Steering - Part 4 - Steering Column Installation

I decided to install the steering column before fitting the body to the chassis because, while the body is supported on its frame, I considered the height would make it easier on my ageing back!

On the face of it, this should have been another relatively straightforward job, and, as usual, it turned out to be anything but.

First things first, a bushing is needed to support the lower extension piece of the column as it passes through the driver's footwell bulkhead.  This part is made specifically by AK, and as it's essential for every build, I'm surprised it's not part of the basic kit (and it's not cheap).  

AK steering column bushing in shiny stainless steel!

I started the installation in the engine bay - another reason for doing this job while the body is off the chassis.  AK had already drilled the hole for the steering column in the driver's footwell.  My plan was to try and fix the bushing more or less centrally over this hole, thus avoiding the steering column rubbing anywhere as it passed through.  I used a ruler placed against the pedal box mounting bolts to establish a vertical line and then set out the mounting positions for the bushing. The mounting holes were drilled using a 5.5mm diameter drill bit.  I also tidied up the AK-drilled hole in the bulkhead with a stepped hole bit just to remove the sharp edges.

Some accurate setting out...

...mounting holes drilled and sharp edges tidied up.

Next up was to mount the BMW column unit inside the body.  This should have been so simple.  The AK body includes the bracketry for the two top mountings and the retained right-hand lower mounting for the column unit.  These are slotted, which you might expect would give some leeway in locating the column in place.  You would be wrong...!

I retained the upper mounting bushings that had come with the column when I bought it.  I used two M8x30mm bolts and nyloc bolts to fix the column to the upper mounts in the body.  The first problem that came to light was, that with the upper mounting bolts both bottomed in the slots in the bracket, the lower mount was around 10mm away from the lower mounting bracket and also misaligned with the slot so that I could not pass an M8 bolt through the bracket and through the column mount.

I initially solved this by sliding the column off the upper mounting bushes, attaching the column to the lower mount loosely using an M8x40mm bolt and then hooking the column back onto the upper mount bushings.  There is not a lot of leeway, and the bolts seem to end up at the extremes of the slots in the AK mounts, meaning the column does not actually have any movement.

Steering Column Mounting Points

Upper Mount Bushings 

Initial Column Installation

I could then slide the nylon bush onto the end of the lower steering column extension and slide this into the end of the column from within the engine bay.  The shiny bit of the steering bushing could then be slid over the end of the column shaft and bolted into place. 

Nylon bushing in place ...

...lower steering column extension inserted into upper column...

...and the bushing housing bolted up.

Job done!  Except that the steering column was now locked solid and would not turn.  Loosening the bolts holding the steering bushing housing in place did allow rotational movement to be restored so clearly something was out in the overall alignment of the steering column.

Another view of the upper column mounting confirmed that something was definitely not right with the upper mounting bracket clearly not parallel to the scuttle hoop.

Misalignment of the upper column mounting

My solution to this issue was to remove the lower mounting bolt and put a number of washers between the steering column and the lower bracket to get the upper mounting parallel to the scuttle hoop. Fortunately, this seemed to do the trick, and rotational movement has been restored!

M8 washers used as spacers on the lower mount

Steering - Part 3 - Steering Column Preparation

The steering column for the AK427 is provided by a BMW E34 unit (which comes from any BMW 5 Series from 1987 to 1996).  I acquired a used unit from the well-known internet auction site when I ordered my kit.  You must ensure the column is complete, including the lower extension piece and the bolt that holds the steering wheel in place.  My column did not include the plastic cowling and I did have to search around to get both the top and bottom sections; I ended up buying them separately.

BMW E34 Steering Column

The ignition barrel and steering lock mechanism need to be removed from the original column as they will not be needed in the final set-up.  The ignition barrel supposedly can be removed by "simply" inserting a stiff wire or narrow probe (I used a 1mm allen key) down the small hole on the face of the ignition barrel to depress a spring-loaded key that locates the barrel in place.  I spent a joyful hour trying to get that to work before I resorted to drilling a small hole into the side of the barrel and using a small screwdriver to depress the key and remove the barrel (which took less than 5 minutes).

