CAUTION: Making alterations to your suspension may cause serious injury as you are off roading in your homebuilt, home modified vehicle, climbing steep slopes and wading in deep water.
Rear Trailing Arms.
Right before you all start - Yes you can buy them, yes there are more beefy items available and yes there is a risk welding suspension components yourself. However, who's to say that what you buy isn't welded buy a trainee or a guy in a garage.
Tonight I wanted to replace my badly deteriorated trailing arm bushes. I have recently noticed that the vehicle is very poor at keeping in a straight line Plus it has a tendency to feel like the arse end is sliding around. On closer inspection the trailing arm to chassis bushes are totally shot.
Its really easy to swop them out and all it entails is removing teh trailing arm. So I undid the three bolts holding the bush to the chassis, then loosened the large nut on the end of the 'chassis end' of the trailing arm, followed by loosening the bolt at the axle. everything cam away really easily to reveal a complete mess.
This is the nearside bush and arm, you can clearly see that the bush had broken in two. The new unit is in the foreground.
This is the offside unit prior to removing it from the arm.
Now the reason its peeled away is due to the suspension lift. As the vehicle is lifted, the standard arms put the bush under stress even when the vehicle is stood still because the std trailing arm is effectively being pulled down. Lifting the vehicle is moving the axle in its articulation plane.
I have +5" shocks on the rear with Terrafirma Shock mounts which, when you add it the +3" springs give the rear axle a huge amount of articulation over standard.
So I thought to myself, well I'm here now how about cranking my arms. So that's what i did.
The standard arms are tubular and designed to cope with normal life which they do quite well. I have never heard of one snapping or bending which wasnt, at the time, being abused off road. So to start with they are strong items. (Heavy Duty Ones excepted).
Firstly I made two cuts in identical places on both arms. This I did with a 1mm cutting disc and went 75% through the arm. These cuts produced a small crank but not enough so I cut again in the same place. This produced a reasonable crank which once offered up to the axle was sitting quite nicely with no stress on the new bush.
Here you can see a std arm against the cranked item.
I then cleaned up the areas to be welded and made a significant goove along the cutting edge with a grinding disc so I could ensure that proper penetration was made. Once the first weld run was made I cleaned up around the areas and ran another seam of weld along both sides of teh first weld run.
The Trailing Arm become some 3-4mm shorter by doing this modification. As a result i used the large disc from the original bush as a spacer. You can see the gap here.
Obviously the arms are just sat in their place and not bolted up in the above picture.
Once fitted you can see that the bush is not under any stress and the crank needed is only small.
I will run these like this for a few days and then pull them off and reinforce them using angle which also acts as rock sliders on the arms. (This is typical sales talk as the only reason you need the angle in the first place is because the standard arms need reinforcing to cope with proper off road abuse).
A quick run down the road and the handling is much improved.
