Hub nut concern(s)

[David.T]

Hi all, this is my first post! I just purchased my first boat - a 1965 Crosby Sea Sled! I bought it for a very nice price, but with a few things that needed attention. I started searching google and kept seeing this site come up with some great answers. Then I was told to come over here by a friend who is a member here. I started looking around more and man, this site is awesome.

Anyway, my first question is: I took the hubs off and stripped the bearings and races out and put new ones in. When I took the hubs off I realized there was not a nut holding the hub in besides a castle nut. From watching a few videos and reading a few threads about replacing and/or cleaning bearings, I never saw a hub that didn't have a nut AND a castle nut. Do some trailers not have both?

My second question is, if both nut and castle nut are NOT needed on this trailer, then how tight should I make the castle nut? Seems to me like it can't be too safe with one nut that's not screwed on too tight... Right now, the castle nut is fairly tight, but loose enough to take off by hand (without a wrench), and loose enough where the tire spins freely. If I tighten it down any more than it is I noticed that the wheel doesn't spin as freely, it spins, but definitely slower and with more resistance.

Your help will be greatly appreciated.

Here's a few pics of the boat!

 

[kenmyfam]

Re: Hub nut concern(s)

Nice boat you have there. Plenty of grease and a little play will keep them running fine for many years. Sounds like you have them just right from your description. Castle nut should have a split pin going through it to stop it backing off.
Welcome to iboats.

 

[robert graham]

Re: Hub nut concern(s)

Spin the hub slowly by hand while tightening the castle nut with your fingers until you feel resistance(tightening on the bearings), then back off just a bit. The castle nut requires a cotter pin or similar retainer to prevent it from loosening. It's just that simple! Good Luck!

 

[Frank Acampora]

Re: Hub nut concern(s)

Well, it depends upon your definition of a castle nut. A true castle nut is a full sized nut with slits in all six sides so a cotter pin can be slipped in to keep it from spinning off. (it is called a castle nut becaust the slits make the nut resemble the top of castle towers--I think they are called crennelations)

HOWEVER: some trailers do have a regular nut CAPPED with a stamped steel castle which also keeps the nut from spinning off. If your trailer only has the stamped steel caps, then that is not enough. You should buy regular nuts for the spindles. There should also be a heavy washer under the nut.

As far as tightening the bearings, there are more opinions than you can shake a stick at.

Personally, I believe the bearings should have a slight pre-load for proper running. The weight of the trailer and boat will tend to spread the tapered bearings apart. SO: I tighten down the nut snugly (with a wrench) while spinning the wheel to seat the bearing rollers into the races. Then I loosen and re-tighten the nut finger tight. This gives a slight pre-load to prevent movement from weight and lateral loads, and also ensures that all rollers are in full contact with the races. Yes, there will be a slight drag on the wheel when turned by hand,but not enough to affect mileage or to overheat the bearings. It is normal for the hubs to be warm to the touch after towing a distance..

 

[Wind dog]

Re: Hub nut concern(s)

Well, it depends upon your definition of a castle nut. A true castle nut is a full sized nut with slits in all six sides so a cotter pin can be slipped in to keep it from spinning off. (it is called a castle nut becaust the slits make the nut resemble the top of castle towers--I think they are called crennelations)

HOWEVER: some trailers do have a regular nut CAPPED with a stamped steel castle which also keeps the nut from spinning off. If your trailer only has the stamped steel caps, then that is not enough. You should buy regular nuts for the spindles. There should also be a heavy washer under the nut.

As far as tightening the bearings, there are more opinions than you can shake a stick at.

Personally, I believe the bearings should have a slight pre-load for proper running. The weight of the trailer and boat will tend to spread the tapered bearings apart. SO: I tighten down the nut snugly (with a wrench) to seat the bearing rollers into the races. Then I loosen and tighten the nut finger tight. This gives a slight pre-load to prevent movement from weight and lateral loads, and also ensures that all rollers are in full contact with the races. Yes, there will be a slight drag on the wheel when turned by hand,but not enough to affect mileage or to overheat the bearings. It is normal for the hubs to be warm to the touch after towing a distance..

What he said +1

 

[scoyt]

Re: Hub nut concern(s)

What he said +2

 

[bigdee]

Re: Hub nut concern(s)

Personally, I believe the bearings should have a slight pre-load for proper running. The weight of the trailer and boat will tend to spread the tapered bearings apart. SO: I tighten down the nut snugly (with a wrench) while spinning the wheel to seat the bearing rollers into the races. Then I loosen and re-tighten the nut finger tight. This gives a slight pre-load to prevent movement from weight and lateral loads, and also ensures that all rollers are in full contact with the races. Yes, there will be a slight drag on the wheel when turned by hand,but not enough to affect mileage or to overheat the bearings. It is normal for the hubs to be warm to the touch after towing a distance..

Having worked in Engineering on many bearing applications I tend to disagree. Heat will create more pre-load so that has to be factored in. Tighten nut snug to seat the bearings then back off until you feel about 1/32 to 1/16 when you grasp the top & bottom of the tire. If cotter pin does not align with a hole always favor on the loose side....loose is always better. A tapered bearing lubed with grease can turn into a tapered LOCK.