To remove the barrel, insert a pin into this hole...

..

...although drilling a small hole here...

...and inserting a small screwdriver...

...is far quicker!

The rest of the ignition barrel mechanism is removed by grinding down the sides of a small boss on the bottom of the ignition housing until it is possible to grip the pin in the middle of the boss with some pliers and pull it out.  The rest of the mechanism can then be easily extracted.

Grind down the boss to expose this pin...

...pull the pin out...

...and pull out the last bit of the ignition barrel.

This still leaves the steering lock mechanism in the barrel.  The easiest way I have found to remove this is to undo the two security bolts holding a plate onto the top of the barrel housing.  I cut a slot in the top of each one using a dremel and used an impact screwdriver to undo them.  This allows the ignition barrel housing to be removed from the steering column and exposes the steering lock mechanism, which can then be levered out and removed.

Two security bolts on top of the ignition barrel housing...

...in the process of removal...

...which then exposes the steering lock mechanism...

...allowing all the components to be removed.

The BMW column mounts need to be modified to fit the AK body.  This involves trimming the top mounting plate of the column and cutting off the left-hand leg of the column mount.  

The top mounting plate needs to be trimmed...

...to leave around 40mm left protruding...

...and the left-hand leg of the column mounting...

...is removed entirely.

The last "modification" required is to remove the large nut from the end of the lower column section.  From Russ Howell's video series, I know that this nut can clash with the side of the pedal box and that AK had advised the nut is not really needed and can be dispensed with.  Easier said than done, as the nut on my column was stuck fast and no amount of leverage and gentle persuasion could budge it.  I resorted to cutting a slot in the side of the nut with an angle grinder and using a cold chisel to split the nut off the shaft.

The large nut on the lower section of the column...

...needed some minor surgery to aid its removal.

I gave the exposed metal parts of the column a couple of coats of black Smoothrite before reassembly and bought a new rubber steering joint for between the upper and lower column sections.  The column is now ready for installation! 

The modified steering column ready to fit!

Handbrake - Part 2 - Installing a Linear Particle Accelerator

The normal handbrake set-up on the AK Cobra is a cable-operated system, utilising an XJS handbrake lever in the cockpit, operating a lever mounted above the differential unit that in turn pulls on the handbrake cables connected to each rear hub.

The original AK handbrake set-up, whereby the cable simply pulled directly on the actuator lever, did appear to have a reputation for not being very efficient (based on a read of several internet forums).  AK has addressed this and modified the set-up with the cable operating the lever via a pulley set-up to provide twice the pulling power.  Improved, but still a bit touch and go come IVA / MOT test time.

AK Handbrake Modification (from AK Build Manual)

I decided to make a couple of further modifications to the system myself to improve the handbrake performance.

The first modification involves the XJS handbrake lever.  I obtained the lever from Simply Performance at the same time as my donor axles.  The photos below show the lever before and after modification...

XJS Handbrake Lever before initial modification...

...and after modification!

The second modification involved the purchase of an electronic handbrake kit from Hollin Applications Ltd.  This kit was developed for the Motability market in the UK but seems to have gained popularity with many Cobra builders over recent years. The kit includes a linear actuator, an electronic controller and a simple switch.  The controller enables the pull / push force on the actuator to be adjusted up to a maximum of 800N or 80kg in old money.  It also meets the IVA requirement of preventing the handbrake from being released unless the ignition is switched on (it does also have the problem that the handbrake can't be released if the battery goes flat - but we will cross that bridge later).  The switch is a bit basic and will do for initial testing, but it will be replaced with something to match the other interior switchgear (when I decide what that will be...)

Linear Actuator

A bracket of some description is needed to mount the actuator to the rear chassis cross-member.  Since I made the decision to go with the Hollins kit, AK has actually started using them in their factory builds and has started selling an electronic handbrake kit including a mounting bracket.  However, I felt the price they were asking for the bracket alone was a bit steep and as I enjoy spending valuable time that I haven't got, making unnecessary bits for this build, I decided to make my own...

Fortunately, I got a bit of a headstart via Steve Sutton's build blog which referenced a solution by another builder Michael de Kok, who had included the details of the bracket he had fabricated for his own Cobra electronic handbrake install.  So, giving credit where it is due, I have borrowed the same design.

