Replacing Linkage Pins and Bushes on Mini Excavators
In 'Part One' of this article we emphasised how important it is to replace your pins and bushes. Replacing pins is generally quite simple, but bushes are a different story.
First of all, try removing the bushes by hitting them with a hammer. You may find that you need a bar to allow you to fit the bush in easily
If step one, doesn't work, you can run a ring of weld around the inside of the
flange bush. As the weld cools down, it will cause the weld to contract, which means that it is now usually possible to hit it with a hammer and push it out
If you are still having problems after step two, you may need to get a mechanic with a hydraulic pin press to help you push the bushes. However, it is rare that it would require this much effort
When you have removed the existing bushes, you will need to replace and fit the new ones
It is worth cooling the bushes down so that they are as cold as possible which will cause the metal in them to contract. This will help to get them in the arm of the machine. To get them cold, put them into the domestic freezer which will help tremendously! On the other hand you should wrap them up well so that they do not contaminate food
When you have cooled the bushes down they are ready to be fitted. You should first of all try pushing them straight into the arm. It may be the case that you have to tap them with a hammer in order to get them in. If they are very tight you may need to heat up the arm slightly so that it expands. When you then insert the bush, when everything is cooled down it will all fit in tightly
If you need new bushes and pins, you need to fit the bushes on first. Then when you are ready to do so, you should simply push the pins back through the new bushes. It is important to make sure that they are bolted securely into place to avoid problems in the future with your new repair
Finally, once your mini excavator is back together you need to make sure that you grease it thoroughly. This will ensure that you get maximum working life out of your pins and bushes.
