MOT Brake efficiency results

[RMA37]

Good morning

I would be interested to hear what sort of brake efficiency figures members are getting on their XK8's. Mine is a 1997 XK8 convertible and last year's figures weren't particularly high, but passed, in fact the car has never failed an MOT. The car is used regularly but less than a 1000 miles this year, total now 31000. Pads and disks look fine, but I thought I'd take wheels off and have a good look around before it's tested this year. I was told not to pull the handbrake up too hard by the previous owner who had it replaced, maybe because of doing just that. Any ideas, tips or suggestions from anyone will be most welcome. Thank you

[mike020150]

Travelling only 1000 miles a year in any car is a recipe for sticking brake pistons unless the brake fluid is changed very frequently (or non hygroscopic brake fluid is used). The actual percentage efficiencies for an MoT pass aren't particularly high and no XK8 with good pads and discs is likely to fail on overall braking efficiency. They are much more likely to fail because low mileage cars develop the sticking pistons mentioned above which then result in braking imbalances.

The advice not to pull the handbrake on hard has to be regarded as somewhat dubious. What would happen if you followed that advice in an emergency? It suggests something there may require attention. Mike.

[RMA37]

Thanks for your reply Mike. Yes I've had sticky pistons on other cars, which were used full time, and it's one thing I'll be checking on this one before it's MOT. The info on the handbrake was given to the previous owner by Jaguar when he had the mechanism replaced. Not sure why, but I guess it was because the car was stored every winter (professionally) and not run during that time.