So, I've officially had my '02 Jag X-Type 3.0 for 3 months now, and I'm still trying to doctor 'her' up from previous owners, granted she only has 71,000 miles..

So, to the point of my post - the day I got her, I had to travel the interstate and after pulling off on my exit (after going 70-75mph) I almost rear-ended the guy infront of me, but it was due to, what I would call a 'slow-reaction' from the pedal to it's brain. Brakes are in good condition, I wouldn't say GREAT, but close.

This problem only happens after slowing down from a high speed. If I'm driving in town (25-35mph), 'she' stops when I brake, but now that I know what may happen when being on the interstate, I'm having to basically brake once I take the exit, so I'm not laying on a 'dead' brake when I get to the stop sign.

My mechanic took a look today (during state inspection), and gave me 3 ideas of where to start; front rotors and brake pads and a new brake booster. I know I should start small and go with the basic things, but is there anything else, besides those 3 things that I shold look into?

I hope I made enough sense as to explaining this problem
Thanks in advance!

 

Was it raining?

 

ibeheav, to what Cambo is asking, if someone put on some unique pads, it may be that the pads require to be a bit warm to get good gripping ability. So, when you are in town, the pads never really get to cool off and therefore, remain sticky and give you the good braking like what you like. But, when on the highway, your brakes have the chance to get to ambient temp and loose their stickiness. Do you notice the first stop of the day being a bit long too? That would prove what I am talking about here.

As long as the steering wheel is not wobbling when you are braking, then the rotors should be fine. You have stopping ability, so, odds are the master brake cylinder is fine. So, that really only leaves the pads as being your problem.

 

I guess I should have stated the weather conditions and that I hadn't just washed my car or passed any water spots, because that was the main question I was asked by the mechanic. But no, no rain or water in sight. Thermo, no wobbling on the steering wheel when braking, and all of my stops are pretty short, only drive on the interstate or at a high speed (out of town) 3-4 times a month. I was hoping it would start with the pads! Thank you both for replying!

 

Could your brakes be binding...heating up at higher speeds so loosing some braking effect .

 

A little update on my situation -

I replaced front brake pads and rotors, and I'm still having the issue. Lately, it's been happening just about every time I come to a stop. I was told by the mechanic that it's a 95% chance of being my brake booster. Cheapest I found was $280, on Amazon.

Was really hoping I didn't have to go this route..

 

lbheav85: Just a thought - if your emergency brakes have not fully released, your rear rotors can heat up, causing your brakes to fade when you need them most - at highway speeds

It's just a guess, but easy to rule out. Raise your rear tires with wheel ramps or jack stands. Or drive one tire onto the curb, the other on the street to gain some ground clearance. Chock the front tires, release the emergency brake, and slide yourself under the rear bumper to look at both rear brakes. The emergency brake mechanism is the cable, spring and lever atop each caliper. If the levers have not returned against the stops, your emergency brakes have not fully release - see attached pic.

The cause could be a stuck e-brake cable, dried grease under these levers, or crud in the brake piston & actuator. Either way, try rotating the levers manually until they hit the stops, then test your brakes on the highway, of course without using the emergency brake.

To get your emergency brake to fully release, there are several threads describing how to lubricate the cable, apply fresh grease under these levers, and rebuild stuck pistons & actuators.

Please let us know what you discover.

 

Ok guys, thanks so far for the advice.. here's another update and now it's gotten worse!

October 10th - I went to my local garage and got my booster put on. This took 3.5 hours (thankfully was only charged for 1.5) and I was told by another mechanic there that the mechanic working on my car 'had a few problems', but everything should be okay. Well, yes, everything was fine for about two days and then it slowly started to go back to square 1.

October 18th - I went on a drive 45 minutes away from my home (wanted to see how the interstate drive would be vs city), goodness, it was a terrifying ride when needing to stop suddenly!

Yesterday, October 20th - I went back to the garage that put my booster on and told them I wanted my car checked over again, since the mechanic 'had a few problems'. So, 2.5 hours later, I was told that a leak was found in my vacuum line (why wasn't this found before?) and they had put sealant on it. So, the mechanic test drove and then told me to give it a try.. NO LUCK! It's worse than before. I'm basically having to lift myself out of the seat to put my weight on the brake pedal.

When I told the mechanic it's worse than before and extremely too hard to press, he said, "Hmmm, I'm thinking that's how they are on these cars." No buddy, I'm not the shiniest tool in the shed, but I do know that with brand new brakes, rotors and a booster, it shouldn't be that hard.

Thankfully, last trip to the garage was of no charge because after the answer I got from the mechanic, I wouldn't have paid anyway!


dwclapp - I had done the tire on the curb thing right after replacing my brakes and rotors and still nothing I hate living so far away from Euro mechanics, but hopefully I can find someone that won't eat my wallet 45 minutes from me. I'm leaning towards the master cylinder, but it's still something I hate to spend money on and it not fix it.

I do appreciate all the advice and tips, though!

 

After a longer run when your brakes go bad, stop the car, go outside and feel with your hand if any of the wheels is noticeably hotter than the other ones. If you have been driving for a while and not braking then they should not be hot, little warm maybe. WARNING: Do not touch the brake discs or you could get serious burns.

 

Why did the garage put sealer on the vacuum line it should be replaced if it is split. They could have partially blocked the pipe using sealer . I presume the booster was a used part , could that be faulty. Your description of events seems to point to a less than capable garage. take it somewhere else and get them to look. It does seem to point to a booster issue.

 

Even if you disconnect vacuum line to brake booster your braking distance would be same, you just need to press brake pedal harder for same braking power. Towed cars with towing ropes from hundreds of kilometers without engine running and car that is being towed has to brake for himself and for car in front and still no problem to stop.

And as for what Thermo said about "unique pads" that don't grip when cold... Not so sure anyone makes so hardcore pads for X-Type and even racing pads have grip when they are cold but they get better when warming up but are usually still better than cheap after market pads.

Hard to say without actually seeing this car but I'd still check if any of the brakes is getting hot while driving on highway, brake fluid that hasn't been changed for awhile gets moisture in it and boiling point of that fluid gets lower, you get little steam pockets in your brake system and voila! no brakes.

Edit: Almost forgot, how could brake booster work in city but not on highway?