Hello everyone i have a 1999 gradall 534D-6 and im having a problem with movement power. When the machine is cold it will move but is lacking power, once it warms up the movement is restricted even more and the front tires start locking up while trying to move. Once its locked up if you jabb the brake petal a few times it will free the brakes up and start moving again but not for long an it locks up again. Some of the things ive already checked is the 4x4 solenoid /spool valve the tilt fork solenoid/spool valve. I also did some speed tests an im only getting around 10mph on blacktop. Also there is Plenty of lifting power it will lift a 4000k load of lumber to the second floor with no issues. Any suggestions or help is greatly appreciated. Getting very frustrated :Banghead
Sounds like a brake issue. Parking brake might not be releasing because of a blown seal in the axle.
Would that be temperature related? Because when the machine is cold it seams to move alot better.
Here is one for you. I have the same exact machine, year, model, etc. I had a very similar problem right down to it feeling like the brakes were locking up. I had some down time so thought I would service my machine myself instead of taking it into the dealer. After I changed all the fluids and filters, the problem started. Eventually, I had to have the dealer come out to the job site and fix whatever it was that I did. 2 days of troubleshooting by the tech resulted in 4x4 solenoid change with no help. Boosted up the hydraulic pressure and that seem to help but it wasn't a fix and they finally told me, sorry, don't know what is going on. Frustrated, I started over. I changed the hydraulic filters again and voila, everything worked as it was supposed too. When they sent out the new filters, though they looked exactly alike, the numbers were different by one digit and the one filter would not allow enough fluid through to operate the machine properly. Once the correct filters were on the dealer had to reduce the pump pressure because it was way to high once the correct filters were in place. Look for that fluid restriction because it will drive you nuts until you find it. Good luck
Indeed. There are two filters side by side, identical elements, one is for return oil, the other, which has a hose clamped onto the outlet tube, is the suction for the drive pump. Drive pump charge pressure is used to release the parking brake, so start at the filter. Need to check charge pressure after that to see where you're at, low charge pressure usually means excess internal oil leakage in the drive pump or drive motors, etc. Could be something in the actual brake, but opening that up would be the last resort.