One of my drivers have been complaining about the hydro brake pressure taking noticebly longer to get up to pressure in her 09 CE300. No previous problems with the brakes, but is this a sign?
The cap check is a good tip and also look for a kinked or collapsed hose to from the rezzy to the brake unit. you may notice when the bus sits a long time the rezzy will fill to the top and when the pumps turn on watch how fast the fluid level drops. So a vented cap and free flow are very important to recharging the accumulators quickly.