I just bought a used z45/22 boom lift and have fluid leaking from one of the drive hubs. Looking at it closer I see a small crack in the cover and fluid appears to be laking around the sealing surface as well. I am thinking that the brake assembly must have a bad seal and that the hydraulic fluid is bypassing the seal and entering the torque hub. Can somebody let me know if they think I'm on the right track? If it was the drive motor leaking I would think that hydraulic fluid would be coming out the back side where the drive motor mates up to the brake housing. Any advice is appreciated.
They are a wet hub. There should be fluid. I would just order a new cover and o ring if it’s cracked.install it add fluid and roll
The fluid in and coming out of the hub is dextron. Not the best lubrication for a torque hub, but i've seen worse. I strongly suspect that the brake mechanism is allowing fluid to bypass into the hub. If I don't fix the incoming hydraulic fluid I think the hub cover will either crack again or leak around the sealed surface. Just my theory from looking at this for a few hours.
You're thinking the cover cracked because of an internal leak? If it had that much pressure to crack the housing, then fluid would probably be pouring out while trying to drive. Did anyone tow or pull the machine recently?
I just got the machine, but I have no reason to think that it was towed recently. The brake mechanism looks like it it a simple hydraulic piston type with springs apply the brake when fluid pressure is not present. It will weep while the machine is just idling. When moving it seems to leak more, but I really can't watch it and drive at the same time. I think that if it were a drive motor it would leak out of the back side of the brake assembly. I don't see how it could get through to the hub that way. So that is what led me to the brake leaking fluid around the piston and into the hub. I came across a video showing a guy rebuilding this same style of brake. Just a couple of oranges to seal the pressure. I know a lot of people on this forum will have more experience with these lifts than I do so that's why i thought I would ask. Thank you for helping me sort this out.
Go to genies website and download the manuals for this machine, and see how the drives are set up.
First thing I did was to get the service manual for this machine. It shown no explode view of the assembly. I have contacted my local dealer to check on part availability and am waiting for them to get back with me.
Does your cover have two plugs ? They do not have enough pressure to crack the cover. Unless your hydraulic tank was filled with dextron also you would also see hydraulic fluid if you where bypassing a seal since the brake pulls it’s supply from the traction control manifold. A lot of people atf in the outer hub since they can poor it from a bottle through the fill plug with a small funnel.
Before I was qualified I broke a torque hub cover when I was trying to reassemble it on the machine. Seems they go together easier when they are horizontal as opposed to vertical. I tried to pull it it together with the bolts. Lesson learned the hard way $$$
The cover has 2 plugs on the side of the housing not on the face. The crack is about 1.5" by the square tag. As soon as I start the machine it is lightly weeping. So there as absolutely hydraulic pressure being pushed into the housing. I believe the brakes are supposed to get 350# of pressure and I have read on here about another unit that would spike to 1000psi when they measured it. So i could see that cracking a large aluminum housing. The final drives I have worked on were not rated for much pressure. I wouldn't think that those torque hubs would be rated to 350#.
Well. If it were me, I'd start taking the planetaries apart. Verify the pump is leaking. Then look on pump for part numbers. Maybe the pump just needs new seals...
I’m like skata pull the cover let it drain. Not going to hurt to let the planetary to run try for a few just to test it if you think it’s passing through the seal. If it’s by passing you should see that right away. Put a gauge on the PBTP port and see what your getting. Sounds like your pretty convinced it’s bad so why not just order the parts and fix it.
Taking the planetary apart would only tell me what I already know. Hydraulic pressure is getting into it. My primary question was has anybody seen this before and is this common. In the absence of that information I blocked off the line going to the brake assembly. Started the machine, and still had fluid pushing out of the brake assembly port. I then loosened up the drive assembly and found fluid coming from there. Looks like the drive will at least need new seals. I'll send it to hrt in Western Kentucky next week. The fact that it was pushing hydraulic fluid through the brake assembly tells me I probably have a seal problem there as well. I called my local genie (MH Equipment) in Bowling Green ky to inquire about parts availability and pricing on thursday. Hopefully I will hear something back this next week. I am surprised that fluid was pushing through the drive with the machine idling. I would normally thing that with the unit idling and no functions engaged that there would be no fluid going to the drive motor. In any case the seals should hold operating pressure and at some point hit a relief valve pressure.
Motor probably has a counterbalance valve, control valve will have an open center spool, so tank pressure, or return manifold pressure, may be constantly present at the motor ports, may also have makeup checks which would allow that small amount of pressure to be present on into the motor case and out through a bad shaft seal, or brake shaft seal.
I had the drive motor rebuilt and the brake assembly rebuilt. Installed them and at least that leak is gone. I will have to reseal the hub and deal with the cracked end plate, but at least the hub isn't pushing hydraulic fluid. The lift still seems to move slow and struggle up any incline. The unit only has a bit over 2,000 hours on the meter and I find it hard to believe the planetaries would have issue. What's the simplest way to check the planetaries out?
Highly unlikely your problem is in the planetary gears if they have oil in them. I would suggest pressure checks if you haven't done that yet, main pressure and if possible the motor reliefs/counterbalances. Does that unit have two speed ground drive?
The drives are single speed. it's a 2wd machine as well.
Sometimes there's a solenoid valve that switches them from parallel to series for high speed, I don't know your model though. Sometimes it might be something as simple as a blown out O-ring on a cartridge bypassing fluid, losing pressure.
Serial number is Z-45-000908 manufactured 6/93.
https://manuals.gogenielift.com/Parts And Service Manuals/data/Service/Z Booms/IO/32960.pdf https://www.jms.co.uk/wp-content/uploads/resources/Z45_22_operators_manual.pdf Learned a lot about that machine, it has basically a small hydrostat setup for the drives, according to the hydraulic schematic for your serial number it should have two speed variable displacement drive motors. There's a troubleshooting section in the service manual I linked to that may help. There should be a toggle switch on the panel, top row left, horn button, then drive enable, then the next toggle should be the two speed, shows a picture of flat or sloped ground if there's anything left of the panel.
I did not know that was a 2 speed switch. I thought it just limited flow for an incline or rough terrain. Thank you for the service manual. I will dig into it this week.
Happy to help, yeah until I saw the hydraulic schematic I figured it was all gear pumps and geroller motors, guess I was thinking too far back!
Genie's manuals do get me sometimes. On page 4-30 they say you can replace the drive loop hydraulic filter. No details on the location, but they give you a picture and description on how to change a fuel filter. LOL
Welcome to my world!
I am going to do some troubleshooting with that manual and that should give me a better idea of how the systems work together. I'm trying to figure out if I have an electrical, hydraulic, or a mechanical issue. I'm gravitating towards hydraulic, but at least now I can check some of the electrical and get a better idea of what the pressures should be. Thanks again for the manual. I had not come across this particular one before.
What is it doing/not doing?
The travel seems slower than it should and once warm it struggles up an incline. I haven't ran it much since I bought it, but I used it the other day to trim a tree down a 400ft driveway. When I first got it I had that leak from the torque hub housing where it was pumping out hydraulic fluid. Once I figured out it was the drive motor I had that fixed and had that particular brake hub redone also. The sensor that detects the boom down seems to be working because it does speed up some when everything is down and retracted. It took me a sold 10+ minutes to get back up the driveway the other day and at one point it felt like the drives were struggling. Almost like the brakes were dragging or the planetaries were binding. I work on diesels and some heavy equipment so I'm usually decent at sorting things out, but I know those systems and how they interact. These lifts are just different and it seems like their systems are harder to isolate.
I should note that all of the other functions on the machine seem to operate well. It's just the drive component