Hi All.
I've recently bought a Mk3 Golf TDI estate that has been well serviced and looked after.
However... the previous owner did mention that he'd always felt that the brakes weren't quite as good as they should be, and I've noticed the following:
On the initial prod of the brakes, there seems to be reasonable force.
However... if you apply them softly three times in succession, the pedal is firm, but the brakes don't seem to be doing nearly enough work, not least compared to the first prod.
My initial thoughts were 'change the fluid', and sure enough this proved to be rather murky.
Doing this has improved the overall bite when braking from higher speeds, but the problem above is still in play which, having tested the master cylinder as per the Haynes book of lies, I'm left concluding that it's an issue with the servo / non-return valve / vacuum pump.
If you brake as above but in a lower gear with the revs much higher, you can feel the brakes biting that much more when you do the second and third prods of the pedal.
So... before I start pulling it all apart and throwing money at parts I might not need, any ideas as to which is the most likely culprit?
I've checked the vacuum pipework between servo and pump, and there's no obvious leaks, and no hissing when the brakes are applied leading to me to wonder whether it's an inefficient servo (however as I've already said, it seems to have enough pressure on the initial prod of the brakes), inefficient vacuum pump (being a diesel, the vacuum for the servo is not drawn off the inlet manifold and is instead generated by a pump driven off the engine), or simply the one way valve in the vacuum pipework not closing and allowing vacuum to go back to the pump rather than being stored in the servo.
TIA for any useful advice.
-- JackH