Wheel Bearing Grease

[HangOutdoors]

Ok, I just got into a discussion at work about the amount of grease you should put into a wheel bearing on boat trailer/trailer.

I have always filled them up till the spring is compressed, but before it really squirts out the sides of the zerk cap. The guy I was talking to here indicated he fills his up until grease is squirting out the sides of the cap pretty good.

What is the proper way?

 

[Bluewater272]

Pump until the spring is under load, but not maxed out. If its squirting out, you've put in too much.

 

[HangOutdoors]

Pump until the spring is under load, but not maxed out. If its squirting out, you've put in too much.

That is what I was taught and do many years ago, but this guy at the office was vehement about his way that I felt the need to double check

 

[UnfixedPyle]

If a little is good then a lot is better right?

 

[AZMark]

Ok, I just got into a discussion at work about the amount of grease you should put into a wheel bearing on boat trailer/trailer.

I have always filled them up till the spring is compressed, but before it really squirts out the sides of the zerk cap. The guy I was talking to here indicated he fills his up until grease is squirting out the sides of the cap pretty good.

What is the proper way?

He is wrong and I have heard that can lead to failure as the grease heats up and expands. If the spring is already maxed it can’t compensate for that expansion.

 

[FSH 210 Sport]

There are two types of bearing buddies as far as I know.. the one type used for land lubber rv’s has a small hole in the side that allows excess grease / pressure to have a place to vent to. The marine style does not have that small vent hole, and relies on some other way for the excess grease to vent when the piston reaches its maximum travel. Since buying a boat I have had both, the RV style makes a HUGE mess if you over fill the BB as when the grease gets hot and expands it flings out at high speed and looks like one of those water color art things they had when I was a kid… truly a mess to clean up.

As you can see from the link below, BB recommends putting enough grease in to move the piston 1/8th of an inch, which provides 3 PSI of pressure. The BB literature also mentions that if you can rock the piston side to side then there is enough grease in the BB.

How Genuine BB® Works | BearingBuddy

www.bearingbuddy.com

This takes several times of greasing and then driving to allow the grease to displace the air pockets inside the hub. I can say from experience that if there is too much grease put into the BB it just ends up glitching out under the bra and becomes a mess to clean up. And while there is a pressure relief in the BB, overfilling and compressing the spring too much will put excessive pressure on the rear wheel bearing seal.

My thinking on this is to keep topping up the BB and towing until the level stabilizes, or as in my case, when filled with too much grease the relief valve just let a ton of excessive grease into the top of the piston and under the bra making a mess to clean up. I then just make sure the piston will rock when everything is cold.


As a side note, my 2020 shorland’r drivers side front wheel bearing seal kept leaking grease. I replaced the seal and reinstalled, still leaked. It wasn’t until I replaced the wheel bearing seal and the wear sleeve on the hub that it stopped leaking.