Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Bleedin brakes

[smilo006]

got the bleedin procedure down to a fine art. Next thing is how to find out where the system is losing pressure / lever going soft.

Any ideas or experiences. Is it a dealer job?

[guest1]

Have you changed any lines recently?
Used new copper washers if you have?
Are you losing fluid level in the master or is it just "going soft".

Any leaks will be apparent at the washer joints cos it's under pressure.
If it's going soft cos of air, then is your master level staying high enough when the lever operates and is your master upright or have you put it at an angle on new bars?
Check yer nipples

[Jools]

Originally posted by smilo006
got the bleedin procedure down to a fine art. Next thing is how to find out where the system is losing pressure / lever going soft.

Any ideas or experiences. Is it a dealer job?

What fluid are you using? Could be that you are using your brakes so hard that you're boiling the fluid, but this is unlikely.

More likely explanation, assuming that you've got braided lines, no fluid leaks, good piston seals and blah blah blah is that the brake fluid that you used might not be as fresh as it could be. Brake fluid is hygroscopic and quickly absorbs moisture from the air unless it's in a sealed container (or a sealed braking system). If your brake fluid gets contaminated like this, the water content that's now part of the brake fluid will boil off leaving you with a spongy brake lever (cos now your brake fluid contains a gas that can be compressed instead of a fluid which can't be)

[Mr_S]

To try and locate a leak, dust the joints down lightly with talc, apply a little pressure to the lever (tie wrap or similar) then leave overnight.

If there's a slight leak the fluid will the forced out and caught by the talc, this makes it a lot easier to see as it'll appear as a clumped mass (you can do the same for oil leaks)

Also, check the reservoir and hose, if it's kinked or blocked it'll give the impression that you're losing the lever because the M/cyl can't be refilled to compensate for the pad wear ( had this at Cadwell, it's disturbing!)

If it's not leaking and the lever's fine, swap fluid type to 5.1, it should be a lot harder to boil the fluid then, and if I remember rightly it's less hydroscopic than 4.