Why have an inner seal on FF?

[snowboardonsnow]

But if you were to claim that oil/grease mix seizes bearings, the sky would fall, a bus-load of Nun's would catch fire or you wouldn't be able to get home after termites ate through the 1/4" plate of your diff housing.
Well then the discussion would continue.

I am surprised the toyota swivel seals can't keep oil in.

Inner seals fail all the time in toyota axles and it turns in to a gooey mess, but doesn't cause any harm other then leaking knuckles.

I actually just rebuilt my knuckles yesterday and on my knuckle there is NO way mine would be able to seal. Its to pitting form years of sitting and not being properly maintained. But if they had been oil bathed from the get go who knows.

I know you guys are probably talking about Rear FFs but I don't have those

 

[roscoFJ73]

Do whatever you like. Throw a hissy fit, cry, scream, call a tow truck or just patch the hole and drive home.

That problem and it's solution is no different in any way to running with greased hubs. It's been covered already in this thread.

If you are only happy using toyota genuine parts and washing your vehicle with toyota approved soap lest the sky fall on your head. That's fine.
Some of the rest of us have the skills and knowledge to do better than the "one size fits all" which comes out the toyota factory.

To put it another way: "Those who say it's impossible should not interrupt those doing it."

Congratulations for going 6 sentences and not mentioning Landrover,Bravo Dougal.
I only use Toyota parts when I have to and I dont believe they make Toyota soap and probably wouldnt bother with it any way.

Its not about skills and knowledge Dougal,we are only talking about leaving one little old seal off. But if you think that requires "skills and knowledge" Dougal,so be it
Oh by the way Dougal ,as fas I know you dont have a Landcruiser,so you wont be doing it anytime soon

 

[Dougal]

Congratulations for going 6 sentences and not mentioning Landrover,Bravo Dougal.

If only you could.

Its not about skills and knowledge Dougal,we are only talking about leaving one little old seal off. But if you think that requires "skills and knowledge" Dougal,so be it

Oh no, leaving one seal out will likely not be enough. That's the whole skills and knowledge I was talking about. You must understand a problem before you can offer a solution.

Oh by the way Dougal ,as fas I know you dont have a Landcruiser,so you wont be doing it anytime soon

True, Toyota don't make any vehicle that suits my needs. I've been shopping for a new work car lately and toyota don't even have a vehicle in that segment. It seems unless you want a camry or highlander they aren't even in the game. Good thing the Germans, Czechs and Koreans are filling the gaps.

 

[ntsqd]

I'm not forcing this on anyone. I'm reporting what I'm doing, why I'm doing it, and what the the results are so far. If you want 100,000 mile durability you're gonna have to wait until I've driven it that far, if I ever do. I'm not interested in why it shouldn't be done, I am interested in data on why it can't be done. So far my results are indicating that it can be done.

I can make some educated guesses about why Toyota chose to go down this different path, and I am not one to change something without first trying to understand why it was made the way that it was. As best as I can determine, those decisions are different in my application.

As far as US trucks being "soft", I differ on that score. I am the third owner of a now 310k mi old Cummins-Dodge. The PO was a Border Patrol Agent. I suspect that he was pretty gentle with it, but the indications are that this truck was a working ranch truck in southern New Mexico for the OP. It's still a fine truck and is about the same condition as my 280k mi old FJ60. Of the two I'd venture that the Dodge is in better shape by a small margin, mostly due to the PO having it painted. This from a truck that gets the frequent comment of "Nice engine, too bad it comes wrapped in a Dodge!" My previous full sizes were equally good trucks, though admittedly none of them were as high of a mileage.

 

[Henry James the 47th]

"Nice engine, too bad it comes wrapped in a Dodge!"

There are REASONS people say that! The Cummins is a great engine, the Dodge surrounding it however leaves me falling short of positive things to say.

 

[ntsqd]

I went into that purchase thinking that if/when the Dodge sheet metal dies that I'd replace it with an older Ford Crew Cab - say a late 60's version. Easier to do that than to do an engine swap and a coil spring/linkage conversion on a late 60's Ford CC. And in spite of contrary rumors, the Dodge frame is a much better frame than the early 60's Ford frame.
However, so far I've been impressed with the Dodge.

BTW, it's Dana 70 rear axle doesn't have those seals and it seems to work just fine. There's a 300,000+ mile durability test right there.....

 

[deaddrift]

OK, I'm more than a little reluctant to mix it up in here with the heavy hitters, but this thread spurred me to make an observation and ask a question:

First the observation: I am rebuilding my front end for the first time and my axle shafts have slight wear. One shaft was bad enough that I decided to replace it, it's shown below. Yes the bearing is bad too. Not sure that burnishing/flaking came from the oil seal but I don't know what else mighta did it.

