Fair Value:

[1693TA]

-8 degrees this morning and this lift fired up just as if it were 30 degrees although the engine cranks a bit slower. It has a new group "31" Interstate battery installed and kept on a maintainer so plenty of starting power.

Hydraulics groaned a bit which is expected but I didn't cycle anything. Just wanted to see if the lift would start.

 

[1693TA]

Wire has shipped. No word on the friction and self vulcanizing tape(s) yet. Also ordered a couple cans of electrical encapsulating/conformal coating/compound today to seal/protect the wiring terminations in the man basket interconnection/junction box.

Only going to do this once.

 

[1693TA]

Wire arrived today and is much nicer, (quality) being automotive engine compartment grade than standard THHN, or MTW. Jacket is very soft and supple with ambient temperatue being 7 degrees F outdoors and the wire outside on the open front porch.

Project t is coming together.

 

[1693TA]

Having the serial number for the machine allowed ordering of the correct and needed cylinder resealing kits. I asked if they had any manuals for this machine and they did not. However the parts guy asked JLG direct for soft copies which they provided and were then forwarded to me. I now have the parts, maintenance, and owner's manuals within the serial number range of the lift so better than before.

Forecast is for warmer weather this next week so I'd like to entertain getting a bit more wrapped up.

 

[1693TA]

Cancelled the order for the cylinder seal kits from JLG. Found the same kits in the aftermarket for $212.72 less expensive so going that way. Should have them on Monday. If the snow continues to melt off I'll prop the boom up into a large tree out back and extract the cylinders to get them into the shop for teardown.

 

[1693TA]

It was really nice today and I was bored so installed a new toggle switch in the man basket for ignition to eliminate the intermittent original, and built up a new test gauge set to use for the hydraulics on this machine. I can now snap the correct coupler onto the test ports without looking for, or building up something to use for the task. Also found a scratchy swing pot so going to remove it and attempt to clean/lube with contact cleaner and order another if it doesn't perform satisfactorily. As of now it attempts to work 100%, but sometimes takes a bit of "jiggling" to make it operate. When working it is very smooth and linear as are all functions.

 

[1693TA]

Found the compromised wire which was the source of the intermittent operation of the "swing" control from the basket. The wiring running into the flexible chain trough beside the boom was severed and vibration would both part the wires, and bring them together citing bundle tension. No worries as all of this will be addressed with the new 16/24 control cable replacement.

I now have all installed electrical functions operating normally and reliably. There are the remnants of the rotary beacon lamp on the rear of the boom which will be replaced, but I have yet to order one. The wire supplying power to this is operational through the toggle switch in the basket.

Think I'll say "thanks" for the help and wish the best to all as I bid adieu.

 

[colson04]

Found the compromised wire which was the source of the intermittent operation of the "swing" control from the basket. The wiring running into the flexible chain trough beside the boom was severed and vibration would both part the wires, and bring them together citing bundle tension. No worries as all of this will be addressed with the new 16/24 control cable replacement.

I now have all installed electrical functions operating normally and reliably. There are the remnants of the rotary beacon lamp on the rear of the boom which will be replaced, but I have yet to order one. The wire supplying power to this is operational through the toggle switch in the basket.

Think I'll say "thanks" for the help and wish the best to all as I bid adieu.

I've enjoyed following your posts here @1693TA . I've never gotten into as big of a project as you are taking on with your lift, but I have been taking notes as you discover different issues and how you correct them. I have an old JLG as well and just knowing how to diagnose things, or where to start looking is highly valuable information.

Thank you for sharing your experiences with resurrecting your old machine. I'm glad it went to someone like you and not off to a scrap yard.

 

[1693TA]

Had another little problem with this lift which was minor but annoying. It being only 2wd and very heavy, it was having a difficult time climbing the slightest of incline. One drive wheel would stall out consistently and the other occasionally. Got tired real quick of winching this big ole sumbitch around too.

Yapping with a buddy whom formerly worked at a JLG dealer in the Chicago area, he sent me service/training manuals on the "F" series hydraulics in both Racine, and Eaton. With this information, I was able to accurately set system pressures which were all over the board, locate a defective check valve in the main pump discharge line, balance the drive wheels counterbalance valves correctly, and generally get the machine to perform as designed. It worked very well on flat terrain but again, wouldn't climb the slightest of inclines easily.

