Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Chris m lang on March 07, 2018, 10:34:30 am
Title: Wheel seal--Stemco
Post by: Chris m lang on March 07, 2018, 10:34:30 am
Does anyone have any experience with changing wheel seal in front axle? I have changed mine and according to Stemco Video after you go through all their torque procedures you want a .01 to .05 end play. I put original bearings back on since there was no discernible wear. I guess my question, is this enough end play? I sure don't want the bearings to overheat. The actual end play I have is .04. Again, Thanks in advance Chris
Title: Re: Wheel seal--Stemco
Post by: Andy 2 on March 07, 2018, 02:27:23 pm
Chris I am sure your fine, when I did mine last summer was in those specs . The book tells you the procedure.
Title: Re: Wheel seal--Stemco
Post by: Caflashbob on March 07, 2018, 02:45:36 pm
I hope you meant .004
My personal experience is that the "legally verifiable" (according to the video) measurable endplay results in a slight steering dead spot in the wheel.
If slightly preloaded, which is a non measureable amount, they dead spot goes away.
Obviously everything else suspension wise must be ok to notice this IMO.
Again my opinion is that the Michelin's latest tires designed-in self steering sipes may have been added to help the vechile stay straighter with non preloaded wheel bearings.
My x foretravel line mechanic preloaded hundreds of unihomes and unicoaches to reduce customer complaints about wander without issue.
I measured hub temps with a slight preload and with .001-.003 end play. No difference in temps over 5k mile drive and measurements. I left the hub cap off for more accurate measurements.
And synthetic oil
The difference is subtle and unless you drove the exact coach set up both ways you probably would be happy with the DOT end play.
The slight preload and the Michelin's(at least on our 40') is magical. Slight pressure on the steering wheel alter the path. Slightly Less truck wind sway.
As preload is not quantifiable the DOT requirements mentioned twice by the gentleman doing the video were setup by the lawyers to be proveable in a court.
I am not telling anyone or suggesting anyone here do anything not per the DOT regulations for commercial truckers.
Just my personal experience and testing.
In a heartbeat if I were doing my own I would at least be down at least to the bottom of the legal .001 limit.
Title: Re: Wheel seal--Stemco
Post by: stump on March 07, 2018, 02:46:50 pm
Your fine .? If you turn the nut in 1 flat what do you read? Does cotter key hole line up then? You might get it between .001 and 004. But you are fine at .004
Title: Re: Wheel seal--Stemco
Post by: krush on November 15, 2018, 10:12:16 am
Old topic, but we also discussed this here: Replacing Wheel Seals need some info (http://www.foreforums.com/index.php?topic=23703.0)
To add new info, I'm doing both front wheel seals and not changing bearings. I will run a tiny bit of preload (no end play). Here's some anecdotal info:
Quote
When I worked at Conway Freight, they wanted 50 ft/lbs of preload on drives, and 25 ft/lbs. on steers. Which went against the 0.001-0.005" end play that bearing manufacturers want. I've seen then done with dial indicator to have end play, I've seen them done a certain torque, the back up 1 flat. I've seen at least 1/2 dozen different ways from good mechanics and have not seen any way more or less prone to failures.
My conclusion is, it's not as critical as most people make it out to be. I even took a Con-Met course on the preset hubs and the guy said that spec is 0.001-0.005", but zero is OK if it doesn't drag. Well then why do you say 0.001" minimum of zero is OK?
I go for 0.001-0.002", I have seen ABS set faults for erratic signal at 0.005" on trailers, so loose is bad. I never seen issues at Conway running 50 ft/lbs of preload, which I thought would build excess heat, but I never seen an issue from it. So if how you've always done it is working for you, it's not wrong.
and right from SKF: Selecting preload (http://www.skf.com/us/products/bearings-units-housings/principles/bearing-selection-process/bearing-execution/internal-clearance-preload/selecting-preload/index.html) with a PDF with even more enginerd info: http://www.skf.com/binary/12-299896/Bearing%20preload_tcm_12-299896.pdf
Title: Re: Wheel seal--Stemco
Post by: krush on November 15, 2018, 10:34:37 am
I'm upgrading to the Pro-Torque nuts from Stemco, but they have new fancier stuff now called teh Zip-Torq. Looks too complex for me, lol
https://www.youtube.com/watch?v=6mpNyRv5ABQ
Title: Re: Wheel seal--Stemco
Post by: craneman on November 15, 2018, 10:41:54 am
This came up before and because as a heavy equipment mechanic we always preloaded Timken bearings, I called Timken and asked a tech there. He said that Timken and other tapered bearings work best with a preload, but said the manufactures of the equipment get the last word. Like Bob said probably a liability issue so do what you feel best. In my experience as heavy equipment mechanic, many specs. called for zero clearance then remove .003 of shims to get the correct preload. It depended on the size of the bearing on how much preload to use. On my crane both front and rear axle bearings were preloaded and I never lost a bearing in 31 years.
Title: Re: Wheel seal--Stemco
Post by: krush on November 15, 2018, 11:28:55 am
It is not possible to make a simple procedure that allows repeatable measurement of preloading a bearing. Leaving 0.001 to 0.005" of play is easily measured (using a dial indicator).
Because of this, and the fact that millions of mechanics need to be able to follow a procedure, the less desirable method of leaving a little end-play is used.
The "rules" are written due to implementation of procedures, not because of engineering constraints.
I always preload. And when the rotating assemble warms up, it likely will expand and increase clearance.
Title: Re: Wheel seal--Stemco
Post by: Caflashbob on November 15, 2018, 02:31:56 pm
Glad I am not the only one to promote preload. My Cummins will not do it for the legal reasons I assume.
I told the subject to further research I might take it back to my old Foretravel mechanic to add preload.
The nut has slots for a locking pin. The slots may not allow the .001 adjustment.
Mine are .001 and .003 respectively and a slight dead spot as i stated is present versus the previous preload.
With preload it was perfect. Without it 90%?
Title: Re: Wheel seal--Stemco
Post by: bbeane on November 15, 2018, 08:30:03 pm
I preload mine, done hundreds of them never lost a bearing.
Title: Re: Wheel seal--Stemco
Post by: DavidS on November 15, 2018, 09:29:15 pm
So after the standard procedure of installing a bearing, how is the preload done? extra lb per ft? or?
Might take my wheels off and see what mine look like.
Title: Re: Wheel seal--Stemco
Post by: craneman on November 15, 2018, 10:22:53 pm
It is not possible to make a simple procedure that allows repeatable measurement of preloading a bearing. Leaving 0.001 to 0.005" of play is easily measured (using a dial indicator).
Because of this, and the fact that millions of mechanics need to be able to follow a procedure, the less desirable method of leaving a little end-play is used.
The "rules" are written due to implementation of procedures, not because of engineering constraints.
I always preload. And when the rotating assemble warms up, it likely will expand and increase clearance.
Actually the hub expands more than the spindle so clearance decreases.
Title: Re: Wheel seal--Stemco
Post by: bbeane on November 15, 2018, 10:28:44 pm
Well I have my helmet and flak jacket on so here goes. For me it's a feel, tighten the bearing down to make sure everything is seated back off a turn, then lightly tighten the nut, install the lock nut done. But as I said I been doing wheel bearings and seals since I was 14 or so. It's a fine line, when you install and tighten the lock nut it will change the preload. If one doubts the ability to preload a bearing a bit loose is better than over tight.
Title: Re: Wheel seal--Stemco
Post by: krush on November 15, 2018, 11:05:22 pm