IRS Conversion - Part three

28th April 2008
Even though I had the jigs fitted onto the car and the brackets looked good I decided that I would like to check the measurements that the brackets where angled up towards and compare them with each side.

First I had to level the car up as the axle stands that I had at the rear of the car where positioning the front of the car lower than absolute horizontal. I used a 2 ton car jack under the front beam to raise the car up to level as indicated on my digital level.

After taking readings on each bracket I found that they where nearly the same 0.02 degrees out. I hit the lower on with a sledge hammer and it came back to the 5.10 degrees on the other side.


After some research into pricing the cost of hiring a generator welder that would be cost efficient to to hire for two days . It was soon apparent that the cost of doing so was going to cost more than it was to hire a qualified welder with a generator welder!

Several phone calls later after scouring the Yellow Pages I found a man that had a portable generator welder that was used to welding farm, equipment. he quoted me no more than £100.00 to do the welding.

He turned up and soon began welding. It was soon apparent that his welding skills with his equipment where far more superior than his.

The brackets welded on easily the work I had done ensuring a good fit had made it a quick job to weld up. My welder used wire rod to weld in the holes under the brackets where I had cut out to much. I have read several articles regarding the installation of these brackets and it seems that this is quite a routine problem experienced by people attempting this conversion.

I trial fitted the gearbox an soon found that I would have to remove material from the frame horns where it interfered with the IRS joint. I measured the distance from the ground to the frame horns and braced the frame horns with timber between the horn and the axle stands. I would use this measurement later to ensure that the frame horns had not moved position.

I bought a 2000 degree blow torch powered from a propane tank. I used this to heat up the frame horns so that thy could be hit and reshaped with an assortment of different weight hammers. (Note here ensure that your propane regulator is correct . Do not let anyone sell you a regulator without trying the torch out on it.)

The metal was very malleable when heated and I found it easy to reshape it. I retried the gearbox and decided that I would need little more room between the IRS joints. I removed the gearbox and started at the frame horns again. This time I got them to the same profile and painted them up with red oxide and then primer and paint.

The assembly of the gearbox A-Arms and spring plates was next.

IRS Conversion - part two

24th March 2008

Previously in the last article I have cut away the body to allow access to install the IRS brackets which are part of the IRS conversion. I had downloaded the Internet article at http://bajaclub.co.uk/PDF_Documents/IRS.PDF from Airsouls. Although this article was written quite well it did not adequately explain the process of cutting in the brackets. As this is the most important part of the IRS conversion this was something that I would new to spend time over.

The first thing which was obvious about the installation was that I would have to either buy; make or borrow a jig that would give me the proper position of the IRS brackets. Fortunately after placing an advertisement on Vzi I was soon in the position of two IRS jigs. One thing I have found with using other peoples jigs is that as you haven't made the jig, its really important to ensure that you know how it works and more importantly if it does.

I decided that I would have to try the jig on a 1303s chassis to ensure that the jig was correctly aligned. It was noticeable straight away that 1303s brackets where different to the ones that are available today. The other obvious difference was that the frame horns seemed to be a different shape . The jig fitted into the IRS brackets on the 1303s chassis . The noticeable thing about the jig on both sides was that the tube that was attached to the end was short on both of the jigs. The reason for this was that the jig would not be able to fit into the bush on the furthest end of the bracket if it was any longer. I returned home happily in the knowledge that the jig was ok and a reasonable fit.

It was at this point that an child hood illusion was shattered. I had always thought that VW cars where superior because they used the metric measuring system way before we adopted it in the UK. When trying to locate a suitable bolt that would fit the brackets this turned out to be 1/2" UNC. Well as you can see the myth was not true.

I took the jigs back to the garage. The first thing I needed to do was to cut away the metal where the bracket fitted into the frame. You can see in the pictures I started by removing material from the flange that braces the frame horn to the torsion tube. I took the material away to the handbrake cable guides. I new I would have to remove more material and take the flange back further before the bracket would fit in and not foul the IRS Arm when it was in place. The next thing I was going to have to do was to use the jig to locate on the bolt hole on the side of the frame arm. To do this the jig would have to be placed on to the car.

I needed to remove more material from the flange on the frame horn so the length of the bracket would fit alongside the frame horn. With the Jig in place on each side the and done up enough for the arm of the jig to make contact with the frame arm. I could use a black marker to draw around the outside of the bolt hole. I then used a Starrett 1 3/4" or 32mm type hole saw to cut out the hole were the bracket protruded through. It is important to note that when you mark the holes you have marked the circumference of a circle.You must ensure you have a centre point of this circle before pop marking and drilling. This can be achieved by using dividers or compass. The hole can be troublesome to cut out as it is very tight to get a drill and Starrett hole saw into you may find that the only way to do this is to purchase right angle conversion for your drill, these are exceptional for getting into tight spaces. The one pictured right came with a key less 10mm chuck for £9.99. I added an £18, 13mm keyed chuck onto it so that I could fit the Starrett arbour which was 1/2" into it . With this hole cut out the bracket could be slipped into this hole and positioned on the rear torsion bar to gain its eventual position. I used this method to locate the position of the bracket on both sides. The main reason for this was that on the Baja club IRS conversion the hole was made too large. Additionally the bracket did not sit entirely in the hole so it had to be cut out precisely. The angle that the brackets protruded from the torsion bar where then compared and adjusted so they where the same, luckily no adjustment was needed. I cut the holes out easily and tried the brackets on each side. I found the driver side (left picture) still required more material to be cut from the flange to allow the bracket to be fitted and marked. This bought the flange under the handbrake cable and would mean that the cable position might need to be changed. It appeared different from the passenger side as it was not interfering with the bracket like the drivers side was.

