Driving yesterday, I smelled a bit of hot plasticky intermittently. On a pretty busy road with a 55 mph speed limit, the pedal got very soft and the smell got worse. I pulled over onto a safe side street. There was smoke coming out of the front right side. I got out of the car, afraid that something had caught fire under the hood. No smoke under the hood but a little was coming out of the front right wheel well. The left front wheel was normal warm from driving. The right front wheel was very, very hot. I got a flat bed tow.

Later, at home, I took the right front wheel off. I wanted to see if there was anything obvious. I didn't see anything and I could spin the hub by hand. I'll measure the brake pads and disc later, but the pads had about 3mm of material left and the disc only had the slightest lip from wear.

What could the problem be?

• Locked brake? Then the wheel wouldn't spin by hand, right?
• ABS fault? I didn't hear or feel the pump operate.
• Riding the brakes? I'd think both front wheels would have gotten hot.
• Something else? Master cylinder?

 

It's likely either a stuck caliper, or more likely, a failing brake hose for that wheel. The hoses fail on the inside, and start acting as a one way valve allowing you to brake, but the hose won't let the pressure release when you get off the brakes. If the car sits for awhile, the brakes will gradually release. If the hoses have never been changed, now is the time to do it. It's not hard or expensive if you DIY. Exercise the calipers at the same time, pushing the pistons all the way in, then using paint stir sticks between the pistons and brake rotor, step on the pedal and push them out. Do this several times.
while your at it, be sure to flush the brake fluid thru the system. 95 model year cars used two different designs of ABS. If your car has a rectangular brake fluid reservoir, there is a very particular way you need to bleed the brakes. There has been a lot of discussion here on the correct procedure. If your fluid reservoir is a triangle, you can bleed them pretty much as a normal brake system, as long as you don't let the reservoir go dry when bleeding them.

Jon

 

Thank you, Jon, that sounds like the most likely cause.

I have the TEVES IV system, which I think means I can bleed them as normal as long as the reservoir doesn't go dry, as you mention. Is there anything I should know about the procedure or hoses? I have the service manuals and will check them out later. Does anyone know a good supplier for the hoses?

 

RockAuto has them pretty well priced.

 

Rockauto is a good source.

 

Any reason to go with the OEM Jaguar parts for 10x as much?

 

No. Chances are they come from the same place in China that the aftermarket ones come from.

Jon

 

Because you might love paying 10x more? You want to support your local Jaguar charity?

No. I have replaced one of my hoses from Rock Auto and I found no fault with the quality. Just pick a reputable brand from their offerings.

 

Thank you, Jon and Vee, I'll take your advice!

 

I had this happen on my 1994 XJS. It was a sticking caliper. They will get so hot the brake fluid boils, hence no brakes. If this is your problem I would suggest rebuilding the caliper with new seals as the high temp may have damaged the existing ones.

When you remove the pistons clean the bores and pistons of any corrosion. The dust seal has probably failed letting water in. Other option is to get rebuilt calipers, relatively inexpensive.

I am not sure just exercising the pistons will fix the problem.

Also examine the brake pads for any damage (cracks) caused by the overheating.

Finally you may want to check the wheel bearings. The heat may have turned the grease to liquid

 

Thanks, Stuart, good advice. I'll look into replacing the caliper, pads, and rotors while I'm in there. Will also check the bearings.