Hello I have a D6D that has an issue. Can’t find exactly the same issue on the internet. Although there is some seal replacement videos I have not found any that explains my specific issue. originallyi thought this was gonna be a tension piston seal rebuild. So I have the tracks split and the idler and yolk rolled forward. To separate idler yolk arm from the plate that connects the grease zerk and track bleed off valve the 4 nuts and bolts have been removed. The insert that houses the track adjustment piston is suppose to come out with the insert. Or at least that was my understanding however the piston remained inside the outer adjustment housing either being firmly stuck in the far back wall of that housing or it suppose to be attached to the spring tension rod? Somewhere In this dozers life, the spring that is suppose to be preloaded and under extreme pressure seems to be decompressed. ?!? The large nut and bolt that goes through the center of the spring is completely loose. You can actually wobble around the shaft freely inside spring. I have concerns about the releaseing of the spring in its current condition. The spring itself appears to be completely intact and nothing that appears cracked. So I prefer to keep the spring in tact. How risky is the spring at this point. Best I can tell, there is no tension due to preload. ‘Again the bolt shaft is completely loose. If there is any pressure still there it would only be what’s there from the spring hold down brackets located in front of the springs. Those brackets which are two piece, each bracket with a total of 4 bolts holding those down. What precautions should be taken to prevent any dangerous conditions. I was thinking of several straps looped around the spring and a chain binder to connect to the frame while removing the brackets that will grant me access to the spring for removal. My hope is to remove the spring and so long as if it is still safe to use , I would like for it to be preloaded again and finishing up the seal repair. oh and speaking of the piston seal replacement is that piston suppose to be stuck tighter then dicks hat band Inside the dust cover. I’m including pictures for better reference. ‘everything I’ve read has painted a different picture rather than what I actually have on this dozer. Most video show that the piston comes right on out the inner open ended slide shaft. > clean it up and slide it back in and put it all back together
as it is shown on this repair manual that piston was suppose to come out with the sleeve. But that piston is still in the cylinder and won’t budge. That’s what I’m showing in this picture.
Can you post a Serial Number so that the appropriate Parts Manual can be pulled up.? There can be differences in the tensioning/recoil mechanisms between different models of D6D. It is important to get the correct one for your machine. The illustration below may or may not be correct. A WARNING.... The recoil spring is often referred to as the "Death Spring" for a very good reason. They have killed people in the past. That spring will still have a tremendous amount of pressure in it, even with the bolt broken. That broken bolt is key. It is what holds the recoil mechanism together for installation or removal purposes. With the bolt having broken there is NO WAY that the spring can be safely compressed in order to remove the recoil assembly mechanism. IMHO the only safe way to attack that spring is to cut it with an oxy-acetlylene torch until all the forces have been released. At that point the rest of the mechanism can be disassembled. I would recommend that you DO NOT attempt to remove the bolted brackets ahead of the spring, whatever safety measures you put in place. The force released as the bolts break loose will almost certainly kill you.
That piston in this picture “number5” is still in the cylinder.
Some reading for you. HeavyEquipmentForums
That large bolt on the center of the spring os only for removal and installation purposes. After the spring is installed onto to machine and both dogs are bolted down to the track frame in front of it that bolt gets loosened to allow the spring to rest between the backing plate and the dogs. Unless there are broken bolts on the dogs or see any cracks or broken welds anywhere that spring should be perfectly contained. With that said they are still widow makers and should be treated accordingly. You could if you want wrap chains around it and the track frame. Those springs are very affordable aftermarket and readily available (at least the last I checked) so if you do decide to remove it just cut it one coil at a time until all tension is released. If you decide to go that route post back here before trying to compress and install new spring because you must compress it properly.
