The JLG 40F Boom Lift Dilemma

[jeffdm]

Hello, everyone. I found this forum when I was sent pictures of a free manlift that I thought was a 40F when I tried to match it up to internet pictures. Now that I have it, it turns out to be a 42C. It has been sitting for some time and has all the normal issues that you guys are probably used to. It has a 3cyl Duetz air cooled diesel. Ive have that in running condition now. I brought the engine up to governor speed and it started dumping hyd fluid from the solenoid valves on the left side of the machine (same side as the injection pump and ground control switches). I found two bolts missing that hold the lower half of the valve assembly to the upper half. The bolts are allen head, maybe #10?, that are installed vertically. I found one of the bolts on the ground under the machine broken off and the other had just a broken piece in it but no sign of the bolt. I hope this isn't too much background....
I removed the valve and disassembled it. Some of the O-rings are formed in the shape of a teardrop (either by design or age).
I guess what I'm asking for is the same as everyone, please: any insight to my immediate problem, how to source parts (I can't find a brand on the hydraulic valve to source seals), electrical diagrams, manuals, etc. You guys know the drill....
I own an auto repair business and have the skill set for testing and repairing a machine like this but I fell from a ladder a few years ago trimming trees (I didn't have a manlift- LOL) and am now paralyzed so access to some of the stuff to work on it sometimes requires a helper so if you tell me to test something I might not be able to get it done right away .

I don't have very good pictures at this point but can certainly take others if needed. I'm not actually even sure if my efforts to attach pictures worked.... so we'll see.
Thank you,
Jeff

 

[jeffdm]

 

[OFF]

Welcome! Those are Racine valves. If you'd like to message me an email address, I'll send you the Racine valve manual.
I see someone has added some relays there beside the valve bank. Must have been a voltage drop problem or something needed a bit of a booster.
I can also send you a set of 40F manuals. They might help some, even though your 42C looks more like the physical size of a 60F. The diesel engine is a huge bonus btw.

 

[jeffdm]

Thank you for the fast reply. That's wonderful. Since all of the wiring has been man-handled at some point, I really have no idea what is original and what isn't.
I hope it's ok to toss out my email here.

I would really appreciate any info you have. I've found approximately zero info on this machine on the web.
Are you saying this machine looks bigger than a 40F? If so, that would explain the protesting coming from my equipment trailer...... When I figured it for a 40F I assumed it to weigh around 14,500....

 

[OFF]

Got your email address, it would be a good idea to edit your post and remove your address, just in case.

 

[OFF]

If you look back in this thread to pictures of 40F's, I think you will see they have a smaller base or platform. Your 42C looks like it was built on a 60 size base. Somewhere in here is a discussion about the 42C.
Check out posts #1395 & 1396 way back on page 70. We had one of the JLG factory guys drop by once and we asked him all sorts of questions.

 

[jeffdm]

Thanks a ton for all of the info. I'll admit while I read many of the pages in this thread, I did not read those pages. I'll do that now. Thanks again

 

[TheBigDog]

I just purchased a 40F (serial number 728396) and not sure what year it is. Everything works on it but want to get up to speed on it, preform all maintenance (so I know when it was all done), and fix her up cosmetically.

She has set outside this barn for the last 2+ years….not sure before that ( I believe I am the 3rd owner). I did have to use a shot of starter fluid to get it started but once started she seemed to run pretty good. It was last inspected in August 2017 and no issues were found. I did find a hose that has a gouge in it going up the boom but not leaking.

I am so glad I found this thread as it has a wealth of info! Hopefully I can get a copy of all the associated manuals and diagrams. I have only read 10 or so pages of this thread so far and look forward to another 70+ pages!

 

[TheBigDog]

One other observation when testing it out before purchasing, It is very jumpy when going in reverse and trying to steer it at the same time. I assume it has to do with the joy stick control on the basket but haven’t had time to look into it yet.

First up will be changing oil and adding fresh fuel to the fuel tank. Then lubricating all the points outlined in the service manual.

