Brake master cylinder “protector “

[ubusboc]

In the process of rebuilding my front brakes and having a problem getting them to work, I came across a small piece in the bottom of the reservoir.  Clymers says nothing about it except not to lose it.  I think I have put it back in upside down but I don’t know.  Anyone have any knowledge of what this is and does it affect the system pressures.  I’m not getting any response to brake lever moving anything.  Calipers have been redone and master has been redone. Thanks

[Chrisj CMA]

Fill they brake fluid with a syringe at the bleed valve

[ubusboc]

I’m getting fluid from bleed screw but flow is more gravity than pressure

[WintrSol]

That little piece is probably the little shield that prevents the fountain of fluid that goes everywhere when the lid is off while the lever is squeezed.

What Chrisj recommended is known as 'reverse bleed'; you force fluid backwards until the reservoir begins to fill. If the banjo fitting is lower than the rest of the MC, most, if not all, of the air is forced out as the fluid reaches the reservoir. What you describe is a large amount of air at the MC, which this method takes care of handily. Be very careful, as brake fluid will etch paint and polished surfaces; I keep a spray bottle of clean water handy, to help wipe any stray drops away.

[ubusboc]

Got it! I’ll give it a try I’ve done everything else I know to do. Thanks

[RonW]

I had a picture of the 'protector' on file. Screenshot from a youtube video.