Got a strange problem on Genie Z80/60 #Z8005-565. At random the left rear wheel will stop driving. Happens maybe once a year, usually after a longer drive (1 mile or more across a site). The left rear wheel will drag a few times and then just stop turning. The rest of the machine will power along as normal, dragging this one wheel. Now here's where it gets weird. You power the machine right down, start it up again, and away you go as if nothing ever happened. Good till next year. Everything mechanical in that drive motor/hub/brake looks really good. Anybody seen something like this before or have an idea of what's going on? :Banghead
Well, my good friend Z80 did it again yesterday. Operators drove it quite a distance, (about a mile) when one rear wheel locked up and skidded. As always they shut it down, start it up and away it goes. Gotta be a brake problem. Another little quirk of this machine comes to mind.......you when hit a large bump, the drive stops completely. You have to shut it down and "reboot" to get it going again. Is that normal? Never noticed a Z45 or Z60 do that. Yes, we've had it back to the dealer twice, they found nothing/did nothing. :bash
When the lower control is first turned on, what version software does the lcd display say is installed? There's not much of a suspension on those Z80s!
As much suspension as you get out of a large foam filled tire (nothing). Forklifts these days have "shock" sensors built into them too. It's running version 1.03 software. The dealer said that was as high as it could go without changing a whole pile of sensors and wiring.
It can be upgraded up to 105 without a hardware change. Both 104 and 105 are great improvements over 103. The Primary Boom Angle Sensor will need recalibrating after the upgrade. It would not have anything to do with the drive situation however. It is really rough trying to find these nuisance problems. Especially when they take so long between instances. It would be interesting to see what the fault is that is generated when the drive shuts down after the big bump thing. The operator is too quick at turning it off and back on to keep going instead of leaving everythig as is and checking for a fault code at the Turntable Controller (TCON). This would help immensely. If a P6R1 or a P7R fault comes up then there is a possibility of a connection issue at the Drive Controller (DCON). P6R1 is the Brake/2speed circuit. Pin 1 (ground / brown) and Pin 2 (12+ / white) of the white plug at the DCON are the power inputs for the DCON. The DCON is located at the Blue end (front) of the machine in the chassis. If at all possible, monitor these connections while driving the machine for miles on a motocross course. ointhead The Electric Rotary Coupler has been known to drop signals in extreme cases as well. It would also be a good thing to plumb a couple pressure gauges at the Traction Manifold to monitor the Charge/HOS Pressure at the Traction Manifold and the Brake / 2-speed pressures at their respective lines. Best results are obtained on the whoop-de-doos part of the track: Assuming the operator is in High Speed while traveling that distance, if one of the Drive Motors drops out of high and back into low, the same symptom can occur. The wheel appears to lock up. I have seen this a few times over the years. The components look fine but the housing the servo piston moves in can have small abrasions in it where the o-rings of the piston ride. This is a non-flow circuit between the 2-speed valve and the servo piston so debris can stay in the chamber indefinitely. Sometimes the debris will push against the o-ring, get stuck there and begin scratching the housing. This can cause pressure equalization on the piston causing it to slam the motor back into low. When the engine is stopped, all the motors shift back to low and the debris is dislodged for the next time, be it a day, a year, a millenium. Check with a bright light in the housing bore where the piston o-rings run back and forth. If it is a hydraulic issue, Drive Pump Charge Pressure is what keeps the brakes released and the 2-speed in high. If charge pressure is dropping down, the leakiest brake will grab first. It is easy for me to tell you to do this and I realize how nerve-racking and time consuming these intermittent problems are, we need to see if it is a charge pressure issue, an electric rotary issue, a wiring issue or a component issue. No small task. I wish Alberta was part of my territory, I love tackling these types of problems.
Thank you Voodoo. 1.03 was a huge improvement over 1.01 that the machine was running when we go it. I'll find a dealer that will do the upgrade to 1.05. We had a very knowledgeable Genie area rep up until a couple years ago when he quit and went to work for one of the rental companies. You've given me a few things to think about, we'll do our best to find it.
yeah, Gavin is one squared-away son of a gun! He is missed. Give Blaine a shot. He replaced Trevor who replaced Gavin.
Oh, you know Gavin? He's awesome. Trevor didn't impress anyone. Haven't seen or heard anything of Blaine yet. Little story behind this machine, we were dealing on a new S85, sent the order to our purchasing department and some no-nothing bonehead intercepted the order and though he'd save the company a few bucks by buying a used Z80 from Florida. Had it trucked all the way up here. 3 years old, owned by a rental company (gotta be a reason they'd sell it right?). It would barely crawl (worn out throttle link), the steering was horrible, and you had to baby-sit the basket level to keep it in range while you boomed up or down. Nobody would use the thing. I found the missing rpm, Gavin clued me into the software update. The machine hasn't sat idle a day since.
Alright, made some big gains on this machine. This time I had a mechanic driving it when it locked up. About a mile, it locked up. He said the engine loaded right up, the wheel stopped and it didn't drop out of high drive. He shut it down, started it up, away he went. it locked up again in about 100 yards. Shut down, start up, this time it only made it 20ft. Again and it locked up right away and stayed locked. jacked it up, couldn't move the wheel at all. We went for coffe, came back, it was free again. The hub was cool to the touch even after driving that kind of distance. I'm thinking it has to be the brake locking up on that wheel. Dragging slightly until it makes enough heat to take up the clearance between the brake discs maybe? Question is, do I replace the entire brake & hub assembly or rebuild that brake? Genie has a hub & brake assembly in stock, brake seal kits in stock, but brake discs & bearings to rebuild the brake are 2 to 3 weeks delivery. That kinda tells me they don't sell many brake discs. Your thoughts?? Take it apart first & see for sure what's going on?
