New D2 Axles.
The cars > Developments and changes
New Discovery-2 (TDI) Axles.
OK...
I decided that I wanted to change the axles on Insanity from the standard Disco 1 axles (using the chrome swivels etc.) and replace these with the Disco 2 versions.
Why did I decide to do this? In reality I am not sure. Some of the advantages that I had been hearing about or found as I started the work.
- Better turning circle.
- Lighter axle configuration.
- Stiffer (less body role).
- Better brakes.
- The Diff's are the same so I can retain the heavy duty pegged units without additional cost
- Many of the original parts are starting to wear out beyond economic repair
- The axle mounting brackets on the chassis have become badly damaged and where going to need replacing anyway.
One claimed advantage I am not sure about, being that the Disco1 axle spares are becoming difficult to get hold of. most if not all the D1 axle parts are the same as a Classic Defender?
On the face of things it would look like this should not be too difficult as both are beam axles, using similar coil springs.
My plan however involved changing the rear axle to use the front radius arms and I still wanted to use standard LR springs in conjunction with the Large fox shock absorbers, so this has meant modifications to the spring turrets on the axels in addtion to changing the radius arm mountings, brake lines etc. etc..
So the starting point, obtain a set of Disco2 axles.
I would not recommend this but you can get a pair of axles and four wheels & tyres into the back of an LR 90.
The Kit of parts supplied by Blackbird industries.
The more astute of you may notice the brackets interned to convert the rear axle to D2 front radius arms are actually D1 items. These where replaced very quickly and without any fuss.
The old suspension Link/Radius arms.
Insanity with the old axles and suspension stripped out.
The old axles and the original brackets. Most of this will be removed.
Front axle build.
The first attempt at building replacement Spring and shock absorber seats involved using some off the self extended spring seats.
The plan was to cut the hole in the middle of the replacement bracket and pass the Shock absorber mounting brackets through this having welded these directly to the axle case.
After many attempts to cut and fit this option I gave up with it as I felt the resulting bracket assembly would not withstand the loads that are likly to be applied .
The Mk2 front spring seats involved using some 6mm Steel spring spacers from Gwyn Lewis 4x4, that are modified to pass the shock absorber mounts again. these are to be assembled onto a support made from 75mm x 75mm 5mm box section.
A lot of cutting and forming to get the dimensions and fit correct. (or so I thought).
The shock absorber brackets are welded to the axle and then the new Spring mounts passed over the top and also welded in place.
This should be strong enough!
Unfortunately I made a mistake with the calculations and forgot to account for the radius arms interfering with the new mounting height.
I actually only realised this properly after making a similar mistake on the rear see later.
so after I make a start on doing something similar for the rear axles and learning of the error, I rework this issue.
Grind everything off again and make up a new set of mountings, this time accounting for the additional height requirements to provide some clearance for the radius arms.
Rear axle build.
On to the reworking and modifying the rear axles, once again the first job was to clean everything off!
Yet another of the countless mistakes I make during this process is to remove both spring turrets at the same time making it more difficult to set up the new radius arm brackets I am fitting to convert the Rear axle to use the front (longer radius arms)
Removing the Watts link bracket takes out a lot of weight, it is quite surprising how much the weight of the axle is reduced after removing everything, shame somethings got to go back in its place.
Replacing the rear radius arm brackets. as already mentioned part of the plan is to use front radius arms all-round.
reasoning;
- Longer radius arms better suspension travel and articulation?
- Moves the mounting points towards the middle of the car, I would like to think this may be a little stronger?
- As I will be replacing the chassis mounting points as well, there is no constraint with the chassis mounting location
- Uses the same part all around the car, simplifying spare parts.
So initially cut of just one side of the old brackets and then with a lot of fiddling packing supporting on sting etc. Align (level) the mounting bush height of the shorter std rear arms with the same point on the longer replacement front arms and tack the new brackets in place. Then repeat the exercise on the other side with the second replacement front radius arm. At this point and until I am 100% convinced everything is correct it is only tacked in place. good job to as this was reworked at least once.
The plan on the rear axles was to use another standard off the shelf, heavy duty Discovery 1 spring mounting as this matched quite closely what was removed from the standard D2 set up. So again the plan is to weld on the shock absorber brackets directly to the axle and the pass the the spring seat over the top having cut the hole for the brackets to pass through. the other advantage of cutting the hole in the spring seats is that the shock absorber end can sit a little lower.
This was all looking really good and I was even a little bit proud of the welding, until.....
Fitting the radius arms to the axle and dropping the spring support plate in place it is immediately obvious there is a problem. I had not accounted for the difference in the radius arm bolt locations when choosing the spring seat mounting. as you can see from the final picture in this set it is not going to work. I have to confess it is only at this point I look closely at what I had done for the front axle and realised that although nothing like as obvious something similar had happened.
So cut it all off and start with Mk2.
Mk2 rear spring seats involved using some more 6mm Steel spring spacers from Gwyn Lewis 4x4, that are modified to pass the shock absorber mounts again the same as the front. These are to be assembled onto a support made from 75mm x 75mm 5mm box section.
The shock absorber brackets are welded to the axle and then the new Spring mounts passed over the top and also welded in place.
How it all looks with everything in place and radius arms fitted.
Note the significant increase in height, this may be an issue later?
While all this has been going on I have also replaced the Diff pans with heavy duty Gwyn Lewis items and added some "stiffeners" to the axle tube.
Chassis brackets.
Now the axles are modified it is possible to hang them in place and for the first time appreciate how far different the mounting locations are going to be.
The original rear brackets are removed. You will see from one photo that it has also been necessary to remove large parts of the interior of the car cutting out the floor to gain clear access.
After significant consideration I decided to use the root (where the bracket meets the chassis rail) of original front D1 radius arm brackets as a datum point on each side. So these are left in place until the new rear brackets are completely welded in place. to ensure consistency I made up a simple special tool consisting of an old core of a bush and a length of steel rod carefully cut and files to the exact length. this was then used on both sides to ensure the the rear bracket are as evenly located as possible.
The brackets are located in place any number of times before finally committing to weld them into place permanently.
Its not immediately obvious from the pictures, it has been necessary to remove some of the seat brackets as well this will all be replaced in due course.
The original rear brackets are removed only after the new rear D2 brackets are firmly welded in place. another "special" tool is created used to locate the new front D2 brackets.
The next job is to make up new axle end and chassis end pan hard rod brackets, as the plan here is to simplify the suspension removing and replacing the original watts link assembly, but this is not entirely simple either with at least two iterations of the bracket made.
At some point while everything else is being welded in place I also build up the hub and brake assemblies.
With the wheels on the ground for the first time since the project started it is possible to see the effect of the additional height of the spring seats. She run a little bit tall and I may have to rethink the rear springs, but that is not a priority yet.
Chassis Centre bearing, Cross-member
The last major piece of work is to replace the cross-member supporting the front prop-shaft centre bearing.
the original cross-member bolted on across where the new radius arm bolts are now located. The centre bearing, exhaust routing and gearbox etc. cannot be relocated to accommodate this, so I have constructed a kind of Suspended Cross member to replace the original.
New brackets are welded onto the new location on the chassis and everything bolted in place.
