Hey guys,
I have a 2004 jaguar x-type 3.0 AWD, oneday on the highway my brakes stopped working properly, I had a leak in my brake lines due to rust. I stopped at a gas station and filled the fluid kept going, reached my destination and then called a tow truck. I got new brake lines.

The mechanic had a lot of trouble getting the car to bleed after placing in new brake lines. He said someone had removed a rubber gasket from the brake fluid reservoir due to which he wasnt getting pressure. He placed a rubber gasket and said that the brakes bleed fine. I took the car for a test drive and it was driving perfectly. But when I was back on the highway I felt that the brakes had come on, and I had to press the accelerator a lot more than usual.

I have taken it to other mechanics and they said that they dont know whats wrong. The brakes automatically seize and then un-seize, happens only to the left side wheels as they get hot and smelly. Anyone ever face this problem? Any help will be greatly appreciated.

 

It's hard to nail down without seeing the car, BUT try turning of the Dynamic Stability Control. the DSC will apply the brake to individual wheels if it detects the vehicle going in a different direction than the one the driver intends through the steering wheel input. If turning off the DSC makes you problem go away, then you know where to start the Wumpus hunt. You might have a wonky lateral acceleration sensor, or yaw rate sensor, if either one is bad the PLC will think you are trying to turn when you aren't and apply the brakes to help you straighten out- when in fact you really are going straight.

MAYBE it's an ABS issue, but you didn't mention any dummy lights or messages. I would check the mechanicals first before monkeying around with ABS ghosts.

Good brakes are the highest priority. You might want to change the rest of the steel lines, if one was pinholed, the rest probably aren't much better. I would recommend not driving the car until it's sorted. Oh, and find a new mechanic. Any qualified mechanic should be able to make short work of a brake problem.

 

With ABS pump problems your brakes should stick diagonally, like FL/RR or FR/RL. Agreed with Ozzlefinch, try turning DSC off.

 

I don't trust mechanics, who do a half assed job, and there is no way one of the rubbers at the reservoir could have been missing or you would have only been driving on 2 brakes until then. I would look under the car, especially at the brake bleeders. If one or two are broken off, it means he bled the brake on that circuit with the brake hose, and that is not the right way of doing the job.

On the cars I worked on, a brake that suddenly starts locking up has air in it, that expands as things heat up. Disc brakes always have a little drag on them, so the friction is there for heat build up. Just an Idea, but if you find a broken bleeder(if the lines are rusty, why wouldn't a bleeder be) I would replace the offending caliper first. I wouldn't recommend drilling out the bleeder, because it could damage the threads and seat.

If the rubber was missing from the reservoir, he could have pushed it in, and damaged a circuit in the master, or you could have been dry pumping a circuit damaging the master cylinder.....Just a couple of things to look at. It is a little crazy, because as 3lvis said, the brakes work diagonally. I disagree with the looking for electrical problems first, that appear after just replacing brake lines......Be cool....Mike

 

The easiest thing to do first is to turn off the DSC when the problem appears, and if the problem goes away immediately then that is where to start. If the problem persists, then the DSC is not the issue. It's a quick and dirty way to isolate the problem to a specific system on the vehicle. Once that is settled, then the Wumpus hunt can begin.

I agree with checking the mechanicals. As I stated if one line was pin-holed then the others probably aren't much better. And to get a new mechanic. Any qualified mechanic can make short work of any brake problem, and they would certainly be concerned about broken or stuck bleeders, collapsed rubber lines, or other noticeable issues. Not to mention they would CERTAINLY use a torque wrench to tighten everything. I have fired more than one mechanic that failed to torque a drain plug or bleeder valve- torque specs are there for a reason and it's to prevent over tightening and damage as much as it is to make sure the fastener doesn't come loose. I've seen more than one leak that could be traced directly to the failure to torque correctly.

 

Thanks for the help, I actually got the brake fluid tested, and apparently its not brake fluid. The fluid inside has a high moisture content hence it was seizing the brakes randomly. This might have damaged a bunch of things in the brake system.
Did you guys ever face this problem?

 

Sadly, yes, I have seen badly contaminated fluid cause problems. I am glad, however, that you don't have any electrical issues and the problem is on the mechanical side. But is the fluid contaminated now? Or is it fixed and you tested the old fluid? I thought your mechanic bled the brakes, if he did, then why is there contaminated fluid still in the system?

BUT...... with that said, contamination like you have is of grave concern. It can rot not only the lines from the inside out, it can pit brake caliper walls, cause crud build up inside the ABS unit that is hard as concrete, and many other issues which are the stuff of nightmares. With a lot of luck and LOTS of brake fluid to flush through, then perhaps it's not too late to salvage your brakes.

If it was my car, I would pull off a brake caliper on one of the rear wheels and open it up to see if it's still good. If it is, then there is a good chance everything else is OK also. If not, then it's time to spend money.

Let this be a lesson to everybody, all fluid is NOT the same! Jaguar gives you an owner's manual free of charge with every automobile, it pays to read it and follow the lubrication chart exactly. When I was in the Army we would use transmission fluid as both brake and power steering in emergency break downs where we had no choice, but that was in the Middle East. In that situation, any lubrication is better than nothing at all. But at home there is no excuse for mixing fluids or using the wrong one, AAA will send a tow truck if you break down- no problem.

Good luck with your Wumpus hunt now that you have picked up its trail.