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JCB 801 track tensioning

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Bivvysenior
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JCB 801 track tensioning

Post #1 by Bivvysenior » Sat Aug 22, 2015 8:16 pm

My 1991 JCB caught a stone in the track and made the track to come off. Managed to get the track back on but now find the track tension very loose and will not stay on when being used,

Using the manual identified how to adjust the track tension, everything looked easy until it came to adjust "the screw.."..

Could not budge the adjustment screw , whilst trying I bent a T bar from the socket set, smashed a wrecking bar....bent a spanner...and this is after a can of PLUS GAS and a blow torch on for ten minutes.

Am I missing a trick or is it just 24 years of a bolt being seized in rust.
Can anyone throw any solutions?

Unfortunately I haven,t got access to a Oxy-Acetylene torch..


TrevorJ
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Re: JCB 801 track tensioning

Post #2 by TrevorJ » Sun Aug 23, 2015 7:18 am

I have not dealt with anything like your machine.

A quick look on the net reveals (though blurred from 777parts) a "tension bolt" in the end of the screw bolt, which seems odd?

However IMO, it will be the nut part that you need to heat to a black/red heat and then smoother the immediate area near the nut (the bolt part) with oil where it exposed and then allowed to cool. after it has cooled, try to budge it, and with no success, repeat the heat oil process. [Also you can warm the nut area to a higher temp quickly (ie hot nut cooler bolt) avoiding the screw bolt and see if the bolt will budge, but don't turn it very far, just to and fro and try to get some oil up inside while moving it to and fro. Allow to cool before unscrewing.]

The rubber tracks would make it difficult to use anything else which is not so directional as a proper gas torch. (You say can, so I envisage an aerosol can type of heating tool.)

Not sure what else might be handy in your workshop. Used to be, carbon arcs were a good tool of last resort for heating some time back.


Jeremy Rowland
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Re: JCB 801 track tensioning

Post #3 by Jeremy Rowland » Sun Aug 23, 2015 10:03 am

Rom my only suggestion here is the oxy/acetylene torch to heat the nut, if you cannot get a torch then get yourself a very sharp chisel or large enough nut breaker and break the nut although I suspect that the nut may be too large for you to be able to do this so its back to the oxy/acetylene hot spanner.

Jeremy


Topic author
Bivvysenior
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Re: JCB 801 track tensioning

Post #4 by Bivvysenior » Sun Aug 23, 2015 1:05 pm

Thank you Trevor and Jeremy for your replies. The digger is used for groundwork around a lake in the Cotswold so it has been exposed to the elements. Therefore, it appears that heat is the solution so I will have to find someone with an Oxy acetylene equipment and try to heat the bolt to free it.


TrevorJ
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Re: JCB 801 track tensioning

Post #5 by TrevorJ » Sun Aug 23, 2015 2:55 pm

Heat would be the preferred method. It's not the only one, as Jeremy has pointed out using a chisel. Another way depends on how much of the nut is exposed -- to which you can place a heavy steel drift or large sledge hammer on one side of the nut area and hit the other side of the nut with another hammer and work your way around the whole nut. It might be enough to loosen things up ... also good penetrants (those that can dissolve rust etc and not just some thin petroleum solvent) can help if left over a number of days.

Also hitting the head of the bolt can help in some instances, but there is some other smaller bolt there in your case, according to the rough diagram I viewed, so that I think would be a no go.


mad-Eric
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Re: JCB 801 track tensioning

Post #6 by mad-Eric » Mon Sep 21, 2015 1:48 pm

I have used with great success an Induction heater if you could borrow one it heats only the part it is in contact with.


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