Originally Posted by NAXJA

The question arises periodically, how to measure lift height if the flares are gone and the fenders trimmed. A long, long time ago someone had a personal web site with a compilation of height measurements, both "clean" (hub to flares, no need to get dirty), and "dirty" (measured under the vehicle, from the axles to the frame. That link seems to have gone away.

Poking around in the back of the '85 Factory Service Manual the other day, I was surprised to find a section on suspensions that gives the factory's OFFICIAL measurements by the "dirty" method. For the benefit of anyone who is interested, here they are:

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Checking Front Ride Height

Measure front ride height with the vehicle unloaded (no luggage or passengers) and with the fuel tank full.

Place the vehicle on a level surface and measure the veryical distance between the top of the axle tube (A) and the underside of the frame sill (B). Refer to Figure 1 for driver's side measurement and Figure 2 for passenger side measurement. Be sure each measurement is taken from the top of the tube and not from the axle or shift motor housings.

With Standard or Soft Ride Suspension, vertical distance should be 17 cm (6-3/4 inches) plus or minus 13 mm (1/2 inch). With Heavy Duty Suspension, vertical distance should be 20 cm (7-3/4 inches) plus or minus 13 mm (1/2 inch).

Checking Rear Ride Height

Measure rear ride height with the vehicle unloaded (no luggage or passengers) and with the fuel tank full.

Place the vehicle on a level surface and measure the vertical distance between the top of the axle tube (C) and the underside of the frame sill (D) inboard of the jounce bumper (E).

With Standard or Soft Ride Suspension, vertical distance should be 15 cm (6 inches) plus or minus 13 mm (1/2 inch). With Heavy Duty Suspension, vertical distance should be 18 cm (7 inches) plus or minus 13 mm (1/2 inch).

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The letters in each paragraph refer to diagrams, which I have no way of reproducing. Once you get underneath and look, though, the measurement points should be fairly obvious.

This section of the FSM also provides a listing of stock springs and spring codes, but it doesn't provide any specifications regarding spring rate for the various springs.

The springs are coded with a 2-letter code. In general, moving up one letter increases ride height by 1/2 inch. For example, stock (standard) front coils are coded FC through FP. If the right front has a spring coded FH and rides 1/2" too low, replacing that coil with one coded FJ would raise it 1/2". Typically, the factory used front coils with one letter code higher on the driver's side, to compensate for the weight of the driver.