Installing races by using a press allows the race to be seated with enough force to ensure a consistent bearing preload. Normal running can cause the bearing cup to seat after a few laps and require readjustment. It's always good to check but there's less chance of a change using the press method instead of hammering. Races can be installed using a soft steel drift and a hammer (Timken Engineering mentions brass can chip easily and leave debris in your bearing). Care should be taken not to allow too much variation in the angle of installation.
Installation of the first taper cone onto a pinion should be accomplished by pressing on the inner ring. A good tip for bearing installation onto a pinion is to freeze the pinion beforehand and heat the bearing in an oven or on a gas grill-off to the side, away from the open flame. For bearings such as Timken standard class bearings, temperatures should not exceed 300 F or the bearing heat treating could be affected. As always, consult the bearing manufacturer for exact temperature specifications. A hot bearing should fall right onto a frozen pinion. Take care to hold the bearing against the face of the pinion until the temperatures stabilize. The engineers at Timken have seen pinion bearings creep away a few thousandths after seemingly being seated properly. Holding the bearing against the surface should prevent that. It's a good idea to check with a thin feeler gauge or by holding the pinion up to a bright light to check for gaps.
Greased UpGrease is simply base oil with the addition of thickeners and additives. Bearings require clean grease of the proper type and in the proper amount. Most racecar hubs use tapered roller bearings which require NLGI-2 grease. The NLGI grade is a representation of the thickness with No. 2 being "moderately soft." A second NLGI designation to look for is "GC." The GC designation shows the grease has met the NLGI's highest standards for wheel bearing grease.
As a side note, currently the highest designation for chassis grease is LB. Premium multi-purpose grease is often designated NLGI-2 GC-LB. While brand and formulation are a hot topic, what really matters is using the proper grade of grease and keeping it clean. A bearing over-filled with dirty expensive grease will probably fail more quickly than one packed properly with clean fresh general purpose product.
How much grease should you use? Bearing manufacturers list the amount of grease (in cc's) required in their technical literature. For those who don't research this type of thing, here's a rule of thumb: Use as much grease as it takes to fill the voids in the bearing and leave just a bit on the outside. Extra grease invites dirt and causes overheating due to an effect called "churning." As far as grade goes, a quick survey of greases in my cabinet yielded NLGI-2 for the most part, along with a few tubs of ultra-sticky NLGI-3 wheel bearing grease. Would using the "3" be a deal breaker? Probably not, but it doesn't hurt to check before using. Preventing cross contamination is an important part of your bearing maintenance program. Using a dedicated tub of grease or grease gun can help maintain system cleanliness. We're all guilty of greasing the truck then pumping grease into a dirty hand to pack wheel bearings. If you do this, you may as well skip the seal since you'll have dirt already in there.
Tapered roller showing signs of wear on roller face. This one is a candidate for replaceme
How To Tighten Tapered BearingsNow, you should have clean wheel bearings ready to be installed into the hubs. After the hub is placed on the spindle, the wheel bearings should be tightened as follows:
Remove the inner seal if not removed already. This allows the drag adjustment to be felt more easily.
Install bearing cones into the cups in the hub without greasing the bearings (for new bearings) or use freshly cleaned bearings.