How do I know when the track/recoil spring is fully uncompressed on my Komatsu D31? I am thinking I might need to remove my left side spring in order to weld a bracket. I want to be sure the spring is completely uncompressed before I start to loosen the mounting bracket for it. Here's a pic of the left side with the broken bracket. The left side spring is about 1 inch longer than the right side spring right now due to the broken bracket.
I have an idea.Remove the broken inner & outer angle iron that is bolted to the track frame .Remove the two bolts in the threaded block on the spring plate.After you get the threaded block out use a cutting torch to remove the broken angle iron from it and clean it up good with a grinder.Use new angle iron on the track frame and weld the threaded block to the new angle iron.Drill holes as needed in the new angle to fit the track frame.The welding & drilling can be done in the shop .Install the new inner & outer angle iron on the track frame.Now,To compress the spring.First try pumping grease in the track adjuster.This should free up the spring plate at the front.now install 4 all-thread rods through the spring plate into the threaded block inner and outer.put nuts on the all-thread and compress the spring by tightening them down equaly untill the spring plate is against the threaded block.then remove the all-thread rods one at a time repacing it with a new bolt.unless I am missing something in the picture,I dont see any reason to remove the spring ,track adjuster,or front idler.The track is holding it together.
Do not cut anything yet. If the spring is longer. The bolt that goes through the center of that assembly is broke. If that is the case you have a time bomb on your hands and someone is going to get hurt. If the distance between the two plates on each end of the spring should be equal from left spring to right spring. If not you have dangerous problems.
Its hard to tell from the picture.If the rear spring plate is not welded to the angle iron that is bolted to the track frame .I dont see any trouble removing the angle iron.The rear spring plate might just be welded to the track frame .We need some close-up pics of this.The only thing I see in the center of the spring is the track adjustment cylinder.Most older dozers used a center bolt it the spring ,this is a different set-up with the cylinder inside the spring.
I have a PDF from the manual for the spring/jack/mounting assembly which shows all the detail and make thinks more clear for this discussion. But I can't seem to figure out how to upload it to this site. I normally use the photobucket site and link to it as I did above but photobucket only takes image files, not pdf files. I've gone to the UCP but can't find the link to the albums mentioned in the "Picture upload instructions" . Can some one tell me how to upload a PDF file to this site.
Dressta1 is absolutely correct. The center bolt is broken and the spring is no longer caged. YOU HAVE A BOMB ON YOUR HANDS AND UNLESS YOU HAVE DONE THIS TYPE OF WORK BEFORE YOU NEED TO GET PROFESSIONAL HELP!!!!! The pressure of the spring when caged is equal to the weight of the tractor. If the track weighs twenty thousand pounds, then the spring will be compressed at twenty thousand pounds and the nut will be installed. The only way I have been able to repair those is to cut the spring one ring at a time from as far away as possible. Usually a large scrap yard torch, getting low to the ground and getting all other people as far away as possible. The job is expensive and risky. Good Luck!!
Hey John C. & DRESSTA1.dcara dose not have a bomb on his highlift dozer.dcara has a broken spring frame and is asking advice on how to fix it.Question to John C. How would cutting the spring help repair dcara's problem?
The end piece to the left with the bolts in it is broken because the reach rod is not holding the spring in compression. The spring in its current position is probably being held by the track. There is no way to compress that spring back in place and put a new rod back in the center. So the only way to somewhat safely remove the spring is to cut two or three coils.
John C is correct. We need to find a break down of this thing. That spring is part of an assembly that is set in place in the track frame. When the spring is in it's released state it is probably another 4" longer. There is no way to put that in the machine without it being part of an assembly. If you look at a breakdown you will see. I would cut links until there is no tension on any of the links. When I would assemble track adjuster springs I would have two forklifts in front of the press on each side to try to contain a misshap. We assembled them in a 100 ton press. It did not require 100 ton but 30-50 not unusual.
The quickest,most cost effective,and safest way to fix the problem is to weld the threaded block back on the angle iron where it broke off.Add some steel plating to strengthen the weld joint.To compress the spring wedge a piece of wood between the sprocket & track rail and back the dozer up abit.Have some all-thread in the bolt holes to help guide the front spring plate on.Install new bolts and its done.Probably last a long time.The worst thing that could happen is it might brake again at the angle iron.I would like to see the parts break down on the spring assembly.I have two dozers that use a center "caging bolt" in the spring.They dont look anything like the picture on this thread.It looks like the angle iron and end plates are the "cage" on this dozer.
It looks like the inner retaing bolt broken a very dangerous situation I would pay the price and sacrifise the spring cut the spring and due it right a little secret in past failed recoil spring traced to weld splatter when making this type of repair there have been far too mainy people hurt with recoil springs and even death the BIG D
What would releasing the pressure in the tightening cylinder do? Looks to me from the pic like the spring is around the cylinder body and is between the end of the cylinder. The reason I ask is it looks like with the spring around the cylinder if the pressure was released that may take the rest of the tension off the sring to remove everything and make the repair and have a mechanic come in and recompress it once the fix is made. Just a thought I had don't know if it would work or not, at least safely but it do look contained to me but I am not there. Something to throw in the mix I guess.
Finally! It took me awhile to find the combination of drawing packages that would convert the PDF to a jpeg file that I could put up on Photobucket and then provide a link to from here. The link to the spring assembly drawing is at the bottom. Anyway, as you can see in the spring assembly drawing there is not a center bolt that I can see. The jack assembly is inside the spring. The jack assembly and spring are mounted to a cross bracket at the rear of the jack assembly. The cross bracket is connected to the 2 angle rails which are then bolted to track frame. Here a link to the spring assembly drawing Here's a couple of views of the spring assembly Thanks for all the discussion folks
dcara,Thanks for the pictures and parts break down on the spring assembly.Pictures always help on these problems.If it were my dozer I would repair it as I described in post #10.Are you a good welder?
