Brake fluid..

[odd]

New question ! :-) (..though Im not sure if this is the proper subforum)

I also have a Suzuki DR650-RSE '95 mod.. This model is like the known DR650, the big thumper, but it has a mini fering and it's kinda heavier (approx. 170 kg dry). I use it for everyday bike, for some small road trips and a bit of dirt-riding.

The "brake problem" started with the front brake brake system. It was veeery soft.. I coulndt even block the front wheel with three fingers pushing it hard at 10 mph. It started to become dangerous!

First move : steel brake lines.
Second move : change of brake fluids (DOT4) with Silkolene brake fluids (higher quality than older ones)

(Notice that the front disk is 300mm in diameter with metal (hard) brake pads.. both products of Braking. )

The problem : the front brake system is totally improved, with lots of stopping power (=endos!) and good feel BUT! when the weather is hot (quite often in Greek summer) the brake becomes TOO STIFF.. Otherways, (when its cold, or during the night) the brake is really soft. I think it's the fluids..

what do you think about it ? :-)

 

[Layton]

Two possibilities.
1. You may still have air in the brake line.
2. I notice you are using the hard brake pads. They don't start to work good until they get hot. Maybe they are not getting up to tempeture when its cold or at night.

Hope this helps.

 

[atc3434`]

Since we are talking about brake fluid, I've got a question as well. Being a total noobie to brake technology, I was wondering if your brakes will go away if you overheat the the entire system. I had some small netting that is used in landscaping get wrapped up in my front brake system a few weeks ago. I didn't notice it at first, and rode maybe 2 minutes like that. Front brake lever went straight to the bars. I stopped, checked out the caliper, all the netting was wrapped up there, and it was pretty freak'n warm. So I pulled it all out... couldn't find any leaks. Pumped the lever up, and its been working completley normal ever since. Could the excesive heat have caused my brakes to go out like that???

 

[dirt bike dave]

Originally posted by atc3434`
Could the excesive heat have caused my brakes to go out like that???

Absolutely. If the fluid boils, it creates bubbles. When you pull in the lever, the hyrdaulic pressure compresses the bubbles instead of pushing the brake pads out against the brake rotor.

Clean, new, high quality fluid will have a higher boiling point than dirty, cheap old fluid. Over time, brake fluid will absorb moisture from the atmosphere and lower the boiling point.

BTW, Motul 600 is an excellent fluid with a high boiling temp.

 

[atc3434`]

Good stuff... that's pretty much what I had figured, just looking for somebody to confirm. Thanks man.