I have a 7,000# car carrier trailer and it has the zerk fittings that shoot thru the spindle. I've never had these before (always packed the bearings by hand) and don't know
1) If they're a reliable way to grease the bearings
2) How much grease do you put in them and how do you tell if/when the bearings have grease in them.
Can some of you guys with experience with this help me out. I haven't seen this discussed here.

From your description, it sounds like you may have what is referred to as "bearing buddies", of something like this. If you look closely on the side of the unit, you should be able to find a small hole that the grease will flow out of when the "bearing buddy" is full.

Everyone has their own opinion but I only use the "bearing buddies" on my light weight utility trailers. I still prefer backing the bearings on my 5er by hand. I can tell you that I have never had any problems with the "buddies" on my light trailers.

Thanks SPDRSG:

No these aren't bearing buddies....IIRC they have a spring towards the outside and put pressure on the grease that fills the entire bearing cavity. This one has a grease hole thru the center of the spindle and it comes out at the rear bearing....I've pulled one since my first post.....it appears that it may be just for the rear bearing which would save messing with the rear seal. What I've decided to do for now is hand pack the outside bearings & shoot the grease into the rears. I still don't know how to determine how much is enough though.

Check out this link. I think it will explain and show what you have.

http://www.al-kousa.com/prod_lubsys.htm

I keep pumping grease in the jert till it moves the spring out about 1/2 way. That way you know the grease is under pressure from the spring. Also, I have noticed allot of the new higher end 5th wheels have these on them now.

As you pump the spring will compress, meaning the plate on the inside will push out.

Jason

The main problem with the "brake buddy" is that it keeps pressure on the rear seal. Mainly used on boat trailers to keep water out. The system I think Tip of The Iceberg has is like the one shown in the link from my prior post. It is the same as on my 5th wheel. The instructions for it are to remove the rubber plug in the cap, use a grease gun and pump until you see new grease come out the hole where the plug was. Of course since it is recommended to remove drums and check brakes every year anyway, our RV dealer still recommends a manual repack along with new seals during the brake check and adjustment.

BillB3857:

Yep.....thats it.....Thanks. Somehow I think that hand packing is better though. You can pull 'em out, clean & inspect them, and know you have the grease where it counts. A whole cavity full of grease just doesn't flip my switches like a hand packed bearing does. Thanks guys for all your help.

BTW.....of the 4 bearings I pulled (outside ones) 3 were Chineese and one was Russian. Guess who's gonna be ordering 4 sets of Timkens?

You have what they call an EZ Lube axle. These are pretty good alot better than bearing buddies. It depends how much you use your trailer but normally 2 pumps in the spring and fall will be sufficent. You can go to www.dexteraxle.com to find out more.