Why do you need to diaphragm in one of these? Seems a bit daft to me. Surely it limits the brake fluid volume and will cause it to spill everywhere when I screw the lid on?!

http://www.cbsonline.co.uk/product/SINGLE_BRAKE_FLUID_RESERVOIR_FLRES1

The diaphragm squashes back above the fluid, as the fluid level reduces it 'unfolds' and takes the space of that fluid, preventing the fluid coming into contact with air.

OK. maybe I should not have mounted it on the inside of the lid then (which looks like what is supposed to happen). When I do that the diaphragm fills will air and wont squash!

does it not squish back on itself if you squeeze it against the lid with your fingers? (so it's flat against the lid).

The idea is it stops moisture entering the reservoir but still allows the fluid level change due to expansion or to take up wear.

Should be a small hole in the centre of the cap to allow air to flow in/out.

I have Willwood resivoirs and I have no Diaphragm in either of mine (front or rear). It also does have a hole in the top of the lid.

What wrong with air getting too it?

I have had no issues with my brakes at all but no feeling alittle uneasy!!

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Originally posted by bi22le


What wrong with air getting too it?

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As above really. Hygroscopic was the word i couldnt remember.

The diaphragm seals the reservoir from the cap and its hole, so that it flexes with the fluid level as air moves in and out between the diaphragm and the lid.

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Originally posted by contaminated
Why do you need to diaphragm?

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