My Cally is lowered 40mm and I was having trouble with uneven rear tyre wear so today I fitted a rear camber adjustment kit to cure this.
The kit is a K-Mac kit I bought from Regal. It cost £180
I did get 1st class service from Regal though, so thumbs up to them!
It works by having the bolt-holes for the bushes off-set from the centre so when fitted, the nut can be loosened and the bolt can be used to rotate the whole bush within the arm. Because of the off-set holes, this alters the angle of the trailing arm, altering camber and toe settings. Its hard to describe this in text but you will get the idea when you see the kit fitted.
I am writing this as a guide to fitting, based upon my own experiences today. Please use this as a guide yourself but dont presume it is 100% accurate for all cars. If in doubt, get a professional to do this for you as this procedure involves removing major suspension components. Safety is of prime importance.
Bear in mind that I have access to a very well equipped workshop. Although no special tools are needed, I wouldnt recomment you try this in the street using a £19.99 Argos tool kit.
Tools you will need are...at least 2 big jacks, axle stands, a few sockets, 18 and 19mm, both normal and deep sockets, a ratchet and various extensions. 18 and 19mm spanners, and an old flat scredriver. I also found a wooden mallet came in handy.
How easy was it? Well, It was fiddly but not as bad as I expected. The Haynes Manual section for removing the rear trailing arms is relevant as a guide but I discovered a major error in the book which I will detail later. If you can fit a lowering kit, you could probably fit this yourself.
Right, A pic before I started. You can clearly see the wheel leans in a lot at the top. (my car is green BTW!)
Firstly, jack up the back end and support it securely. You need to get right under the car to work on it so the higher you can get it the better. Make sure it is well supported as you will be doing a fair bit of pushing and pulling.
Remove the wheels and using a jack under the end of the trailing arm to support it, undo the lower shock mounting bolt. Lower the arm and remove the rear spring. Re-attatch the shock to the arm.
The Haynes manual says to disconnect hand-brake cable, hydraulic pipes etc, but as I wasnt removing the arm completely, I left everything connected.
The book then says to "remove the nuts and bolts" that hold the trailing arm to the subframe. These are 19mm nuts and bolts and were quite tight.
Put some effort into it Duck!
Fine for the inner mounts, but the outers were a problem. The outer bolt cant be removed.
As you can see in the pic, there is about an inch between the frame and the sill, so there is no way a 5 inch long bolt can be removed from the bush.
The only solution was to lower the front end of the subframe. This is done by undoing the single large and 2 smaller bolts that hold the mounting plate to the floor at each side. I left everything connected to the frame so it would stay roughly in place. It might be a good idea to disconnect the brake flexi-hoses as they get strained a bit. I didnt as I couldnt be bothered with bleeding the system afterwards.
Taking care not to strain the flexi-hoses too much, lever the subframe down until the bolt can be withdrawn.
Ok, Time to press out the old bushes. A tool is included with the kit to do this. Simply pass the long bolt through the bush and fit the nut and washer onto the other end. Screw it down and the bush will be pulled from the arm into the cup. This takes about 2 seconds with the impact gun but if you are using a ratchet, be prepared to spend a while tightening this!
Mind your ears Duck, it will be loud!
Lubricate the insides of the poly bushes and fit them into the arm. Push the metal insert into the bush. Its tight so a little gentle persuasion with the mallet helped a lot here.
Make sure you get the bushes the right way round! there are 2 sizes in the kit. the larger inserts go on the outside of the arms and the smaller go to the inside. Also, The larger bush has to be fitted the right way round. it had "out" printed on one end. This goes to the outside of the car.
Right, time to get things back together.
Simply lift the arms into place so the new bolts can be fitted.
That sentence makes it sound really easy! be prepared for a lot of swearing at this point as it is very tricky to get the bolt-holes lined up. A lot of levering, a lot of hitting with the mallet and some more swearing got it done in the end. Using the flat scredriver to lever the arm about helps a lot. I just put the bolts in pace, but didnt tighten the nuts at this point. If you havent remembered to put the special washers on before you put the bolts in place, now is a good time to start crying.
Once the arms are in place, lift the subframe back into position and bolt it securely to the floor-pan.
You now need to roughly set the camber untill it can be done with the proper alignment equipment. I opted to set it to the minimum amount of negative camber the kit allows. This means rotating the outer bush so the arm drops to the lowest position, and the inner bush to the highest position.
Tighten the new nuts and fit the split-pins provided.
Re-fit the rear springs, wheels and lower to the ground.
Stand back and admire your handywork.
All that needs done now is to get the camber and toe setting set properly by a garage with 4-wheel alignment equipment. I was too late to get it done today so it will have to wait until next weekend when I have time off. Driving home with the kit at the basic settings, I noticed the rear seemed a little more stable when cornering. Hopefully when set, this will get even better and eliminate my tyre-wear problems.