This is an expansion of the following thread:
http://www.celica-gts.com/forums/index.php?topic=29576-----
Photographs courtesy of myself and silverliftback.
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So, are you getting tired of that boxy two-spoke steering wheel in your Celica? Well, doff your hats, roll out the barrel, step right up and improve that with an awesome three-spoke Mk4 wheel! It's about the same size as the Mk3 wheel and is a much nicer piece to hold.
You will need:
- A 1986-1989 Celica GT/GTS wheel
- Phillips screwdriver
- 19mm socket
- Breaker bar
- Mk3 horn contact ring
- A couple small washers
- Glue of your choosing
- Drill with various bits
- Dremel with various bits
- Female spade connector
- Crimp connector of some sort
- Crimp tool
- Piece of wire
- Wire strippers
- Personal protective equipment
Additionally:
- Drill press
- The strength of 10 men
- or -
- God summoning abilities
- Your favorite drink
- A degree in mechanical engineering
- A consideration for one's own safety
- Patience
- A sense of humour
Step 0: A few notes on the Mk4 wheel:
As I wrote above, you can use any '86-'89 GT/GTS wheel; but each one is a little different. Take a look:
Toyota made the GT-S wheel a bit fancier! But, see those cruise control buttons? They cannot be used for the Mk3's cruise control module, as they are resistor switches. There are only two wires for the three switches, and each switch produces a different resistance when pressed.
The Mk3 cruise control module requires regular switches on multiple different circuits (see the wiring diagram). The Mk4 switches could potentially be used with a microcontroller for some fun LED interior lighting, per silverliftback's suggestion.
When you're salvaging the wheel from a Mk4 in the junkyard, you
do not need the rotating horn ring and connector for the cruise control switch. You can leave this component behind.
You could also paint the lettering with a silver paint pen like silverliftback did.
Step 1: Remove your old, rotten and smelly wheel
Remove the screw underneath the middle of the foam crash pad, and push it up to remove the pad. Disconnect the horn grounding wire. Take your 19mm and breaker bar and bust that nut loose. Screw it back on a couple threads, grab the wheel at 9 and 3 o'clock, summon the power of the Egyptian god Sutekh, and
pull. Wiggle right and left and the wheel should come loose without busting you in the snoot.
I recommend using a sharpie to mark out the position of the steering shaft while centered so you can correctly center the new wheel when you install it.
Now throw the wheel away.
Actually, don't do that yet.
Step 2: Remove the steering column covers
Locate the 6 screws underneath the lower column cover, and remove them. Carefully remove the covers (adjust the steering wheel tilt as necessary).
Step 3: Transfer the horn contact ring to the Mk4 wheel
Remove the horn contact from the Mk3 wheel. We'll be attaching this to the Mk4 wheel with the OEM screws and glue.
Before transferring the ring over, I'd highly recommend cleaning the ring of any corrosion or dirt. Windex seems to work pretty well for this.
Then give 'er a coat of dielectric grease (only on one side!!).
You'll need to center the ring on the back of the wheel and make sure the spade connector goes into that cutout. Don't worry, you won't hit anything metal inside the wheel when you put the horn cover back on.
Use a pen or punch or whatever you'd like to mark out where you're going to drill.
Grab your drill bits and start with a 1/16" bit as the pilot. Work your way up to the 3/32"; that's the largest hole you can make that still allows the screws to thread into the plastic.
Once you've created the holes, run a screw in and out of each hole to create the threads. Test fit your ring with the screws
and make sure not to tighten them all the way. There's going to be a little gap, and you also need to make sure the ring is flat against the back of the wheel. Excessive tightening will cause the ring to sit unevenly or even bend.
Now, put some glue down where the back of the ring contacts the wheel. I used superglue for this.
Secure the ring in place
carefully with the screws and let the glue set.
You're almost there! There's one little thing I discovered while testing out the wheel each step of the way; because of the limited number of positions the ring can be placed, one of the screws gets
really close to the metal frame of the wheel and it can contact and short the horn.
You'll need to get a couple of small washers to space out the screw. In my case, not doing so caused a short. Don't worry, this will not cause a clearance issue behind the steering wheel.
And there you go! You're over halfway there!
Take a swig of your favorite drink. Beer, water, soda, whatever. I prefer
GROG because
Mungo like grog!!!
Step 4: Adding holes for turn signal canceling functionality
The OP of the forum post at the beginning of this write-up didn't need to drill the metal in the wheel to add signal cancellation. I did, however.
Here's the cylinder for the turn signal canceling.
Those two small cylindrical extrusions fit into these holes in the back of the Mk3 wheel.
They're a perfect 30mm apart.
When measured out on the Mk4 wheel, it seems you have to drill a little bit into the metal
and plastic. Without a drill press, this was tricky for me...
...but possible. Use a 1/16" pilot like before, and work up to a 7/64". Test it out and make sure the turn signals cancel as you turn the wheel.
Step 5: Wiring
A simpler step. As we are not going to utilize the cruise control switch, we won't need this three-pin connector.
Chop the green ground wire and grab a piece of wire (mine came from a chopped up radio harness), a female spade connector and a crimp connector.
As I feel no remorse for shaming the Mk3 wheel and tossing it out, I chopped off the spade connector from the Mk3 horn and used that instead. Basically, you will need to create a wire with two female space connectors of the same size on each end.
Step 6: Trimming the steering column covers
The Mk4 wheel doesn't quite fit into the hole created by the Mk3 steering column covers. You will need to get a Dremel and remove 2mm of material from both the top and bottom. Get out your safety glasses and wear a long sleeve shirt. You don't want hot bits of plastic being propelled into your eyes or skin.
I used these two Dremel wheels; one coarse grit for material removal, and one finer grit for finishing.
It wasn't the most beautiful job - I mean, I am no Michelangelo - but it provides the clearance required and you won't see it with the wheel installed.
Mungo make hole!
Stick the two pieces together and give it a test fit on the wheel face-down. You should be able to move the collar around side-to-side a little bit with the hole over the back of the wheel.
Step 7: Wrap-up
Get excited!
Put the wheel in your car, torque down the nut to 25-30 ft-lbs, connect the wire for the horn button, tuck away the unused cruise button connector, and attach the horn button and its single screw in the back of the bottom spoke of the wheel.
And enjoy your Mk4 wheel!
- A Guide by twotone_ra64
