Front SuspensionThis is a pretty standard Ford Gen 1 Radius Arm suspension. Simple, bullet-proof and easy to maintain. The radius arms are attached at the Sport frame about where the existing transmission cross member attaches. Standard coil springs are used to support the chassis/body and a track bar is used to locate the axle under the vehicle.
Pieces:
1)
Ford radius armsRadius arms, radius arm caps, washers, frame end bushings, nuts, bolts and bolts from a Gen 1 Ford Bronco - 1966-1975. All my stuff came off a 1975.
There are several companies that make aftermarket radius arms in various configurations so there are alternatives to OEM. See links below.
Note: Some are not usable on a Sport because of angle/frame differences. The blue James Duff extended arms, for instance, will not work no matter how hard you try.
Any aftermarket OEM dimension radius arm should work.
Note: Typical aftermarket radius arms use Heim joints at the frame. This is fine for a trail or mostly trail - NOT DD - vehicle. There is no insulation in a Heim joint so all shock, road noise, vibration, etc. will be transferred directly into the frame. This is not desired for a DD vehicle. Recommended for a DD is something like a rebuild-able Currie Enterprises Forged Johnny Joint.
2)
Ford radius arm axle bushingsThere's nothing special about these bushings. Like the ones that go on the frame end, use the polyurethane bushings for long life. The extra flex of the stock rubber bushings isn't worth the time and expenditure of changing bushings every couple years. Several companies make and sell these.
Note: The axle bushings come in various degree off-sets. Changing these bushings is a way to change - fine tune - alignment and pinion angle to an extent. You will not be able to purchase these ahead of time since you won't know what you need until things are being assembled.
3)
Ford radius arm axle tube wedgesAgain, nothing special here. Several companies make these for both Dana 44 as well as Dana 60 axles with the standard 3" tube
4)
Coil springsMany companies make coil springs in various rates, variable rate, and length. Again, you won't know what you need until you're assembling everything. Springs need to not only be matched to the front end for weight and height, but to the rate of the rear springs. Unbalanced spring rates between front and back can create unpredictable behavior both on and off road.
I've been extremely happy with my Skyjacker coil springs. That would be a good company to start with.
5)
Coil spring axle padsSpring pads, retainers and bolts. These are available both OEM as well as aftermarket. I would recommend buying these new as salvage yard 40 year old pads are going to be in pretty bad shape most likely. These get a LOT of stress and they're a PITA to change out if one breaks. I had to change out both of mine about 4 years after the build. The headache of saving $30 during the build was nowhere near worth two weekends of tearing apart the front end.
Note: These are what hold the springs to the axle. If one breaks, you are not going ANYWHERE.
6)
Coil spring bucketsCoil spring buckets with retaining strap & bolt. Again, there are OEM as well as aftermarket options. Both work perfectly fine. Aftermarket options frequently are adjustable which makes matching springs easier as you can adjust the buckets for different height springs.
7)
Ford radius arm shock mountsThese are just little tabs that bolt to the radius arms behind the axle. Nothing special, but you definitely need them.
Depending on the radius arms, these may or may not be integrated. OEM radius arms require the shock mount tabs.
8)
ShocksAnother part that will need to be purchased at assembly time since you won't know what length you will need until you mock everything up. Rancho makes many different configurations as well as lengths. I prefer the RS9000 adjustable shocks for both front and rear because they can be tuned for the suspension. No OEM non-adjustable shock is going to be even close to tuned for the vehicle they're going to be installed on and that's not a good thing either on or off road.
9)
Suspension travel limiting strapsThese may or may not be required. They may be desired even though they may not be absolutely required. These are nylon/Kevlar straps that bolt to the frame and radius arm and limit downward axle travel. Measurements for length will need to be taken at time of suspension mock-up.
Depending on the drive shaft configuration, downward travel may need to be limited to keep from overextending the drive shaft slip joint, slip yoke, u-joint angle, or tie-rod angles.
The more 'droop' the better, is not always desirable either on or off road. Limiting independent movement between the axle and body in a street driven vehicle is very desirable for safety reasons. It also may be desirable off road for reasons of stability and to protect parts from running at undesirable angles. i.e. tie-rod ends, u-joints.
10)
Track bar1 1/4" x .25" DOM tubing
Ford lower track-bar end bushing shell
Ford lower track-bar end poly bushing
3/4" x 3/4" Heim joint
The track bar is used to locate - or position left to right - the axle under the vehicle in a 3-link or radius arm suspension. There's nothing real special about it other than it needs to be very sturdy as the side loads are significant. The above specs are considered to be the minimum. 1/4" plate should be used for the brackets and well welded and reinforced.
This is the only part where use of a non-OEM part is desirable. The axle end of the track bar is fabricated using a Ford Bronco lower track-bar bushing shell welded to the DOM tubing. The upper end uses in place of the stock bushing, a 3/4" Heim joint. The very strongest, best quality available - because if this breaks, you will loose all steering. The reason for using a Heim instead of the stock Ford Bronco bushing track-bar configuration is to improve articulation and reduce stress at the frame. A polyurethane bushing is retained at the axle end to reduce transfer of road noise, shock, vibration, etc. to the frame, chassis and cab. Side affects include reduced wear on the OEM poly bushing as well as more positive - or tighter - feeling steering. This is very desirable for a DD vehicle.
Note: As an alternative to the 3/4" x 3/4" Heim joint, use of a Currie Enterprises Forged Johnny Joint should be examined as that may supply extra strength as well as being rebuild-able.
Note: Plenty of clearance between the track-bar frame bracket, Heim joint and track bar must be given to account for compression of the radius arm axle and end link bushings, as well as flex of the frame. 1/4" IS NOT "PLENTY OF CLEARANCE"!
This is EXACTLY how you DO NOT mount a track bar.
Notice that there is almost no clearance between the Heim joint and bracket as well as the bar and bracket.
This bracket should have been built wider with mis-alignment spacers between the Heim and bracket.
Measurements:
General:
The Ford OEM radius arms attach to the frame about where the Mitsubishi OEM transmission cross member attaches. This will almost certainly require that a custom cross member be fabricated. The design will depend on several factors, one of which is whether a single or two-piece front drive shaft assembly is used.
The track bar may or may not need to be formed to clear the differential. It takes significant force to bend 1.25"x.25" DOM tubing so specialized equipment may be required for this part.
The track bar and drag link need to be as close to the same length as possible, as close to on the same plane as possible and as close to horizontal as possible. The ideal - perfect - scenario is that both are the same length, on the same plane and perfectly horizontal. Any deviation introduces 'bump-steer'. Some amount is inevitable and may be so little as to not even be noticeable. This is definitely a case of 'the less, the better'.
It is possible to get close in regards to length, but not practical to be exactly the same length. This is more of a consideration in long travel suspensions. However, 'on the same plane' and 'as close to horizontal' is very important - more so for a street driven DD vehicle. Great care should be taken to accommodate these two requirement as much as is possible.
You do not want a vehicle where every time you hit a little bump or dip on the highway, it tries to tear the steering wheel out of your hand.Grease all poly bushings with full synthetic molly HP grease before final assembly.
Gen 1 Bronco '66-77 (all my parts are '75) -
Bronco GraveyardJames DuffBC BroncosTom's Bronco PartsWild Horses Four Wheel DriveBlue Torch FabworksCurrie Enterprises Johnny JointsEdward