Cat D6D track tensioner replacement and recoil tension spring lost preload

[jjdow68]

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!

 

[pittsburgh cat man]

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

 

[1466IH]

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.

 

[jjdow68]

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.

 

[pittsburgh cat man]

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.

 

[1466IH]

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 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.

 

[LCA078]

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.

 

[Glum]

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.

 

[1466IH]

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?

 

[jjdow68]

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.

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?

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.

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.

 

[jjdow68]

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.

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.

 

[jjdow68]

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 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.


;

 

[jjdow68]

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 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

 

[LCA078]

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.

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.

 

[Nige]

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.

 

[1466IH]

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

 

[jjdow68]

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.

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.

 

[jjdow68]

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 absolutely the sleeve is

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.

 

[Vetech63]

Yes absolutely the sleeve is

Put the grease valve back in it and see what happens when you add grease.

 

[shopguy]

I hope you have it fixed by now but I have one apart if you need me to measure something