Sky track 7038 Boom Cylinder repack?

[Hilltop366]

Removing cylinders in tight spaces you sometimes have to think beyond the tight spaces, as in it is often easier to take the other end of the hoses off and feed them through as the cylinder is pulled than removing them from the cylinder. 

[Don P]

The soft hoses in our boom go to the tilt cylinder up front. The extension cylinder has soft hoses at the rear and a hard line running to the front fitting.

[Old Greenhorn]

 8) 8) 8) 8)
Can you guess?!
 I started working the phones. I called Jakes guy (I gave him your regards Jake) and he tried but had no success.  Then I called NewWoodguys guy and he said they really don't do telehandlers mush, but was very quick to offer me the phone number of a company called Web Equipment in VA and I got hold of what I will call an 'old parts counter man' from ways back, he took the phone down to the manuals section and walked through it with me. No joy, but he did share with me that the 7038, 8038, and 9038 have almost identical booms and construction. Good to know, because at that point I was ready to buy the manual for a different model, but he didn't have those either. He could likely hear my desperation when I asked if he could suggest ANY other leads or places to look. He just said, "can I call you back in a few minutes, I have a contact I'd like to try?" SURE!
 15 minutes later he called back, "What's your email address?" I gave it, and he emailed the service manual before we were off the phone. I asked what I could pay him for it, he just said "don't worry about it, when you need parts maybe order some from us". Well yeah!  So it's printed and in a binder already and the procedure is not what I would have expected and I will have to study it more. But right now I am compiling a list of seal kits and part numbers to order from my new hero, Brain Foster at Web Equipment. :D I thought Bill had already ordered the seal kits, but he was waiting to order them all from the same place. I need to run down to the machine and confirm a part so I can get the right number. One of the steel lines is messed up and it was left dead inside the boom, we'd like to replace that also. Not sure if they will ship that. Don, we have 4 steel lines running through the boom on this machine, plus the chains, so it's pretty tight.
 Thanks again for all the help fellas! 8) 8)

[newoodguy78]

 8) 8) Further proof of the resources available here. Glad you found it. 

[GRANITEstateMP]

Old crusty parts guys are the best!!!

[Hilltop366]

The ship has returned to port. ;)

[thecfarm]

That is good news!!!

[Jeff]

Pretty durn awesome.

[Old Greenhorn]

Yeah, pretty awesome, but also pretty routine when you look at the track record of this forum helping folks get things figured out. 
 The second half of the day I put together a list of what we needed came up with a list of 7 seal kits and 1 steel line. I figured the right thing to do was order them from the folks who helped us out. Well I called in the list and what do you know? SkyTrak JLG has all that stuff discontinued and NLA from them, but they don't make the actual seal types and sizes available. SO the only way to fix stuff is to take it apart and then match up parts and order them. I think that's BS but what can I do?
 The main thing is we have the manual and I have now read the procedure 4 times, very slowly and it's still a bit complicated. It's over 20 steps some of which won't be fully clear until we get part way into it. One thing I know is, I never would have come up with this way of doing it. We do have to remove the top (end) section of the boom to get the cylinder out and you can't do the seals without the cylinder out. It's making a lot more sense now and I am very glad I insisted on getting that manual otherwise we would have done everything we could to avoid taking the boom apart and wasted a whole bunch of time.
 Getting this back together may be a lot worse than taking it apart, and the manual just says "to re-assemble, reverse the process."  :D ;D >:( but nothing about how to snake those cables and chains back around the rollers and pulleys. This will be fun.

[Firewoodjoe]

Never pull anything out without a rope on it. Makes it a lot better later. Just tie the rope on the end and pull its backwards to reassemble. I was quoted $1100 for a cylinder seal kit yesterday🤦‍♂️ They found a aftermarket one for $450. Stuff is getting out of hand on price. Yes it's a big cylinder but my lord it's just a bag of rubber and plastic. 

