How to unstick a track tensioner?

[MattE]

Seals are 30 bucks.... put the torch to er'

[bdcz]

KenP, I like your idea of drilling a hole, that's something I have considered as a last resort but it really wouldn't be hard to plug afterwards I guess. I don't believe my relief is plugged because while it is open I can pump grease into the adjuster and right out the relief again. I'm not sure what your comment regarding grease versus hydraulic pressure is all about. I'm an engineer too and I don't believe the cylinder cares whether I'm putting 2500 psi hydraulic fluid pressure or 2500 psi grease pressure. They are both basically liquid so if the cylinder can hold that much pressure it doesn't matter which fluid. The only difference being the safety aspect you warn about. I would make sure no one is close to the cylinder if I use hydraulic pressure. I tend to think the cylinder is designed to take very high pressure. Like I said in a previous post, most full sized grease guns are going to put out several thousand psi pressure. Measure the piston size and leverage your grease gun applies to the grease and you will find that 2000 to 3000 psi is very reasonable to achieve. So in the end I'm not sure if hydraulic pressure will help me or not. The reason I think it might is because it is hard to say whether I'm getting the full grease gun pressure since I cannot hold the grease gun against the zerk hard enough to get a good seal while stuggling with one hand to pump the grease gun. Perhaps another thing to try is to hard plumb the grease gun to the adjuster with no leaks so that I can use two hands to really reef on the gun. I'm thinking I'll try hard plumbing the grease gun first with some heat, if that doesn't work I'll try the hydraulics with some heat. At least with hard plumbed hydraulics I know I'm getting good pressure. I won't resort to a lot of heat until I've exhausted all else and resigned myself to the fact that I might have to pull the tracks. I just keep hoping that one of you experienced guys have a slick trick up your sleeves. I've also considered other ways of putting pressure on the front idler to push on the adjuster. I've seen some mention of people using a hydraulic jack between the blade and the front of the track. Unfortunately if you calculate how much force you would have to apply to equal what a shot of 3000 psi pressure would do it would be around 5 tons and you still have the springs to deal with. I'd be afraid to put five tons against the outside edge of my blade for fear of breaking something. As soon as we get some nice weather around here I'm going to work this again. In the mean time I'm still open to any suggestions.

[KenP]

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[Lavoy]

A high quality lever grease gun will do 8,000 PSI, maybe more, pistol grips are rated about 4,000psi, so hyd pressure will not really gain you anything over what you have unless you use a Porta-power pump.
I understand the arguement as far as pressure rating, but if you look at the wall thickness of the barrel, it is substantially thicker than the barrel of a 3,000PSI hyd cylinder. As to pressure on the adjuster, I forget the rating on the track spring, but it has a 1" bolt containing it, and I believe it is rated in the thousands. I will guarantee that the adjuster sees thousands of pounds of force on it frequently. If you have a 350 loader nose down in a hole and try backing it out, ALL of the power of the engine is transmitted directly to the two track adjusters less your track slip. When in reverse, the top side of the track is always under tension, and the track springs and adjusters are designed to take the worst case scenario which would be low gear, reversed, and one clutch pulled. I can't tell you what that force would be, but it is enough to back a 12-15,000lb crawler up an incline that a man can not walk on, so it is substantial. I have stood a 350B crawler loader on it's nose, and the spring do not compress all that much, so that would be somewhere in the neighborhood of 6,000lbs of force on each adjuster. On a 2" ram that is a little under 2,000PSI/each.
Not that it makes it correct, but I have screwed the end of a lever grease gun hose directly into the grease zerk hole and "jacked" many of these apart. If it goes, good, if it does not, it is junk anyhow and nothing to be lost by breaking it. Grease is not expansive, so even if you break the barrel, it is not going to spray everywhere like it might if you were using hyd pressure. I personally have never blown one up, even with a lever grease gun, but I have had ones that will not move even at that pressure, so in the scrap dumpster they go. Occasionally, they will bypass the seal, and grease will come out around the ram, but they are still junk if the ram will not come out.
Lavoy

[bdcz]

KenP, good thoughts and you might be correct. I think we are just operating off different assumptions. I was assuming the engineer designing the thing would plan for it getting stuck and someone having to use the entire pressure of their grease gun to move it. I could be wrong of course so I'm checking through all my manuals to see if there are any hints. I have repeatedly applied all the pressure my grease gun can dish out with no ill effects. I just looked in my shop manual and it refers to the special "low pressure" grease gun for adjusting the tracks. Rats, now it is decision time. If I use high pressure will the thing break lose before someting brakes? If I do apply the hydraulic pressure I will make sure no one is close by and I will apply short pulses in case she blows. I've seen all that kind of stuff happen too so I appreciate the safety caution. I guess my approach will be to apply a good amount of heat before I try any pressure in hopes the expansion will break things loose first. You are correct, if it moves like it's supposed to it will never see the high pressure. When I rebuilt the adjusters I machined them out to accomodate a larger, heavery duty, higher temperature lip seal that should be good for 450 degrees F. That should help avoid taking the thing apart. Thanks for the input, I'll let you know what happens when I actually work on this again.

