Ford Full-Size Cars 1968-1988 Repair Guide

Tires and Wheels


See Figures 1, 2, 3 and 4

Inspect your tires often for signs of improper inflation and uneven wear, which may indicate a need for balancing, rotation, or wheel alignment. Check the tires frequently for cuts, stone bruises, abrasions, blisters, and for objects that may have become imbedded in the tread. More frequent inspections are recommended when rapid or extreme temperature changes occur, or where road surfaces are rough or occasionally littered with debris.

The tires on your car have built-in tread wear indicators molded into the bottom of the tread grooves. These indicators will appear as 1 / 2 in. (12.7mm) wide bands when the tread depth becomes 1/16 in. (1.6mm). When the indicators appear in 2 or more adjacent grooves, at 3 locations around the tire, or when cord or fabric is exposed, it's time for new tires.

Check the wheel lug nuts with a torque wrench. Make sure they are tightened to 85-105 ft. lbs. (115-142 Nm). Loose wheel lug nuts can cause shimmy and vibration, and could also elongate the stud holes in the wheels.

Make sure the wheels and hubs are clean. Stones wedged between the wheel and disc brake rotor or brake drum, or lumps of mud and grease can unbalance the wheel. Check the wheel pilot hole for rust. Rust in this area could prevent easy wheel removal, it should be cleaned before installing the wheel.

Check the wheel for any obvious damage. Wobble or shimmy caused by a damaged wheel can eventually lead to wheel bearing failure.

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Fig. Fig. 1: Use a penny to check tire depth

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Fig. Fig. 2: A tire depth gauge, available at most automotive parts stores, can give you a more accurate reading

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Fig. Fig. 3: If a tire shows gaps like this, replace it

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Fig. Fig. 4: Tire wear diagnosis


See Figure 5

Front and rear tires perform different jobs and can often wear differently. To obtain even tire wear and maximum tire life, the tires should be rotated at approximately 7,500 miles (12,077 km) and then each 15,000 miles (24,156 km) thereafter. Rotate the tires according to one of the diagrams in the figure. Note that if the vehicle is equipped with a temporary spare, this tire should not be included in the tire rotation.

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Fig. Fig. 5: Tire rotation patterns


See Figure 6

Do not mix tires of different construction (radial, bias ply or bias belted) on the same vehicle. Vehicle handling will be seriously affected with the possibility of loss of control.

All tires have identification marks pertaining to size, tire pressure and load range molded into the sidewall of the tire. The Department of Transportation grades all tires for tread wear, traction and temperature resistance. This Uniform Quality Grading System information is also molded into the sidewall.

The tread wear grade is expressed as a number. The number is derived from a test conducted under controlled conditions on a government test course. If a tire is graded 150, it means that the tire wore 1 1 / 2 times as well on the test course as a tire graded 100.

The traction and temperature grades are expressed as the letters A, B or C; A being the best and C being the minimum standard that all tires must meet. The traction grade represents the tire's ability to stop on wet pavement, in a test conducted under controlled conditions on a government test course. The temperature grade represents the tire's resistance to the generation of heat and its ability to dissipate heat, once again during a government test conducted under controlled conditions.

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Fig. Fig. 6: Types of tire construction


At least once a month, check the inflation pressure on all tires, including the spare. Use an accurate tire pressure gauge. Do not trust the gauges on service station air pumps, as they are not always accurate. The inflation specifications are listed on the tire pressure decal which is located on the right door pillar. Check and adjust inflation pressures only when the tires are cold, as pressures can increase as much as 6 psi (41 kPa) due to heat.

Inflation pressures that are higher than recommended can cause a hard ride, tire bruising, carcass damage and rapid tread wear at the center of the tire. Inflation pressures that are lower than recommended can cause tire squeal, hard steering, rim dents, high temperatures and rapid wear on the outer edges of the tires. Unequal tire pressures can compromise handling and cause uneven braking.