Thank you for the reply and the insight. The spring under load is 20 inches and at free release the spring is 25 inches. According to caterpillar. I haven’t measured the spring but I will to verify the load. If the spring measures to be under full load then perhaps I should leave it alone and just concentrate on removing this piston that seems to have lodged itself into the back of the housing cylinder. My understanding is the piston should have come out with the sleeve but it did not. Any recommendations on how to get that piston out. after seeing the info that you guys have sent it appears to me that piston is suppose to float. I haven’t seen a scenario in any repair manual or repair video so far that would lead me to believe that piston is supposed to be fastened to anything. But the fact that it so tight it made me hesitate to go at that piston not knowing for sure. I didn’t want make this worse by trying to remove something that is somehow bolted down. 4x 06525
Oh wow this is interesting and makes me hopeful. so the fact that the rod is loose doesn’t necessarily mean it’s broken. There are no broken bolts on the dogs. Haven’t seen any cracks anywhere. To me nothing looks compromised concerning the spring. That loose rod is all I’m going by as the concern for the spring. Hell it might be perfectly normal as it is. However the piston be ing stuck in the cylinder is what lead me down this rabbit hole. Any thoughts on removing a stuck piston.
Then the illustration I posted above is correct. Can you post a photo of the area circled in the illustration below. Are the end of the bolt, the washer, and the nut all still there.? EDIT: Thinking a bit more about it the possibility exists that the piston is seized right at the back (left side as per the illustration below) of the the track adjuster cylinder and this is what has pushed the bolt to the left and has it hanging loose.?
I’ve had ones that worked around drilling rigs be a real pain getting out because of the salt brine
In order to disassemble the tensioner cylinder and remove the piston it is likely that you will have to remove the entire cylinder from the machine. To do that will require the recoil spring to be correctly de-tensioned. I think you're stuck between a rock and a hard place.
I think you need to look at pilot between coils to see if there are any cracks. Was idler slammed the whole way back? Second thing to note is compressed length is so it will fit it during assembly
yes I will go get some better pictures to send. i thought I had better pictures than I actually have. If I haven’t said this yet I sincerely appreciate the help.
Did you remove the grease valve from the barrel? Trying to pull that out with suction on it will be near impossible.
I was thinking maybe welding a washer end wise on the top of the piston pin so I could attack a slide hammer and possibly dislodge the piston that way. Thoughts? Everything went by the book,so to speak, right up until the piston stayed in the cylinder. Very straight forward then this.
As per what @pittsburgh cat man posted above you should check very carefully that the 7M1859 Pilot Assembly (will be visible through the coils at the front end of the spring) is not cracked. If it is cracked then it will have to be replaced. Removing the existing piston and fitting a new one will not fix the problem. The issue is that to replace the pilot the spring has to come out.........
Yes sir all that came out the sleeve etc. there was zero grease pressure on the tensioner piston. Here is a picture of the sleeve.
I cleaned up all the old grease inside the cavity to get a better visual. This is a picture of piston in cavity after cleaning it up.
Oh I see. Well there is grease in there around the spring. I just assumed the grease was due to the busted seals. But I see what you are saying here. I’ll need to clean up inside the spring to get that grease out to possible get a visual of the pilot assembly.
Maybe I'm not following mechanically how these pieces work with each other but it appears the stuck piston simply pushes on the thru-bolt and there are no joining mechanisms (screws, pins, insets, etc.). If so, it may be just that the piston face surface as has simply rusted/seized on the bolt end face surface. Have you tried to gently pry the piston sideways with a long screwdriver or crowbar? Otherwise, I'm struggling to understand what would hold onto the piston if the cylinder is removed. It should just "drop", right?
I wish I knew. I’ve taken over this project from someone that passed away. All they had done was separate the tracks and taken off the track rail covers. The rest of it is where I came into the picture. I.e. what I have done so far disconnecting the idler, winching it forward, removing nuts and bolts from tension cylinder, taking sleeve out, noticing the piston not in sleeve. I’m now concerned about the pilot assembly because there is grease in between the springs as I will illustrate in this picture. I will say this though, looking from the inside of pilot assembly, at the part I cleaned out , it looked and felt like no cracks to the housing. At least that part of it. the picture of the stuck piston is the inside of the pilot assembly. It’s the second picture attached. ‘could it have blown out the back of the pilot assembly? That something I don’t have a visual of the back side. I’ll be cleaning that up best I can and try to get a camera in there to inspect. As mentioned this looks like between a Rick and a hard place. This sucker is out in the middle of nowhere so this will have to be a field repair. the options are dwindling. indid price a spring but not aftermarket. I was quoted 2200 bucks from cat just for the spring. ive tried to download the picture showing the grease inside the spring coil but for some darn reason the files to big. Good grief. Anywho! There is some grease back there so I suppose it’s very possible the pilot assembly is compromised in some way.