If you have the time, it would be interesting to see the condition of the brake components. Its pretty darn expensive to replace the whole hub assembly just to fix the brakes! 3 grand or so? Are these the numbers you came up with? 102778 Drive Hub with Brake, 59.3:1 (from serial number 539 to 957) — 102557 Seal Kit — 102558 Bearing Kit — 58284 Cover — 33441 Wheel Stud, 3/4 -16 — 22811 O-ring, Brake — 102535 Brake Disc Kit — 102536 O-ring Kit, Brake Before making any decisions on this I would put a pressure gauge on the test port at the Traction Manifold and watch the pressure before and after the wheel locks up. If the pressure starts dropping a significant amount then the brake with the strongest springs will lock up first. I would hate to make that expensive an investment only to find an issue elsewhere. Recently I was at a location in Virginia that had a S80X with the same issues. It turned out being a crack in the traction manifold. The pressure gauge showed the decreasing pressure. When it dropped close to 100psi one of the rear brakes would start pulsing and then eventually lock up. After cooling a bit it would work fine until it heated up. Ideally we should see about 280psi at the manifold test port while driving. back to the parts issue: Did you ask Genie Parts if the parts could be drop shipped from the vendor? Also, Lift Out of Service (LOS) can go a long way to expedite the order.
those part numbers look like the ones I found alright. I'll check in the morning to make sure. That hub & brake is $4365 up here, and that's if the dealer brings it in on a stock order. Be an extra couple hundred to fly it in special. We'll for sure hook up a gauge and drive it before we tear into it. Thanks again for the insight. I didn't know there was a LOS program, I'll check into that.
Part numbers were the same ones I came up with. They'll make a partsman out of me yet. Pressure at that port is running at 320 psi when it's warm, no pressure drop at all when it locked up. And it locked up way sooner this time, maybe 1/2 mile so it's getting worse. Looks like it's rip & tear time.
Hub is out & apart, nothing really visably wrong with it. A little blue on the steels, they have been heated up, but lots of lining left, no scoring, nothing piled up. I was surprized at how small those brake discs are.
Is there an exploded view of this hub & brake assembley available? There's nothing in either manual.
yes, what is the name and numbers on the ID tag on the hub?
must be just oil, they are all perfectly smooth. RexRoth 7287 GFT 17 T3 7003 ration 92.50 SN 1109271 FD 2004
Just a concern: The tag calls out a 92.5:1 ratio the parts manual calls for a 59.3:1 ratio for your serial number. please check the other three hubs to verify there is not a mismatch. edit: it is my assumption that this is a 4 wheel drive? if 2 wheel drive or machine with floatation tires then 92.5 is ok as long as the others are the same.
It does have the larger flotation tire option on it. and it is 4wd. I'll check the plates on the other hubs, make sure they match. Good thing you caught that. Nothing better than flying in a $4K part the wrong ratio At this point we're thinking seal kits, clean up the plates, put it all back and try it again. Only thing troubling is that the wheel stopped quite suddenly like a brake applying. It didn't grab/release/grab/release/grab like you'd expect from a tight brake pack. Wish we would have found something totally destroyed. That makes it easier.
do not rule out the drive motor. they are easy enough to swap from one side to the other to see if the problem follows the motor or stays at the drive hub. Also, if you haven't tried it yet: The divider-combiner for front left-right and rear left-right are identical. They can be swapped to see if the problem follows the divider-combiner valve or stays the same.
Well, I guess I shouldn't be too surprized the seal kits were all wrong. I thought the seals would be the same regardless of ratio. silly me. I got the dealer working on finding the right numbers for our 92.5 to 1 ratio hubs.
81383 DRIVE WHEEL 92.5:1 101533 SEAL KIT (81383) 101534 BRAKE DISC KIT (81383) Item Number: 81383 Item Description: WHEEL DRIVE, 92.5:1*** Item Weight: 234.000 lbs Quantity Available: 5 in NORTH BEND, WA Item Number: 101533 Item Description: SEAL KIT (81383) Quantity Available: 1 in SOUTHAVEN, MS 4 in NORTH BEND, WA Item Number: 101534 Item Description: BRAKE DISC KIT (81383) Quantity Available: 2 in NORTH BEND, WA
thanks man. I ordered the seal kit and disc kit. Passed on the whole hub, it's came up as $7350.00
Parts were correct this time, thank you. Everything back together, switched drive motors left to right while it was 1/2 apart anyway. Took it out on the road and drove it over a mile with no hint of a problem. One thing we noticed while swapping drive motors - the cavity between the motor & brake was full of oil on the side we had all the trouble with. That same cavity on the good side was dry. :beatsme Thanks VoodooMojo, couldn't have done it with you.
bad o-ring at the small brake port on the hub/motor junction or perhaps a seal issue with the drive motor? It would be interesting to look at the cavity at the side that was dry after running it for awhile to see if the motor is leaking.
We'll for sure check it on the next service. :cool2