As previously stated, radial tires have a highly flexible sidewall and this accounts for the characteristic sidewall bulge that makes the tire appear underinflated. This is normal for a radial tire, so you should not attempt to reduce this bulge by overinflating the tire.


Aluminum wheels are standard on certain models of Crown Victoria and Grand Marquis and optional on others. These wheels are coated to preserve their appearance.

To clean the aluminum wheels, use a mild soap and water solution and rinse thoroughly with clean water. If you want to use one of the commercially available wheel cleaners, make sure the label indicates that the cleaner is safe for coated wheels. Never use steel wool or any cleaner that contains an abrasive, or use strong detergents that contain high alkaline or caustic agents, as this will damage your wheels.


Store the tires at the proper inflation pressure if they are mounted on wheels. Keep them in a cool dry place, laid on their sides. If the tires are stored in the garage or basement, do not let them stand on a concrete floor; set them on strips of wood.


When buying new tires, give some thought to the following points, especially is you are considering a switch to larger tires or a different profile series:

  1. All four tires must be of the same construction type. This rule cannot be violated. Radial, bias, and bias-belted tires must not be mixed.
  3. The wheels should be the correct width for the tire. Tire dealers have charts of tire and rim compatibility. A mismatch will cause poor handling and rapid tire wear. the tread width should match the rim width (inside bead to inside bead) within an inch. For radial tires, the rim width should be 80% or less of the tire (not tread) width.
  5. The height (mounted diameter) of the new tires can change speedometer accuracy, engine speed at a given road speed, mileage, acceleration, and ground clearance. Tire manufacturers furnish full measurement specifications.
  7. The spare tire should be usable, at least for short distance and low speed operation, with the new tires.
  9. There shouldn't be any body interference when loaded, on bumps, or in turns.


See Figure 7

  1. If equipped with a conventional wheel cover, remove the cover by inserting the end of the lug wrench and prying against the wheel cover flange.
  3. If equipped with optional anti-theft wire wheel covers, pry the center ornament cover from the wheel cover using the key wrench. Use the key wrench to remove the lock bolt, then pry the wheel cover from the wheel.

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Fig. Fig. 7: Anti-theft wire wheel cover used on late models

  1. Loosen, but do not remove the wheel lug nuts. If equipped with anti-theft lug nuts, insert the key into the slot of the lug nut, then position the lug wrench or socket on the key. Apply pressure on the key to keep it from slipping and loosen the lug nut.

The key must be held square to the anti-theft lug nut. If it is on an angle, the key and/or lug nut may be damaged. DO NOT use an impact gun on the anti-theft lug nut key.

  1. Raise the vehicle until the tire clears the ground. refer to the Jacking procedure in this section. If any service is to be performed, or if the wheel and tire assembly will be removed from the vehicle for any length of time, the vehicle must be supported with jackstands.
  3. Remove the wheel lug nuts. If equipped, remove the anti-theft wire wheel cover pedestal.
  5. Remove the wheel and tire assembly from the hub. If corrosion has formed around the center pilot hole so the wheel cannot be removed by hand, use a suitable wheel puller to remove the wheel.

Do not apply heat to a frozen wheel in an effort to remove it, as the heat will damage the wheel bearings.

To install:
  1. Clean all dirt and corrosion from the hub mounting surface and center pilot hole of the wheel. Apply a thin coat of disc brake caliper slide grease or equivalent, to the axle pilot flange to reduce corrosion.
  3. Install the wheel and tire assembly on the hub. Install the anti-theft wire wheel cover pedestal, if equipped.
  5. Install the lug nuts. Tighten them alternately and evenly to draw the wheel against the hub.
  7. Lower the vehicle.
  9. Tighten the wheel lug nuts to 85-105 ft. lbs. (115-142 Nm) using a star-shaped pattern.
  11. If equipped, install the wheel cover by hand, being careful to line up the tire valve stem with the hole in the wheel cover. Make sure the wheel cover is securely attached to the wheel.
  13. If equipped with anti-theft wire wheel covers, install the lockbolt and tighten with the key. Install the center ornament cover.