Genie towable lift hydraulics question...

[Dougster]

Very regrettably, I bought myself a 1998-vintage Genie® towable boom-type lift, a very early Model TMZ-34/19, a couple years back. The thing was bought used and abused (and very badly butchered/horribly maintained) out of a rental place in Connecticut. Turned out to be in far worse shape than I ever dreamed was possible... but the price was right (all the $$$ I had) and I was in very desperate need at the time. Little did I know how much time, money and effort it was going to take to make it minimally safe and workable again. Anyway, that's the background story.

My question for today is this: Does anyone know what brand(s) of hydraulic components might have been used by Genie on such a beast in that 1998-ish timeframe? I can't find any names on any hydraulic components other than the hoses.

Genie parts are in very short supply for this old beast and what is available through the Genie dealers is extraordinarily expensive. Any hint(s) that might lead me to the original source for the many hydraulic components I need to replace would be most appreciated. Thanks!

Dougster

 

[lumberjack]

I have a 2004 50/30... Can you post a picture of yours?

 

[Dougster]

I have a 2004 50/30... Can you post a picture of yours?

Be happy to. Do you just want a general picture of it or are you looking for something specific?

Dougster

 

[lumberjack]

General, looking for similarities.

 

[willie59]

Exactly what hyd components are you looking for?

 

[Dougster]

General, looking for similarities.

Here are two shots from a couple years back the day I dragged it home.

Dougster

 

[Dougster]

Exactly what hyd components are you looking for?

My most immediate problem is that the (normally closed) solenoid valves controlling the jib boom and the turntable are leaking by. I'm assuming (until I learn otherwise) that the cartridges need to be replaced. The jib valve is sold by Genie in 4 separate pieces, but the turntable valve is only sold complete.

Dougster

 

[willie59]

So the jib boom drifts down, no problems with main and secondary booms drifting down? And you can push the basket and make boom swing? What S/N is this machine? Have you downloaded the parts and service manuals for this unit?

 

[Dougster]

So the jib boom drifts down, no problems with main and secondary booms drifting down? And you can push the basket and make boom swing? What S/N is this machine? Have you downloaded the parts and service manuals for this unit?

Very little jib boom drifting down until I activate the pump (for any other function) or I manually open the drain solenoid valve at the pump. Then the jib boom moves up or down... or just down in the case of the manually-opened drain solenoid valve. Clearly, the jib solenoid valve itself is leaking by pretty badly and the jib boom is just responding to system pump flow or to the manually-opened drain solenoid valve. No such problems with the upper or lower booms. For now, knock on wood, they are rock solid.

Yes, I can push on the lower boom or basket and turn the turntable slowly around.

This is one of the original series (1st of 5) of TMZ-34/19 machines. 1998 vintage. Serial number T34-1XX.

Dougster

 

[willie59]

The swing would almost have to be a problem with either the couterbalance valves on the swing motor manifold or the manual rotate valve on manifold is either open or faulty. It's possible that you have faulty o-rings on the left/right solenoid cartridge valves, and for that matter, pretty much any time I'm troubleshooting problems with machines that use solenoid cartridge valves, I pluck cartridges out and inspect o-rings for failures, pretty common problem.

I still haven't got my head around exactly what the jib cylinder is doing, or not doing properly.

 

[willie59]

If you could describe just a bit better what that jib is doing, might be able to offer some advice. In any case, the main boom, secondary boom, and jib boom all use the same (part #) solenoid valve. You could switch jib solenoid valve with the one in either main boom or secondary boom, see if problem moves. However, before you remove those solenoid cartridge valves, make sure the booms are at rest in saddle, open manual descent at proportional valve, and open manual knob at solenoid valves to make sure there is no pressure on solenoid valve cartridge.

 

[Dougster]

The swing would almost have to be a problem with either the counterbalance valves on the swing motor manifold or the manual rotate valve on manifold is either open or faulty. It's possible that you have faulty o-rings on the left/right solenoid cartridge valves...

Correct. Lots of possibilities here. Could be the hydraulic motor itself, the relief valve (Genie calls it a relief valve vs. counterbalance for whatever reason), or the left/right solenoid valve. The manual rotate valve is definitely closed tightly, but it could even be that. This one could get ugly. The only good news is that I can probably put it off until after this summer if we are talking about a super-costly repair.

...and for that matter, pretty much any time I'm troubleshooting problems with machines that use solenoid cartridge valves, I pluck cartridges out and inspect o-rings for failures, pretty common problem.

You bring up a very interesting point that I've not gotten a solid yes or no answer to: Is it reasonable to replace the cartridge valves o-rings and expect nice, tight performance again? Everyone says to just replace the cartridges given the personnel safety concern... but I am not exactly made of money. I do have access to a huge variety of o-rings, although without the exact spec, I would have to use a visual "best fit" approach. In addition, time is not on my side for this one. Don't have a lot of time for trial and error.

I still haven't got my head around exactly what the jib cylinder is doing, or not doing properly.

Think of it as if the jib boom's solenoid valve wasn't even there in the line. The jib boom is merely reacting to system pressure or lack thereof.

Dougster

 

[Dougster]

If you could describe just a bit better what that jib is doing, might be able to offer some advice. In any case, the main boom, secondary boom, and jib boom all use the same (part #) solenoid valve. You could switch jib solenoid valve with the one in either main boom or secondary boom, see if problem moves.

