How To: Install D1 Spec Boss and Short Hub

there was recently a gorup buy on another forum offering a D1 spec removable steering wheel boss and a shorter-than-OEM hub

the following shows how i fitted it. it's not exhaustive and neither do I think it is the best/easiest way so read through and use it for inspiration

note: my horn is a single wire set-up and this guide is relevant for that

Things Needed

D1 spec hub and boss

Allan keys which come with each item

21mm deep socket


ok, so first of all here's what you get with each bit of kit:

D1 spec steering wheel boss:



so you get 2 red wires, 2 black, a set of bolts and allan key for fixing the boss to the hub, 2 spacer things for electrical continuity through the boss and the boss itself

D1 spec short hub:



with this you get the short hub plus allan key and bolts to fit the steering wheel


Preparing your boss

so you will notice there's a little metal ring inside the top of the boss. you'll want to ease this out with a screwdriver then slot it back in so the little ridge in it sits on top of the boss:





then, put one of the spacers on top so that the little tab bit goes into the slot in the ring (giggity)



stupidly i didn't take pictures of the next bit, but now connect one of the wires from the tab to the negative terminal in the top of the boss. this will be the ground for the horn.

i also didn't photograph it, but it's easy as piss - connect a wire to the positive terminal in the top of the boss. this will connect to the horn button

you will then need to disconnect the two parts of the boss - push in the little button on the side of the boss then slide up the bit with carbon effect past the button until the two parts come away from each other

Fixing the hub to the car

before starting, make sure your wheels are pointing straight and the steering wheel is sitting flat

so, first up you'll need to remove the steering wheel and OEM boss. this is done by removing the horn button to expose the 21mm nut and undoing itso it is most of the way off, then wiggling the steering wheel left and right until the hub comes loose. there are guides out there for this if you need help!

you will then see this sight:



you will see there is a little plastic circular thing in the middle, with 2 prongs. this is to do with indicator self-cancelling. when you put the hub onto the spline, make sure those prongs go into the little holes in the bottom of the hub, badly-pictured below:




now, you can rotate the hub until the small hole punch is directly upright. this helps with making sure the steering wheel is at the correct angle when finished. in my pictures it's slightly rotated 'cos im stupid and didn't set the wheel straight before doing the swap



now you'll need to put the 21mm nut back on and tighten it up very tight

next, connect the red wire to the positive terminal in bottom part of the boss:



then place the bottom part of the boss onto the hub, lining up the hole punch on the boss with that on the hub (i put a bolt in above it to illustrate):




now put a bolt on every second hole around the boss and do them up tightly.

fitting steering wheel to the boss

piece of piss this bit - using the countersunk bolts, connect the steering wheel to the boss so that the "d1 spec" bit is upright:



i didn't photograph it, but you'll then want to attach the wire on the positive terminal to the positive terminal on the horn

now simply place the steering wheel over the boss and rotate it gently until it clocks together



what you'll probably then do is soon realise that it's out of alignment

in which case, remove the removable bit, in which case you'll need to remove the hub again and rotate it slightly to fine tune. it took about 3 adjustments until i got there or thereabouts