3,500 pound Dexter axle bearing pre-load?

[Carb_Cleaner]

I'm putting a new drum-brake system on a single-axle cargo trailer. It has a torsion suspension. I have the components ready to go and one of the old, non-brake assemblies removed. It occurred to me, I'm not certain about the torque for the pre-load on the bearing. Is it hand snug, hand snug and lightly back off or is there a torque spec?
I've heard about such, but this is my first hands-on experience with a trailer axle, bearings and axle nut. I know you don't get Medieval on the axle nut. It has the EZ-Lube bearing hub (with a zerk fitting), if that matters.

[noteven]

Deleted

[Learjet]

Wayne Dohnal wrote:

PaulJ2 wrote:
When you are all done grab the wheel on the top and bottom and try to rock it. You should "feel" a tiny bit of play but not see any. Perfect!

That's how I check it out. If there's no clink-clink when cold, it's too tight.

I agree, if no end play I go one click to have the smallest amount of end play. Of course, this is after I seat the bearing, then loosen the nut.

[Wayne_Dohnal]

PaulJ2 wrote:
When you are all done grab the wheel on the top and bottom and try to rock it. You should "feel" a tiny bit of play but not see any. Perfect!

That's how I check it out. If there's no clink-clink when cold, it's too tight.

[Huntindog]

Ron3rd wrote:

Lynnmor wrote:

Ron3rd wrote:

Ranger Smith wrote:
From what I remember when doing mine it was torque axle nuts to 50 ft. lbs and then back nut off to next cotter pin slot.It is a little more involved than "hand snug" as everyones idea of hand snug is different

That is correct, and I don't remember the exact torque required but it's in the Dexter instructions available for download. Basically, you torque the bearing to the spec and rotate the wheel to seat the bearing and then back off to the first cotter pin hole. My old trailer had Dexter 3500 lb axles and I did this several times, easy process.

BTW, most techs I've watched don't use a torque wrench; they tighten the nut down with a large Crescent wrench or Channel Locks, rotate the wheel and then back off the nut. Probably close enough but I prefer to go by the book as it's no harder.

Wrong again, this will result in a pre-load condition.

Wrong? Then Dexter's instructions are wrong. Take it up with the factory! The bearings are supposed to be preloaded btw.

The bearings are NOT supposed to be preloaded.
They are to have a small amount of play commonly called end play... There is often a spec for this, but it is so small as to need a dial indicator to measure it.Most people don't have one (I do) so the procedure of torquing them while rotating the wheel, then backing off the nut then hand tight, then backing that off was developed so most junior mechanics could get it close enough.
The reason for the endplay is to allow for expansion when the parts heat up. When they are at operating temp, the end play is close to zero.
If you have no endplay when it is cold, then it will be tight when hot, and the bearings WILL fail.

Go back and read the manual again. Slower this time, as you didn't comprehend it all the first time.

[PaulJ2]

Lynnmor wrote:
You are getting some bad information here. There is no pre-load on the bearings, should be a very small amount of clearance.

Agree. When you are all done grab the wheel on the top and bottom and try to rock it. You should "feel" a tiny bit of play but not see any. Perfect!

[MEXICOWANDERER]

smkettner wrote:
For the real pros you also bend and cut the cotter pin in a specific way every time as a signature. This is to verify if you were the last person to assemble the bearings if an issue arises.

Ratz! Busted!

Long leg had double bend. I liked the one where I Scotch Taped across the battery fillers on my toad, then had the oil changed and specifically asked the service dept to check THEIR Wal-Mart battery.

"All finished sir!"

Raised hood.

Looked.

Raised doubts.

Sure the tape was unmolested. So was the dusty lid on the brake master cylinder and so was a paper match stick jammed into the automatic transmission filler tube with the dipstick.

But they did check my air filter and recommended I change it. Oh yeah forgot about the wiper blades in July in California. They did check tire pressure and noted the left rear was 5 pounds low which agreed with my pre-service check.

Back in the old days, I used to wash bearings in clean solvent then air dry with high pressure air (no spinning allowed).

Then rinsed with tricloroethylene brake cleaner. Bearing packer packed. I guess they don't have the time to do it right these days.

[Lynnmor]

Ron3rd wrote:

Lynnmor wrote:

Ron3rd wrote:

Ranger Smith wrote:
From what I remember when doing mine it was torque axle nuts to 50 ft. lbs and then back nut off to next cotter pin slot.It is a little more involved than "hand snug" as everyones idea of hand snug is different

That is correct, and I don't remember the exact torque required but it's in the Dexter instructions available for download. Basically, you torque the bearing to the spec and rotate the wheel to seat the bearing and then back off to the first cotter pin hole. My old trailer had Dexter 3500 lb axles and I did this several times, easy process.

