New leaf springs or just add blocks.

My is a 1990 bronco. I was hoping y'all could give some input on whether or not to get the kit with new ones or the one without. What is some signs that my leaf springs are bad.

Yo,
I don't suggest blocks.
If Body Leans to one side there is a Weak rear spring.
Side-to-side vehicle lean should be verified by measuring the fender lip-to-ground dimension before beginning diagnosis and service actions. Normal acceptable limits are:
Maximum of 16mm (5/8-inch) variance between left and right front wheel lips to ground.
Maximum of 19mm (3/4-inch) variance between left and right rear wheel lips to ground.



NOTE: Codes identifying the front and rear spring options and springs are printed on the Safety Standard Certification Label. Replace springs in pairs if one is found to be damaged or worn. If a spring should require replacement because it is damaged, worn or due to a leaning condition, replace only with the same part specified on the label. In rare instances, the spring codes will not reflect the springs as installed due to a DSO option or assembly plant substitution. If a DSO option number is shown on the certification label, the District Office can establish whether springs are affected. If the factory-installed springs do not agree with the code printed on the Safety Standard Certification Label (right and left spring part number should match), replace the damaged or worn spring with a new spring of the same part number as the damaged or worn spring. It will not be necessary to replace the matching, non-worn or undamaged spring.

Place the vehicle on a flat, smooth surface.
Inspect vehicle for any heavy add-ons that may cause excessive weight on any corner of the vehicle.
In cases where the excess weight is a snow plow, a rear tailgate lift, etc., the vehicle must be diagnosed with the equipment in place.
Measure corner weights if necessary.
Vehicle should be empty, fuel tanks full, no cargo such as tools, equipment or debris in the pickup box or rear body section.
Vehicle must be sitting on the wheels and tires and not a hoist, jack or jack stands.
Check all wheels (1007) and tires:
Wheels must be same size and design, right and left side on each axle.
Wheels size and design, tire size and tire design should be as indicated on the Vehicle Certification Label.
Check air pressure of all tires; inflate to specifications indicated on the Vehicle Certification Label.
Check front and rear suspension. Make sure the same spring is on the left/right front and left/right rear. The front springs have I.D. tags indicating the part number. The rear springs (5560) have the part number stamped on the bottom just behind the U-bolt attachment.
Jounce the vehicle's front and rear suspension to normalize the vehicle static ride height.
Measure the height of the right and left fender lip openings for both front (dimension A) and rear (dimension B) .
Calculate the side-to-side differences for each dimension. If these differences are greater than 16mm (5/8 inch) between left or right front and/or 19mm (3/4 inch) between left and right rear, adjustment can be performed following the Vehicle Lean Correction procedure.

Rear Lean

A side-to-side lean at the rear of the vehicle can be adjusted by approximately 10mm (3/8 inch) by installing a shim between the rear spring (5560) and rear axle (4001) on the low side of the vehicle. A "low at the rear" vehicle can be raised approximately 10mm (3/8 inch) by installation of one shim on each side. Use the following procedure to install the shim (D7TZ-5742-A).

1. Raise the vehicle frame until the weight is off the rear springs but with the tires still touching the floor.
   

1. Loosen the spring U-bolts to allow the rear axle to separate from the spring approximately 13mm (1/2 inch).
   

1. Position the shim (D7TZ-5742-A) between the spring and the spring seat and with the tie bolt head through the hole in the shim. On 4x4 vehicles, position the shim between the rear spring and axle spacer. Tape may be used to hold the shim in position.
   

1. Make sure the spring leaves are properly aligned and the spring U-bolts contact the edges of the spring assembly or axle seat.
   

1. Tighten the spring U-bolt sufficiently. The spring bolt end should extend through shim into axle seat hole.
   

1. Tighten U-bolt nuts to the following torque specifications:
   
   • 102-135 Nm (75-100 lb-ft) on F-150 4x2 and 4x4 and Bronco.

....
Check if Rear Spring Clamp is Damaged or missing.

Squeaks:
Loose mounting bolts. TIGHTEN.
Loose shackle bushing. REPLACE.
Loose rear spring. INSTALL rear spring anti-squeak inserts (if none currently installed).

Yo,

Alsi inspect leaf spring's shackles for rusted-out sections or looseness.

Rear Spring, Bronco




 

Item Part Number Description 1 N802114-S2 Bolt 2 N620483-S56 Nut 3 5775 Rear Spring Shackle Bracket 4 65092 Rivet 5 N806085-S8 Nut and Washer Assembly 6 18192 Rear Shock Absorber Bracket 7 18080 Shock Absorber 8 5005 Frame 9 N804028-S2 Bolt 10 N620484-S56 Nut 11 5776 Rear Spring Shackle 12 N804028-S2 Bolt 13 5775 Rear Spring Shackle Bracket 14 N806368-S56 Nut and Retainer 15 N647096-S Rivet 16 N620484-S56 Nut 17 5560 Rear Spring 18 5796 Rear Spring Cap and Plate 19 5729 Spacer, Rear Spring
(F-150 4x4 Only) 20 5729 Spacer, Rear Spring
(Bronco Only) 21 4001 Rear Axle 22 N800751-S101 Bolt 23 N605705-S2 Bolt 24 N806496-S100 Nut and Washer 25 N804028-S2 Bolt 26 N806368-S56 Nut and Retainer A — Tighten to 53-73 Nm
(39-53 Lb-Ft) B — Tighten to 113-153 Nm (83-113 Lb-Ft)