Excellent observation and you worded it better than me. I hope someone chimes in. And to your point. Yes I did try to pry side to side thinking and hoping for the same thing you mentioned. That’s why I’m thinking maybe get a washer or links of chain a welding on the end of the pin to get a better grip to pull on that sucker.
I meant to reply to your specific and replied to the whole sorry for the misstep. But yes I will be going back to clean up the area and look for cracks. And I will have tape measure in hand for spring specs.
In this last picture. Page 50 in the manual. I’m confused about the second picture from the bottom. Is that not a roller.
Yea it looks to be an error in the manual. Your machine seems to be as it should. Just remove the piston from the cylinder (put some compressed air in there through the grease port if it is stuck, but it would come out with a bang) that you have already removed, replace the seals and reassemble.
I have used grease thru the valve to push stubborn ones out.
Some times it takes me awhile the piston is stuck in pilot not the cylinder right. The thru bolt on back of spring push it in and see if there is space between big nut and rear pilot if you have space you could give it a wack with hammer that bolt is open to center of front pilot where piston is
Ahhh, the BFH method rears its head again. Hopefully Pittsburgh Cat is spot on....
Ok so I think I could get a decent wack on the rod on the back of the spring. if I can line it up I don’t see why that wouldn’t work. It’s tight space between the sprocket and hitting the top of that nut and rod. Would be a heck of a lot more force then prying from the inside. defi Something I’ll be checking when I’m back to the machine.
I wonder if dirt/grime is holding the piston tight in the pilot. I don't know how much of the piston would stick out past the cylinder at max extension but I wonder if the piston just got too far out and the ramming action of the track tensioner packed dirt all around it...effectively concreting it in. Either way, good luck with the hammer and be safe!
Yea now I see the piston is stuck to the end of the rod. Might be a silly thing to ask. Have you stuck your hand up there and just tried to pull it off? As there is nothing really for it to stick to.
Yes many times annd can budge it and I have also tried with a very small pry bar. Small pry bar , not by choice but due to being such tight quarters. Got a couple really good tugs on it from each side, left and right and got zero wiggle from that. in the picture if you look to the back end, back of the piston, you can see some seal material that is possibly pinched to the tapper in the pilot assembly. while cleaning out the old grease I pulled a lot of seal material out of the housing. I was hoping it to be chunks of leather but it looked more synthetic or hard plastic. But was not the green seal material you see on the top of the piston. The green chunks were there but it also had that other material in there as well. my Hand barely fits in there around the pin but as you can see in the picture I was still able to reach to the back to clean all the grease out of it. That’s also when I got the chunks.
I'm thinking they have the wrong cage bolt in the spring there is no way the piston could get back that far with the right cage bolt
Better start reading the death spring thread
Are you inferring that someone may have used any bolt that fit, or better yet made their own bolt, instead of buying the right one from Cat? Say it ain't so!!!
Ah yep brave soles!
Interesting. I will clean it up and take some pictures and post them up. Hopefully I can get some answers to what’s going on inside the coil of that spring. It’s a shame I’m not standing there in real time while talking to you guys.
just read the death spring trap thread…yikes! I can tell you this I’m not gonna intentionally do something sketchy I’m thankful to this forum and everyones input. It’s given me pause and better understanding of how this tensioner and spring operates. Not sure if the cage bolt is machined with that pecker on the end, The part that presses against the piston, or does It come in 2 pieces.
Cat ones are forged one piece Normaly with track adjuster out cage bolt is loose.
10-4 well the bolt is definitely loose hopefully not broke lol. We shall see!