Second the question: I am rebuilding the hubs as well as the knuckles with new wheel and trunion bearings. I'm worried about this idea of overpacking grease leading to premature wear. I used synthetic lithium grease in the hubs and put a fair amount in there. When I pulled my hubs the entire knuckle was filled with grease, which is what I had intended to do myself. Naturally I am also going to pack the bearings. How do I tell "too much grease" from "enough grease"?

 

[cruiseroutfit]

Fwiw there is a very detail thread from folks that tried this somewhere out there here on Mud or it could have even been PBB. I remember it vividly as many of the same arguments for an against were presented just as they were here.

My take, if I were in a pinch I would skip the seal for a trip home but I see no reason to ditch the seal given the longevity offered by the current system. I prefer packed wheel bearings versus bathed wheel bearings particularly for field repairs. I've not been into my rear FF axle for about 5 years now, good enough for me

 

[lostmarbles]

.......... One shaft was bad enough that I decided to replace it, it's shown below. Yes the bearing is bad too. Not sure that burnishing/flaking came from the oil seal but I don't know what else mighta did it.

Hi Deaddrift

I do think that shaft was thrashing around against the oil seal ....

But I'd expect it to have completely demolished the seal to end up with that much damage.

(It looks to me like its been hitting more than just a rubber seal lip.)

I am rebuilding the hubs as well as the knuckles with new wheel and trunion bearings. I'm worried about this idea of overpacking grease leading to premature wear. I used synthetic lithium grease in the hubs and put a fair amount in there. When I pulled my hubs the entire knuckle was filled with grease, which is what I had intended to do myself. Naturally I am also going to pack the bearings. How do I tell "too much grease" from "enough grease"?

No more than this for your hubs:


(1980 Chassis & Body FSM)

As far as the knuckles are concerned ... I don't think you need to worry (so long as you don't let that grease dry out to the point where it doesn't want to move at all). Surplus grease there will soon get pushed out your wiper seals IMO.

(On the rare occasions when my knuckle grease gets too dry I squirt a little gear oil in there.)

 

[mudgudgeon]

OK, I'm more than a little reluctant to mix it up in here with the heavy hitters, but this thread spurred me to make an observation and ask a question:

First the observation: I am rebuilding my front end for the first time and my axle shafts have slight wear. One shaft was bad enough that I decided to replace it, it's shown below. Yes the bearing is bad too. Not sure that burnishing/flaking came from the oil seal but I don't know what else mighta did it.

Second the question: I am rebuilding the hubs as well as the knuckles with new wheel and trunion bearings. I'm worried about this idea of overpacking grease leading to premature wear. I used synthetic lithium grease in the hubs and put a fair amount in there. When I pulled my hubs the entire knuckle was filled with grease, which is what I had intended to do myself. Naturally I am also going to pack the bearings. How do I tell "too much grease" from "enough grease"?

There is a good tech write up with pics at Welcome to Land Cruiser Owners On Line (LCOOL)

Go to the technical pages for 80series landcruiser

Edit
http://www.lcool.org/technical/80_series/80_series_technical.html

There is two tech articles, CV (airfield) re-packing and wheel bearing re-packing

 

[ntsqd]

My prime reason for trying to go without that inner seal is because of what it does to the cost and complexity of having custom length shafts made. Without the seal the shaft can be a simple double splined end shaft. With the seal there now has to be a seal surface for the seal to work. Since normal splined shaft mfg practice is to make the shaft slightly smaller than the minor diameter of the splines, needing a seal surface means raising a surface back up to what ever that diameter might be (a "camel hump" as it were), and requiring that this surface have a high surface finish spec. I would expect such requirements to double the price of the shafts, at the least.

Occurred to me that the trailer that a friend & I built supplies supporting evidence that the hub seals will be fine partly submerged in oil.

Note the D60 wheel hubs. What you can't see is that the spindles were cut off of the D60 housing (square spline shafts were also cut off the flanges) and welded into a large OD tube, which has fill and a drain port in the center (fill cap has a vent hose extended up as high as it could go). There is something in the range of 3-3.5 gallons of 90wt. in that axle tube. When first filled it weeped a little from one of the seals, but since then the trailer has been to Bend, OR and to San Felipe, BCN along with many trips to the dump and a couple to the desert. Long ago the weeping stopped and the axle has been dry on the outside ever since.

Deaddrift, that damage doesn't look like typical seal wear, nor does it look like something that has been rubbing or beating against another metal part. It looks like fretting corrosion that has since been polished, but there's nothing nearby that could have done that. Tis a puzzler.

