The step by step process of rebuilding a set of UCAs with improved caster far a classic Mustang, Cougar, or Falcon
Rebuilding UCA
Even though Ford made quality parts it is still a good idea to rebuild the UCA bushing for better grease-ability and improved caster. The first thing you will need to do is remove the UCA from the spindle.  The easiest way to do this without damaging the ball joint is to make a ball joint removal tool out of a couple 3⁄4” bolts and a 3⁄4” all-thread connector.  I personally made mine with two pieces of all-thread, two 3⁄4” nuts and one all-thread connector.  I did this to make a recessed area for the ball joint bolt ends to fit into.  Once the UCA has been removed, it can be disassembled and inspected.  As with any auto part rebuild, inspect all parts being reused and replace any that are questionable.  When rebuilding a UCA it really makes sense to replace the shafts and ball joints with new parts.  The best source for new "take off" UCA rebuild parts at about half the price of normal is www.opentrackerracingproducts.com The next step is to modify the UCA bushing. I recommend starting with a bushing shaft assembly.  Take a cut off wheel and cut a grease groove perpendicular to the thread on the underside of the shaft.  I cut the groove into the shaft from the end all the way past where the O-ring seats and to a depth just past the depths of the threads. This is done for two reasons.  First, it allows grease to get to all the threads and, second, it provides a grease escape so that when you grease the bushings you don't push the O-ring out. 
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The information regarding cutting grease groves into the bushings came from MustangSteve of www.mustangsteve.com. Once the improved grease-ability has been achieved, our attention can be turned to improving caster.  Install the pivot shaft, including the cap nuts, in the UCA so that the shaft is perfectly centered as it was designed to be.  Many measurements and adjustments will need to be made to perfectly center the bushing shaft.  Completely remove the forward cap and, once it is free of the UCA, loosen the rear cap just to the point where it comes loose from the UCA body.  At that point, loosen the rear cap another 1/3 of a turn further.  NOTE:  The amount loosened may vary, 1/3 of a turn is a good starting point.

Reinstall the cap and shaft into the UCA body, including the forward cap.  This process should move the shaft forward about .1”, however, individual results may vary and you will need to take careful measurements and make sure the shaft is moved no more than .1”. 

NOTE:  Moving the shaft more than .1” can affect the way the shaft and retaining nuts work together, which could cause an unsafe condition.  Moving the shaft forward moves the UCA assembly backwards and gives you more positive caster.  Before you make an improved caster modification, make sure you have enough clearance between the rear zirk and the shock tower wall.  Once the UCA bushing is lined up where it needs to be, tighten the cap nuts down to the point where the UCA travels without binding up, and then tack weld the caps on three side so they don't back out. 

NOTE:  as with any other welding, the safety of this modification relies on the strength of these welds, so if you are not confident in your welding skills, have a certified professional do it.
  The reason for welding the bushing caps in place rather than tightening them to the point where they will stay put themselves is because, often times when the caps are that tight enough to not come loose, it puts the bushings in a bind and will cause the assembly to squeak and/or cause premature failure of the assembly.   Also, I have found that it works best to rebuild both UCA assemblies at the same time so that they can be positioned bushing shaft end to bushing shaft end to ensure that they are mirror images of each other and have the same amount of improved caster adjustment.  At this point the UCAs can be installed making sure the arm goes to the rear of the shock tower.  As with any front end work an an alignment will need to be done once the car is back on the road.

UCA rebuild parts

Cutting a grease groove in the shaft


Prepped for welding

Prepped for welding

Rethreading the UCA with new caps



Measuring side to compare shaft offset

UCAs  with offset shafts mirrored

Having the car aligned:
There are several things to keep in mind when having your car aligned.  First, factory Ford settings WILL NOT make for a good handling car.  The original Ford settings were created with tires made in the 1960’s in mind and are not the ideal settings to maximize performance.  Second, make sure you trust the alignment shop.  Aligning an early Ford can be very challenging, especially with a “shim” type alignment because as you change either camber or caster, the other setting is affected.  This makes the process very time consuming and some alignment shops will align the car to settings easy for them, rather than the setting you requested.  NOTE:  for best results, have the alignment shop print out a before and after specification sheet.  Third, aligning a classic Ford, especially a pre-1967 car, is not an exact process and, due to the effects that changing either camber or caster have on each other, the alignment shop will need a set of tolerance specifications to align the car within.  The following is a print out that I take to my alignment shop every time I have my car aligned.

Please align to these specs “1960-1966 Mustang and Falcon Performance Alignment with or without UCA drop”. 

These specifications are in order of importance.


1.  NO more than .25 degrees difference between driver’s side and passenger’s side.

2. +2.0  to +3.5 degrees caster. 
NOTE: for cars with Adjustable strut rods.  Please attain as much caster as possible using the shims (at least 1.5 to 2.0 degrees), and then use the adjustable strut rods  to increase the caster and make the sides the same.  Also, please note that the caster difference between the driver’s side and passenger’s side needs to have no more .25 degrees difference prior to the adjustment of the strut rods.

3.  -.5 to 0 degrees camber.  No positive camber, please.  There is no problem having a slight variation from driver’s side to passenger’s side to account for the crown in the road.

4.    1/16" to 1/8” toe in

If you run into any problems attaining these specs, please call me (your phone number here).



Please align to these specs “1967-1970 Mustang, Falcon & Cougar Performance Alignment with or without UCA drop”. 

These specifications are in order of importance.


1.  NO more than .25 degrees difference between driver’s side and passenger’s side.

2. +2.0  to +3.5 degrees caster.  

3.  -.5 to 0 degrees camber.  No positive camber, please.  There is no problem having a slight variation from driver’s side to passenger’s side to account for the crown in the road.

4.    1/16" to 1/8” toe in

If you run into any problems attaining these specs, please call me (your phone number here).



Disclaimer on Daze Tech Tips
      I am not an expert in this field. I have performed these modifications myself with very good results. I am passing along restoration and performance tips for the purpose of education.  If you are concerned about reliability or safety issues, I do not recommend that you or any other individual perform these changes or attempt to modify your cars from stock configuration except under your own volition.  I do not assume nor accept any liability for the use of this information or how it is applied.

















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