BTW, most techs I've watched don't use a torque wrench; they tighten the nut down with a large Crescent wrench or Channel Locks, rotate the wheel and then back off the nut. Probably close enough but I prefer to go by the book as it's no harder.

Wrong again, this will result in a pre-load condition.

Wrong? Then Dexter's instructions are wrong. Take it up with the factory! The bearings are supposed to be preloaded btw.

Nope! Just checked Dexter's instructions. There is no pre-load. You should not be giving incorrect information.

[Ron3rd]

Lynnmor wrote:

Ron3rd wrote:

Ranger Smith wrote:
From what I remember when doing mine it was torque axle nuts to 50 ft. lbs and then back nut off to next cotter pin slot.It is a little more involved than "hand snug" as everyones idea of hand snug is different

That is correct, and I don't remember the exact torque required but it's in the Dexter instructions available for download. Basically, you torque the bearing to the spec and rotate the wheel to seat the bearing and then back off to the first cotter pin hole. My old trailer had Dexter 3500 lb axles and I did this several times, easy process.

BTW, most techs I've watched don't use a torque wrench; they tighten the nut down with a large Crescent wrench or Channel Locks, rotate the wheel and then back off the nut. Probably close enough but I prefer to go by the book as it's no harder.

Wrong again, this will result in a pre-load condition.

Wrong? Then Dexter's instructions are wrong. Take it up with the factory! The bearings are supposed to be preloaded btw.

[Lynnmor]

Ron3rd wrote:

Ranger Smith wrote:
From what I remember when doing mine it was torque axle nuts to 50 ft. lbs and then back nut off to next cotter pin slot.It is a little more involved than "hand snug" as everyones idea of hand snug is different

That is correct, and I don't remember the exact torque required but it's in the Dexter instructions available for download. Basically, you torque the bearing to the spec and rotate the wheel to seat the bearing and then back off to the first cotter pin hole. My old trailer had Dexter 3500 lb axles and I did this several times, easy process.

BTW, most techs I've watched don't use a torque wrench; they tighten the nut down with a large Crescent wrench or Channel Locks, rotate the wheel and then back off the nut. Probably close enough but I prefer to go by the book as it's no harder.

Wrong again, this will result in a pre-load condition.

[time2roll]

For the real pros you also bend and cut the cotter pin in a specific way every time as a signature. This is to verify if you were the last person to assemble the bearings if an issue arises.

[MEXICOWANDERER]

Personally I use (and prefer) smkettner's, method, right down to the last detail contained in his response. But I am a fraidy cat. After 20 miles or so driving after a bearing adjustment, I check hub temperature with my hand.

[Ron3rd]

Ranger Smith wrote:
From what I remember when doing mine it was torque axle nuts to 50 ft. lbs and then back nut off to next cotter pin slot.It is a little more involved than "hand snug" as everyones idea of hand snug is different

That is correct, and I don't remember the exact torque required but it's in the Dexter instructions available for download. Basically, you torque the bearing to the spec and rotate the wheel to seat the bearing and then back off to the first cotter pin hole. My old trailer had Dexter 3500 lb axles and I did this several times, easy process.

BTW, most techs I've watched don't use a torque wrench; they tighten the nut down with a large Crescent wrench or Channel Locks, rotate the wheel and then back off the nut. Probably close enough but I prefer to go by the book as it's no harder.

[Carb_Cleaner]

Sweet. Thanks for all the replies. I knew it was something like set the bearings at X amount of torque, back off, hand tight, stand on your head if it's a full Moon on a Tuesday then back off a little. Putting the first brake assembly, new bearings packed with Mobile 1 grease (on Dexter's list of approved greases), onto the axle in about a minute.
This is what I've found on Dexter's site:
50 Ft/lbs while rotating the hub, back off, then finger tight. Back off to engage the cotter pin or, in my case, not a cotter pin but a "retainer" (it slips over the nut with a machined flat spot that the axle holds). It's not "pre-load", as mentioned above. It's actually "end play". Just a touch.
Directions here, page 56:
http://www.dexteraxle.com/i/u/6149609/f/600-8K_Service_Manual/Hubs_Drums_and_Bearings.pdf

[RAS43]

eHoefler wrote:
Tighten the nut to 15 FTPD rotate the hub while tightening. Back off the nut without disturbing the hub, tighten the nut finger tight, inert locking device, if not lined up, back off just enough to engage the lock.

A winner here!

[ScottG]

Either no or very little play is acceptable. Not really pre-load.