# Standard Hardening of pins and bushings in earth moving equipmen



## plowjockey (Aug 18, 2008)

The old backhoe has two very large pins and bushings, where the hoe swings.

They are not terribly sloppy, but do have some wear and the swing stop switches, etc., would probably function a little better, if they were more snug. The botton pin looks like everyone was too lazy to climb downd there and grease it as often as the easy-to-get-to top pin zerk.

Anyway, the costs of these four items, is more that what I paid for the unit, so we are looking for alternatives.

When it comes to pins and bushings, generally are they both hardend, not hardended, or is one non-hardened and therefore, to be "sacrificed", to be the piece that wears.

We think we might be able to flip the pins (since they are rather long) and just drill a new mounting hole.

The bushings my bro can machine, but he does not know if they are normally hardened. We have not Pulled thi apart yet.

Is there any type of standardization in this area?


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## ace admirer (Oct 5, 2005)

not sure of the correct answer to your question,,,,but i have rebuild a couple of dozen or so of them. pins are no problem....we always just turned them from normal mild cold rolled steel. cross drilled or not for a grease zerk and drilled for a retaining pin or bolt. the bucket bushings,,,,,thats something else and depends on what equipment your shop has... I have a large swing arm drill....i mount the bucket to the base and drill down through the worn bushings. then turn new bushings that are pressed and welded in. if you don't have the large mill or drill ....then turn the bushings, flame cut out the old bushings and hand fit the pins and new bushings in the assembly, then tack (very little tack) the new bushings in.....taKE THE pins out, final weld the bushings controlling warp as much as you can. then hand ream as best your skill will allow to realign the warped bushings...........so yes its best to take 5 minutes once a day to grease the machine.....

the swing pivot usually is an assembly of cast steel or mild steel weldment either way usually with replacement thinwalled hardened bushings. if the pivot is worn through the thinwalled bushing, it will needto be repaired like the bucket repair mentioned above.

but i have seen carbon pins used as cores and the worn area welded up around the carbon cores...then the cores removed, leaving a serviceable renewed surface.


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## Ray (Dec 5, 2002)

Hi, I've made lots of pins for all kinds of equipment, and most are cold roll steel, so they will wear before the bronze bushings. I've also installed lots of pins and bushings and installed more than I can remember, in swing arms buckets, articulating centers, and dozens of typs of equipment, its not that hard, but above all be safe. Be sure you put blocks under all movable parts, like boom arms buckets etc. you can use the hydraulics to help line things up, on one side. alot of people are killed every year by raising a front loader then walking under it and loosening a hydraulic line, for repair. I know it sounds incredibly stupid, but sometimes folks just don't think when they are broke down and in a hurry. 
Some of the new equipment has chromed and slightly harder steel than the cold roll, and they are expensive as hell, and you can make them too but you need to send them off to heat treat to harden them, Oh they are a slightly carbon and will take heat treat for hardening. When they go they can damage the bushings, core and plates around them if left to wear, and alot of frame work will need done too.
I have had to cut these machines completely apart and remake the booms and arms from scratch, cutting everything away and making and rewelding everything back, and paint. It takes awhile working 12 hours a day. ray


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## davel745 (Feb 2, 2009)

I believe the bushings are usually heat treated to resist wear and are tough so they won&#8217;t pound out. The pins are usually tuff but soft. I don&#8217;t think replacing the bushings with mild steel will work for very long. What might work is to make the bushings from a steel that will work harden. 

We usually cut out the worn bushing and fit in the new bushings and align them with the new pin through the bushings and weld them in with the pin in place. Almost all the time that works well enough. But there are a lot of different ways people have worked out to replace bushings.


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## Ray (Dec 5, 2002)

Most of the companies and individuals around here just go to the local welding and machine shops and have the pins and bushings made there to fit, by the machinists & welders, usually the bushings are bronze, as I said I've made many of them. experience helps to put them easy .... PM me and I'll tell you how to make an easy install of the bushings if you need info. I usually air arc the bushings out. good luck,
if they are not too bad and you don't use it much, they could do for a good while, but once they start wearing they can go fast, just don;t let the wear go past the bushing, to save work and money, ray


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