I don't think bolt will be broken once the spring is in frame and nut is backed off against big washer and the 1/2 inch bolt in the end of the cage bolt the cage bolt is just going for a ride The end inside the pilot is the only thing doing any thing
Just another warning about that spring and cage bolt. I never trust an old nut and bolt. If that bolt or nut or any component involved with compressing that spring look compromised in any way shape or form(rusting/pitting, flat spots or damaged threads or the nut just turns excessively hard) just cut that spring. I have only ever had it happen one time but I was removing the spring from a 951B and had left the track connected and overtightened the track adjuster to help compress the spring and then tightened my nut nut down like you are supposed to keep spring caged. Went about splitting the track and removing idler, track adjuster and the spring. I had the spring in mid air hanging from my boom and getting ready to set down when there was a very large bang and **** flew everywhere. Come to find out the threads inside of the nut were compromised enough to where the bolt pulled the threads from the inside of the nut. The load bang was the nut hitting the back of my service truck at mach Jesus and putting a dent in the rear drivers side compartment. Things are replaceable...you are not. Just take your time and assess everything as you go.
Damn that’s scary as all get out. I don’t even want to think what that would have done to somebodies noggin. After reading these scenarios I have developed a healthy terror even thinking about this situation. What’s your thoughts about this piston being stuck inside the pilot assembly? It’s probably wishful thinking but I’m hoping I don’t even have a spring tension issue maybe it’s just a stuck or rusted piston. How would you recommend dislodging that piston? Wouldn’t it be better that the next move would be an attempt to dislodge piston rather than go to the cutting torch? Thank you for sharing your experience and look forward to hearing more.
I wouldn't cut the spring Let we ask you this on the rear of spring did you try pull the bolt out the back If so how far did it come out.
I wouldn't mess with the spring unless absolutely necessary. When that machine is in operation there are an incredible amount of forces being applied to that spring and all of its components so with that being said you can get fairly creative in trying to remove that piston. I am not very familiar with that era of machine so I am afraid I can't be a whole lot of help with that part. How deep is it inside the bore and what is the bore diameter? Would you be able to reach in and weld a 1" or 1-1/4" nut to the center of it? You could then use a piece of puller rod or high tensile all thread and then put a heavy plate with hole in the center over the end of your opening and make a puller of sorts. A 30 ton hollow ram would be ideal but I know most folks don't keep those in their arsenal of tools.
It also may be worthwhile to push the piston out from the bolt side. Can you get a jack or powerpack on the front side of the thru-bolt and push the piston? Maybe even a few hard whacks with a BFH might dislodge it. And if it helps, wrap a chain a few times around the spring/frame to give some sort of safer work area.
Unless someone has modified something, that piston should fall free with a few shakes and bumps from a prybar. The face of the piston pushes against the end of the bolt so there should be nothing holding the two together besides some rust and dirt.
Can you show a picture of the track adjuster housing(the piece that the grease fitting is in) laying flat as if it were positioned in the machine and looking straight through from the face? Is that thing just a hollow tube? Does it not have an end on it?
Yes sir I have a small slide hammer am]nd was thinking along the same lines of welding something to grab onto on the end of that piston and give it a good pull.
Yes sir that was also thinking that way. Once I get that back cover off I believe I can can a short handle sledge in there and give a few taps. I was also gonna bring log chain and binders to wrap it up good, that could either save me or make for more shrapnel should it go south. lol kidding.
I haven’t done that yet. When I get back to the machine. Hopefully today. on my list of things to do to do are: measure tape the length of the spring. Fully erased is 25.25 inches. When compressed to full compression it is 20.25 inches. That spec came from caterpillar. im gonna clean inside the spring all the old grease to give me a way to get the oscilloscope camera in there and get good, pictures of the condition of the tension bolt , the outside of the pilot assemble, and the pilot sleeve. I’m looking for cracks or ruptures and I hope I see nothing of the kind. lol I’ll run the oscilloscope in the cylinder and look for any cracks or scale rust see if there are any obvious problems. ( I did get some decent pictures ad it cleaned up good to get those pictures that I took with the iPhone) but im gonna get better visual with a better camera next time I’m there. next will be removing the rear protective cover to grant better access to the bolt and nut aka the cage bolt. From that I’m gonna see from where iand how it’s so loose. Im gonna get pictures of all this area to. Looking for extra wear and Cracks in the bolt. from all these findings it could go several directions. But I hope it’s an all clear with the spring. And either a tap from the bolt to knock that piston free. Or a weld on the end of the piston to give me something to grab and pull on. the included picture is the iPhone of the inside of the cynlider wall. I’ll get better images than this next time I’m there. i havent tried the cell signal out there but if I can and get to another dilemma ill snap a picture and post it up. ‘thanks everyone. ;
Yes sir the sleeve is hollow and it’s out of the machine. The piston that is suppose to ride inside that sleeve is stuck to the back of the cylinder housing. The first picture is the sleeve with grease fitting sitting on the table. The second picture is the piston stuck in the back of the cylinder. It’s not a great picture but what appears to be rust in and around the back of the piston is actually a bunch of seal material that I have pulled out in small chunks. I’ve thought that and mentioned in earlier post that maybe at some point that piston was slammed back and somehow pinched some of the gasket material to sort of wedge itself in there. at this point even with a small pry bar placed on the piston she acted like she was meant to be there. So from there it brought me here “dazed and confused” . lol
While you're at it, may want to count the coils and take a few pics of the spring as a whole. And look at the ends to see if there was any modifications to the spring itself. No telling if someone tried to fit a different spring in there. I seriously doubt it but you never know on old machines.