 

[kenmyfam]

Re: Hub nut concern(s)

Having worked in Engineering on many bearing applications I tend to disagree. Heat will create more pre-load so that has to be factored in. Tighten nut snug to seat the bearings then back off until you feel about 1/32 to 1/16 when you grasp the top & bottom of the tire. If cotter pin does not align with a hole always favor on the loose side....loose is always better. A tapered bearing lubed with grease can turn into a tapered LOCK.

Completely agree. Touch of play. Using the same method in industrial applications for years with tapered bearings. Bearing with a little resistance needs maintenance sooner than one with a hint of play. Both methods will work though, just for how long ??
Just my humble opinions though and not wishing to start a "thread argument" about the subject.

 

[David.T]

Re: Hub nut concern(s)

Thanks so much guys. Great answers and exactly why I joined this forum. From everyone's answer, seems like I did good. I took it for a ride today and after about a 15 minute drive I pulled into a gas station and touched the hubs. Both hubs were barely warm, so I'm thinking it's all good! Thanks again guys

 

[Fed]

Re: Hub nut concern(s)

20 ft/lbs while spinning the hub to make sure everything is seated properly then back off & tighten to 1 ft/lb.
Does anyone here believe 1 ft/lb pre-load is detrimental to a set of bearings carrying 1000 lbs?

 

[tinkerguy70]

Re: Hub nut concern(s)

20 ft/lbs while spinning the hub to make sure everything is seated properly then back off & tighten to 1 ft/lb.
Does anyone here believe 1 ft/lb pre-load is detrimental to a set of bearings carrying 1000 lbs?

This sounds about right to me.
It's been working for me for about 25 years or so.

 

[smokeonthewater]

Re: Hub nut concern(s)

20 ft/lbs (or as much as 50 on bigger trailers) while spinning the hub to make sure everything is seated properly then back off & tighten to snug, then back off 1/8 to 1/4 turn depending on thread pitch of spindle and lock with cotter pin... backing off more if needed to align holes for pin

with the slight changes above that's how I do it and how most service manuals instruct setting up tapered wheel bearings in automotive applications

 

[Fed]

Re: Hub nut concern(s)

That's strange, my Ford service manual says to pre load @ 1 ft/lb?
Mine must be special

 

[smokeonthewater]

Re: Hub nut concern(s)

That's strange, my Ford service manual says to pre load @ 1 ft/lb?
Mine must be special

eh other than my dually I've never had a ford lol... I'm thinking 73-87 full size chevy

either way should work ok

 

[UncleWillie]

Re: Hub nut concern(s)

...service manual says to pre load @ 1 ft/lb...

1 ft/lb is a mighty strange number!

I understand that you really mean 1 lb-ft.
Even that is strange, as it would typically be spec'd as 12 lb-in.
lb-ft below 15 are usually stated in the lb-in units.

Torque wrenches in the lb-in range are hard to come by with 1/4" drive sockets in the 1.5" range as they are typically used with bolts under the 1/2 inch size range.
Even then they seldom measure below 20 lb-in.

To be practical, you would need an oz-in wrench and torque to 192 oz-inches.
This is almost a jewelers tool to torque a trailer axle nut! :faint2:

Spec'ing an axle nut to 1 lb-ft is a lot easier to say than actually trying to doing it with any degree of accuracy.

I vote for finger-tight and back off to the previous hole!

 

[Fed]

Re: Hub nut concern(s)

Can't get nothing past you Willie.

My manual actually says 1.5 Nm but I did a rough conversion so people here would understand.
Pulling about 1 Lb on a bar about a Foot long works for me.

On another point my GM book says to tighten to 13 Nm then back off 1 to 1.5 slots.
I guess this would be vehicle dependent but these sizes are for common trailer bearings down here.

Way different to Smokes' book.

tighten to snug, then back off 1/8 to 1/4 turn depending on thread pitch of spindle and lock with cotter pin... backing off more if needed to align holes for pin

I think the point is that there should be pre-load rather than free-play.

 

[Frank Acampora]

Re: Hub nut concern(s)

Well, I wasn't going to get drawn into this but I have time on my hands and I am bored.

Let's think about this: All roller and ball bearings are designed to resist forces. Ball bearings are NOT designed to resist appreciable lateral forces while rollers are designed to resist "Vertical" forces. Tapered roller bearings are designed to resist appreciable lateral forces as evidenced by the fact that they are used almost exclusively in lower units to resist propeller thrust forces. (What kind of pre-load is that?)

Now back to our trailer application. Tapered roller bearings must resist both lateral and vertical loads in addition to impact loads applied by the wheel as it travels.

