Standard Hardening of pins and bushings in earth moving equipment

[mscher]

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?

 

[Tim Frank]

Re: Standard Hardening of pins and bushings in earth moving equipment

My experience is that bushings are always the "sacrificial lamb".

 

[wifisher]

Re: Standard Hardening of pins and bushings in earth moving equipment

Neither is hardened in my experience. They are both made from various grades of steel, but there is typically no heat treating applied to pins or bushings. Are there actually bushings in the bucket, or is it welded together? Most of the time the bucket is welded together, and then the "bushing" is line bored to the proper dimension to fit the pin. If there are bushings in it, you can drive them out and get proper dimensions from them. Many buckets do not use bushings though.

You said that your brother can machine the bushings, can he machine the pins for you too? There is not much to making them. Usually you can buy TGP that is the correct OD, and then just cut to length and bore the grease passages as needed. Look at the retainer on your current pins, and either copy them, or cut them off and reuse.

If you can post some pics of the bucket, I may be able to tell you more about it.

 

[Bondo]

Re: Standard Hardening of pins and bushings in earth moving equipment

Ayuh,... You don't mention the make of it,..
But,...
Every hoe I've worked on has Replaceable Bushings...
Most are available in at least 1 Oversize/ undersize...

Btw,... It's always a lack of Grease...

 

[stackz]

Re: Standard Hardening of pins and bushings in earth moving equipment

sounds like a plan. flip the pins and drill new holes to get away from the worn portion. machine up some new bushings and drill in some grease fitting holes to help extend the life of them.

or you could do like my grandpa and find a piece of metal pipe that will work as a bushing and cut it to length :facepalm:

 

[Bigprairie1]

Re: Standard Hardening of pins and bushings in earth moving equipment

It's extremely unlikely that hardening was part of the process put into the pins. The primary requirements of the pins in this application is toughness and strength. Hardness would be an issue and included in the process if the pin was riding along anti-friction bearings or equivalent, not a bushing.
The guys are right here as well, the bushing is the sacrificial element in this system. The pin is probably made of 4140 Steel or similar. Do not use a 'lighter' version such as 1020/1040 steel.
The original manufacturer makes a lot of money off of 'spare parts' which have a very high mark-up. Myself, I would simply measure up the pin and have it made locally, with specific steel specifications included...its done all the time.
The bushing should be replaced and you can usually get 'oversize' bushings if needed.
As Wifisher said, it would be easier to give a bit more helpful info with some pics showing the arrangement and some info on the pin size (1-1/2"?? 2"? or?)
Good Luck
BP