With the holes cut and the bracket positions marked. The gauge of the metal could be seen easily with the holes cut and looked to be no more than 2mm. I could start removing material from the torsion bar end working towards the rear of the car. This was going to be a slow procedure of cutting a strip back then trying the jig and bracket in place until a good fit was made. I would start by removing half and then use smaller increments on each cut back. I new the end of the bracket was supposed to sit outside the frame arm thankfully to a picture in the Airsouls article on the bajaclub website.

Once the brackets where made to fit, the jig and bracket where then fully done up in preparation of the brackets being tacked in place. Before they where tacked in I went back and took more measurements of the original brackets to ensure everything was in line and in place. When I tried to get my Arc welder running on my Honda Generator I soon found that it drew too much current from the generator to weld with. I would have to hire a welder generator for machine hire company to allow me to get the brackets welded in and the new A Arms fitted.

Cont.

Rear Body Modification

12th March 2008
After the first attempt at installing the IRS brackets I realized that the rear body dropped quite low into the area where the new IRS A-Arms where going to fit. I had already cut down the drivers side battery box and removed the side of the frame horn ready to use the IRS bracket jig. I had been thinking about the frame horn trusses and new that they needed to fit between the upper shock absorber mounts in addition to needing to create space for the passenger side A-arm to move. The spare tyre well placed a bulge on the underside of the body that was directly in the way of any bar that would traverse the top shock absorber mounts. I was already committed to rebuilding the battery box bottom and decided that whilst I had access to the rear of the car that I would cut out portions of the spare tyre well laving enough space for the new IRS parts and the frame horn truss to fit. You can see from the two images above the differences in the bottom profile of the buggy. The height of the rear projections in to the chassis had been reduced substantially.

The picture to the right shows the inside view from the rear seat area. You can clearly see that the cut-outs follow the line of the battery box. With the areas rebuilt and the rear shelf extended to meet the new back of the spare tyre well area. This hopefully would leave enough clearance for the frame horn truss to be fitted, if and when I managed to find one for sale at a reasonable price.

Finally I was nearly ready to see if the new gearbox fitted.

Installing the IRS A-frame brackets - part one

11th March 2008
The fabrication of the Jig for locating the position of the IRS A-Frame brackets was not something I needed to do as I found a seller on www.volkszone.co.uk , who was wanting to sell the jig he had for building his own IRS. I picked up the jig from him and was soon aware that he had not used the conventional bolts that bolted the A-Frame in to position the brackets. The tubes that ran inside the brackets was only the size of a 1/2" UNC x 4" bolt. This did not give a steady position for the brackets and I decided that before using them I would have to check them against a real IRS chassis to ensure that they gave the correct position in practice. This would not be a problem as I new the location of a 1302s chassis that was bare at a friends workshop.

I decided that I would not be able to fully position the brackets, but decided to clean up the frame horns and remove the surplus material along where the bracket would sit. Once I had the jig problems resolved I would be able to cut into the frame horn to get the final position of the bracket.

I started with the off side of the car removing the brake hydraulic lines that where still left. It was pretty clear at this point that my battery box was to low to gain access to the bracket position. I was also worried that being so low the A-arm would hit the bottom of the box as the suspension moved. This was not going to be an easy process with the body attached to the car, but I decided it looked feasible. I started by drilling a hole in the fibre glass that I could push the blade of a jig saw through. This allowed be to cut along the back and the inside of the battery box several inches from its bottom. I then managed to use an angle grinder to cut from the inside of the box the outside edge of the battery box. The angle grinder was also able to cut the box around the torsion bar, which enabled the bottom of the box to be removed.

With the bottom of the battery box removed I had access to the flange that ran along the outside of the off-side frame horn. I started to cut the metal with the angle grinder and cutting disk alongside the handbrake cable. I was able to cut the material back all the way to the torsion tube. When I had finished cutting this area out I switched to a grinding blade and cleaned the of the paint. I knew I would have to build a new floor to the battery box at a later date but I was pleased with the progress I had made with the drivers side.

The weather forecast for the next few days was awful and I was not able to get into the garage to cut the other side down. I had decided I wanted to cut the fibreglass on the nearside of the car , which was rumoured to be for a spare wheel. This was ludicrous of course as there was no way a beach buggy wheel would fit in this space. The main reason for removing this area was to allow for the future placement of a German Kafer Cup type Torque Bar Kit. As seen on the left. The design of this needed to allow a bar to cut straight across the spare tyre well and under the rear seat rear of the buggy. Currently this was an expensive piece of kit and I wanted to see if I could build in space for it to fit should I be able to get hold of one or build one.

The weather was suspected to get worse so this was all put on hold for better weather conditions that where more favourable as the high winds had nearly took the garage door off already.