 

[Michael Huckenpoehler]

Hello, I just aquired this lift which I believe is a 40f. I would like to find manuals. for it. When I got it all the valves were sticking, I have them all free now except 2 which are still sticking half the time. There seems to be some water in the hydraulic fluid. As soon as I get all the leaks fixed, I am going to change the fluid.
Mike

 

[jeffdm]

Good morning all.
Still working on resurecting my 42C that was sitting in a field for years.
My current problem: The rotating function is not working properly. I worked for most of one day then is started slipping. Meaning that it is not very responsive when you attempt to rotate and does not stay locked in position when you stop rotating. I removed the hydraulic motor nad sent it to the hydraulic shop. They said the brake did need work but that the motor seemed to work fine on their test bench.
I reinstalled it after the brake repair and it works exactly the same. Working on it this weekend, I noticed smoke would come from the hydraulic motor when I operated it; the sort of thing you might expect to see from belts slipping. I'm doubtful there are belts involved though. I'm now suspecting a problem in the coupler that the motor mounts to but I do not know anything about the inner workings of that part.
I have to get a friend over to help with this since I can't reach that from the wheelchair and I was hoping someone might be able to give we some ideas what to be looking for as we take it apart.
Thank you.

 

[OFF]

One other observation when testing it out before purchasing, It is very jumpy when going in reverse and trying to steer it at the same time. I assume it has to do with the joy stick control on the basket but haven’t had time to look into it yet.

First up will be changing oil and adding fresh fuel to the fuel tank. Then lubricating all the points outlined in the service manual.

Hi, normally I get a notification when anyone posts in this thread, not sure what happened this time. Your "new" machine looks good. I see you have Cutler/Hamer controllers which means it will be a very dependable unit. The parts to repair those controllers are quite common so should be easy to find the "blocks".

 

[OFF]

Hello, I just aquired this lift which I believe is a 40f. I would like to find manuals. for it. When I got it all the valves were sticking, I have them all free now except 2 which are still sticking half the time. There seems to be some water in the hydraulic fluid. As soon as I get all the leaks fixed, I am going to change the fluid.
Mike

Hi Mike, just message me an email address and I'll send you those manuals right away. Sorry about the delay, I didn't get notifications and I wasn't checking regularly either.

 

[Michael Huckenpoehler]

Off, I appreciate your help. I just sent you a message. Update on the lift, I rebuilt the cylinder on the back of the boom that keeps the platform level as the boom moves up and down. Wow, is my oil contaminated with water and sludge! Next up is to fix the leaking wheel hubs, and then flush the hydraulic system.

 

[Michael Huckenpoehler]

Does anybody know how much oil the hydraulic system takes on these?

 

[OFF]

Does anybody know how much oil the hydraulic system takes on these?

I can't find capacities listed in the manual either.....
I remember it being about a 45 gallon drum, maybe a little less.

 

[TheBigDog]

Does anyone know what a good replacement starter relay would be for the 40F? I am having intermittent starting issues. I have a new battery and am in process of replacing some very old / corroded battery cables and want to replace the starter relay while I am at it. I couldn't find a part number in the manuals....it just references the starter relay.

 

[TheBigDog]

Does anybody know how much oil the hydraulic system takes on these?

I just read it in the service manual that it has a 40 gallon tank for hydraulic.

 

[OFF]

Does anyone know what a good replacement starter relay would be for the 40F? I am having intermittent starting issues. I have a new battery and am in process of replacing some very old / corroded battery cables and want to replace the starter relay while I am at it. I couldn't find a part number in the manuals....it just references the starter relay.

Is the starter relay black or silver? Does it have 2 small terminals, or only 1?

black with 3 terminals (only one small terminal) NAPA UNI-ST82
black with 4 terminals (two small terminals) NAPA UNI-ST81

Silver with 4 terminals NAPA UNI-ST85

 

[TheBigDog]

Is the starter relay black or silver? Does it have 2 small terminals, or only 1?

black with 3 terminals (only one small terminal) NAPA UNI-ST82
black with 4 terminals (two small terminals) NAPA UNI-ST81

Silver with 4 terminals NAPA UNI-ST85

It is the black one with 4 terminals. Thanks @OFF !