Steering goes heavy and will not self-centre

One owner described the mechanism to the federal regulator clearly enough to be worth recording: road grime and salt pit the shaft where it enters the steering gear, the rough shaft tears the seal, the lubrication leaves, and the truck becomes hard to steer and will not return to straight on its own without being helped round. That is a single report, which is why this entry carries the weakest confidence tier on the site — read it as one plausible explanation among several, not as an established pattern. The reason it earns a page anyway is that the symptom is common on trucks of this age and the four causes below are cheap to tell apart in the order given, starting with the fluid. Steering is safety-critical. Heavy steering is not the same as no steering, so the truck is drivable, but a wheel that does not come back to centre is a wheel you are fighting: get it looked at by a qualified mechanic rather than living with it.

Gen 11990–1991USWorks worseAnecdotalSafety-critical

Drive gently — repair soonManeje con cuidado — repare pronto

Safety notice — Steering.

This affects a safety-critical system. Reference material only: for safety-critical work, consult a qualified mechanic.

Esto afecta un sistema crítico para la seguridad. Material de referencia únicamente: en trabajos críticos para la seguridad, consulte a un mecánico calificado.

Anecdotal. This entry is not backed by factory documentation — treat its values and steps as a starting point, not as if they came from the factory manual.

Anecdótico. Esta entrada no se apoya en documentación de fábrica — tome los valores y los pasos como punto de partida, no como si vinieran del manual de fábrica.

Symptoms

The wheel stays where you left it after a corner instead of unwinding by itself
The steering is noticeably heavier turning one way than the other
A wet film or drips at the point where the shaft enters the steering box
A dry, gritty or notchy feel through the rim as you turn

Likely causes

The steering box input shaft is pitted by grime and salt, so it saws through its own seal
The input shaft seal is torn and the box is losing pressure and lubrication
The power steering fluid is low, aerated or long past its life
A joint in the intermediate steering shaft has seized and is fighting the return

Diagnostic steps

Check the power steering fluid level and look at its colour and smell — dark, foamy or burnt tells you somethingPoints toThe power steering fluid is low, aerated or long past its life
Clean and inspect the shaft where it enters the steering box for pitting, rust scale and a wet sealPoints toThe steering box input shaft is pitted by grime and salt, so it saws through its own seal · The input shaft seal is torn and the box is losing pressure and lubrication
With the front wheels off the ground on a jack and axle stands, turn lock to lock by hand and feel where the effort changesPoints toA joint in the intermediate steering shaft has seized and is fighting the returnRules outThe power steering fluid is low, aerated or long past its life
Disconnect the intermediate shaft and turn the column and the box separately, so you can tell which side of the joint is stiffPoints toA joint in the intermediate steering shaft has seized and is fighting the returnRules outThe steering box input shaft is pitted by grime and salt, so it saws through its own seal

Fix paths

Flush and refill the power steering system

$Difficulty 2/5

The cheapest thing to eliminate, and worth doing first even if it turns out not to be the answer. Old, aerated fluid makes every other symptom on this page worse.

Rebuild or replace the steering box

$$–$$$Difficulty 4/5

A pitted input shaft will destroy a new seal, so a seal on its own is not a repair. This is the job where a rebuilt unit usually beats a kit.

Replace the intermediate steering shaft

$$Difficulty 3/5

A seized joint in the shaft between the column and the box gives exactly the no-self-centring symptom with a perfectly healthy steering box. Prove which one it is before spending money on the box.