Front suspension

Resources:

  •     Assembly manual: 65 Roadster Mk IV
  •     Factory Five Koni Front Coil-Over Shock assembly instructions
  •     Koni Series 30 1720 adjustment instructions
  •     Factory Five Front Front Tubular Lower Control Arm assembly instructions

Link to the front suspension album.

Overview:

The front suspension has five primary components: the lower control arm (LCA); upper control arm (UCA); spindle; hub; and the Koni coil over shocks.  The spindle is connected to the LCA and UCA via ball joints.

Front schematic


One modification was made in the LCA assembly: the F5 LCA bushings were replaced with Breeze bushings.  In the Breeze set, the bushing is approximately 3/16” longer than the F5 original, in principle filling the space in the lower rear bracket.  

The Breeze bushings were inserted, and the F5 one replaced, by placing the Breeze bushings over the F5 bushing and tapping the Breeze bushings with a soft-headed ‘dead blow’ hammer.

The Breeze bushings didn’t fit perfectly because the frame ears were slightly asymmetrical side-to-side:

Frame ears

From the table above you can see that there is a gap between the steel bushing and the frame ears that needs to be filled with a washer.  The washers that came with the kit for such a task are 1/8” thick.  The DS rear required a thinner washer and although the PS rear should have accepted the 1/8” washer, the fit was too tight and a 1/16” washer (McMaster-Carr) was used for for spaces that needed gap filling.  Note that because there is a difference in the frame ear gap compared to the DS and PS, the PS arm was positioned against the front ear (both front ears are 5 1/4” from the edge of the square X-member upright).

Notes:

  1. The Factory 5 tubular lower control arm (LCA) mounts in the outer holes. [Pre-1994 Mustang donor arms and the Factory 5 tubular LCA’s go in the outer holes (the Factory 5 tubular LCAs are based on the pre-1994 Fox Mustang parts in terms of their length); 1994 and younger Mustang donor arms go in the inner holes.]
  2. The complete kit comes with F5-designed spindles that get rid of the need for a SN95 spindle adaptor bracket (as in my 2008 build) and which has superior geometry, thereby reducing bump steer.
  3. The shock ‘hat’ was cable-tied to the springs (see above photo).
  4. Each bolt/nut combination has a specific torque specification.  Nuts were locked into place using Permatex Threadlocker Blue.
  5. The LCA has the ball joint already in place.  The UCA needed the ball joint assembly inserted and tightened.  The ball joint nut is 1 7/8”; a socket costs about $45.  Alternatively, a bench vise can be used to tighten the ball joint.  Threadlocker Blue was used to secure the UCA ball joint.
  6. The spindle and hub have extremely close tolerances.  In my 2008 build I needed to cool the spindle and warm the hub to get them to fit.  This time I used a bit of lithium grease on the spindle and the hub slid on with just a bit of wiggling and a light tap with a rubber mallet.
  7. The hub nut requires 225 ft. lbs. of torque, which is difficult to achieve with a normal-length torque wrench.
  8. The hub nut requires a 36 mm socket.
  9. The ball joint bolts has holes for the cotter pins that secure the castle nuts.  It is critical when tightening the castle nuts that the nuts are torqued so that the pin can thread the hole and not hit one of the ‘castle’ points on the nut.
  10. The lower shock attachment assembly required a thin washer (#94589A450 purchased from McMaster-Carr) to take up the gap left by the supplied spacers.  The upper assembly required some filing of the supplied spacers (~0.005”).
  11. I used red fingernail polish to mark nut/bolts sets that had been torqued to the proper specification.

Note on bolt orientation:

There is considerable opinion on the correct way to orient bolts, e.g., should the nut come loose during acceleration, etc., what will happen?

As with many questions of this type, I turn to Carroll Smith (’Nuts, Bolts Fasteners and Plumbing Handbook', SAE Books): pg. 97-

‘Myth: “Bolts must always be installed with the bolt head up and facing forward so that, if the nut should fall off, gravity and the force of the airstream will tend to keep the bolt in place.” There is nothing wrong with installing bolts in this manner.  In fact, in the interest of standardization, I usually do.  But to hope that gravity or air pressure will keep a bolt in place is unrealistic.  There is a place in the world for dreamers- but that place is not in engineering.  Neither is it anywhere near an airfield or a racetrack.  There is absolutely nothing wrong with installing bolts wrong end up or backwards, when it is more convenient to do so.’

Front Koni shocks:

The assembly of the front shocks followed the Factory Five directions without a hitch.  [Note: the Koni Series 30 monotube shocks can be mounted either body up or down.  I mounted them body up per the F5 instructions.  Note that the sets of bolts are of a different length:  the upper attachment bolts are 3 1/2”; the lower 3.0”.

The Koni shocks are adjustable.  The Koni shocks that come with the Complete Kit are the Series 30 shocks.  The expectation is that the shocks are in ‘0’ setting as delivered from the factory.  Several threads on ffcobra.com have indicated that the shocks are not necessarily set to ‘0’ on delivery.  As such, the settings should be checked, using the Koni instructions, prior to attachment to the suspension.