Hubster, my 14s front brakes were feeling pretty weak, lever was firm but coming back to the grip when hot so I decided it was time to change fluid and bleed the brake system.
I used new DOT 4 fluid and bled a lot of air out of the system, now feels like new again and lever is very firm and out where it should be.
My question is on the black rubber diaphragm in the front reservoir. The service manual and owners manual say nothing about the purpose of the diaphragm or whether it should be fully collapsed or fully extended when servicing the reservoir.
I assume it prevents the brake fluid from sloshing around when the level is low and thus prevents unmasking the intake port to the master cylinder.
Also creates less space above the fluid to draw in moisture.
The manual says to service to the top line but when you do this and the rubber diaphragm is fully extended, it pushes fluid out as you screw the reservoir cap down. I ended up filling to the low line on the reservoir and then with the diaphragm fully extended and with the cap screwed on, the level was pushed up to the topline.
This seems like a fairly important detail omission in the service manual. Is the proper method to collapse the diaphragm completely and then service the reservoir up to the top mark?
What sayest thou Sir Hubalot?