Replacement of wishbone bushes
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The difficulty factor in this job really depends on how long the bushes have been in place. On my car we first tried using a 15 tonne hydraulic press to remove them. They wouldn't budge!
Some people attack them with a welding torch but this is dangerous due to the toxic fumes generated.
A method I found successful was to use a radial hole saw (example photo below) with a high torque drill to cut through the rubber section of the bush. A heavy duty cordless drill gave the best results, used at low speed (high torque), but I had to let the drill cool down occasionally. Do not attempt to use a drill which is not designed for high torque use - you will destroy the drill motor before you get the bushes out!
If you use a higher drill speed the rubber will melt, stick to your hole saw and possibly emit harmful fumes depending on just how hot it gets!
If doing both upper and lower wishbones, two different saw diameters will be required for the different diameter bushes. The hole saws need to have a minimum cutting depth of 24mm and you will need to cut from both sides. Outside diameter of the hole saw should be as close as possible to the inside diameter of the bush outer shell, so that the minimum amount of rubber is left inside the bush shell.
Once the rubber and centre steel cylinder have been removed from the bushes, you need to carefully saw through the outer steel shell of the bush. This can be achieved by threading the blade of a hacksaw through the bush before fitting the blade into the hacksaw frame. It is very difficult to saw to an even depth right through the length steel shell without damaging the wishbone. I made a cut into each side of the bush shell before 'peeling' each side of the shell inwards with a cold chisel to until the resistance was reduced to the point where the bush shell could be pushed out of the wishbone arm. Not surprisingly, the amount of corrosion between the bush outer shell and the wishbone arm correlates directly to how difficult it is to remove each bush.
When fitting the new bushes, with a hydraulic press, first coat the surfaces with some sort of anti seize product.
Note: When we discussed this on the BEEF mail list back in 2002, someone brought up the possibility of bushes having being replaced with items made from a modern synthetic rubber such as Viton, which is a fluoroelastomer. At the time we had no knowledge if bushes being made from Viton (although it is used in some automotive fuel applications), but care should be taken just in case. If a fluoroelastomer burns it emits hydrogen fluoride gas, which on contact to water turns immediately into hydrofluoric acid, which is very very dangerous stuff!
If you drill at low speed with a sharp hole saw and don't allow the material to get too hot you should be okay regardless of what the bush is made from. There was also a suggestion that the bushes could be frozen first.
The usual disclaimers apply
