4-Wheel Steering

There is a great mod out there that was initially conceived by a guy named TG, from the Monster GT forum. I have tried this mod and it works awesome. It might be just the ticket if you are racing at a very small, tight track, or if you just want the coolest basher around!

If you get involved in this project, you will quickly notice there are a variety of ways you can get it done. You will need to be handy with a Dremel tool and you'll need a drill and tap for 3mm screws. Take your time and think it through before you start cutting and grinding. I have copied and pasted from the Monster GT forum thread, plus added a few comments of my own. A lot of the text below (in italics) is from TG.

When you're done, this is what you'll have (pic below is TG's truck). Pretty cool, huh?

TG - I was going to wait until I finished this hop up but I will give you all a brief preview. I purchased the FT steering kit for the front end and have added an “L” shaped servo horn to the steering servo creating a link point for a new rod that travels down the length of the chassis. I manufactured a new swivel point (ball bearing’s and another “L” shaped servo horn) in a mirror image of the steering servo in the rear of the MGT. I have taken my original steering linkage (with ball bearing’s) and front skid plate from the front and have mounted them in the rear. NOTE FROM Chevy-SS: You need to mount a front-style skid plate to the rear, which will involve grinding out the chassis, plus drilling and tapping new holes for the four 3mm screws. Reversed the rear knuckles and am currently waiting for a new front skid plate for the front and a set of front tie rods for the rear to finish. After setting up the linkage I figure I will get about 25% of the front-end steering travel to the back steering.

With this mod at the current linkage settings (30%) it will turn one truck with in side of the factory steering. This in it’s self is not all that impressive, but when under power… holly sh_t batman this thing is now turning in side of two feet. Under power the rear end pushes out and forces the front to cut in. On loose dirt it will do donuts inside its self.

Here is the list of parts I used to create the 4 wheel steering modification:

NOTE FROM Chevy-SS: I would not start buying parts until you have carefully reviewed the entire process and decided how you want to proceed. The list below just gives you an idea of the number of pieces needed. Most likely, you will only need SOME of these parts, so think before you start spending money.

2 Ofna “L” shaped servo arm part # 10751 $6.95 ea.
TA front axle part # 8443B $7.45
2 flanged ball bearings 3/16” ID x 5/16” OD $2.45 ea.
TA front & rear turnbuckle eyelets & balls part # 25121 $11.45
TA 3/16” axle shims part # 7368 $1.45
TA factory team steering kit part # 25395 $62.95
TA front steering turnbuckles part # 25120 $5.45
TA front skid plate part # 25128 $9.45
Miscellanies hardware. $8.00

TG continues -  Taking the original front skid plate and mocking up the rear end I found that I needed to flatten the plate due to the differential not being at the same angle as the front. Mounted the bell crank shafts to the skid plate and mounted the skid plate to the diff, before I mounted the plate to the diff I put a couple of drops of yellow paint on the ends of the shafts so when the plate was mounted to the rear diff they left two donuts marking where I needed t drill the chassis for the two top mount screws for the bell crank shafts. Also marked the other four holes that are left at the other end of the plate.

Next came some Dremeling out of the chassis to accommodate the new bell crank and new linkage. Drilled the new holes in the top of the chassis for the bell crank and new servo post. Mounted the new servo post using washers to sandwich the plastic pan. The top washer is a 1/8” x 1” which over laps the aluminum chassis and a slandered #6 washer on the bottom. Mounted the bell crank and connected the linkage to the servo arm. Turned the knuckles a round and added two new front turnbuckles to the rear bell crank. Removed the servo arm from the servo and added the second “L” shaped arm to it and then created a linkage arm from 1/8” steal rod and two turnbuckle eyelets.

After play with the linkage a bit I got the new long front to back arm the correct length and JB welded the eyelets to the steal rod. That is pretty much it in a nutshell, all for about $130.00. You could do this with out the factory team steering kit and do it with a $5.00 plastic bell crank part # 25125 and reduce this cost to $70.00. I just needed the FTSK for the servo saver. The one thing I did notice is that this mod does not allow for a servo saver for the back steering bell crank (Note from Chevy-SS, I did put a servo saver into mine, see below). Might put in a second FTSK if this becomes a problem for the linkage and or servo.

End of TG text.

Also, a thought about alignment. This 4WS setup forces you to make all steering adjustments in the linkage. For instance, if your truck is tracking left, you can't use steering trim adjustment on your TX, as that will also move the rear wheels and your truck will be crabbing sideways. You need to set steering trim at zero and simply use turnbuckles to get everything tracking straight and aligned.
 

ANOTHER OPTION - servo in rear. This is the best way to do four-wheel steering, in my opinion.

Now, if you don't want to mess with linkages from the front to the rear, you can always try TG's second version, which was to mount a servo in the rear. I believe the idea to add the servo in the rear came from Canadian-MGT. Check out the pics below. I don't think this one needs much explanation. It's a cool idea. Way to go TG and Canadian-MGT!

Here's the link to the full thread on the forum: http://monstergtforum.com/forum/topic.asp?TOPIC_ID=1899