Hello, This is my first post so I hope it makes sense !! I have a 2003 4CX that I bought new & has 7300 hours. I have had an on-going & worstening brake problem with it over the last 200 hours or so. It started with, one day having no brakes- i.e. the pedals went straight to the floor- the reservoir was empty. I have owned this machine from new & we have maintained it ourselves so there has not been a problem with incorrected fluid being used in the braking system- always JCB light 15 oil. We bled the two sides (although I didn't know about holding one pedal halfway done whist bleeding the other side) & all seemed fine- the brakes worked again. However, this problem re-occured with increaseing frequency- to start with I had to fill the reservoir every day & after a couple of weeks the contents of the reservoir dissapeared in 3/4 minutes! There is no external leak so the only thing for me was the internal brake piston seals. We replaced these & bled the two sides (without the opposite pedal half way down method) & the brakes seemed fine. but, after road testing it the same problem occoured- on the right side. When I pressed hard on the R/H pedal I felt the fluid escape & the pedal go all the way to the floor. When removing the reservoir cap the R/H side was completely empty & gurguling as if sucking the fluid down. We re-bled the system twice but now the fluid dissapears in a few short minutes. mht1 156 seems to have had a similar problem although provoked by adding brake fluid. jcb jeff gave a very comprehensive reply- maybe you aor anyone else has an answer? Thanks
Check your rear diff oil level. If it is bypassing the piston seals it will add oil to the diff oil....Jim
Ok, thanks for that
Also check the servo units if not the piston seals in axle gone
Hello, Yes, in fact it was the mastercylinders that were leaking & the servos were sucking the brake fluid from the reservoir to the servos. They were both full of brake fluid! I have replaced the two mastercylinders & washed out the servos. Everything seems fine- for the moment. Many thanks for your comment.