You are correct. All three booms use the exact same solenoid valve. It's pretty clear from testing so far that the other two valves are working properly. I don't see any point in messing with them at this time. I am all set to remove the faulty jib boom valve this morning and take a close look at it. Again, the point of my OP was to determine whose valve this is (i.e., the original equipment manufacturer) so I can possibly obtain a new one locally ASAP. Alternatively, I may do some running around this afternoon to see if any of the local hydraulic shops can make a match or at least fit some new o-rings if that is the problem. Worst case is having to order the replacement part from a Genie dealer... and wait.

However, before you remove those solenoid cartridge valves, make sure the booms are at rest in saddle, open manual descent at proportional valve, and open manual knob at solenoid valves to make sure there is no pressure on solenoid valve cartridge.

Excellent points.

Dougster

 

[Dougster]

Pix of the valve in question...

The jib boom solenoid valve (sans solenoid). O-rings look okay. In fact, everything *looks* okay.

Dougster

 

[willie59]

The o-rings and backup rings on that cartridge do look good, o-ring has a good round profile, backups are not shearing by groove. When you have problems with o-rings, they are typically flat, lose that round profile, oil under pressure will pass by o-ring and put pressure on backup ring causing it to shear around the outside. They look good on that cartridge.

The reason I suggested switching cartridge from jib cylinder to either main boom or secondary boom cylinder was to confirm for certain that problem is jib cartridge valve. If you move it to, say, secondary boom, fit cartridge from secondary boom into jib, and now jib works proper but secondary boom doesn't, you've pretty much confirmed faulty valve.

A lot of rust and corrosion of the hex on that cartridge valve, that where you'll find the markings of who made the valve and the part number. See if one of the other cartridge valves are in better shape around the hex and will give you some info.

Will the swing actually turn the machine, left and right, by operating controls?

 

[Dougster]

The o-rings and backup rings on that cartridge do look good, o-ring has a good round profile, backups are not shearing by groove. When you have problems with o-rings, they are typically flat, lose that round profile, oil under pressure will pass by o-ring and put pressure on backup ring causing it to shear around the outside. They look good on that cartridge.

I agree. Visually, the valve looks fine. Brought it to a couple of hydraulics places yesterday. No one could identify it or explain its failure other than to say that sometimes these valves just simply fail. In the end, I ordered a replacement through the local Genie parts rep. None in stock anywhere and only two left at Genie's Washington state warehouse so I figured that I had better act quickly. Been there, done that with "obsolete" and "permanently back-ordered" parts. New one will be here early next week God willing.

Interestingly, the local Genie parts rep did have some thoughts on who the original valve manufacturer might have been... but he felt it was not an off-the-shelf valve and that I wouldn't be able to get it through a third party or buy it cheaper or receive it faster than going through Genie.

The reason I suggested switching cartridge from jib cylinder to either main boom or secondary boom cylinder was to confirm for certain that problem is jib cartridge valve. If you move it to, say, secondary boom, fit cartridge from secondary boom into jib, and now jib works proper but secondary boom doesn't, you've pretty much confirmed faulty valve.

Understood. If it is something else that failed, I will certainly have egg on my face... and that *is* possible. In fact, I am already thinking about what my next step will be if the valve block itself, integral to the cylinder assembly, has cracked or corroded. Not a pleasant thought. But losing another day for more testing was just not acceptable.

A lot of rust and corrosion of the hex on that cartridge valve, that where you'll find the markings of who made the valve and the part number. See if one of the other cartridge valves are in better shape around the hex and will give you some info.

This old (1998) ex-rental machine had to have been pretty badly rusted before the seller decided to do a quick cosmetic paint & decal job and dump the thing. Half the new paint has flaked off since I bought it. Despite the low price I paid, I feel I got screwed pretty badly. We now wish we had bought a newer "self-leveling" machine that was available for roughly double the price. That said, I couldn't find any readable markings at all on any of the valves or those nuts.

Will the swing actually turn the machine, left and right, by operating controls?

Yes, it does. I do have some concerns about turntable bearing wear, but that's a different topic for another time. For now and for current purposes, probable leak notwithstanding, it should be fine.

Thanks very much for your thoughts and help!

Dougster

 

[willie59]

Keep us posted.

Also, when you get the new valve cartridge, check the hex of cartridge for markings that would identify it for future needs.

 

[Dougster]

Keep us posted.

Also, when you get the new valve cartridge, check the hex of cartridge for markings that would identify it for future needs.

Will do... and thanks again for your help.

Dougster

 

[Dougster]

The rest of the story...

Got the new solenoid valve from Genie only to find out that it had a different size requirement for the coil... so back to my local dealer for a new coil. Fortunately for me, they had one in stock. All said and done, $156.08 and a week later, the jib boom is working fine again.

Also, when you get the new valve cartridge, check the hex of cartridge for markings that would identify it for future needs.

The new valve had plenty of markings with which to identify it. It is a Hydac solenoid valve with a Hydac coil. Model number was stamped right on it. I have a fairly local Hydac distributor, although they don't stock these particular parts. But next time, I will go direct for sure. It should be faster to get the parts and cheaper by almost half.

Wish that were the last of my expensive issues with this machine, but no such luck. This 14-year old "used and abused" ex-rental machine is going to be a work in progress for a long time to come. For now, I am hoping that I can get the machine marginally usable within another week or so. For now, I will just have to deal with the turntable problems. The much bigger problem now is leveling and stability. It's an old, tired, worn out machine with just an awful lot of wear and tear and corrosion and breakage in just about every area. Even with all new leveling jacks, the machine refuses to stay level in normal use... an indication that something is worn out or badly overstressed within the outrigger assemblies.

Dougster

 

[willie59]

If it refuses to stay level during use, I'd be real apprehensive working in that platform. I'm not real familiar with that machine, do you work switches to operate outriggers, or is it self leveling?