Starting on PAS

In order for us to sell the 90 before emigrating, Helena needs to be able to drive the 109.  For that to happen, it needs PAS, and it’ll probably be of benefit to me when we come back and I’m that much older.

The system I am using is a Defender column and steering wheel (complete with the plastic column trim and the stalk switches as the SIII stalk won’t fit) mated to a Range Rover P38 steering box and pump.  The P38 box fits outside the chassis, so doesn’t need the cross member removing, and the bolts all run above and below the chassis rail, again being easier for installation with the cross member in place.

I have been looking at numerous other installations of this combination to see what is best, and initially seemed to have a problem.  The Tdi’s oil cooler unions mean I have to site the box about 1.75″ further back than most, the box’s rear mounting flange almost in contact with the chassis bracket for the bump stop, check strap and brake hose.  A test fit after careful measuring and cutting of the inner wing showed that the axle would impact the bottom of the PAS box and the steering arm on articulation.  This was rectified by removing the redundant Panhard rod bracket on the axle.  Now clean, the axle will be well clear of the PAS.

For attachment, I had been considering using a system of sandwich plates to avoid welding (I wouldn’t trust my own and didn’t want to damage the galvanising).  The plan was to have a large 8mm plate outboard of the chassis that the box would sit against, and a vertical clamp made of more of the 8mm plate ahead and aft of the cross member, all cross-bolted and using anti-crush tubes to clamp the box in place.  I got as far as making up cardboard templates of the parts (the front clamp is a complex shape that ties through the two steering damper mounting holds on the dumb iron gussets and routes around the radiator support beam), including a shim to take up the thickness of the dumb iron drop sides to the front springs.  Thinking about the forces involved made me nervous, though.  The torsion on the box will try to twist the plates in the opposite direction, putting significant side loads on the chassis rail.  A welded plate and reinforcing gussets would be stronger as they would spread the forces over a larger area and the gussets would stop the chassis rail’s top and bottom surfaces from buckling.  I have no doubt the 8mm plate would have been stiff enough, but I think there is a chance the top and bottom faces of the chassis could have buckled without additional stiffening.  So, I will be getting some gussets and a plate cut up at the local engineering shop to then weld in place.  At least they’ll be cheaper than the clamp system.

Mounting the PAS pump will require a custom bracket on top of the timing case, where an aircon compressor would be installed.  I already have an 8mm plate bolted there to mount the Kenlowe Hotstart, so I just need to add the vertical sections to bolt the pump onto.  I have already worked out the longitudinal alignment off the double pulley on the water pump (I used a second water pump pulley reversed and countersunk the three pulley bolt holes to allow the countersunk bolts to centralise the pulley on the shaft as the shaft boss is too short to protrude through two pulley wheels).  I need to buy a short V-belt to run the PAS pump from the water pump to find the lateral and vertical position.

A quick check of the P38 drag link shows that it roughly 3-3.5″ too long, while the existing drag link is far too short.    I may end up with a custom link, which is a pity as I’d like to keep costs down – I will need a custom high pressure hose too.