Armed with this information pertinent to the machine and having the testing equipment to isolate and troubleshoot I took after it. I plumbed in two flow meters, restriction valves, and gauges to measure things. Ultimately I discovered with both wheels locked via ratchet straps to timbers the tires were resting upon precluding rotation, the left rear, (looking from the rear) was stalling easily. Both drive wheels were equal in pull till the hydraulic drive pressure was increased to 1250psi indicated at which the left rear tire would cease pulling. Obviously this wheel motor was slipping or bypassing fluid internally as the flow was still there. Removing this drive wheel from the system through isolation, I was able to apply 2000 psi to the other wheel easily with minimal internal leakage. Isolating the right drive wheel the system again would only achieve 1250 psi again. Looking at the flow meters, I was running about 6gpm through the system and this left rear drive motor was bypassing almost four gpm internally while the motor was stalled.

Rebuild kits, or replacement motors are NLA so I go online and found a pair of drive motors .1ci larger in size and ordered them. With the replacement motors installed, actions and reactions are smooth and predictable and the wheel slip is gone. While the machine is still very heavy, the very same inclines it would not climb are easily surmounted. All good I suppose. I've not converted to diesel as of yet but that is in the future as this gasoline engine is tired and very underpowered for the unit.

Manual sent me:



Motors out. Yellow one is bad. Apparently black one has been rebuilt, or replaced at some point:



Defective motor replaced:



Counterbalance valve(s) to adjust drive wheel actions. Yellow circle are hydraulic lines directly from the spool valve section driving the machine:



Looks a bit better after everything was pressure washed clean. Lot of dirt and oil of course was removed.

 

[colson04]

Have you tried to drive this lift onto a deck over trailer before or after your drive motor repair? After reading your post about the inability to mount a hill, I'm wondering if I have a similar problem with my lift. I can't drive up onto a standard deck over trailer, like a deck over gooseneck, or deck over tag equipment trailer. Because of loading issues, I ended up buying a low deck equipment trailer to haul my lift on, and somedays, I have issues getting up those ramps. Now you have me thinking I might have bigger issues related to either flow, or a motor bypassing. Just one more thing to add to the list.

 

[1693TA]

Have you tried to drive this lift onto a deck over trailer before or after your drive motor repair? After reading your post about the inability to mount a hill, I'm wondering if I have a similar problem with my lift. I can't drive up onto a standard deck over trailer, like a deck over gooseneck, or deck over tag equipment trailer. Because of loading issues, I ended up buying a low deck equipment trailer to haul my lift on, and somedays, I have issues getting up those ramps. Now you have me thinking I might have bigger issues related to either flow, or a motor bypassing. Just one more thing to add to the list.

I have not as of yet. This thing is so heavy it is much easier to climb any incline with the engine end over the drive wheels. If rotated the opposite way, it's a bit light on the drive wheels. The winch for my semi trailer is remote controlled so if it won't climb the ramps to the deck, I'll winch it up. Don't know if it would be a voluntary effort or not by it's own power.

If you have two or more drive wheels stalling, and you know your system pressure is within specifications, it could be either a counterbalance valve, or drive motors as your drive wheels should not operate independent of each other. If you have only one, or possibly two drive wheels stalling, (4X4) but stalling together, I'd certainly look at the counterbalance valves. Only plumbing in pressure gauges and flow meters will tell for certain. However, system relief pressure is the starting point and that has to be correct.

 

[colson04]

I'll have to look up my manual and see what it says.

Machine is currently down and waiting for a replacement Accesory Valve to be made. The factory one is aluminum and cracked, causing a massive leak while engine is running. Contacted JLG, part can be ordered, but no ETA available on when one could arrive. My valve body is at a local machine shop, waiting on them to machine a new one from steel. We already tried welding the aluminum and re-machining it, but it cracked again in the repair.

 

[1693TA]

I'll have to look up my manual and see what it says.

