i have a case 621b w/ no brakes. took some pressure checks at the brake valve next to the brake hyd. pump that is powered off of the engine. i had 250psi at idle and 1000psi at full throttle. anyone know if these pressures are correct? where do look next? feels like i have no pedal.gotta give it a good bath before i dig in deep.
there should be a low pressure warning light on dash, there is also a 800psi accumulator on the right side of the frame under cab. With your pressure readings you still should have brakes. The brakes are internal wet brakes 3 fiber and 4 steel disks per wheel, if you have bad piston seal your hyd fluid will be disappearing into your final drives. Also there is a bleed screw at the top of each brake housing, have someone push pedal and see if you have fluid getting out to the brakes.
the low pressure light is flashing. i have 2 accumulators on the right side. i'll have to look into bleeding the brakes
i bleed the brakes yesterday. no air at all nice stream of oil shooting out of bleeder. assuming i have vents on the diff's i have no leaking there. i starting to think my discs are bad. probably so with 23,000 hrs.
Is your light flashing all the time? Even worn disks should give you some brakes. I have one that flashes when the loader idles but shuts off when it comes off of idle. Your sending unit is in that small valve that's by the pump. You said you had 1000psi there when you had the machine at operating rpm?
Also if you are gonna do brakes, you will want to go thru a ZF dealer and not case. Parts cost half as much. I have info if you need it.
light is flashing all the time. yeah i had around 1000psi at full rpm. pedal is real soft but still getting alot of oil when bleeding the brakes
Prob need to check pressure's down the line, from pump valve to foot valve, then foot valve out to wheel. You have to have a nitrogen set up to check accumulator. You might have good volume of oil at the wheel and low pressure.
These wheel loaders had a habit of brake valves failing. There is a quick connect coupler near the brake valve. You should see 2500 psi at the brake valve. Once this pressure is reached the brake pump flow is returned to tank through the valve. The pressure will now drop to 1450 psi before the pump builds the pressure back up to 2500 psi. At 1250 psi a low brake pressure warning will light, at 900 psi the transmission will declutch. There is a seal kit available for the valve as well as a relief. However if a spool is scored or damaged a new valve will have to be ordered.