Dealer Bulletin 68-T-18 – Never Pre-Load Wheel Bearings

Bulletin 68-T-18 — Pontiac Motor Division Dealer Technical Bulletin, Section 3, dated August 16, 1968. Attention: Service Manager.

Subject: Never Pre-Load Front Wheel Bearings.

Short answer: Front wheel taper roller bearings must never be pre-loaded. This bulletin establishes new adjustment and lubrication procedures that supersede all previous procedures. Bearing “burn-up” caused by over-tightening is not covered by warranty if prior service is documented.

Important: Front wheel taper roller bearings must never be pre-loaded. These procedures supersede all previous procedures.

Adjustment

The following numbered steps correspond to the photographic illustrations in the original bulletin:

  1. Hand-spin the wheel.
  2. Back off the nut until just snug — just loose (1/4 to 1/2 turn).
  3. First seat the bearings; this overcomes any burrs on the threads.
  4. Hand-snug up the nut.
  5. Loosen the nut until a hole in the spindle lines up with a slot in the nut, then insert cotter pin. Note: Under no circumstances is the bearing to be even finger-tight.
  6. When the bearing is properly adjusted there will be from 0.001″ to 0.005″ end play (looseness).
Note to Novice Mechanics: It would be desirable to use a dial indicator (1968 Service Manual, page 3-2, Fig. 3-2) to check for proper end-play as described in step 6, until you become familiar with the amount of movement associated with correct end-play.

Lubrication (New Recommendation)

Every 12,000 miles the bearings should be inspected and lubricated with a high melting point grease. The bearings should be cleaned and checked for signs of galling and damage from dirt.

Note: Before reassembly, put a slight amount of grease on the inside diameter of the bearing cone to ensure that the cone will creep, which will help prevent galling.

Caution: Protect the bearings during clean-up operations on the brake backing plate and drum to keep out dirt.

The seal should be inspected and replaced if there are signs of dirt or water entering the area.

Warranty

Replacement of wheel bearings due to “burn-up” is a direct result of over-tightening the bearings. This repair is not covered by warranty if a review of the car’s service history reveals that the hub and drum assembly had previously been serviced (removed for any reason, either by your own dealership or an outside service).
This is a transcription of the original dealer bulletin for easier reading and search. The complete original scan is shown below, including the figures.

Reference:

  • 1968 Pontiac Service Manual, Page 3-2, Figure 3-2

Content last modified: June 13, 2026 at 10:06 am

Categories: Dealer Technical Bulletins, Dealer Technical Bulletins - Section 03 - Front Suspension, Suspension and Steering - All, Suspension and Steering - Suspension

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