PDA

View Full Version : Clutch hydraulics rebuild



SunbeamTom
03-06-2007, 10:55 AM
I'm rebuilding the clutch master and slave cylinders also cleaning out the line, Is there any reason NOT to use DOT 5 in the clutch system ?
Thanks for any and all input on this theme.

Tom J

tdskip
03-06-2007, 07:20 PM
Here is a fairly useful link with some pro/con's Tom.

https://www.ducatimonster.org/faq/faq_brake_fluid.html

RonMacPherson
04-06-2007, 12:01 PM
Good basic, but outdated info.
First it is hyGroscopic, not hydroscopic. i.e. the esters absorb moisture from the air(and anywhere else it comes in contact with the fluid.
Dot 5 is NOT compatible with all sealants used in brake/clutch hydraulics. Forget exactly formulation it is right now, but one of them commonly used in aftermarket hydrualic slaves dies soon after silicone 5 is installed.

There is a new formulation out, hard to find, most stores do not even know of it's existence unless asked to contact their suppliers. It is dot 5.5 a silicone blend that is reportedly compatible with ALL rubber compountd. As far as the compressibility of silicone versus ester based(3/4/5.1) minimal difference. Properly bled system will feel MARGINALLY softer. Someone did a pedal pressure test a few years back(can't find it now, might have been Carroll Smith for Circle Track, just can't remember) and the pedal pressures were only about 25 lbs. different, measured on the brake pedal.