When you go to take more photos is there any way you can improve their quality.? Different phone maybe.? The ones you have posted up to now are generally not helping to clearly identify the problem because the image resolution is so poor. Help other people to help you.
So in theory the piston should be quite a bit smaller than the bore of the housing inside the spring since it is supposed to fit inside of the tube that goes into the tube
Yes I agree most of the pictures are fuzzy. I do have some better photos that would focus I have tried several times to attach them and it keeps giving me a “file to big“. Any suggestion on how to work around that situation. Tomorrow I’ll ask my son, way smarter with his phone stuff than I am, to help me get better quality pictures and I will see if some of the videos can be downloaded As well. ‘I’ve been ashamed of the quality of the ones I’ve shared but it’s weird the next photo would not have enough available file space. pleases if anyone has instructions on how to downloadload slightly larger slides. Many thanks.
Yes absolutely the sleeve is
Put the grease valve back in it and see what happens when you add grease.
I hope you have it fixed by now but I have one apart if you need me to measure something
Update: Got back to the dozer project yesterday. first picture is from inside the outer cylinder wall of the tensioner. The back side of the cylinder is missing. The square part is were the front of the bolt(the part shaped like a cone in picture 3) is supposed rest on. Where did it go? looks like I’ll be cutting the spring out to fix this. in picture 2 that the back of the bolt that I had to beat on to push the inner plunger out of the cylinder. It was literally embedded in to the back of the cylinder. I was hoping it just stuck in there by old packing material. No such luck! it was a round hole stuck in a square peg. Literally! any suggestions on where to source a whole new setup. Spring, bolts plunger, inner sleeve. I need the whole thing I reckon. The spring is in good shape but no way to take that off safely. No choice but to cut it out.
First I would get a new bolt there is actually a square hole in the pilot and a square on the bolt I would get a new center bolt and try it
you are correct the bolt has a square bottom of that cone shape. But it is suppose to rest in a square part of the base of the cylinder. what is missing is the back part that keeps the bolt saddled in place. If I was to put a new bolt in it. it would simple fall out the back of the cylinder. any Ideas on how to remove the spring, keep it in tact, without being so dangerous. Maybe run a large bolt with a backing plate on the exposed end Of the spring?
The only way I would consider removing that spring in your circumstances is to cut the coils with oxy-acetylene until all the preload had been removed from it. I don't see any safe way to put a load on the spring to hold it in place without it being a danger to the person(s) working on the tractor. YMMV.
To cut the spring bolt even laying in the spring is a good thing when you cut the spring always make sure it is a full coil and not broken part way around last you can see the spring going when you cut it and it will scare the out of you
I was afraid of that.
Thank you for reply Should I cut away the old bolt and run a new through it from the opposite side in order to keep the spring stable while I cut it out?