[bdcz]

OK KenP, I know I can be an idiot some time and we engineers are the last to read the complete manual. I just found some instructions in the shop manual under the section about the description of the track system while I was looking under assembly and dissassembly before. It addresses this issue exactly. It says that if the adjuster gets stuck you can hook up a regular grease gun or pressure source and apply up to 8000 psi. It does caution that you should cover the adjuster with a heavy canvas in case something blows. So apparently it is designed to take a maximum of 8000 psi. I'm going to hook up the hydraulics and let her rip. Unfortunately I only have tractor hydraulics available at 2500 psi. so if that doesn't do it I may have to scrounge up a high pressure hand pump or something. I'll let you know. Thanks for your help. When all else fails, read the manual.

[KenP]

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[bdcz]

Lavoy, you obviously have a lot of experience with these machines. If a good grease gun won't move them I wonder if before you scrap them why you wouldn't at least try putting the thing in a press and trying to get it to move? If you can get it to break lose you might save the whole unit. I'm thinking if the hydraulic pressure won't move it I'll try a Porta-Power unit. My grease gun is old and tends to leak down. Just in case I ruin mine or can't get it lose are there replacements available? I need to do some work on my machine this summer. I think we talked a year or so ago about me needing a new shift lever. I still need one but have not had a chance to take the old one out yet. I have just retired so I will have time this summer to fix a few things. Getting the adjuster working will be number one. Then I'll remove the shift lever and see what I need.

[Lavoy]

The trouble is a press only seats them deeper, and that might be going backwards. If you had the time, and could leave the adjuster out, you could throw it in a pail of water for a few weeks and see if the rust would soften up.
I did send one that I had given up on to a customer that just did not believe that they could not be broken loose and wanted to try it. He worked at it for quite a while, and did eventually blow it up, but never got it loose. I think he had it in a press of some sort, said it made a hell of a bang when it blew, but nothing hurt.
A good lever type grease gun is only probably $30, and one thing you can do is fill them with diesel fuel or hyd oil if you want something thinner in case it will seep out and loosen the rust up.
New complete aftermarket adjusters are about $350 I think, just put on on my 350 late last year.
If you do get yours to come apart, I use a cylinder hone to clean the barrel up, you can sandblast the rod to get all the rust off of it.
Lavoy

[PowerStroker]

just get a couple of sticks of dynamite in the right position and you should have it apart in no time putting it back together might be allitle harder though.

[bdcz]

Thanks guys. I just really can't figure how this one ever seized up in the first place. I just rebuilt them about 4 years ago and the machine has never been run in water and it is stored indoors. I always clean the machine up quite good after each use. I don't remember, does the ram fit quite tightly in the cylinder along its entire length or just up near the end where the seal is? Is there a wiper on the end of the cylinder? It might make some sense to turn the ram down 1/8 inch or so in the center of it's bearing area. Oh well, at least no matter what happens it sounds like it can be fixed, just takes time and money that's all. I've gotten 10's of thousands of dollars worth of work out of this $6000 machine so I can't complain. I will make a trip to the store this coming week and get the necessary plumbing parts to hard plumb a new grease gun to the adjuster. Then I'm going to apply as much heat as I think I dare and give it a try.

[KenP]

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[bdcz]

KenP, yep good advice. I will probably just use a propane torch and will keep that moving as well in attempt to get uniform heat buildup. A slow uniform rise is better than a lot in a small area. Thanks.

[bdcz]

Well, I got it loose. Wasn't as hard as I thought. I had been soaking it with penetrating oil all winter. I tried with just the normal grease gun application but still no luck. Then I hard plumbed the grease gun to the tensioner and applied heat. I heated the cylinder until it was almost too hot to lay my hand on. Then she moved. It's still tight however since it takes everything I can give it with the grease gun to move and it won't go back in by itself. So I think I need to pump it in and out a little to loosen things up and then I'll hope it stays loose. Since I got it to at least move I tried pushing it back in by putting a hydraulic jack between the back of my blade and the track on the front of the idler. All I can do is compress the tensioner spring but the ram won't go back in. Any thoughts?

[KenP]

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