I completely forgot to take any photos of the fabrication process, so thankfully you can all just see the final bracket before and after powder coating!

Final bracket before coating (don't be too harsh on my welding)...

...and after powder coating

I fitted the handbrake actuator to the bracket using a long M6 bolt with a couple of spacers that I machined from some offcut of steel bar.

The actuator is installed into the bracket.

I then drilled and tapped some holes in the rear cross-member and fixed the bracket/actuator to the cross-member with some M8x1.25 bolts and spring washers.

The handbrake actuator & bracket are fixed to the rear cross-member.

I also needed to replace the operating lever from the item that AK supplied.  I fabricated a new lever from a 5mm thick steel plate with a small section of steel channel welded on the end.  The channel end needed to be reworked with some light grinder action to prevent the lever from fouling on the chassis at full throw.

New handbrake operating lever

I trial-assembled all the bits and wired up the control board temporarily to test out the operation.  Thankfully it all seemed to work OK with the actuator shutting down at extension once the load from the handbrake cables started coming on; the control box is preset from Hollins at 50kN load.

The final assembly involved powder-coating the operating lever, making up a couple of nylon spacer washers and bolting it all back together with copious amounts of copper grease.

Final handbrake assembly

Rear Axle Reassembly - Part 11 - Finally completed

Once my new half shaft spacers had arrived I could get on and (hopefully) complete the rear axle assembly.

Upon removing the spacers from the packaging, I was disappointed to find that they were both made from steel, and not some more exotic metal, as the price I paid for them might have suggested.

Could a golden spacer lie within...No!

I installed both spacers (4mm on offside / 7mm on nearside) and a single rear camber shim on each side initially.  It actually turned out that I needed just the single 4mm spacer on the offside and the 7mm spacer plus two shims on the nearside to get a camber setting of 0.3 degrees negative on both sides.

Spacer in place on differential output flange

Oh look - those shims do fit after all...

0.3 degrees negative on that side...

...and 0.3 degrees negative on the other side.  Job done!

With that done, I could remove all the 7/16" nuts from the half shafts for the last time and replace them with 7/16" Nylocs.  These were torqued up to 90Nm / 66lbf ft.

The next job was to remove the original drive nuts from the hub end of the half shafts and replace them with new items.  The Jaguar service manual recommends that the splined end of the half shaft within the rear hub is covered in thread lock over 30-50% of the radial area.  I used Loctite 270 and covered the rear part of the splined section before reassembly.  As well as a new drive nut I also replaced the conical washer with a new item.  

Today's thread lock is Loctite 270...

...applied over the rear of the splined section

New conical washer and drive nut (note the red insert)

The drive nuts need to be tightened up to a whopping 225lbf ft / 305Nm of torque.  I tightened them up initially using my air spanner.  I then used a large pry bar against the wheel studs and braced against the floor to stop the hub from rotating and dug out the largest of the torque wrenches from my tool arsenal.

Top tip - push the wrench down rather than trying to pull it up or side on otherwise you may end up pulling the chassis off the axle stands.  Also, try and position yourself away from the pry bar.  Mine ended up bending like a banana and if it were to break free from the wheel studs, it will cause serious damage!

Drive nut installed and tightened to ridiculous torque level!

The last step was to install the rear shock absorbers.  These are fitted in place with 7/16" x 4.5" bolts, M12 washers and 7/16" Nylocs in the top mounts and 7/16" x 2.5" bolts, M12 washers and 7/16" Nylocs in the bottom mounts.  AK only appear to supply a single M12 washer per bolt so I splashed out and added an extra washer to have one under the bolt head and one under the nut on all mounts.

Shiney new shock absorber - fitted so adjuster knob is at the bottom and facing inboard.

Mounting bolts - these were given a liberal smear of copper grease before installation

Rear Shock Absorber installed

The final step was to torque down the shock absorber mounting bolts to 38Nm (28 lbf ft) for the upper mounts and 64Nm (47lbf ft) for the lower mounts.  And that is the rear axle finally completed!