[Old Greenhorn]

Well, having retired from that business I understand the seals more than most folks generally. The common seal and wiper designs were produced in the millions and were fairly cheap, but we also did some very high pressure stuff and seal life was terrible so we worked with the seal company to develop special seals just for a single application so they would last a reasonable amount of time before rebuilds. Because they were specials, they were only available through us and they has a higher price. Instead of us buying them for 2 bucks a piece we were spending 30-50 bucks a pop, but the tools worked for a longer time. I have no idea what are markup was but I'm sure it was up there someplace.

 I just did some general digging on the Skytrak part numbers and have no problem finding the kits as A/M. Prices still range, for one kit I found it for as little as $36. and as much as $185. I can't imagine what a $1,100 kit would look like. Holy cow, it must be gold.

 Years ago I maintained a machine that required cylinder rebuilds after 40 hours of operating time. It was a high pressure water jet running at 125,000 psi. The cylinder body had a 4" OD and a 1" bore. After 500 hours, we cracked the cylinder. ;D There were 4 cylinders in the setup. The seals were 2 piece, very special, made from Turcite and a brass compression ring. You slid the seal in the pocket then had to 'set' the brass compression ring over it with a special tool. First time I did a cylinder rebuild it took me 9 hours. By the last time I did it I was down to 45 minutes. That included re-lapping all the check vales and doing the hydraulic side as well. Seals are funny things, they are.

[Peter Drouin]

I was going to tell you about web co. But I thought they only lulls like mine.
I get all my stuff from them.
Like the planatery I had to get. $7400.00


 

 

 

 

 

[thecfarm]

I use to work on those robots that require high water pressure to cut out automobile trunk parts. But we only ran 60,000 psi. Yes, they rebuilt quite often. I think you are right on the 4 inch and one inch part.
I only programmed the robots. Just told others what needed to be fixed.
There was a 4 inch wide round piece of brass about an inch thick too.

[Old Greenhorn]

Right you are Ray! There was a brass puck that set in a pocket in the face of the hydraulic piston to capture the head of the 1" water piston if I am recalling right. That was, frankly just about 20 years ago since I left that company and about 25 or so since I did my last rebuild before teaching a younger guy that is still there.
 I will tell you it freaked me out when I found that crack in the cylinder and I called the service guy at the manufacturer and expressed my concern in meaningful ways. The guy just said "yeah, they all do that, How many hours? about 500 right? and it cracked on the 13th thread from the end right? Yeah, those cylinders only go 500 hours. We'll send you another one and one for stock because they will all start going now. They're only $500. a piece."  Yeah, a 'throw away part' I used it for a pencil cup on my desk for a while, but it only held 4 pencils. :D

[Don P]

After a relaxing weekend working on the box truck rollup door... luckily she called dinner last night as i was looking hard at just chainsawing the back of the truck off .. we got back on the Lull today. The parts aren't in yet but the inside of the boom was a scary swamp. I took these pics then moved it to where we could hook up the pressure washer to cold water in the cold wind and have a lovely time. About a gallon of purple power later we had it cleaner than it was. We then removed the hoses and lo and behold they are about 9' long each and 3/8" so pretty cheap to replace. One hose is in good condition, the other is almost all braid. That far in we'll replace both. While DB was washing I piddled with the dozer and got the alternator charging.

I think this would be a late 70's-80's 644 Highlander II, JD powered. We also have a new master cylinder to put in this round.


 


The extension cylinder came out the back;

 

Back end of the cylinder on the left, rod on the right, piston nut end, it all looks remarkably good.


 

I did find 2 cracks in the boom while we were cleaning it up, places where it had been repaired before. I'm pretty sure this machine rolled with the boom extended at some point, there are some hefty repairs.

And I've found zerks I ain't never seen before  :

[Southside]

Don, how many levers in the cab? My 644 is a Highlander II and is a '92, pictured here. My 1044 is only a Highlander and is from the '80s with a different lever arrangement.  



Same JD engine in both, only difference being the 1044 has a turbo.

