What is the purpose of the small filter-mesh inside the brake-fluid reservoir of a car? What is it supposed to keep out?
A mechanic was changing the brake-fluid in my car and to get this small filter out he had to put a screw-driver and thin pliers down the side of the filter, creating small grooves in the filter. He also punched a tiny hole in the mesh itself. So the filter is probably not 100% effective anymore. Is that a problem?
I cannot find this spare part anywhere and suspect that I have to buy a whole new brake-fluid reservoir if I want a new filter (it's a Fiat Ducato model 244 from the year 2004).
Just to clarify. The mechanic took the filter out in order to put a small vacuum hose into the brake-fluid reservoir and suck the fluid out. Afterwards he bled the brakes. Then he reinserted the filter in the reservoir before he filled it with new brake-fluid.
But the mesh is so fine that I wonder if it's intended to keep out small dust particles or whatever. Because the mechanic poked a tiny hole or two in it, probably not even half a mm wide, and there are also slight grooves in the sides of the plastic-cup where he put in the screwdriver and pliers, so I wonder if that is perhaps enough to make the ultra-fine mesh ineffective at whatever it is supposed to keep out?