after another few kms drive, the brakes tighten. Of course all the way home it gave a scrubbing sound and the steering wheel shaking a bit. Post that, when i slow down and shift the gear to neutral, it comes to a stand still as if brakes are being applied.

What does all this indicate please ? Is this only the pads and the discs, or something else too ?