I was having trouble bleeding some SLX brakes today and wanted to check the 2 tiny holes in the bottom of the reservoir were clear . above one of the holes is a small shiny flat piece of metal that clips in place . I removed it and it flew off somewhere in to the depths of the garage.Anyhow ..all is sorted now but I didn't replace this little piece and wondered if anyone knew what it is for and whether it's important. I have seen them on motorcycle master cylinders too and presumed it was a kind of baffle to keep fluid above the hole when the going gets bumpy but please feel free to educate me otherwise. you can see the same clip in place on a different master cylinder in the image below ( submerged in the fluid )
I..er... I don't know.
Hope calls it " Deflector plate"
But I am still non the wiser lol
Blimey, never even knew master cylinders had that little part in them.
By tomorrow though, you will have a hundred or so theories on here I bet! Lol
I presume that there is a diaphragm on top of the fluid to allow it to expand back into the reservoir. My guess is the deflector plate is to stop the diaphragm from getting sucked down and blocking the port if it's really low on fluid. Which means it probably won't make any difference except in extreme circumstances.
Two functions.
1. Stops the port being "sealed by the diaphragm in use (as mentioned above).
2. When pushing fluid up from the caliper, such as resetting the pistons, it stops a fountain of brake fluid launching towards the ceiling.
Thank you. Every day a school day.
Thanks Onza..out of interest how did you know that/ where did you find the info?