Master pin questions

[Columbo]

I’m working on a few undercarriage repairs on the excavator and I may need to split the track to remove the idler. This machine has aftermarket DCF rails (p/n DCF 1-0324 is cast into the links). I could not find any typical master pin arrangement when I examined the pins. One of the pins is slightly shorter and with rounded ends, I think this is the master and it looks like it is a friction fit without other retention? Can anyone with experience with DCF undercarriage confirm that this is the master pin style they used before I go medieval on it with a sledgehammer? Pics of both sides of the pin and one showing a neighboring pin for reference are below. Thank you!

Outer:
Innner:

 

[ahart]

I’m not sure what your situation is but I usually don’t split the track to pull the idler unless I can do it very easily. I just walk the track off of the machine and slip it back on when done. Again, your situation could be different but that’s the way I typically handle it.

 

[Columbo]

Thank you for the suggestion! These rails don’t have many hours on them, would that technique still work on newish rails?

 

[1693TA]

I've not done on of these myself but have seen several as ahart mentions to walking the track from the machine.

 

[Tones]

If the link indicated is the master pin I doubt a hammer of any size will move it the way the link is kinked.
I'd go with aharts method

 

[Columbo]

Yeah, the stuck links are another consideration. When I bought the machine it had been sitting quite a bit so it had numerous stiff links. Most worked themselves free with use but there are still a handful that are stuck.

 

[ahart]

Yes it will work with a new set of rails, just let your slack off all the way and take it off the idler first.

 

[uffex]

Good day
The attched may be helpful
Kind regards
Uffex

 

[John C.]

Why do you need to remove the idler? A master pin will almost always have a dimple in one or both ends. Most of the Cat excavators that I've put hands on used a T headed master pin that was retained by a cotter key after the A series machines. If you have a pressed in pin and don't have a pin press available, you will need to burn a hole in the ends of the master pin, let it cool, and then it can be driven out. You will need the pin press to install a new master pin when you make the tracks back up. A master pin is not expensive and I've prefer doing that over hiring someone to push one out that is worn anyway. To press on out requires removing a pad which can be a pain in itself.

If you split the track on the idler side you can just back up the machine enough to clear the idler and then pull the idler out with a bar and it will turn on the track chain moving forward. The front of the recoil spring will show and you can get a line around it to pick the backend up slightly and remove the assembly from the track frame.

 

[Columbo]

In answer to John C’s question, at the end of last year this side of the machine made a loud squeak when tracking forward. When I pick the machine up on this side and run the track forward the squeak was still present. So, since none of the lower rollers were touching the track (with the track off the ground) I figure the noise must be the upper roller or the idler. I jacked the track off the upper roller and it turns freely, with resistance, and has no side-to-side play that I can feel. It does move in and out a small amount- is that normal? Given that the upper roller appears good I have to assume the idler is making the noise.

 

[Tones]

That loud squeak could be a rock jammed against the idler and the frame. Before you go any further jack up the digger and block it up then have a look.

 

[uffex]

Good day
Any lube around the Idler hub?
Kind regards
Uffex

 

[Columbo]

Good day
Any lube around the Idler hub?
Kind regards
Uffex

Not that I can see. Thanks!

 

[JD955SC]

To me unless I’m crazy the top picture shows a cracked pin, two splits almost crossways to each other.

 

[Columbo]

No, what you’re seeing is the X I scratched in the pin to mark it as I didn’t have a paint marker on me. Good eye though!

 

[Columbo]

Well, I found the source of the squeak. Looks like this idler has been missing the bearing for awhile, the shaft is worn partly through.

Interestingly, the roller directly behind this idler also failed at the end of last year. Coincidence or did the failed idler take out the roller?

 

[Simon C]

Must of been a lot of clunking from that old clunker. LOL. Should run a little smoother on that side with a new idler.
Simon C

 

[Tones]

I bet the otherside isn't to far off from needing replacing.

 

[Columbo]

I’ll check the other side over carefully too. I’m a little surprised at the extent of the failure as the remainder of the undercarriage has relatively low hours. The previous owner replaced the undercarriage at some point and the machine spent a majority of the time thereafter sitting at his yard (which has caused several stuck links on each side of the track). The chains are stamped DCF and so is this idler so I assume that the idler was replaced at the same time. I’m not really familiar with DCF but the information online seems to show it’s a version of Trek?

The local independent repair house sells ITR, any issues using an ITR front idler here?

 

[Tones]

I've used ITR parts in the past which had the same longevity as Berco OEM parts with a lower cost and better availability.
Check out Komatsu parts also. I replaced the idlers with them, Berco idlers were lasting 1000 hours. Komatsu idlers had 4000 hours on them when I sold the machine and were OK at that time. They were twice the price of Berco.