If any of you have a leaking reservoir cap and haven't ridden your bike over winter be careful on your first trip out. I was going out on Saturday, rode the bike up the drive, pulled the front brake and nothing. Good job the rear brake is so good and I could stop with just that (ha). Bled the brakes and they are fine now so my guess is that the leak in the cap has allowed the fluid to absorb moisture (there are no other leaks) degrading it. That and the fact that I had not ridden the bike for a couple of months meant that rather than a gradual increased sponginess they got the point that they failed completely.
Sounds a bit odd to me , if water boils when your brakes are hot that one thing but unless your drive is really long surely that's unlikey? Given a bleed sorted it isn't it air in the system? Just my 2 pence and I'm no mechanic but just thinking out loud
I'd bet that pure water in the system would give you braking, maybe not for long though. So I'd agree that water contamination wouldn't cause you to have no brakes at all, straight away.
Seems quite a few (although not me) have suffered with this. Solution seems a) periodically remove, clean, replace lid (!) or b) buy an aftermarket one.
Brake fluid is hygroscopic i.e; It has the property to attract and absorb moisture (water). If the brake res.cap was loose (ish) then there is every chance the fluid absorbed the water. Water, containing air (oxygen) will cause your resulting problem. Had similar issue myself so changed to cnc'd caps. .
Water isn't easy to compress , the oxygen molecule tends to stay attached until you heat it hence why the brake fluid tells you it's boiling point when wet ( I.e absorbed some water. He went up his drive and had zero brakes. You can use water as a hydraulic fluid indeed it is used as such with small amounts of additives . Thats why it's a puzzle to have zero brakes from the get go. That's what's confusing me , guessing isn't more likely that small pockets of air in the system when left standing Rose to the highest point in the system and formed a pocket of compressible air now it's bled it's fine . I don't know but don't understand the physics behind absorbing water and zero brakes before any heat is generated .
Mine leaks very small amounts every now and again...... i did read up on here and realised not to try and tighten it further as the screws will distort things further. Took it off, cleaned round the top and edges and reset and tighten the screws back up to normal ....jobs a good un and leak stopped
Just check that the rubber seal is seated correctly - I have had this issue after a service and found that the seal was not fitted correctly. There is a little locating pin in the lid that should match up with a little hole in the seal - just check this ...
Water is just as incompressible as hydraulic fluid. Water only becomes a problem as far as compressibility is concerned when hot brakes cause the water to boil and it produces bubbles - those bubbles are compressible. Water contamination in cold brakes will not cause a slack lever.
Depends how much you use them. I find the clutch needs bleeding at the m/c every 1500-2000 miles on this and the old multi. Brakes have never been an issue tho