Any recommendations on were to buy a new spring, bolt and track adjuster innerand outer sleeve Basically the whole setup?
just stick the old one back and thru the pilot as long as there is a full coil when you cut, bolt will keep it in only do one cut per coil don't widen the cut. like I said You will jump when you cut thru the first few coils I've cut a good many and I jumped as bad on the last one as I did on the first one
The back side of the pilot is busted out. So the bolt is not doing anything . The square part of the bolt that is supposed to to cradle in the back of the pilot is somehow missing as well. In the picture you can see how the bolt is resting to the side of the pilot. Thats why I’m wondering if I should cut the old bolt out and try to run large bolt, possibly some 1 inch all thread through from the front side and a backing plate. Tighten it down and start cutting?
This recoil could be removed and parts saved without all the cut coil talk, the service books would describe the method to use, all it amounts to is removing the pilot rod and grease adjuster and fitting a replacement thread rod with a cap to cover the grease cylinder hole, then you press the recoil to strip it, there is another way of doing it that involves a chunk of round bar in the sprocket tooth to recoil the spring , remove the front recoil stops and drive forward to release the tension then undo the grease valve on the adjuster, this way works well on half worn tracks.
sorry no center bolt I will cut it every time. long time ago they pressed recoil springs on a huge horizontal press they shot one out of it once the power of one of those springs is amazing. I'm with the notion spring is a lot cheaper than me
I have all the CAT Service Press tooling for recoils and have done ever so many repairs of this sort but still show due respect to the task, I will say the later Hi-Drive recoils are a lot easier and feel safer to do, so only work within your limits of what your Gut feelings are happy with, I will say some or lots of the recoil parts are getting hard to locate, the D6C/D is probably one of the better catered for Tractors in the After Market, but always check before you start lighting the Cutting set just what parts you can still find. Best of Luck
thank you tctractors question: what Size thread rod would you recommend or use in a case like this? I could definitely some round ½ inch plate to fit over the the end of the cylinder. would I be able to ratchet the nut down enough with a cheater bar? Found a wonderful d6 manual online that answered a ton of question and also after digging deeper into the project i re-read the things mentioned earlier from the members in this forum and I have a better understanding now. nige “nailed it“ from the very start. I just didn’t understand til I got the thing further apart. as far as parts goes…I have been able to find the parts for the D6D and they will press it all together. If I goo all out with all new parts that’s the spring, inner and outer cylinders, pistons, backing plate,nuts,bolt,washer safety bolt and washer. All pressed and ready to set in all for 1400.00. Of course I would love to get that darn spring off safely and reuse it . I am tempted to try and use a thread rod just to see if it would compress just enough to get the front brackets off. I don’t see what it would hurt to try that because if it can compress than it’s know different, in terms of danger, as it would be when I put a new one back on. They are both pretty dangerous until they are back in the cradle. the trick would be using the correct materials so there is less chance of a possible catastrophic come apart.
I know very little but the nut on the end is a 9M3770 which is an 1" 3/8 high tensile nut. Since it is used to compress the spring so you can remove it from the machine it would make sense that a high tensile all thread rod of that diameter is adequate enough to compress it for removal. I was just watching a jpaydirt video where he discussed this exact issue with the D9G/H machines. He said the cat people will come out and cut holes here and there to get access to the spring, then cut the spring. He said he uses 2" high tensile all thread with a plate bolted to the front to compress the two springs (he said the D9g/h machines have an inner and outer spring) for removal if the rod is broken like yours is. The spring is an 8M6229 if you want to cut it and price a replacement. I have the service manual here if you want photos of the relevant pages. jpaydirt video discussing the broken spring bolts starts at 17 mins 50 seconds in.
I have compressed them many times with a 100ton hollow ram, appropriate sized puller rods and flat plates on either end.
is a 100 ton the minimum ? I’m not sure what size ram I could fit in there to compress the spring assembly. see if I’m following you correctly? in the provided picture: -run the appropriate thread rod into and thru the spring assembly. -put correct nut and washer on back side. -put thick plate, cut to fit, with bored hole in center over the exposed stud. -put nut and washer on to lock in and secure the flat plate. -place the hollow end of ram over the nut and washer and align the back/base of the hollow ram up against the track roller support. As seen in the picture. -compress the spring enough to run the nut up the new threads to hold the compressed spring -then remove the support brackets on the dozer push arms. -remove compressed spring take to a shop to decompress in a vertical press.
