I have bought myself a nice new rack and want to get it mounted so that I can finish what ive started with the wishbone brackets.

Ive read as much as I could find (not a lot) and want to know what the pitfalls are before I cut and weld?

I.e. are the book dimensions on this accurate?

I think Triton recommended dropping it 10mm .I have read that it’s easier to raise the rack than drop it when trimming it up for bump steer.

I will also brace it when happy with the position so it won’t flex.

Any help on this would be gratefully received.

Thanks and regards warren

oh yeh book car mk2 escort rack

I managed to achieve near 0 bump steer by repositioning the Mk2 escort rack lower on the inclined mounts. It ended up with the pinion housing nearly touching LB.

Make it lower than you think you need, then use spacers to bring it up to height - you then have some room for adjustment.

It's very hard making negative spacers if you fit it too high!

David

My understanding is you should get the rack arm movement as parallel as possible to the lower wishbone. Ideally, The rack pivot should line up with the wishbone pivot as well. You want them to move in the same arc as much as possible, which should reduce/eliminate bump steer.

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Originally posted by bernie955
My understanding is you should get the rack arm movement as parallel as possible to the lower wishbone. Ideally, The rack pivot should line up with the wishbone pivot as well. You want them to move in the same arc as much as possible, which should reduce/eliminate bump steer.

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The problem with making the tie rods parallel with the upper/lower wishbone is that it doesn't take into account the other wishbone, which in a non-parallel, unequal length configuration, forms a trapezoid.
I don't know if it will work in the case of a Book Locost, but a good starting height for a rack is, with the tie rods horizontal, around the mid travel of the suspension.
In other words, if, for argument's sake, you have 50mm of droop and 75mm of bump, then with the suspension 12.5mm into bump, the rack and tie rods should be lined up with the TRE on the steering arm.
Whether that's physically possible with a Locost can be determined by anyone with a Locost and a suitable rack, but chassis members or some other obstacle may prevent it.
Some fore and aft movement of the rack may be necessary to fine tune the bump out.
Alternatively, if you can measure the relative positions of the TRE on the upright and plot its positions on paper at full droop, full bump and ride height, it's a simple task to describe three identical circles from the centre of the TRE which, if you're lucky, will all intersect the same spot.
I can tell you in the case of the Locost, they don't, so there will be some fine tuning to be done with either a straight edge or a laser pointer to optimise the rack's position.

Thanks ill get stuck in then.

Only allowed a couple of hours in the garage this week due to family.

And that was grudgingly "Are you coming in yet" 2 min latter “Are you coming in yet”: o and so on.

But have made a start on the mount

I wouldn't make any of it too permanent until you install all the suspension and steering and cycle it to see how it performs.
Only when it's all working optimally, weld it all solid.