What happens when we allow clearance instead of pre-load? several things. 1. The line contact of each roller is reduced. That is: The full length of the roller is not in contact with the race. 2. the number of rollers in contact with the race is reduced. 3. The wheel can move in all directions instead of tracking straight forward. Impact loads will increase and may "Brinnell" the bearing. (Brinnel number is a measure of how much a piece of metal will be dented by a hardened ball pressed into it. In this case, it refers to the actual damage inflicted on a bearing race.) 4. It is possible for the rollers to skid instead of roll.

All these factors reduce the load bearing capacity and service life of the bearing.

To illustrate concept 2: In a tapered roller bearing, the inner diameter is smaller than the outer. Thus, you have in essence two concentric circles , one slightly smaller than the other. If these circles are inside each other and one is moved to touch the other, it will touch at a tangent--one point. Thus, in a tapered roller bearing set loose, under load only one roller will bear on the race, taking all the load.

Grease is at its simplest oil retained in a "soap" base. It is used to keep the oil where it is needed. In a bearing application, oil will weep out of the "soap" base and lubricate the bearing. You can see this in your mechanical grease gun where if left to sit for long periods, the oil will weep out to the outside of the gun through the pull rod hole.

Failure of a tapered roller bearing will result if the grease base hardens and/or no oil is available. The bearing will then overheat and either grind itself to death or weld itself together.

So, in short: For tapered roller bearings in wheeled applications the correct procedure is to pre-load slightly and be certain that fresh grease is available to it.

 

[bigdee]

Re: Hub nut concern(s)

Well, I wasn't going to get drawn into this but I have time on my hands and I am bored.

Let's think about this: All roller and ball bearings are designed to resist forces. Ball bearings are NOT designed to resist appreciable lateral forces while rollers are designed to resist "Vertical" forces. Tapered roller bearings are designed to resist appreciable lateral forces as evidenced by the fact that they are used almost exclusively in lower units to resist propeller thrust forces. (What kind of pre-load is that?)

Now back to our trailer application. Tapered roller bearings must resist both lateral and vertical loads in addition to impact loads applied by the wheel as it travels.

What happens when we allow clearance instead of pre-load? several things. 1. The line contact of each roller is reduced. That is: The full length of the roller is not in contact with the race. 2. the number of rollers in contact with the race is reduced. 3. The wheel can move in all directions instead of tracking straight forward. Impact loads will increase and may "Brinnell" the bearing. (Brinnel number is a measure of how much a piece of metal will be dented by a hardened ball pressed into it. In this case, it refers to the actual damage inflicted on a bearing race.) 4. It is possible for the rollers to skid instead of roll.

All these factors reduce the load bearing capacity and service life of the bearing.

To illustrate concept 2: In a tapered roller bearing, the inner diameter is smaller than the outer. Thus, you have in essence two concentric circles , one slightly smaller than the other. If these circles are inside each other and one is moved to touch the other, it will touch at a tangent--one point. Thus, in a tapered roller bearing set loose, under load only one roller will bear on the race, taking all the load.

Grease is at its simplest oil retained in a "soap" base. It is used to keep the oil where it is needed. In a bearing application, oil will weep out of the "soap" base and lubricate the bearing. You can see this in your mechanical grease gun where if left to sit for long periods, the oil will weep out to the outside of the gun through the pull rod hole.

Failure of a tapered roller bearing will result if the grease base hardens and/or no oil is available. The bearing will then overheat and either grind itself to death or weld itself together.

So, in short: For tapered roller bearings in wheeled applications the correct procedure is to pre-load slightly and be certain that fresh grease is available to it.

I have to disagree Frank for two reasons. First; you have to factor in the heat that is created by the tires and brakes will expand spindle and add preload. Second; TIMKEN specifically states that you need .004-.007 end play to PREVENT bearing lock-up and wheel separation!

 

[Frank Acampora]

Re: Hub nut concern(s)

Heat is not a factor since everything --spindle, hub, bearings-- expands approximately the same. Thus, clearances or interference will remain the same.

I can not disagree with Timken but I will continue to set my trailer bearings as I always have: Slight pre-load.

Anecdote about Timken stated clearance: Old Chrysler two piece lower units used a tapered roller both on the front gear and reverse. Shaft end play tolerance was--you guessed it--.004-.006.

Now when I say slight pre-load, I mean just that. Excessive pre-load WILL cause bearing problems. Again, in the Chrysler two piece lower unit: I bought a 105 and it drove me crazy. It would run great then suddenly harden to a stop. It would always start right up again and repeat the process. I never could figure what was going on. One day I had reason to open the lower unit gearcase. A-HA! The rear bearing outer race was not seated on the shims by about .030, thus pre-loading the bearings by that amount. I think we all can agree that that is too much!

I postulated that he lower would heat and jam, then because it was in cold water would immediately cool and free again. After I seated the outer race properly the problem never reoccurred.. Here, heat was a factor since the gearcase was aluminum and in direct contact with the water while the shaft and bearings were steel and not in contact with water--thus, a differential in expansion.

Point? All things in moderation.

 

[smokeonthewater]

Re: Hub nut concern(s)

heat IS a factor with wheel bearings also... parts do not all expand at the same rate or for that matter even distribute heat evenly