Haynes Roadster Steering Rack

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I had neglected to make a jig for the steering rack, but mounting it turned out to be very simple.

To do this job, I was armed with a height from the bottom of the chassis rail to the top of the central portion of the steering rack. I had taken this from my CAD drawings and calculations done some time ago.

I knew, after much measuring and re-measuring, my suspension pick-up points were well within a millimetre of my CAD. I therefore ignored these from the equation.

I had a brand new Ford MK II Escort “quick rack” bought at Stoneleigh Kit Car show last year. I cut the cable ties that secured the rubber boots in place and rolled them back out of the way. The ball joints of the steering rack arms and the central section of the rack were now exposed. I then turned the steering linkage to check what the full range of movement the the steering arms was. Conveniently, the arms moved until butting up to the body of the steering rack.

By measuring the length of the steering rack body and dividing this by two (633/2 = 316.5) I had the centre line of the rack. Using several right-angle squares, it was easy to line this centre line up with the centre-line I had scribed into my chassis. It was also easy to get it perpendicular to the chassis line.

All that was left to do was get it to the correct height and level it up. I did this with a height gauge and a digital spirit level. As a double check, before welding, I checked each end of the rack was at the same height (they were). I then tack welded it up, removed the rack and finished welding.

It was one of those jobs that you stand back from and think “That was too easy – What’s Wrong?”

Well OK, I might re-make one of the rack clamps as it isn’t possible to get it as tight as I’d like, but that is it.

I did have a lovely set of billet aluminium rack clamps, but these as for solidly mounting a steering rack and I have decided to use Polyurethane bushes. After all, although this is a sports car, it will be daily driven and I don’t intend to race it. – Hence the homemade 2.5mm steel belt plate. The rack clamps were carefully linished to prevent the clamps from wearing in use.

Haynes Roadster Steering Rack

Although it was a bit late, I crudely doubled checked that the steering rack ball joints lined up with the suspension pick-up points. I did this to check for bump steer (with the steering in the neutral position). The racks steering arm ball joint certainly lie on the intersection line of the two suspension points, but until I make the steering rack extensions and ream out the tapers on the uprights’ steering arms, I cannot check the intersection of lines at the Instantaneous Roll Centre (I.R.C.).

Bump Steer

In the photo above, you can see that the track rod end is fitted to the underside of the steering arm. I need to weld up, drill-out and re-ream the steering arms so that the track rod end mounts on top of this arm. I have some spare uprights and the Brother in Law found they TIG weld quite nicely without problem.

Steering Rack Universal Joint

In the above photo you can see a 14mm universal joint attached to the steering rack. This was one of those ‘It looks too cheap to be any good’ experiments. They were on Fleabay advertised as ’14 x 14mm Diameter Steering Universal Joint Motor Coupling Screw OD28 L60′ and came from Yueqing, China. The ones I had looked at in the U.K. were about £80 before delivery. These stainless ones were £12 including delivery and even cheaper if I bought several. It turns out they look pretty good quality and do the job perfectly. I’ll have to drill the rack to accept a split pin, but after I tapped it on with a mallet the splines on the rack gripped the U.J. so hard I’m going to struggle to get it off. The split pin would be just a back-up fail safe.

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Files

Ford Sierra - Sectioned IRS DWG CAD
Front Suspension Sierra - DWG CAD
Front Suspension Cortina - DWG CAD
Ford Escort MK2 Ball Joints - DXF CAD
Ford Escort MK2 Steering Rack - (Left Hand Drive) - dxf
Ford Escort MK2 Steering Rack - (Left Hand Drive) - DWG CAD

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