Does this sound like vacuum pump?

Went to use 300Tdi brakes yesterday and pedal stuck solid part way down with no braking. It worked when I released it and tried again but repeated it a few seconds later. Seems ok up and down the drive today. The pump was replaced a couple of years/ 12000 miles ago and doesn't seem to be leaking. Previous threads seem to point to the pump when pedal does this. Can anyone confirm this?

Don't want to replace the pump unneccessarily and need to get it fixed quick cos I need it for work.

Cheers

lagpunktortoni said:

Went to use 300Tdi brakes yesterday and pedal stuck solid part way down with no braking. It worked when I released it and tried again but repeated it a few seconds later. Seems ok up and down the drive today. The pump was replaced a couple of years/ 12000 miles ago and doesn't seem to be leaking. Previous threads seem to point to the pump when pedal does this. Can anyone confirm this?

Don't want to replace the pump unneccessarily and need to get it fixed quick cos I need it for work.

Cheers

Click to expand...

If the vacuum pump fails you should still be able to brake but would have to pretty much stand on them.

Is the vacuum pump ticking?

Try pulling the vacuum pipe off the servo and see if it has suction.

Doesn't sound like vacuum pump - pedal sticking half way down. Loss of vacuum gives hard pedal but still works .
With engine off press and release brake pedal a few times to exhaust vacuum .
Then with brake pedal pressed start the engine - you should feel the pedal go down as the vacuum begins to help .
No change means no vacuum being produced by pump .
I often came across the problem in older VW dsls when the diaphragm in the vacuum pump split - but as the edges of the split could sometimes seal against each it could work on and off which could be a bit confusing ( and scary ) .