Preferred Wheel Bearing Grease

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

User avatar
170C
Posts: 3182
Joined: Tue May 06, 2003 11:59 am

Re: Preferred Wheel Bearing Grease

Post by 170C »

WOW! 500 hours as a recommended time for changing the grease in Cessna wheel bearings. And I’ve been cleaning and repacking mine every year (like most others likely do). Sounds like any good grease should work. AN-15-G that G must stand for GREEN :mrgreen: What do you think Bruce? :lol:
OLE POKEY
170C
Director:
2012-2018
User avatar
ghostflyer
Posts: 1390
Joined: Mon Apr 21, 2008 3:06 am

Re: Preferred Wheel Bearing Grease

Post by ghostflyer »

500 hrs on a wheel grease change ???? OMG , I clean and regrease every 100hrs.the felt seals to me are useless as water and dirt still get in . In the dry season we have the fine red dust and that just hones in on the grease and bearings . My hub caps are owner made and keep 80% of water and dirt out on the outside bearing with the inside seals invites everything from water to sand,brake dust . These Moulded seals could be a good thing . I have often thought about my boat trailer wheel hub seals [rubber mounded type] being used on my aircraft . I have tried to use Cessna standard wheel hub caps but they make my wheels rotate in flight causing brake clatter. So,a flat round piece of 36 thou aluminium was cut over size so it touches the tire when screwed to the rim . This is my hub cap and it works well.
User avatar
Stankasica
Posts: 16
Joined: Tue Oct 18, 2016 9:08 am

Re: Preferred Wheel Bearing Grease

Post by Stankasica »

My 1952 owners manual also states 500hrs for the wheel bearings, but that must be for a hangar queen.
Stan Kasica N2458D
KSNC. Chester,Ct
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Preferred Wheel Bearing Grease

Post by Bruce Fenstermacher »

Stankasica wrote:My 1952 owners manual also states 500hrs for the wheel bearings, but that must be for a hangar queen.
So how exactly would a hanger queen accumulate 500 hours? The recommendations are in increments of operation unless a time recommendation is given.

Clearly most small aircraft wheel bearings should be cleaned and repacked because of contamination no matter the hours of operation and that has to be based on the environment of operation. Most wheel bearings are cleaned and packed each year so a inspection can be properly performed not because they need repacking.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Preferred Wheel Bearing Grease

Post by GAHorn »

Bruce Fenstermacher wrote:George will be on here shortly to tell you what he's always told us and what I use. Plain old WalMart boat trailer grease.
I agree with Bruce's agreement with that nut.

The "approved" Service Manual for our airplanes, (Cessna 100-Series Service Manual, 1962 and Prior) states in Section 2, page 10 to use "Mil-G-25760" grease for wheel bearings. It then instructs "The Military Specifications listed below are not mandatory but are intended as Guides in choosing satisfactory materials. Products of most reputable manufacturers meet or exceed these specifications."

I use Marine and Boat trailer wheel bearing grease for all grease-points on my airplane because it is waterproof, cheap, and is SLOW to deteriorate because it is GREEN. (ghefer said it correctly,... USE THE SAME GREASE CONSISTENTLY and/or remove all traces of old grease because the base soaps used may differ without notice in different brands/suppliers. Lithium is most common, but aluminum, or any other metallic-salt or binding agent may be used to carry-and-hold the base oil in the grease. Mixing them will cause failure of bearings and components.)

NEVER SPIN A BEARING using compressed air! It is DANGEROUS to your personal safety! The cage will NOT contain the rollers which "chatter" and are damaged, and can explode out of the cage and cause serious harm to your person and anyone else in the vicinity! I've personally witnessed this done in a shop and the sudden "pop" and the shattered windshield of the car across the shop was testimony to the velocity of the roller. The almost-severed thumb of the idiot spinning the bearing was caused by the cage which became as a knife when the rollers shot out of the bearing.
If you use compressed air to clean or dry a bearing...do so judiciously and from the SIDE of the bearing. DO NOT SPIN A BEARING WITH AIR!
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
170C
Posts: 3182
Joined: Tue May 06, 2003 11:59 am

Re: Preferred Wheel Bearing Grease

Post by 170C »

Gosh there are a lot of greases out there. Just go to any auto supply store, Wal Mart, etc. and look at the variety. And that doesn't count specialty sources.
Regarding the caution about not mixing greases, I suppose the only way to properly clean old grease out of a Scott 3200 is to disassemble it. Correct? I have never had mine apart and with all the springs and other items in there, I'm not sure I want to do so. Would be interesting, but I would hate to have pieces flying all around, getting lost and not get it reassembled properly. Mine works just fine and I somehow hate to fix what isn't broken, but I am going to change greases and I don't want to be using two types on my plane.
OLE POKEY
170C
Director:
2012-2018
User avatar
gfeher
Posts: 571
Joined: Fri Sep 26, 2014 9:19 pm

