1973 - 1978 GMC Motorhome Rear Wheel Bearings - Repack or Replace with Andrew

The factory service manual calls for repacking the rear wheel bearings every 24,000 miles. Despite this, my coach had 55,000 miles before I got it back on the road and the drums appeared to never had been taken off.

I apologize in advance for not making it clear in the video - you DO NOT need to hammer out the bearing cups/races if you are only repacking the bearings. The only thing you will need to do for a "repack job" is remove the wheel seal to gain access to the inner wheel bearing. The bearing cups are one-time use only, so if you hammered them out I strongly urge you to replace your complete bearing assembly with new.

It is paramount on this project to work clean and to use a brass or bronze drift when servicing the bearings. You need a material that is softer than the cast metal of the brake drum or damage will occur!

In hindsight, my bearings were not worn out and repacking them would have been fine. However, I installed new TIMKEN bearings and have no regrets. Combined with the ultra high-tech Redline Oils CV2 synthetic grease, I do not have any plans to pack or replace them until atleast 100,000 miles. The new grease is much better than what was available in the 1970's.

If you are only repacking your bearings, this is a fun job that costs under $50 to do completely right. You will just need the cleaning supplies, (4) new wheel seals and two tubs of grease. I recommend buying (6) seals... one extra in case you botch the job and one more extra as backup to keep in your coach emergency parts bin.

The wheel seal part number is 21771 and is very common, available in stock at most auto parts stores. There is discussion online about some seals "failing" a .25" measurement test but I had no problems. Do your own research on that.