Front Hubs Filled with Grease

[RKF]

I run into this occasionally and it always makes me scratch my head. Yesterday, when I removed the front wheel hubs to service the bearings, I observed that the previous owner had packed the middle of the hub with grease. This doesn't seem correct to me, since that part of the hub doesn't make contact with the spindle or any other part. Is there a reason for packing the center of the hub with grease or is this unnecessary?

[Wagon Master]

Unnecessary to pack it clear full. It does however question the logic of a "bearing buddy". I've seen those used to the point of pushing the rear seals out on trailers!

[cnicol]

Only the tiniest amount of grease is actually "in play" lubricating a bearing, Packing a bearing is mostly about reserve. Filling the entire hub simply isn't necessary and with heat, grease in a completely-filled will expand and push past the grease seals; potentially fouling brake shoes.

"Bearing Buddies", found on boat trailers are a different story. Boat trailer hubs are frequently submerged in water and a grease-filled hub leaves no place for water. Bearing Buddies include a piston and spring system that keeps the hub filled and under pressure while also providing a place for grease to temporarily go when hubs warm-up in highway operation.

[66vairguy]

Great comments. They do make "water resistant" grease for boat trailer wheel bearings.

This also applies to the LM rear axle hubs!! ONLY coat the inside of the hub with a thin coat of grease to resist corrosion and pack the bearings. Decades ago the Corvette folks (same axle design) put Zerk on the hubs and jammed them full of grease trying to keep the bearing going. It was a FAILURE. Didn't help the bearing life and when the hubs heated up the grease squeezed out past the seals and lubricated the BRAKES - not good.

[joelsplace]

I don't fill them but put quite a bit in there. When it is 120 degrees outside with hard brake use and 80mph tends to make the grease flow so I want enough to keep grease in the bearings when it does.

[vairmech]

You have to realize why this started way back in the first cars, even horse drawn wagons. It has to do with dirt and water and keeping it out. Going back to the early cars the wheel seals were nothing but felt and water could intrude into the bearing area, so to keep the water out you filled the area with grease. If you look on the older cars and even some of the early Corvairs you will see a raised area around the hub on the backing plate. What is this for? It was to catch the extra grease that came out so it didn't get on the brake shoes. Also if you go back in the old shop manuals they recommended cleaning and packing the bearings every 5-15,000 miles.

As far as how much grease does a bearing need? It only needs what little grease is around it in the roller cage. Contrary to what people think grease does not circulate! Anything extra in the center of the hub is just wasted, the way the hub is built with everything tapered away from the bearing, the grease is not going to magically go to the bearing. For many years now I have just packed the roller bearings with just a little more on the races and set the bearings in and adjust. I do this on front and late rears and I have had no failures in ???? years, not even on the race car with high speeds and lots of brake heat.

[66vairguy]

Good advice Ken. I'll add the LM rear bearing issue was mostly how they were set up. The shop manual range is too great!!! I learned from Steve Goodman, and the Corvette folks, that setting the tappered roller bearing play to 0.002 - 0.003" gives the longest bearing life. At the GM max of 0.006" you can expect the bearing to fail within 20,000 miles based on comments I've read. While a good axle design - setting them up with shims is tedious for best tolerance. I suspect the factory specs. were fairly wide, I assume to speed up getting them done and on the car. I find many of the center spacer tubes are not cut square so the compress some when you tighten down the yoke. I'm amazed how crude these spacer tubes were cut.

[RexJohnson]

A bearing that is loose will live for a very long time. Maybe not quite as long as perfectly set up but still for a long time. A bearing that is to tight will not live long.

[jimbrandberg]

The LM rear shim selection I have is not all that it should be.

[66vairguy]

The LM rear shim selection I have is not all that it should be.

Jim - if you mean you don't have enough of the smallest shims, yes that is an issue, but easy to solve. When I can't get down to 0.002 to 0.003", then I find a shim that makes it too tight, THEN carefully work the BIG collar on sand paper on a flat surface and check with precision caliper to keep it square. Yes setting up rear axles correctly is a tedious and time consuming job. That said done correctly you won't be doing it again (at least in my lifetime )

BTW you must check tolerance with the yoke nut torqued down (I use a fixture, not the yoke). Sometimes I see little change (less than 0.0005") other times it compresses up to 0.002". I have a slip axle setup like davemotohead uses.

[Lane66Monza]

While I had the tires/wheels off my enclosed trailer for replacement this weekend, I elected to get new bearings, races and seals for the axles. I never did any work done on the hubs in 23 years., but I figured it was time since a heavy load and long trip was in store for the trailer. I found the left bearings some how had been contanminted by water.. Between O'Reilly and Advance, I was able to get the 4 bearings, 4 races and 2 seals. Hubs were cleaned and new bearings packed with red grease in my bearing packer . Hubs had red grease wiped all over the inside metal, following race installations. Hub rear bearing and seal was installed. Front bearing was packed. Seal rubber portion was lubricated with grease.

Axle stub was wiped down with red grease and hub with front bearing installed. Washer and nut was installed tight, then backed off until free turning, then one more castle nut slot. But that was still too tight, so nut was backed off another castle nut slot and cotter pin installed. Red grease wiped over cotter pin and inside of dust cap. Cap installed. This was repeated on the other side.

For those interested, I use the Lisle Handy Packer Bearing Packer, Model #34550. I bought it over 25 years ago. It saves time when packing any wheel bearing. You just have to keep using the same brand name red grease. Mixing brand names of greases is not recommended, unless they are made to a MIL or SAE spec..Even then I avoid mixing grease, if I can.

I had Discount Tire install 4 Wrangler Steadfast 285R45/15 tires on my 2018 Silverado yesterday. While truck was there, I had them remove the 9 year old, 1k mile tires off the trailer wheels and install & balance the new ST205R75/15 trailer tire. So the trailer is ready for that area. Still working the new electric tongue jack and LED lights I am putting on. At my request, they drill 2 large holes in the tires to prevent any further use of the removed tires. They agreed, since there disposal relies on other people to remove and destroy. Tires looked like new, but trailer sat in the sun most of the last 9 years. They had minorold rubber cracking on them.

[Dennis66]

I have also noticed that with trailer bearings. Pull the cap for an inspection and find moisture inside the cap. Pull and clean the bearings and find very small pitting where the rollers contacted the shell. Condensation (Florida humidity). This would be one reason to pack the cavity (can't say that should apply to a car wheel where brakes are involved). Trailer is also about to see some long distance hauling so it will be getting another inspection.

[joelsplace]

I'll keep doing mine like I have. Grease flows with time and heat and the oil also tends to leak out of the base. It happens in new tubes of grease on the shelf. Some worse than others. After being exposed to summer heat I have a new case of Mobil1 that is soaked in oil. In the last couple of years I've had at least 3 other brands do the same thing. When I fill the hubs the correct amount the oil can't flow out of the bearing.

[Dennis66]

On CARS (and light trucks) I like to hand pack the bearings, then I smear a generous coat of the same grease all around the inside of the race and assemble everything. Of course, I could go into my oil and sparkplug preferences too

[Lane66Monza]

I may use the Lisle bearing packer. But when the bearing is pulled out, it is inspected for 100% grease application. Then, it is coated with grease on outer ring ang race is covered before mounting to each other. I don't risk a dry portion of the bearing or race.

[jimbrandberg]

In the front I put grease on the spindle and cavities in the hub and even in the hub cap because it feels good.
I've got more than a few little tubs of grease from my buddies estate so I don't feel bad using more than is needed. I don't think I've ever had too much so that it oozes out.