I want to use as many of the Toyota Starlet parts as possible by retrofitting them into the Mini as this simply makes the wiring simpler to install and any potential troubleshooting easier. This includes the combination switch assembly for the wipers, lights, indicators etc as well as the ignition barrel. So about a year ago with plans to fit the Starlet parts to the Mini steering column, I cut off all the mounting brackets from the Starlet steering column and disposed of the column. Soon after, I was hit with a problem...
In Western Australia we need to get formal approval for any substantial vehicle modifications. The approvals are valid for 2 years and my previous approval had lapsed, so I recently submitted a request to the Department of Transport for an approval extension. This was approved with one glaring difference to the previous approval - I now required a collapsible steering column to be installed. Having disposed of it a year ago, I had no collapsible steering column to use to adhere to the updated engineering requirements however I was fortunate enough to find someone who had another EP82 Toyota Starlet steering column, albeit with a heavy coat of surface rust.
This steering column was missing the lower uni-joint but I eventually found that the lower uni joint from an old G102 Daihatsu Charade (1989 model) column had the same spline configuration as the Mini steering pinion spline and fitted on perfectly.
Dismantling the Toyota Starlet steering column was as easy as removing a single circlip at the top of the column assembly and gently tapping the inner shaft out of the main tube. This revealed the mechanisms that allows the column to compress/collapse. The inner white plastic ring in the photo below (at the bottom of the column assembly) is a bush for the inner shaft, but the larger white plastic ring is part of the collapsible mechanism that allows the inner tube to collapse through the outer tube.
In Western Australia we need to get formal approval for any substantial vehicle modifications. The approvals are valid for 2 years and my previous approval had lapsed, so I recently submitted a request to the Department of Transport for an approval extension. This was approved with one glaring difference to the previous approval - I now required a collapsible steering column to be installed. Having disposed of it a year ago, I had no collapsible steering column to use to adhere to the updated engineering requirements however I was fortunate enough to find someone who had another EP82 Toyota Starlet steering column, albeit with a heavy coat of surface rust.
This steering column was missing the lower uni-joint but I eventually found that the lower uni joint from an old G102 Daihatsu Charade (1989 model) column had the same spline configuration as the Mini steering pinion spline and fitted on perfectly.
Dismantling the Toyota Starlet steering column was as easy as removing a single circlip at the top of the column assembly and gently tapping the inner shaft out of the main tube. This revealed the mechanisms that allows the column to compress/collapse. The inner white plastic ring in the photo below (at the bottom of the column assembly) is a bush for the inner shaft, but the larger white plastic ring is part of the collapsible mechanism that allows the inner tube to collapse through the outer tube.
The collapsible mechanism on the inner shaft is also quite low-tech. There are a two plastic shear pins (hard to see, but they are next to the paint dots in the photo below) that are inserted through the two parts of the inner column. Under a predetermined force, these pins will shear and allow the column to compress/collapse.
Now that everything was disassembled, I also cut off the the tilt adjust mechanism as it was complex and unwieldy. I decided to set the column at a fixed angle.
Using a combination of chains and clamps to hold the inner column on the centerline of the drivers seat, it took a long time to finalise the position, height and angle of the steering wheel/column to find a comfortable driving position. I found that changing the angle of the column by just two degrees made a marked difference to the feel of the driving position. I referenced some info online from physiotherapy/ergonomics seating guides which stated that with a straight arm, your wrist should be able to bend over the top of the steering wheel and then whilst holding the wheel, elbows should be bent at approx 120 degrees.
To also ensure that the steering wheel was square to the driver, I clamped a long piece of timber to the wheel and with the timber level, made sure that the distance from the A-pillars to the timber was the same.
To hold the column in position while I fabricated some mounting brackets I welded together this structure from some scrap steel to hold the top and bottom of the column, leaving the middle area open to work around, then removed the temporary chains and clamps.
The main issue with designing the mounting brackets was that approx half of the column projected out past the dash rail and would need a reasonable amount of support if the steering wheel is leaned on (eg whilst getting in & out of the car). After trialing a few ideas I decided on a braced triangular bracket that mounted to the lower dash rail - where the factory steering column was bolted to.
This support bracket is made from 2.5mm steel and is bolted through the lower dash rail with three M8 bolts. To clamp it to the dash rail, I made a plate with captive nuts on it - similar in design to the factory configuration (rusty bracket in the photo below). The support bracket sits under the dash rail and this plate sits above the dash rail.
In the factory configuration of the Mini, the "arms" of the brake/clutch bracket (pedal box) are clamped to the lower dash rail by the factory steering column bracket, so this new bracket had to support the Starlet steering column AND the Mini brake/clutch bracket. This is the reason for the asymmetrical shape of the new column bracket - the left hand side of the bracket has to be slightly wider to go around the brake/clutch bracket.
To mount the steering column to this support bracket I made a semi-circle mount (that was then welded to the underside of the main support bracket) and a matching saddle bracket.
If I bolted this together as above, the assembly would be rigid and the collapsible part of the outer steering column tube would not work so I cut some slots on one side of the saddle bracket. These slots in combination with some custom plastic bushes should allow the column and saddle bracket to slide away from the main bracket and still allow the collapsible mechanism to work.
The lower part of the column is mounted via a small bracket and bolted to the side of the factory brake/clutch bracket.
The next step was to join the two lower uni joints. Luckily there was no need to shorten the entire column so this was a simple task of cutting off the splined shaft on the Daihatsu uni joint (right hand joint in photo below), slightly shortening the splined shaft at the bottom of the Starlet column and machining an adapter/coupling to join the two.
These pieces were then welded together, making sure that the yokes of 2 uni joints were aligned - the yokes need to be aligned to provide constant rotational movement between the main steering column and the steering rack pinion. The welds in the photo below look a bit patchy because I had to weld small sections at a time otherwise the assembly would get too hot and the grease in the uni-joints would start to leak out past the rubber seals.
With everything bolted in, there was still some movement in column. The lower dash rail was not as rigid as I had hoped and it twisted slightly when the steering wheel/column was leaned on so I welded two braces from the lower dash rail to the firewall. This prevented the lower dash rail from moving and stiffened the main column mounting bracket significantly.
With everything bolted in, there was still some movement in column. The lower dash rail was not as rigid as I had hoped and it twisted slightly when the steering wheel/column was leaned on so I welded two braces from the lower dash rail to the firewall. This prevented the lower dash rail from moving and stiffened the main column mounting bracket significantly.
The final column position also meant that the brake pedal fouled the shaft between the uni joints.
This was an easy fix by cutting a section out of the lower half of the pedal, bending up a new piece from 8mm steel plate and welding the new piece in to clear the uni joints
As a final check, I fitted the upper column surround/trim and ignition barrel and found that the connector (and therefore the wiring harness) at the bottom half of the ignition barrel was very exposed - too exposed for my liking. At this point, I'm unsure if I'll make a fibreglass cover for the whole thing, or relocate the ignition barrel somewhere in the dash.
The end result was an ergonomic driving position, however this task took far longer than first expected. Taking into account trialing and re-doing some bracket designs, the whole job took somewhere around 40 hours.
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