Chums, I have a 9” brake servo in the shed, taken from a MK2 Golf. PLEASE NOTE it is NOT on the car and nor will it be for several months. Is there a way of testing that it works? On the bench, NOT on the car. I know there are a lot of capitals above but I am trying to preempt someone saying “does the pedal go down when you start the engine” TIA
Never found the need to test one off the car, guess you could rig up a test piece using an old servo pipe and a schrader valve! Pressurise it see if it leaks.
Just wanted to make sure it works before installing it. It would be a massive pain to find it didn’t work after installing the engine! I watch a couple of YouTube vids and there are a couple of ways. One is to connect it to a vacuum pipe on a running car so could unplug the golf and connect it to that. The other (less scientific way) is to push the plunger in, plug the vac hole and see of there is any air leak noises.
Right, should you be able to do this? Isn’t there supposed to be some kind of membrane or something. Or, is the seal only complete when the MC is connected?
My engine oil sucker-outer pump creates a vacuum, could you connect one of them to the vac pipe and see if anything moves? Mine turns out to be rather good for priming my oil boiler pipes, handy bit of kit! I think you need to mount a MC and vac spigot to test it, explains normal function fairly clearly which implies a test protocol (apply force to replicate brake pedal use, measure output force with and without vacuum applied). I'm imagining a weight to imitate the pedal force, and a pressure gauge to measure the output. Not going to be a quick test is it?!
put a master cylinder on it, find a random servo hose in your shed/scrappy/wherever, hook it up to your engine and start it. stop engine, wait a bit, remove vac line or the master cylinder from servo. if it goes 'whooosh', its storing vacuum
Just to round this one off. In the absence of a MC I made a plate and sealed it with silicone. Then simply connected it up as normal and hey presto it works The plunger becomes easy to press and although there isn’t a whooooooosh! There is a whoosh when the pipe is disconnected after the engine is switched off.
