BRAKE FLUID LEAK FROM MASTER

[cbradley400/4]

Can anyone advise with this little problem ?
I appear to have hydraulic fluid leaking in small spots on to the petrol tank of my 400/4.
The cap has not been off for some time?
Many thanks.

[mick]

Hi i would wash off the spills with some soapy water first, then check that the cap is on correct and tight ,also check the banjo bolts are tight and also the brake hose itself for signs of splitting etc, cheers Mick.

[cbradley400/4]

Thanks,i'll check that out.

[bikerburke]

hello i had a similiar problem when i was rebuilding my 500/4 turned out to be the master cylinder,you may see fluid by the brake lever pivot if so you probaly need a rebuild kit and a pair of long nose internal circlip pliers.cheers  bikerburke

[cbradley400/4]

Many thanks,belatedly.

[dave400]

Many thanks,belatedly.

So what caused the leak.

Cheers

Dave

[cbradley400/4]

I'm not sure.I got a spare master cylinder but haven't fitted it yet as the leak is intermittent and it stopped again!
The bike's been off the road recently as it's burning oil at 5000+ rpm and just won't run right.The points and ignition have been checked as have the carbs.It needs a compression test and the head lifting as i'm told it's likely to be rings.There's 40K + miles on the clock.Any further views would be greatly appreciated.

Martin

[SteveD CB500K0]

Burning oil = rings or valve stem seals.

When you check the compression, pour a bit of oil down the bores and retest. If the reading goes up significantly (like from 90/100 psi to 150+ psi) then you need a rebore.

If the reading doesn't change, its not the rings so must be the valve stem seals.

[cbradley400/4]

Many thanks.