Just started up the cat for the first time in 6 months, after a battery charge. She sat in the driveway all winter and still had 32psi in all four paws. Started up first try with old gas in the tank a she immediately started purring like contented kitty.

However, she did not want to move after selecting R. Felt like the wheels were rusted and locked up. It took a little gas to free them up.

Now the issue, when apply brakes, pedal felt mushy, brake pedal pulsated and front end had a shimmy under braking. Drove for about 30 minutes. Brake pedal seemed to firm up a bit but the shimmy and pulsating never went away. It feels like a warped rotor in the brake pedal but the rotors were fine when I parked it last November. There is no pull to the left or right under braking. If some of the calipers are sticking, could it result in the symptoms I am having. Any suggestions would be appreciated. Thanks, Tim

 

I drove new Dealer Trade Cadillacs for many years and the same thing happened to cars that were stored outdoors in the damp/wet weather. The part of the Brake Rotor that was exposed to the weather would rust. The part that was pressed against the Brake Pad would be free of rust.

The result was moderate to severe pulsations when braking.

The techs referred to it as "Lot Rot".

The rotors had to be turned on a Lathe to remove the Rust.

 

6 months in the driveway without use will cause quite a bit of rust especially on the rotors, and possibly the pad backs, exposed areas of the pistons and brake hardware. Try some really agressive braking to clean off the rust (in a safe area). If that does not clear it up, the brakes will need to be inspected.

 

Paul and WhiteXKR,

thanks for the replies. I am guilty of the lot rot for sure. Will try some more aggressive braking to see if I can scrape off the crud. I did try this to a limited degree but backed off due to the extent of the front end shake. I was worried the shaking going on might break something else.

Do you think I might have any luck using steel wool and some rust remover on the rotors?

thanks, Tim

 

Tim: I just spoke with the Service Manager at the Cadillac Dealership that I drove cars for, and he said that the only remedy for the rusty rotors was to cut them, or, in extreme cases replacement.

 

When I had my '03 XK8 inspected by a Jag dealer shop before I purchased the car, I was told that Jaguar does NOT recommend machining the brake rotors at any time... I am sure my eyebrows went up a bit. Sounds like a good way to make more money. Any comments on that? Proper machining of brake rotors has always helped extend the life of rotors on my other cars.

 

I will not change the pads on a car without replacing the rotors! I know a lot of people will do this for on the cheap, but I value safety with my brakes want them back to OEM specs when they are replaced. After market brakes for the most part are better quality than OEM.

 

The problem can be dealt with by using an angle grinder equipped with a rotor surface kit made by 3M that removes the rust and pad debris with abrasive disks.

'Turning' on a lathe is not required and just machines away expensive metal. If a rotor is well and truly warped, it's junk.