Brake Master Cylinder Sight Glass Replacement

Hi Guys,
I’ve just found a great way to replace crazed plastic sight glasses on master cylinders without having to buy a whole new master cylinder at $250 ea.

I tried optometrists first, and their machinery couldn’t cut a small enough circle of lens material, then I bought a cheap watch and took the glass out of it, but it didn’t fit well enough, so I siliconed the joint but it still started weeping after a couple of weeks. I contacted a number of places that laser cut plastics, but that didn’t work for me either.

Then I took it to a watch repairer called A. Miles & Co, in Wooloongabba QLD, and they were able to find the right size watch glass and fit it in tightly with a special tool. After so much mucking around, it was great to finally get it done so easily and well, and for only $33.

I’d thoroughly recommend them, or any good watch repairer in your area, although they would need to have a fairly large stock of watch faces.[^]

Thats a handy tip. I wonder if there are any traditional watchmakers/repairers in the UK who could tackle it? Or has anyone found another way to replace the old yellowed lenses on the m/cylinders?

Hi i found some lenses for Dambach lift truck that fitted then stuck them in with loctite green bearing saver.Tried several silicon sealers but no success this mod was done to an FJ 1200 5 years back and still working.[8D]

Had to replace some Crazed Windows.
They are Plastic from the Factory.

I found a good place to get the Mineral Glass discs;

The price was great, and the 5x7 Bubble Envelope delivery was cheap and fast.
These guys ( were crazy,… minimum order of $15usd, minimum International Shipping is $45usd.
That’s almost $80cdn at current exchange rate, for the first part.

I ordered the 16.8mm 1mm thick Mineral Glass ($1.25 each). There is a little bit of movement still in there, so next time I might get the 16.9mm and splurge for the 1.5mm thick ($2.00 each) (VF1000F).
Such a Deal!