Bearing Preload/Castle Nut Adjustment Question

[Steven@147]

Hello Fellow Grand Design Owners,

I'm currently in the process of replacing the severely greased brakes on our 2017 303 RLS which has < 3,000 miles on the trailer. I'm replacing the complete backing plate/brake assembly, hubs and upgrading to 16" wheels and Goodyear Endurance tires during the process.

Yesterday I replaced the brakes/hubs on the Left Front (Drivers) side and today I replaced the Left Rear (Drivers) side. When installing the new hub with new bearings/races I followed the procedure in the Lippert brake/axle manuals by torqueing the Castel Nut to 50 ft-lbs while rotating the wheel, backing off to remove the torque then hand tightening before installing the cotter key.

The Left Rear preload/castle nut adjustment went perfect, after following the procedure the cotter key hole was lined up perfectly with a slot in the nut after the hand tightening step. This provided just the right amount of runout for when the bearing expanding upon heating.

However, my issue is with the Left Front hub. Again I followed the procedure in the Lipper manual exactly. After hand tightening the Castel Nut the cotter key hole was not lined up with a slot in the nut. The Lippert procedure say to back the nut off just enough to line up the cotter pin hole. When I follow this procedure the runout seems excessive to me. Probably 1/16" or maybe just a bit more that that amount. End play can be felt when gripping the wheel on the edges and rocking it back and forth. You can hear a slight knock when rocking the wheel back and forth. This just seems too loose to me.

Thus the reason for my message. What would you do, should I

1) look for a washer shim to take up a bit of the space behind the Castle Nut with the nut pinned per the Lipper procedure or
2) tighten the Castle Nut just a bit past hand tight to enable me to line up the cotter pin hole with a slot in the nut that takes up the excessive runout.

FYI, when I removed the hub as installed by Lippert/Grand Design the Castle Nut was not loose on the axle spindle, I had to use Channel Locks to loosen it after removing the Cotter Pin. This makes me think the factory had the same issue with this axle spindle and implemented Option 2 above.

One other question pertaining to the Self-Adjusting Brakes. The Lipper Manual says to pre-adjust the brakes by expanding them against the hub until it is difficult to rotated the wheel, then rotate the starwheel in the opposite direction until the wheel turns freely with slight lining drag.

What is the purpose of this step, is to to center the brake linings within the hub and to minimize the number of adjustments the self-adjusters have to make to set the brake linings at optimum spacing? How much do you guys back off the starwheel after adjusting the linings against the inside of the hub.

Thanks in advance for your feedback!

Best regards,

Keith

Folks got you covered. What you are experiencing maybe just a difference in outer bearing washer thickness or just how the spindle was made.
On initially adjusting the brake shoes, their instructions is getting you to the right place in a round about way. It gets kind of cumbersome with two screwdrivers stuck in the hole. One to hold the latch out of the way and the other to back off the star wheel. A lot of us will initially adjust the brake shoe star wheel so the drum barely drags on the shoes when spun and then let the self adjusters do their thing.

you got it

[geotex1]

Others have steered you fine. What is important to understand is that the tolerances for unsophisticated trailer axles are larger than automotive applications. Could you shim it? Sure, but it's not easy to find the shim packs these days in parts stores so you have the variety of thicknesses to work with. One thing that is proper practice and failed to be written in the instructions is to rotate the drum while preloading. Helps on making sure the seating is squared. You are doing a great job DIYing!

[bobter3]

Thanks for the recommendation WhittleBurner, I did already try preloading the bearing assembly again to 50 ft-lbs, same issue. : (

Best regards,

Keith

The only piece of advise I can offer is to try a different castle nut or swap the nut from 1 axle to another. Sometimes where the threads start may be the reason the slots are off.

