CAT 307C Track Tensioner

[Haymaker101]

Hey guys,
New to me 2006 CAT 307C. Track tension is losing grease, looks like wiper/seal of some sort has gotten pushed out, can see on cylinder.
I’m waiting on manuals, but in the meantime I’m trying to figure out the best way to pull idler out.
1. Walk the track off and remove idler. (Have Skidsteer and forks to put back on)
2. Split track, is there a Master Link?
3. Enough room if I unbolt some track pads?
Please let me know how you would do it. Thank you!

 

[Haymaker101]

Here’s the best picture I could get. Thanks

 

[Nige]

Got a Serial Number.? You can have the procedure from the correct Service Manual with that info.

 

[Tones]

Usually when that seal gets damaged is because the tracks are worn out allowing the over extension of the piston. Some pictures would be helpful.

 

[Haymaker101]

Here’s the serial number. How do I measure exactly to gauge how worn out/stretched out the tracks are?

 

[Nige]

FYI your machine is a 2005. Built 24th May.

How do I measure exactly to gauge how worn out/stretched out the tracks are?

Put a grease gun on the tensioner and tighten the tracks. Measure or estimate how much of the piston #5 is showing outside the tensioner cylinder #4 compared to the length of the cylinder itself. In the illustration below the tensioner is fully collapsed and you can see where the piston seals are. If the seals are getting anywhere close to the end of the cylinder when the tracks are correctly tightened then the tracks are close to (or past) their wear limit.



Attached the procedure for removing the tensioner. Yes there is a master link on the tracks and you also have to remove the front track roller to make enough space to remove the tensioner from underneath.

 

[Haymaker101]

Hey Nige,
Thank you very much for taking the time to send that attachment. I will print out and bring the CAT in the shop ASAP. Hopefully rebuilding or replacing the seal is pretty straight forward. I’ll keep you guys in the loop over the next few weeks

 

[Tones]

Hey Nige,
Thank you very much for taking the time to send that attachment. I will print out and bring the CAT in the shop ASAP. Hopefully rebuilding or replacing the seal is pretty straight forward. I’ll keep you guys in the loop over the next few weeks

You better have a look at the other side as well, it won't be far off needing a fix.

 

[Haymaker101]

Is there anything else I can do besides visually check over the other side? Thank you

 

[John C.]

You haven't stated whether you have steel or rubber tracks. Here is a video to give you a little back ground on excavator undercarriage with steel tracks.

 

[Haymaker101]

Hi, this is a great video with a lot of good useful information. It’s making me think my undercarriage is a little more worn than I thought! It is a steel track 307C. I will let you guys know how the future repair goes

 

[Nige]

It’s making me think my undercarriage is a little more worn than I thought!

Go back to Post #6, grease the adjuster until the tracks are correctly tensioned and measure the extension of the piston as suggested. Report back with your measurements.

 

[Haymaker101]

Morning, split the track and installed new seals on the tensioner. Everything went well. Upon further inspection though the track chains are worse then I thought. A couple of them are even worn through to the link!
New chains, hardware and sprockets are around $2,800! So eventually I’m going to have to do that too.
The tensioner is 6” long to the first O ring and I’m around the 5” mark. Chains are stretched!
Also, notice how one track is backwards? Hummm….Thanks for the advice guys, great site as always.

 

[Nige]

Pretty much as expected. Not good news for you but it confirms what we were thinking that the tensioner seals failed as a result of the assembly being over-extended.

 

[Haymaker101]

There are tons of places online that sell track chains and sprockets (claim to be the best quality and price), but are their certain suppliers that support HEF or vendors that people would recommend?
Any guess why the right hand track is backwards?!
Thanks

 

[Tones]

Any guess why the right hand track is backwards?!
Thanks

Sloopy workmanship.

 

[Haymaker101]

I’m going to do track chains this summer when I have more time, but right now I need to get this excavator to the farm to do some prep work before planting ASAP.

Here’s my thoughts, the chains are stretched to the point where the travel on the grease tensioner is maxed out and the grease is getting by the O Ring. 6.25” long shaft. I don’t think I can take out a track link because they’re 6.5” center to center. I don’t think I’ll get the tensioner back in even when fully retracted.
So, can I weld a 2” long piece of Solid round bar onto the track tensioner piece to gain travel? Pro and cons? It should be able take up the slack without over extending the tensioner. I’ll cut it off once I install new chains.
I’m all ears and open to any better options. Thanks guy

 

[Bluox]

Divide the 6.25 track link by 2 and that is how far back the adjuster will move in.
Pull one link.
Bob

 

[Haymaker101]

Okay, will do. Thank you for the advice Bob. Is there a way of telling whicch way the pin drives from? Please keep in mind this tracks on backwards so I’m going to remove from machine entirely and spin around correctly. I’ll let you know how I make out

 

[Haymaker101]

Morning everyone,
Removed a link and everything looks good. I want to thank you guys all for the advice. Well worth it and also got the track going in the right direction as well. The left side however does stick out 3 inches further, ha ha. Probably not too far behind for needed link removed before I run out of adjustment!