Re: Preferred Wheel Bearing Grease

Post by gfeher »

Yes, the only way to clean out the old grease is to disassemble it. But it's not difficult. It's not like a watch where you take the back off and springs go flying. Yes, it has three springs, but they stay put. The wedges also stay put and you don't need to remove them. If you take apart your main wheels and repack those bearings, you shouldnt have any problem with the tailwheel assembly. If you are really concerned about remembering where things go, take a picture with a smartphone when you separate the halves. But I doubt you will have a problem. When you have it apart, inspect the kingpin/spindle carefully for cracks, especially at the base and where the grease holes are. Also, clean, inspect and repack the bearing. It's just a Timken like on the main wheels, just smaller. When everything is clean and inspected, and the bearing repacked, fill the whole inside with grease as you put it back together. You can't over fill it as any excess will squeeze out when you put the halves together. Then tighten the kingpin/spindle nut in accordance with the Cessna 10-24-50 S.N.L. to properly load the shimmy dampner. (First seat the bearing by tightening the nut until you can't swivel the fork. Then back off the nut to where the fork swivels freely. Then slowly tighten the nut until the fork just begins to bind when you turn it. Then back off the nut just enough to line up the cotter pin hole with the next castellation of the nut - no more than 1/6 a turn.) You can download a copy of that service letter here:
http://cessna170.org/forums/viewtopic.php?f=24&t=13770

Edit: I forgot to mention. When you upen it up, there will be 5 holes for springs, but only 3 springs. (The 170 only uses 3 springs.) So make note of which holes have springs for when you put it back together. That's probably the hardest part of the operation.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
User avatar
DaveF
Posts: 1516
Joined: Sat Nov 03, 2007 1:44 am

Re: Preferred Wheel Bearing Grease

Post by DaveF »

I take my tailwheel apart every annual for cleaning and greasing. There's always some clump of grit I'm glad to clean out.

You won't lose any parts, but it's easy to forget which pieces came out from where. In particular, keep track of which dust cap is upper and which is lower. Keep track of how the bronze thrust washers come out. Make a note of how the bearing, spacer, washer, and dust cap come out. It's strangely easy to reassemble the thing with the fork facing the wrong way. As Gene said, take a lot of pictures. You can also find good exploded view drawings of the assembly on the Chief AIrcraft, Airframes Alaska, Univair, and Spruce web sites.
User avatar
brianm
Posts: 134
Joined: Fri Dec 09, 2016 12:04 am

Re: Preferred Wheel Bearing Grease

Post by brianm »

I found these videos very helpful when I did mine:

https://www.youtube.com/watch?v=S-0i2MTe-A0
https://www.youtube.com/watch?v=X1uAd0KSnCc
https://www.youtube.com/watch?v=8MGri0D50hg

It shows the Baby Bushwheel fork, but the process is identical.
Brian M
N2669V - '48
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Preferred Wheel Bearing Grease

Post by GAHorn »

Frank, keeping the various greases from being mixed up is easier than which "brand" or store you bought it from.

When you make your logbook entry...RECORD which grease you used, when and where. You can even write it on the wheel with a Pilot Point Pen or other indelible marker.

All you really need to do is record the TYPE of base used in the grease, such as "Lithium" based grease. (Which is the most common type.) It doesn't matter if it's black, red, or brown... as long as it's the same BASE soap. It won't matter if it was Wal-Mart, Pennzoil, Mobil, Shell, or whatever as long as that base is the same. (That statement applies to mineral/petroleum oil greases. Synthetic greases should never be mixed between brands or mil-specs.)

The marine boat trailer grease I use is "aluminum" based, but that is actually not real common. And there are others. I mark both the grease containers with indelible pen in LARGE letters... as well as record it in the maintenance record. (Personally, I also completely clean out old grease whenever I grease anything anyway so never run into mixed-greases problems.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
170C
Posts: 3182
Joined: Tue May 06, 2003 11:59 am

Re: Preferred Wheel Bearing Grease

Post by 170C »

Thanks George. I am going to use Green Grease, that's not a joke, that is mfd by Omni Lubercants in Lewisville, TX. Its a marine grease. I, too, clean my bearings before repacking them.
OLE POKEY
170C
Director:
2012-2018
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Preferred Wheel Bearing Grease

Post by GAHorn »

Frank, the Marine Grease I use on my wheel bearings and tailwheel is also green. (It's slow to wash out.) :twisted:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
170C
Posts: 3182
Joined: Tue May 06, 2003 11:59 am

Re: Preferred Wheel Bearing Grease

Post by 170C »

But it makes those wheels go so fast :mrgreen:
OLE POKEY
170C
Director:
2012-2018
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Preferred Wheel Bearing Grease

Post by GAHorn »

170C wrote:But it makes those wheels go so fast :mrgreen:
I never take-off or land at high speed. Only as slow as possible because I don't want to hurt that green grease.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
Post Reply