@1466IH @tctractors @pittsburgh cat man The issue as I see it is that here we have a machine owner with no previous experience trying to work on a damaged recoil mechanism which will not be easy to safely disassemble. IMHO there is a big difference between the perception of what's safe and what isn't between someone well-experienced in undercarriage work and a person who has never seen the job before. @jjdow68 - take a look at this THREAD that @tctractors posted. There may not be a lot of photos of recoil mechanisms but it will give you an idea of the size of tooling required to work on undercarriage components.
The only thing I will say about the threaded rod and nut trick. We tried that a few times after i got one out and released the threads on a good grade 8 nut were almost gone I would not do it again nor would I let the young guys do it
This is all very true. I should have a little more clear with my reply. I have the equipment and use it regularly and I forget that not everyone repairs equipment for a living. If a person does not have the tools and equipment to tackle a job like this they will quickly realize that a recoil spring is cheap compared to about $10,000 in tooling
14 ton its the pushing force the spring puts on the tracks when in normal use. That comes from the service manual. Of course it will have to be compressed when you put your new parts in it prior to install.
Thanks Nige ! The thread from tctractor that you shared is very helpful. I really appreciate everyone’s input. I learn from each of you guys. the place that Quoted me 1400 for the whole new setup told me the spring is 500 dollars. So most of the 1400 is labor. So its really not that bad money wise. Among the many things I’ve learned so far. I wouldn’t dare try this procedure without someone who knows exactly what they are doing and of course the proper tooling. I’ve learned a lot and will continue to ask questions to learn more! ‘thanks again everyone ‘cheers
I did put pictures of recoils being repaired in the CAT Sprocket Pulling tread I used to post up, the compressing of a D6C/D recoil is around 15 to 18 tons force I tend to recall, the comment about nut thread damage when using good grade thread bar can be sorted by using high grade nuts and putting 2 nuts on each end, the other day I stripped a recoil on a D6N late Series that used 4 short lengths on 16 mm grade 8.8 stud bar with a good push off a 65 ton Service Press cylinder and no Drama, the tonnage would have been 25 to 30 ton to release the load, as for the D9G/H recoil strip out you use the top roller bracket mounting bolt holes to bolt down a press frame with a long cylinder travel and lengths of all thread with nuts put in the front plate to control release the front plate that traps in the 2 springs, no need to cut holes every place.
Gentlemen, I don't mean to hijack this thread and if I would be better served by starting a new please let me know. I have a 1960 D6b with broken springs and leaking tension cylinders. What you have been discussing here is essentially what I am about to embark on. I have been fortunate to find and purchase new springs. I can't say the same for the cylinders. I have to hope that I can rebuild them as I have found seal kits. I am not new to track work or the mechanics of a dozer but this will be my first rodeo on tension springs. My first observation is that I will have to compress the springs by 7.5 inches just to get them to fit in the space allotted. Is this typical? In my situation the springs are broke in multiple points leaving no tension or stored kinetic energy in them at all. The previous owner placed angle iron spacers to the cylinder rod to prevent compression.
Update on the D6D . It’s been a long while but here is the latest. i used a cutting torch and cut the spring out. It’s a bummer because it was still a good spring. I went ahead and bought a new spring and all the rest of it. Which would include the nut, bolts, internal adjust piston, seals, the outer housing of the tension adjuster, all compressed and ready to install. The only part I was able to salvage /reuse was the backing plate. That’s the back side of the adjuster where the nut and bolt are. this all came at a cost of 1400.00 dollars. I hope to get it installed soon. Just haven’t taken the time to finish it up. As I understand it. I should be able to set the spring assembly back into place then back the nut off the spring just enough to put tension on the brackets. then reassemble.
Not sure where you are on your project but I wrangled with saving the spring to save a buck but it couldn’t be done by me. I didnt have the tooling resources to do it. Cutting the spring out was very simple and not near as dramatic as I thought it would be. It was loud but not a shower of slag like I was worried about. In your case I would cut it out. Cut each link though because it can have load up all the way to the end. Not to mention cutting it up sure makes it easier to pull the sections out. I cut a few rounds of them in 2 places. Made life easier in removal. Hope this helps and good luck with it.
Much easier to put track on put block between track and sprocket and back up and compress spring a little toucan back nut off with your fingers