The photo showing the end cap with the grease fitting is the nut that holds the whole thing together. I see welding on the side pieces to the track frame and on the end pieces with the bolts in them. I also see the bottoms of the track rails looking fiddle string tight. This looks like someone else tried a quick fix in the past and then pushed the problem down the road. You can do whatever you want with the thing. But you can't say you weren't warned. Good Luck!
I was thinking the same thing but wanted to get other opinions before I did anything. Before I can do it though I would like to get the de-headed bolts out of the inside bracket. Apparently, their heads were torn off when the outside bracket broke. I could weld this also if I have to, but I prefer not to. Anyone have any secrets they care to share on how to get these de-heded bolts out? FYI - The broken bracket used to be dangling downward but I compressed the spring enough to fish out. I used a 1 inch steel rod about 9 inches long in the sprocket valley and then backed up about 3 feet which compressed the spring enough to get it out. Thanks
25C you were dead on with this one and I was wrong. I have never seen a plate used as retainer. I think you are suppose to pull that entire frame out to compress it and the bolts hold it in place. To prevent the frame from moving they use dowels. Good call 25c
No dressta1,you were not wrong.You and John C and myself were giving advice with limited information.We were going off a picture on the first post and the advice of using caution when working around a track spring is good advice on any dozer.dcara's nexed challenge will be getting the broken bolts out of the inside spring frame block.That sucks laying under a dozer drilling out broken bolts.But that may be what has to be done.
I appreciate the words of caution. I was talking to a heavy equipment mechanic a couple weeks ago about this and he expressed EXTREME caution also. He said that he saw a spring release one time when they were removing an idler wheel and it shot the jack piston 50ft across the shop and THROUGH a cinder block wall! YIKES!! Luckly nobody was hurt. Some thoughts I had on the broken bolt removal were. 1) Remove a couple track pads above the work area so I don't have to crawl under the loader to do all the work. 2) Grind a couple flat surfaces on the bolt stubs to get a wrench on them if I have room enough for a my grinder. Then use a torch to heat up the bracket before I try turning the de-headed bolts. 2) Cut the de-headed bolts flush with the bracket and then drill them out. There is not enough space to get a regular drill in there so I may have to use my battery operated right angle drill and just keep charging it. 3) If the above doesn't work I'll just weld it on since the cost, work, and risk of pulling that whole spring/jack assembly off is prohibitative.
Heat the bolt block cherry red and then quench it with water , that will break the rust and make them easy to turn . Get a heavy washer and put over the stub if it is protruding and weld the washer to the stub . Get a large nut and weld it to the washer , weld on the outside of the nut as you can get a better weld . Welding on the inside is hard because the slag builds up around the rod which shields the metal and you get a porous weld . Shield the ram and seal with a piece of tin to keep the heat away when using the torch . On Edit . If i were doing the job , i would disassemble the whole show and renew the side angles rather than trying to repair the old ones . But this entails proper equipment and knowledge .
Great info Iron Horse! I'm not sure what the "idler slides" are just yet but I'll find out and look at fixing/replaceing them to keep this from happening again.
The idler slides are the parts that guide the idler roller , they are on ether side of the idler wheel and envelop the track frame . If you look from the front of the track frame you will see that these are worn and have an over sized gap on top of or below the track frame . It is possible to weld some flat steel stock to the inside of the guide to close this gap . An 1/8" clearance is all that is needed . Also , looking at your photo , there is rust on the track adjuster ram . You will need to get some emery tape and buff this off before you ever let the ram retract as it will damage the ram seals as it retracts .
Just a side note on extracting (ANY) bolts with the heads missing/ broken off. If they are broke below the surface on the rail / parent material we have used extractor rod. These rods work great anywhere a bolt is broke off below the surface. Having an auto darkening mask helps too. You just start welding on the centre of the bolt. These rods are designed to push the flux/slag to the outside therefore they will not damage the bolt hole or end up welding the bolt to the material. Secondly they pile up easily, in other words you can pile the weld up past the top of the material surface. You can actually weld with these and pile a weld up infinately but in most cases an inch or so will do. After you are done welding them, quench with water then walk away have a coffee let things cool right down. I have actually piled weld high enough to get on with vise grips and turn broken bolts out. If they don't turn out it gives you a great "peg" to weld a washer and nut to.
"Get a heavy washer and put over the stub if it is protruding and weld the washer to the stub . Get a large nut and weld it to the washer , weld on the outside of the nut as you can get a better weld . Welding on the inside is hard because the slag builds up around the rod which shields the metal and you get a porous weld ." DING, DING, DING! We have a winner! After trying everything else it took welding nuts on to get the broken/de-headed bolts out of the left inside bracket. I heated the inside bracket almost red hot with my torch and then poured water on the studs before I tried to turn them. To my enjoyment they backed out fairly easily. On the outside bracket I welded the broken piece back on and then ground the excess material down until I could get a piece of 1" square stock into the corner and weld it in place to provide extra strength to that section. Here's a pic of the repaired broken bracket, and the to old studs with the nuts welded on. On one of the studs I was able to screw the nut on enough to easily reach the inside stud. None of this is my best welding, but its not my worst either. All that remains is to get some lock washers (which I somehow forgot), compress the spring again (with the pin in the sprocket trick) and screw it all together. Thanks to everyone for all your ideas. Anyone have any ideas on what might have broke this bracket to start with? I certainly want to avoid operating conditions that will cause this problem again.