Machine is currently down and waiting for a replacement Accesory Valve to be made. The factory one is aluminum and cracked, causing a massive leak while engine is running. Contacted JLG, part can be ordered, but no ETA available on when one could arrive. My valve body is at a local machine shop, waiting on them to machine a new one from steel. We already tried welding the aluminum and re-machining it, but it cracked again in the repair.

What model? Seems like an 40H? Is that two, or four wheel drive? Eaton hydraulic controls? I think the Racine valves were gone by the time the "H" series was in place but I'm not an authority on it.

 

[colson04]

What model? Seems like an 40H? Is that two, or four wheel drive? Eaton hydraulic controls? I think the Racine valves were gone by the time the "H" series was in place but I'm not an authority on it.

I have a 45 HA. Nice machine, has done well for me, but wasn't cared for very well in its previous life.

Eaton/Vickers valves. The current part broken has Eaton stamped on it with a model number that just leads to more dead ends.

 

[1693TA]

What does the valve control? Where is it mounted? I found a parts breakdown for the machine and need serial # also.

 

[1693TA]

Got a question before I get off path going down a possible rabbit hole. All functions work with the controls responding with high linearity when commanded to do so from both the basket, or ground control. However a seemingly strange phenomena to me; the engine idle speed is faster in the "platform control" selection, than the "ground control" selection. There are no electronics involved with the engine governor which is a belt driven "Pierce" from the looks of it.

The choke, and fast idle solenoids work as they should when commanded, as does high flow for faster ground speed travel. It is almost as if a dump valve opens/relieves when the controls are switched to basket control having seemingly less parasitic draw/drag on engine power. The valves on this machine are "open center" so I'm not really certain why it uses dump valves either unless they are electrically activated to relieve pressure in a circuit? There has been a lot of rewiring on this machine over the years and the original wiring diagrams do not match 100% of what is actually installed I don't feel. However, when I step on the pedal in the basket, all functions come to life but the engine rpm does not slow. If "Hi Engine Speed" is selected via toggle, the engine accelerates which would be considered normal.

I've neither proven, nor disproved anything yet, but am wondering if this is normal operation before I spend much time on it. As mentioned everything seems to work well in function, but there is about 200 engine rpm difference between "Platform" and "Ground" control selections.

Maybe "Off" can shed some light and once again, everything seems to work normally except this engine speed thing which could be normal?

 

[colson04]

My JLG 45HA (1994 vintage) is the opposite. When control is set to ground, engine runs at a fast idle and stays there throught functions. When switched to platform, engine speed drops to low idle, and then kicks up to fast idle when I step on the foot peddle. This machine is dual fuel, carburetor, Ford 4 cylinder gas engine.

I have rented several other lifts that that respond the same way. Fast idle only while in ground control, low idle while in platform until peddle is stopped on to engage high idle.

 

[1693TA]

Do you have a switch for high idle other than ground or platform control? This one does in the platform.

Guess I should say high idle selection runs the engine at 1800 rpm where low idle in ground control is about 750 rpm and platform selection is just over 1000 rpm.

 

[OFF]

What you describe sounds perfectly normal for a "F" series JLG.
Here's why.
On ground control, the hydraulics are loaded and ready to function - the dump valve is closed - meaning it is not dumping
On basket control, the hydraulics are NOT loaded. The dump valve is open and dumping back to the tank. When in basket control, the dump valve only closes when you step on the foot pedal. This is a safety feature. Should one of the valves malfunction and start moving a function on their own, it can be stopped by lifting your foot off the pedal. Later machines had a double safety. You needed a foot on the pedal and a switch/controller activated before the dump valve came on.

 

[1693TA]

Thanks kindly. I've been out recreating scenarios this morning and have found exactly as you describe. The dump valves are functioning as they should. I think this non original engine is tired. It doesn't seem to use much oil but will push the oil level dipstick out of it's tube there is so much crankcase pressure, (blowby). I've been leaving the oil fill cap on the rocker cover loose and it dances around pretty good from the pressure but doesn't come off. Lot less oil mist in the compartment that way too.

You load the hydraulics up and it almost bogs. Not close to dying out, but really labors. I have a mechanical 5.9ltr Cummins I'm going to replace it with once I find an SAE #3 flywheel housing so I don't have to do a lot of cobbling to get it in there. Measurements look as though it will fit fine with mount modifications.