 

[deaddrift]

Thanks guys. Hijack over.

 

[astr]

I finally got around to servicing the rear axle on my FZJ80. In addition to doing the brakes, I pulled the hubs. Knowing that the maintenance by the PO was severely neglected, I didn't know what to expect. On one side, the axle seal had leaked and the hub grease had washed out. The bearing were fine. On the other side, the axle seal was fine, the hub had grease and the bearings were scored and pitted. Maybe just coincidence and general lack of maintenance.

As I stated earlier in this thread, as an experiment, I'm going to depend on the differential gear lube to lubricate the wheel bearings rather than packing them with grease as per the FSM.

I replaced all the bearings (Timken) on both sides and the two large seals that go between the hub and axle housing. I INTENTIONALLY LEFT OUT THE TWO SMALL SEALS BETWEEN THE HUB AND THE AXLE. I did not grease the bearings, just dipped them in gear lube. I set the preload as per the FSM. I verified that gear lube would travel to the bearings when the level in the differential was to factory spec.

So now I am totally dependent on gear lube from the differential to lubricate the wheel bearings, the same as most Dana FFs. Let's see what happens. I plan to check the bearings at 10K, 25K, 50K and 100K (if the rest of the truck makes it that long). I'll report back at those times or if problems arise sooner.

Meanwhile, I'll stay away from buses loaded with nuns

 

[Dougal]

Your biggest problem will be the initial seal. I had to machine one of the seal faces on a rover stub to get a seal. The originals being grease sealed in that year had two slight tracks worn by the grease seal.
I spent half an hour on the lathe trying to polish them out, then gave up and took a cut. All good now.

This set of axles have had their bearings oil bathed for about 6 years now and that was the only problem and on one stub only. The previous set were oil bathed for 21 years, approx 500,000km, and those bearings were in better shape than the 10 year old, 70,000km, greased bearings from these second axles.

 

[astr]

The seal surfaces on the axle looked good so, other than cleaning them up with some steel wool, I left them alone. I'll be watching for leaks.

Thinking a little further, in the stock setup, the axle housing is vented via a vent tube so any changes in internal pressure as a result of significant temperature changes such as might occur when driving through water, are equalized. However, the hub has no way to equalize pressure except through leakage around the seals as it sealed from the axle housing by the axle shaft seal and from the outside by the axle housing seal. As neither of these seals are designed for significant pressure, one or the other will leak to relieve the pressure. Hopefully, it will be the axle shaft seal so you only get some gear lube into the bearings. On the other hand, if the axle housing seal leaks and it is submerged in water, you will suck in water into the bearings.

By eliminating the axle shaft seal, the hub can equalize via the axle housing thereby minimizing the chance of sucking in contaminants.

 

[45Kevin]

I suppose the only downside here would be lack of oil to the upphill side in an extended off-camber situation.

Also, if you broke an axle and removed it, you would loose your oil.

 

[astr]

I suppose the only downside here would be lack of oil to the upphill side in an extended off-camber situation.

Also, if you broke an axle and removed it, you would loose your oil.

Good point! If you broke an axle, you would want a block off plate otherwise you would also loose some of your diff lobe.

 

[Dougal]

I suppose the only downside here would be lack of oil to the upphill side in an extended off-camber situation.

Also, if you broke an axle and removed it, you would loose your oil.

There is plenty of oil trapped in the hub in an off-camber situation. To drain an oiled hub you need to remove it and sit it flat for days.
If you break an axle and you can pull the shaft then you can refit the broken end to seal the hole.

Andy, I pull the inner axle seals. Some people leave them, but intentionally damage them enough to let oil flow flow over time and pressure equalize.

 

[astr]

Got about 100 miles on it and so far no leaks so it looks like the seals are holding the gear lube in OK. I popped the little cosmetic center caps off and threw a cheap IR thermometer in the truck. I would suspect that any impending bearing problems would be signaled by an increase in hub temperature. Now I just need to remember to check it when I stop.

 

[astr]

As promised, I am reporting back after removing the inner axle seals. As I originally stated, I did NOT pack the bearings with grease but am depending on the gear lube from the differential to keep the bearing oiled. 15K miles later and no problems. Most of the driving was highway driving of which at least 3K involved heavy towing (another FZJ80 on a tow dolly, military trailers, construction equipment, etc). I decided recently to fix the parking brakes so I had a chance to inspect the bearings. There was no significant change in bearing preload from when I assembled the axle. There was no sign of any leakage past the big seal. The outer bearings looked like new. I did not pull the inner bearings as that would have required removing the big seal which probably would have damaged it. All back together with original bearings and seals.

Experiment continues!