master pin ?

Mr. T. Minnesota · Jun 22, 2014

Forum Members,
Have been on the N tractor and Allis forums for several years. Am new to this forum. With that I have questions. Recently purchased an HD3 Allis crawler and got her running. In the process of reviving the HD3 the last thing I checked on were the bushings and pins. They are worn. Found a set tracks in the area with a flaw in one track. When removed from the previous they torched the master pin between the links. It appears to be a clean cut but wonder what was there to begin with. Was there a bushing with the master pin? What is special about the master pin when replacing it? Any and all info about master pins is welcome!
Mr. T. Minnesota

Carlyle hoffman · Jun 22, 2014

Generally the MASTER pin is the only 1 that can be removed without a track press. Mainly to open the track for more easily done maintenance.

AJ. · Jun 22, 2014

Are you sure that you do not have sealed and lubricated track with an alligator split link that is held together with the track pad bolts. The master pin in a dry track is the same as all the other pins apart from having a mark on it to id that link from the rest,it is the bushing that differs,the master link bush is shorter than the rest and does protrude into the counter bore of the links,have a look at the two drawings posted.
AJ

JDemaris · Jun 22, 2014

If OEM AC tracks - the master pin has a head on one side and is held in place on the other side by a snap ring.

Mr. T. Minnesota · Jun 22, 2014

AJ,
Thanks for the reply. The master pin is a dry version. Have a very specific question-the tracks are miles away and I kind of understand the configuration.As you explained the master pin does not extend into the outer link sections. Key question, is the existing bushing pressed into the inner link sections or does it freely move horizontally? Hope that made sense!! To remove the master pin the po cut the pin between link sections. I will have to remove the left over pin sections. What kind of material to replace the 1.25 od master pin? Any other tips or info is appreciated.
Mr. T. Minnesota

NCWayne · Jun 22, 2014

If it"s a "normal" master pin, like another post said, the bushing is shorter so it doesn"t socket into the other link, which allows the two links to come apart when the pin is removed. Beyond that, any undercarriage supplier should have the correct master pin for the track. The tracks are probably aftermarket so just tell them what kind of machine it"s on and they ought to be able to get you the right pin both in diameter and length. The pins are undercut in the middle to assist in installing them. With that pin should also come the pieces you are asking about. What it will be is two thick "washers" to fill in the space where the ends of bushing would ride if they were there, and a couple of belville washers (disc springs). They go in before putting the links together and are usually a PITA to get to stay in. With the links together simply drive the new pin in and your good to go.

As far as getting the pieces out, if the pin was cut where I"m understanding your saying it was, getting the pieces out is nothing more than driving the two pieces left in the link out to the middle of the link.

Good luck.

AJ. · Jun 22, 2014

OK so they cut the link to split the track,you now will have to take out two pins to replace the link,turn the track on its side,use a piece of pipe to support the link on the underside,weld a handle to a suitable piece of bar to make a drift,get a helper to hold the drift and a 14lb hammer and knock out the two pins,the bush in the male end of the chain may have to be trimmed off if it is not the master link,with the other bush if its not the master you will have to cut out the middle in order to get the bits of the link out,ie if its a standard pin the bush protrudes into the links a 1/4 inch each side,by cutting a piece out of the middle the links will move in and they are off,you now need a master bush,spacers and a left and right link,if there is a good link in the old chain you could use that, if not go a track shop and they will press them together for you.
AJ
PS. The bush is a press fit in the links.

master pin ?

Mr. T. Minnesota

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Carlyle hoffman

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AJ.

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JDemaris

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Mr. T. Minnesota

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NCWayne

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AJ.

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