Tractor Boy Posted January 21, 2019 Share Posted January 21, 2019 Lost the servo assistance on my 90. Had a look at the vac pump and there was nothing going on so swapped it for a new one. The old vac pump appears to be broken as the piston is easy to push in and out across the range. I guess either the seals or valves bust perhaps. Took it for a quick spin down the lane with the new pump fitted and I have some servo assistance but not enough in my opinion. Standing on the brakes it will only just lock up on a damp road (insa special tracks so not the grippiest tires on wet tarmac). I am wondering if the servo is knackered also... but if I test it it seems fine as I can feel the pedal sink an inch or so when I start the engine up. What do people think, is the new vac pump not 100% or is the servo on the way out. Thanks Ian Quote Link to comment Share on other sites More sharing options...
cackshifter Posted January 21, 2019 Share Posted January 21, 2019 If you have a means to measure it, I tried a brand new Wabco pump and that produced .9 bar (on a cheap boost gauge intended for a petrol engine); its knackered predecessor produced .3 bar. Could also be the non-return valve, and that's a cheap easy thing to change. Quote Link to comment Share on other sites More sharing options...
radioactive man Posted January 21, 2019 Share Posted January 21, 2019 Thanks. Quote Link to comment Share on other sites More sharing options...
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