Originally Posted by etstrine

Cromagnon, I am not an expert by any means but I do need to ask about your switching from dot4 to dot5 brake fluid. It is my understanding that if a brake system is not designed for dot5 fluid you should get that stuff out of there 'immediately'. Dot5 fluid can corrode systems not specifically designed for dot5. That may or may not have contributed to your most recent system failure but it will surely contribute to one in the future. Look at your owners manual or the cap on your reservoir and only use the fluid specific to your bike.

Originally Posted by sgdiesel

Do some research on seal material compatibility between DOT 4 and 5, especially when changing between the 2.

An o'ring or rubber seal might only cost you a few pennies, but it's value in a safety system is priceless!

Originally Posted by AnotherBlackSG

Maybe I'm missing something here? When going down a long, steep grade, I use the engine (lower gear) more than anything else to keep me at a safe, steady speed. Why would anyone "ride" the brake/s in that situation??

Originally Posted by cromagnon

Etstrine and rkoivisto had the best answers.
Checked the level and it was low. Also guy at Autozone where I picked up some fresh DOT4 said 4 & 5 together causes evaporation ... I'll take his word for it since it was low. Completely flushed it out ran about 2 pints through the bleeder, then brought it up to level. Should be OK. Thanks everyone ... good learning thread I guess

Originally Posted by cromagnon

Was riding the Blue Ridge Parkway on Saturday. Was a blast, most of the leaves were already down, so hardly any traffic. Oh yeah it was cold too. Anyway had the wife on the back and was zipping along pretty good. Decided to exit the Parkway at Afton mountain. Coming down 250 decided to jump on Route 6 which twists and turns down the mountain really steep. After a couple of wild turns hard on the brakes, my rear brake went out completely. My wife could tell there was something wrong, I used the engine and the front brake to come to a stop. Turned around went back up the mountain and got back on 250 where it's pretty much a gradual descent.
After a while I managed to pump the brake back up. Must of overheated the brake fluid and foamed it up.
My question is, after 2 more days of riding on flat roads, the brake seems to be working fine. Should I be concerned and replace that fluid? I put Dot 5 synthetic in the last time I changed the pads.