The GMC CCKW

started my GMC last week after it had been sitting in the shed for 6 months and - no brakes!
opened master cylinder cap - no brake fluid there - and no obvious place where its gone.
Have bled the brakes and booster ( 3rd series I think ...?) and brakes function great ( for now)
Just wondering where I should go looking for the missing fluid.
Note haven't pulled wheels off yet to look at wheel cylinders - but these were resolved in stainless several years ago.

If brake fluid is disappearing from your CCKW master cylinder with no sign of external leakage It will be in the vacuum chamber of the hydrovac. It is caused by the failure of the seal for the push rod between the vacuum servo and hydraulic piston.

David

Hat the same problem as david says it is the hydrovac.

I have some pictures on

http://home.kpn.nl/gerards_j/rembekrachtiger_1.htm

sorry only in Dutch but i think the pictures speak for it.