porsche Posted March 27, 2013 Share Posted March 27, 2013 when the engine was finally started some weeks ago after getting on with build I noticed a tapping noise , friend who is a mechanic came and said he thought vacum pump or cam , so today after much much swearing pump is off , ran engine for 30 seconds and did not notice noise , oil all over place but hey ho that will wipe up , so how does pump work and how do i know it is knackered I noticed whilst playing around the garden in it the brakes where a bit `dead` , not much pressure against the foot , the plunger looks ok , and it is easy to flop in and out , should it have resistance ??? Thank you all again for help , oh did my radiator surround today , cut mounting blocks off surround and just welded the pins straight onto frame , dropped about 1 inch , jobs a gooden . Quote Link to comment Share on other sites More sharing options...
steve b Posted March 27, 2013 Share Posted March 27, 2013 It should have plenty of spring pressure on the plunger , 300Tdi I assume~? You could drill the rivets and strip it to see if its fixable and if so re-seat with pop rivets cheers Steveb Quote Link to comment Share on other sites More sharing options...
porsche Posted March 27, 2013 Author Share Posted March 27, 2013 no spring pressure , so is it just banging against cam , making noise ?? Quote Link to comment Share on other sites More sharing options...
steve b Posted March 27, 2013 Share Posted March 27, 2013 And the bits inside the pump . They do sound terminal when they break , stick a new one on and all will be well cheers Steveb Quote Link to comment Share on other sites More sharing options...
porsche Posted March 27, 2013 Author Share Posted March 27, 2013 borrowed one from mate with spare engine , it does feel different , will try tomorrow and if all well get new next week , busy day tomorrow auto centre consol coming aswell !!! Quote Link to comment Share on other sites More sharing options...
Boydie Posted March 27, 2013 Share Posted March 27, 2013 Very basic unit, a spring loaded plunger/piston which is operated by two cams at 180 degrees on the camshaft (2 depressions of the plunger piston per rotation of the camshaft) The vaccumm is achieved by two simple plate popper valves at the end of the "cylinder', one closes on suction, the other closes on compression, air is sucked out of the brake system and discharged into the engine sump. Being WABCO they are very cheaply made, unservicable and bloody expensive to replace, but other than that they seem to last for a donkeys age. Quote Link to comment Share on other sites More sharing options...
Jode Posted April 6, 2013 Share Posted April 6, 2013 Very basic unit, a spring loaded plunger/piston which is operated by two cams at 180 degrees on the camshaft (2 depressions of the plunger piston per rotation of the camshaft)The vaccumm is achieved by two simple plate popper valves at the end of the "cylinder', one closes on suction, the other closes on compression, air is sucked out of the brake system and discharged into the engine sump. Being WABCO they are very cheaply made, unservicable and bloody expensive to replace, but other than that they seem to last for a donkeys age. Although the pumps aren't serviceable, you can drill out and replace the rivets on the Wabco pumps as noted by steve b, either using new rivets or M5 bolts (IIRC) plus nylocs. The most common fault with the Wabco pump is oil leaking through the cover because of rivet wear, however if its internals are b..ered then you'll need a replacement. I seem to recall reading somewhere that Volvo used a pump that can be used in lieu of the Wabco.... Quote Link to comment Share on other sites More sharing options...
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