Any help would be appreciated.
I have a 300 TDI Discovery (96) auto box, and the cruise control stopped working, I checked the hoses and they were split so I replaced the one from the actuator to the "Tee" piece and the one from the brake switch to the "Tee" piece, The one from the pump was also split at the ends so I cut the damaged bits off.

The vacuum pipes now hold the vacuum and the pump works as I put 12V across two of the terminals, it sucked the bellows on the actuator in, if I clampped the pipe it would hold the vacuum no problem, if I stopped the pump the vacuum was lost.

So is there supposed to be a one way valve in the pump that to keep the vacuum? or does the pump run continually to maintain the vacuum?

Should the actuator arm move much? mine dosen't.

If the vacuum system is as I suspect OK where do I go next?

Cheers

Have you accidentally loosened the cable connection in the end of the bellows ? it has a rod with a ball on the end which is retained by a screw cap.

Cable from bulkhead (presume throttle) is still attached to the arm that pivots with a rod into the bellows. The bellows don't seem to pull the rod in very much though (when I suck on the vacuum pipe) certainly not enough to accelerate the engine.

Sonic 1 said:

Cable from bulkhead (presume throttle) is still attached to the arm that pivots with a rod into the bellows. The bellows don't seem to pull the rod in very much though (when I suck on the vacuum pipe) certainly not enough to accelerate the engine.

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The vacuum pump has a bit more suck than u have also have a look at the brake vacuum dump switch and the switch on the clutch pedal if you have a manual box,

Thank's, what I might try is run the pump and see how much it will suck, I have already changed the switch and dump on the brake pedal (auto box) as that seemed a bit suspect, the vacuum system does seem to hold the vacuum no problem.

Then the hose connections are iffy worth a check maybe.

I had simialar probs with my cruise but found it to be the brake dump switch. however once this repaired I found engine would not accelerate and found it to be the adjusting ferrol on the bellows where the cable connects. The gap between the front of the bellows and the first edge nearest the bellows of the ferrol should be 16mm so check thats right and cable adjusted up properly

hope that helps cos mines running ok now gd luck