Reduced brake Efficacy

[SimonR]

I've noticed that the brakes on my R-Series VP are a little unresponsive and I'm wondering why.

If I just jab them on while travelling relatively slowly they work perfectly well as you'd expect, however, stopping from motorway speeds isn't very encouraging. The worst thing is that they seem to fade quite badly meaning that I have to increase pressure on the pedal, the other thing is that if I brake hard for a long period then the last bit, just as the car is comming to a halt, makes a loud grinding sound that reverberates through the bodywork rather.

I took the wheels off last week and can report that there's plenty of wear left on the discs and pads, but I don't know when they were last changed. The car has done 49K so I suspect they have been changed at least once in its lifetime but do you think that aging pads could cause this problem? Could it be old fluid as well? From the history it's possible that they could be original, circa 1983...:eek:

Thanks for replies - I actually have a set of Ledders Driveshaft/brake/bearing asemblies and a new servo/master cylinder to go on but I'd be interested to know what's going on as I'm not going to be able to do the work for a while yet and am therefore going to be driving it.

[E_T_V]

Did you remove the pads the check them? (as they can wear quite unevenly) If you just checked by looking at them I'd suggest taking them off for a better look.

Personally I'd change the pads anyway (they'll only cost you a tenner for a new set), then while you are changing them, clean up the caliper, copper grease all the pivot and sliding points, and the back of the new pads, then bleed a whole new set of fluid into the system. Old fluid absorbs water which then boils when the calipers reach 100 degrees (not very hot really) giving you spongey brakes. If you are experienceing brake fade then it sounds like the brakes are sticking on, (probably a seized caliper) generating the excess heat.
Also it is worth checking the rear brakes too as the cylinder often can leak.

[talkingcars]

The pads could be glazed. It maybe wear on the drums as well.

If you are changing the master cylinder I would put new fluid all the way through the system and if changing the pads consider doing the discs as well.