Vibration suspect brakes

[Hadleigh007]

Hi Everyone,

Thanks for all your help through the forum so far it is very much appreciated. I was on my way to the train station to pick up a friend on Friday. Suddenly at 50mph there was a very strong vibration through the steering wheel. I pulled over, had a good look round inspecting the tyres but couldn’t see anything.

I set off again and the vibration had gone, however next time I touched the brakes there was a very strong vibration through the steering wheel again, and the vibration at 50mph returned.

I pulled over again and as I was slowing wound the drivers window down and could here a slight catching at the drivers side front. In my infinite wisdom when I stopped, I touched the drivers side disc… boy was it hot!! I checked the other discs, they were hot but not as hot as this one. Incidentally last time I washed the car the front drivers side wheel seemed to have more brake dust on it than the other wheels.

After letting the car cool for ten minutes, selecting drive and reverse a few times the wheel was free. I then gently drove the car the rest of the way (a 65 mile round trip) with no problems just being very gentle with the brakes and using them as little as possible.

My question therefore is what do I do now? How do I check if the disc brake is always binding, if the disc is warped or if a brake calliper piston has rusted a little and caused it to stick.

Any advice appreciated as always,

Thanks.

[ptjs1]

Hadleigh007,

On many cars, vibration under braking often points to warped discs. However, on X308s a number of other factors can also give that sort of symptom.

Based on what you've detailed, if it was my car, I would start by:

- checking the brake pads. When they wear right down, they can lose the friction effectiveness unevenly leading to vibration under braking

- checking that the front flexi hose is not worn. If a flexi-hose starts to collapse internally (often difficult to see) you can get fluid lock as the brake fluid is pumped to the caliper but can not release back, thus causing the brake to slightly lock on.

- checking for a sticking caliper (as you've mentioned). If you remove the caliper (but not disconnect the brake lines), you can often work it free, remove any slight corrosion of the caliper piston in situ, lubricate it and refit

- removing any rust on the edge of the disc. Whilst this won't cause the hot disc to which you've referred, it can cause vibration under braking as the pad catches the edge of the rust.

Good luck with resolving the problem

Paul

[daveji]

With a primary safety issue like brakes I would consult my independant professional. Much better to leave it to someone who knows what they are doing and takes full responsibility for their work.

[joejag308]

Another point to look at re Pauls flexi brake pipe tip.....
If you are replacing the flexi brake pipes ...for a few more quid you may as well get the braided type....this stops the odd bit of expansion under heavy braking and also gives that more solid pedal feel......these cars can certainly go a bit but you also need to stop them too..........Joe

[robv12]

certainly sound like a binding brake on the side of concern

the checks that ptjs1 suggests are quite within the capabilities of any good diyer, however should you not feel confident to the do the work yourself and get your hands dirty, then a visit to a freindly garage would be the next move

should you need to purchase a new caliper, sit down before you ask Jaguar the price, £258.00 plus vat I think was the last one I had a quote on, try a local factors, Dingbro, TMS, PartCo or similar, I got mine for £53.00 plus vat delivered

[Hadleigh007]

Well in the end the Jag had to go to the garage as I couldn't even get the wheel off. Happily in the hands of the right person, the wheel was removed to reveal a build up of rust and collected brake dust. Half an our with a file and some copper grease, the brake components were reassembled and now run freely. Thanks for all the suggestions.