[Old Greenhorn]

Yeah, zerks in places I couldn't fit my pinky sometimes. :D
 I am jealous of that see through boom! Ours is one, big, long, narrow, dark box. ;D It only has two access holes to knock out the cylinder pins and of course they each don't line up at the same time. I also noted the holes do not completely line up from side to side, just to make it fun. According to the shop manual we have to (after doing about 10 other steps) remove the front section of the boom (just slide it out they say  :D) and then remove the cylinder through the front. We have yet to decide on a supplier for all the seal kits and Bill is still trying to see if he can get the local Skytrak dealer to just do the repair for us saving us a lot of fun no doubt, but also a lot of time that we could be doing other stuff. Lumber orders are coming in and if it ever stops raining I have a bunch of logs to mill up so I can make room for hemlock logs to fill orders. It's spring and things are busting out. 

[Don P]

It's spring, the time when we sing that Dylan song "Everything is broken" :D  

I'll get a pic of the dash. Similar but older controls on the left. Those black knobs, F/R and 1/2/3 by pulling on 2 sleeved cables that go back to shifters on the bellhousing. Those cable sheaths love to get wet and freeze. Same gauge location, our key is working there.

Floor mounted long handled joystick for boom lift and extension vs your short one, fine work is tough. slightly behind and below that by my right leg is a 4 gang block with fork tilt, that front cyl which is loose and chained right now, it is the hoses and lines in the boom. then a missing handle that would be 2nd boom function. I removed the last of those steel lines today just to clean it up. 3rd is carriage sled, 4th is frame tilt, this one has only one frame tilt cyl, on the front right corner. I'm not 100% I have 2&3 in the right order. Brakes are a single bowl master under the floor, lines to dual piston calipers on front and rear shafts, brakes are central not wheel mounted.. Park is another caliper around on the same discs with  sheath and cable to pull them on, brake handle is where yours is.

[Southside]

Sounds like the 1044. On the freezing cables, check where the cable is hooked to the transmission, on the F/N/R there is a shelf that sits below the swing arm and it packs with mud, which will freeze and prevent gear shifting. Thought it was the cable getting water into it until I discovered that spot. 

[Don P]

We used our precision jigs and fixtures to reassemble the cylinder. I held the oak 2x4 while DB "Hit it like I live". It slid together, and we returned it from whence it came.


 


Hooked, took apart and hooked up correctly a few times. New hoses in the boom.Everything works and blowing oil like a stuck pig, but just getting fittings snugged down, alas the only remaining leaker is at the rear where it's about 30 minutes in, but looks like we'll have it tomorrow.

 

Had enough time to slap a coat of paint on the back door of the gristmill truck. That's a new bottom panel and seal. I have now gradurated from Todco Online U, the spring winding episode 3 times I liked it so much. The Lull was a piece of cake, the door drove me nuts.


 

[Old Greenhorn]

Good for you guys Don! I don't care what you say, that's a big and not so fun job. Roll up doors is another one. I messed with the springs on one of my garage doors for a week and it drove me plum crazy, one side tight, one loose, then the other way round. Geez!
 Sometimes I think life is just a series of maintenance projects.

[Don P]

Well that last leak was a good bit of the day. There is a section of line about 8" long with several fittings to get the lines around the pivot end of the boom. In all the moving and wrenching, it pinholed and that was our leak.
While DB took that to town I removed and replaced the brake master cylinder. I saw a tag on the rear axle while under there, 1981. When the new line got back we installed it and buttoned the boom back up. Then we fought brake bleeders and began bleeding till the end of our patience.  Which was about school bus time because I ran into a neighbor down at the bridge on my way home. He had waited for the bus, he and his great granddaughter were playing and skipping rocks. Funny thing, when we first moved here his daughter put me in the ditch, and just about everyone else on the road. Several years ago his granddaughter totaled my truck with her fine driving skills. This one looks to be about a decade away from taking the wheel. I know a couple of people that have a good shot at being great great grandparents... early and often  :D.

Hopefully we'll load the Lull and a work basket up and take it to the next little job tomorrow.
Today was the first farmer's market of the season, 4:30 came early as she got ready to go. I need to make more walnut trays and boxes, the 2 I sent sold, none of the pine.