Replacing Track Pins

[JCB814]

Newbie Question !

Can anyone give some general advice: We just broke a track pin. Machine: JCB 814. The pin sheered off.

Can anyone give some general pointers on replacing a pin?

We have the end of the sheered pin stuck in the track-link … do we need to heat it to release it ? or is it a simple brute force extraction? To get the machine back to the yard (50 yards) we just need to get the old pin head out and insert temporary a pin etc. (we are out in deep clay !)

Help!

 

[02Dmax]

Yes, you'll most likely need heat to get it out. And you'll need heat to get the new one in. Is it worn badly? Depending on how much of the head is left you might be able to blow a hole through it with a torch and that'll make it come out easier.

Sent from my SPH-L710 using Tapatalk 2

 

[John C.]

Cut a hole in the center of the pin head and let it shrink for a bit. Then you will be able to move it with a 4 pound hammer and punch.

 

[JCB814]

Thanks guys, we have managed to get the track back on and temp a pin into the one socket-link that we could, then secured the other side with a strop. Then *very carefully* tracked back to the yard. Now got to deal with the broken pin. It is obvious why it broke … poor maintenance on the track-plate bolts (all over tightened with their thread stripped) that we had not seen. Going to deal with the pin replacement after an overhaul of the whole track±! ..mostly lots of new track-plate bolts (which I assume are high tensile). Need to find a good supplier of said bolts here in the UK.

Going to have to find a mobile hydraulic pin-press service here in the UK or try to heat / 'pursuade' the pin in - is this possible for us to do (if we have a gas axe) - given that we have never done it before?

 

[trackdoc]

Don't use heat, it will make the link brittle.
A track pin on a 13 ton machine should sledge in with out too much bother cold

 

[DMiller]

I take it this was the 'Master' pin? If not you need to get the rail(s) to a track shop to see what is going on with the pins and bushings. Only the master pin will drop a track in half, if it was a segment link and the bushing ears/segment link eyes are that worn you will be repeating this over and over until you do see a track shop.

 

[Scrub Puller]

Yair . . . trackdoc. Do you have any real world evidence of this statement?

Don't use heat, it will make the link brittle.

I have been hearing it for over fifty years and about forty years ago started cherry-redding tack links for assembly and, over hundreds of thousands of track hours never saw a failure due to any change in metallurgy . . . some things sound right in theory.

I realise that in these days of SALT I would have to review my methods although you blokes have got it easy with Alligator links. (he grins)

Cheers.

 

[mitch504]

Yeah, I've sure heated enough of them, with no problems

 

[trackdoc]

Yes, I have saw links crack after being heated.
I have never saw the need to heat them, either the pin press or a sledge seems to put them in

 

[Scrub Puller]

Yair . . . mitch504, trackdoc.

Us blokes who worked scrub in remote areas got pretty familiar with track repairs. The soil for the most part was quite abrasive and the tractors ran continuous in second gear at WOT often for 12 to 16 hours a day.

The early Berco tracks were very crackprone and for some reason the chain would crack in sections, that is to say a dozen adjoining links would crack and the rest of the chain would be okay.

I made up an indexing jig on the "C" frame and, from components flown in by Cessna we could assemble a complete new section of track and install it overnight . . . it would have been impossible to do that sort of job working cold.

We also got quite good at building airstrips. I think our record with two D9's was 45minutes from virgin scrub to the Cessna on the ground.

Cheers

 

[td25c]

Agree Mitch & Scrub.... Lost count of how many times I have heated up a Boss on the rail to help get the pin out .

 

[JCB814]

Hi Guys,

Re some of the above and Master Pins: It was a sheared pin that caused the failure, not a pin actually dropping out of the link. The pin sheared as the chain links were not secured to the track - they parted enough to shear the pin under load. Bad maintenance and a lesson learned *the hard way* on our part. Used to laugh at jet washing the tracks down - but will do this regularly now to check all the bolts as we have found other plates with 'lose' ones.

Any UK peep's on here care to recommend anyone with a mobile press and/or track spares, so that I can cost out what our repairs are going to be?

 

[Scrub Puller]

Yair . . . JCB814. I googled pictures of your machine and it looks to be a conventional excavator with presumably a conventional track arrangement.

In view of this I just don't understand this statement . . .

The pin sheared as the chain links were not secured to the track - they parted enough to shear the pin under load.

Do you mean the track plate was loose on the track chain?

If so I am doubtful that would have caused your failure, the tracklinks should stay together with no assistance from the plate . . . there are pictures on this site of an excavator working with no trackplates on at all.

It should be no big deal to get you going. Some pictures would help folks on here give you better advise.

Cheers.

 

[JCB814]

Hi Scrub Puller,

I am sure you are correct, we were just looking for a reason for a pin to break and what I wrote (above) were our first thoughts as we have never had a broken a pin before, but thinking about it now and reading your reply I can see what you mean. Not sure then what broke the pin, but the track chain it was in is bent too (splayed out) and I think this made us think the track plates themselves were involved. I take it that over time pin-heads can wear in their chain sockets and this is what we are looking at. I will try to add some images as we do the repairs .

 

[Scrub Puller]

Yair . . . Gotcha JCB814. You should take what I say with a grain of salt as I have no knowledge of your machine . . . if in fact your pins have "heads" it has a different track system to which I am familiar.

Best of luck with repairs and look forward to seeing pictures.

Cheers.

 

[JCB814]

Yes, the pins seem to have some form of 'cap' at each end, although I may be mistaken and am looking at some form of hardening process and a machined end. In fact, thinking about it that is almost certainly the case ..

 

[Scrub Puller]

Yair . . . JCB814. Way out of my league then mate, perhaps it's some form of tank style track.

Seems strange on a conventional machine, most pins are of one dimension and can be fitted from either side.

As I mentioned some photo's would be a revelation. (he grins)

Cheers.

 

[JCB814]

I doubt that there's anything odd about our pins, just our newbie ignorance on these matters! Pic's to follow when we are next able to get onsite and fix the tracks (a few weeks from now ).

Another related question: If they are not structurally essential, how concerned should we be about 'lose' pads? (the four bolts securing the pad to the link being loose). We seem to have a lot ..:-(.

 

[mitch504]

All the modern excavators I've seen, though I've only seen one JCB trackhoe here, had standard dry tracks. Some of the old stuff had crane tracks, where the pins go through the ends of the track pads.

In standard dry tracks, you have chain links, (called rails) that have a pin through each end and a plate ( called a pad) bolted on to each link. When new the pins are straight smooth rods. They are pressed into the wide end of each link. The narrow end of each link has a straight piece of tubing,(called a bushing) pressed in and sticking out a little. The extended end of the bushing sticks into the end of the link where the pin is pressed (called the boss).

It sounds to me like you are describing severely worn tracks. Do the tracks bend from side to side at all? If the ends of the pins are bigger than the middle, that sounds like normal wear.

As the others have said, post a pic if you can, and I hope all these words have helped. I tried to give you a track 101 class.

Good luck,
Mitch

 

[JCB814]

Thanks Mitch504, at least I can now refer to everything with the correct name!