[gsitexas]

Folks got you covered. What you are experiencing maybe just a difference in outer bearing washer thickness or just how the spindle was made.
On initially adjusting the brake shoes, their instructions is getting you to the right place in a round about way. It gets kind of cumbersome with two screwdrivers stuck in the hole. One to hold the latch out of the way and the other to back off the star wheel. A lot of us will initially adjust the brake shoe star wheel so the drum barely drags on the shoes when spun and then let the self adjusters do their thing.

you got it

Thank you very much Steven@147. You are absolutely correct, trying to keep that adjuster latch out of the way when backing off the star wheel is not the easiest of task. I found the best way is to removed the covers from both adjuster holes and use one with a long screwdriver to hold the adjuster latch out of the way and the other to adjust the starwheel. Definitely a pain with the jack in the way!

I've initially adjusted the brakes just dragging on the drum that results in one wheel revolution when spun by hand, hopefully that's not too tight.

Best regards,

Keith

[gsitexas]

Others have steered you fine. What is important to understand is that the tolerances for unsophisticated trailer axles are larger than automotive applications. Could you shim it? Sure, but it's not easy to find the shim packs these days in parts stores so you have the variety of thicknesses to work with. One thing that is proper practice and failed to be written in the instructions is to rotate the drum while preloading. Helps on making sure the seating is squared. You are doing a great job DIYing!

Thank you geotex for the feedback and encouraging comment, much appreciated!

Best regards,

Keith

[huntindog]

Thank you geotex for the feedback and encouraging comment, much appreciated!

Best regards,

Keith

First I hate the term preload when it comes to bearing adjustment. A properly adjusted bearing HAS play!. It has to as when it heats up in use, it expands and then runs at zero clearance. If you have no clearance cold, it will be too tight hot. You can use a dial indicator to measure it or just follow the instructions.
That said, the fact that you said that bearing was tight from the factory raises a red flag.
It is possible that bearing/race set is either defective, or now damaged from being too tight. I would replace them.
A spun bearing on the road is not fun. Don't ask me how I know.

[gsitexas]

First I hate the term preload when it comes to bearing adjustment. A properly adjusted bearing HAS play!. It has to as when it heats up in use, it expands and then runs at zero clearance. If you have no clearance cold, it will be too tight hot. You can use a dial indicator to measure it or just follow the instructions.
That said, the fact that you said that bearing was tight from the factory raises a red flag.
It is possible that bearing/race set is either defective, or now damaged from being too tight. I would replace them.
A spun bearing on the road is not fun. Don't ask me how I know.

Thank you huntindog, I am replacing all brake assemblies, hubs and races/bearings. I am following the LCI written procedures exactly and in each cased the Castle Nut can be turned CW/CCW a very slight amount after installing the cotter pin. This is not how one of the hub/bearing assemblies was received from the factory. I checked that spindle closely and it has no damage. It could be due to the fact that I have put 1500-2000 miles on my 303 RLS since purchase and no trip was more than 75 miles each direction.

Best regards,

Keith

[gsitexas]

The only piece of advise I can offer is to try a different castle nut or swap the nut from 1 axle to another. Sometimes where the threads start may be the reason the slots are off.

Great idea bobter3, I'll see if I can purchase another castle nut as I'm only upgrading one hub assembly at a time.

Best regards,

Keith

[Johnnyd53]

If the wheel rocks enough to hear it as you said I would lean towards tightening it enough to get the cutter pin lined up. I think a little tight is better than too loose.

[Skifishnsurf]

Great idea bobter3, I'll see if I can purchase another castle nut as I'm only upgrading one hub assembly at a time.

Best regards,

Keith

Old school (My rig is too new to check bearings yet), I have a question: Is the castellated part in the nut itself (one piece) or is the nut a plain hex nut with a cap with castle tabs that fit over the nut? If the latter, there are six corners of the nut and the cap has many more castle positions, so after setting hand-tight, carefully try the castellated cap at different angle positions WITHOUT MOVING THE NUT to find a place where the axle cotter key holes line up. Good luck!