Why have an inner seal on FF?

[astr]

Don't know where to post this but I figured more folks would have FF on the diesel forum.

From reading many threads on MUD, it seems that one downside of LC FF rear axles is that the bearings require routine grease packing as they are separated from the differential lube with the inner axle seal. On all of the Dana FF's, there is no seal so the axle bearings are lubed by the lube in the differential. Seems to work very well.

Why not leave out the inner axle seal and eliminate the routine repacks of the bearings? Maybe the lube level in the dif would have to be raised but it seems like it would work.

Has anyone tried this?

 

[Henry James the 47th]

I don't know if the hub seal on the back would keep the oil from coming out - I suspect not.

 

[Tapage]

I don't know if the hub seal on the back would keep the oil from coming out - I suspect not.

but that's the idea .. they share the same concept as the front bearings .. although repacking should be as frequent as you do in the front ..

 

[Henry James the 47th]

Yes, that's right. They are the same as the front...

 

[lostmarbles]

In my opinion, the further away you can keep oil from brake linings ... the better.

And I don't think grease is significantly-enough inferior to "pure oil" to be capable of noticably reducing wheelbearing life.

Hence I support retaining the inner seals on the rear axle.

It is of course even more important to have those seals in good nick on the front axle because the swivel seals (wiper-ball-seals or whatever you call them) on the steering knuckle housings can't hold oil and will readily leak it out all over your wheels (and brakes).

My 2c.

 

[doug720]

There was a few posts recently about this on the 60's forum. NXTCY posted about how he runs his FF without the seal and lets the gear oil lube the bearings with no I'll affects.

I'm a SF, so I can't speak from experience. But all my other vehicles that have FF are oil lubed.

Doug

 

[astr]

There was a few posts recently about this on the 60's forum. NXTCY posted about how he runs his FF without the seal and lets the gear oil lube the bearings with no I'll affects.

I'm a SF, so I can't speak from experience. But all my other vehicles that have FF are oil lubed.

Doug

I tried to search on NXTCY and had no luck. I'd be interested to see what he has to say.

 

[doug720]

Here is thread and it was a post by ntsqd in post #32.

https://forum.ih8mud.com/60-series-wagons/599315-full-floater-vs-semi-floater-axles-2.html

Doug

 

[roscoFJ73]

I had the bearings done on my 75 series this year at 270000klms and they were still good after all that time.They hadnt been done in the 7 years I have owned it.
A mechanic told me its not uncommon for the bearings to last the life of the vehicle.

The 70 series FF is a well tested piece of equipment,I cant see the point in changing it just because some other manufacturer does it different.

 

[astr]

I sorta suspected that the majority of responses that I would get would tell me why it wouldn't work, all from people who hadn't tried it. Well, Mr. Toyota never put a Chevy V8 or an Isuzu diesel in the Land Cruiser, yet many have and are happy with the results. You have to think a little outside the box to make forward progress.

I do thank everyone for their responses even if they were just an opinion. I just picked up a beater FZJ80 with a FF so I may just go ahead and try it. I'll report back the results. So if you see a green FZJ80 by the side of the road with smoke comming from the rear end, wave as you go by and yell out "I told you so"

 

[lostmarbles]

I sorta suspected that the majority of responses that I would get would tell me why it wouldn't work, all from people who hadn't tried it..

Brilliant basis on which to dismiss advice from people who were donating their time to be helpful Astr.

I've heard people say washing detergent works instead of more-costly brake fluid. Yet I haven't tried it myself. (And I bet most, if not all, of the others in this thread haven't tried it either.) So why don't you go ahead and experiment with that one too!?

 

[OGBeno]

A mechanic told me its not uncommon for the bearings to last the life of the vehicle.

Your mechanic is correct Rosco. The design parameters for wheel bearings (front and rear on FF systems) is the life of the vehicle if they adhere to the Toyota "severe" usage intervals.

30K miles on the wheel bearing repacks, 60K intervals on full front and rrar end rebuilds.

Toyota disclaimers this with water crossings. According to Toyota technical documentation, if you do frequent water crossings, at your earliest chance you must drain and refill the diffs as well as repack wheel bearings.

If you adhere to these parameters, either the Koyo (internal) wheel bearings or the Timken (outsourced) wheel bearings will last the life of the chassis in any given environment.

As I always tell my customers, if you think of your LC as an industrial machine or an airframe, and treat it as such, it will last longer than the average Western human

 

[roscoFJ73]

I sorta suspected that the majority of responses that I would get would tell me why it wouldn't work, all from people who hadn't tried it.

When I had a HJ61 the innner seal had gone and there was oil leaking everywhere. Why would I want that to happen again by removing the seal myself?
On hot days they can sometimes seep grease,so oil is going to drip.
There is some good reasons why Mr Toyota never put a Chev v8 in his landcruisers and that is because they are 2nd rate compared to most of his engines.
The Isuzu diesel is fine,but the landcruiser diesels are top notch.

As for the other post where ntqsd claims he has removed his inner seal,this is all he has said

I just didn't bother with those tiny little seals. Let the diff lube run down that axle housing and lubricate those bearings. That is how all of the Dana FF's and large truck FF's work.

LOL Its not exactly a ringing endorsement,he hasnt done a 100000 mile trip over bad roads and come back saying how great it works.
For all we know he went around the corner and bought milk and paper and couldnt see any oil dripping down.

 

[Dougal]

Landrover used to run oil-bath wheel bearings, with the result that wheel bearings would last the life of the vehicle. The oil bath as well as lubricating and cooling better, ensures you've got a good enough seal to keep water out in river crossings.
Put simply if your seals can keep the oil in, they keep the water out. If not you should notice the oil drips on the inside edge of your tyres.

In the early-mid 90's landrover/rangerover went from oil bath bearings to grease lubed CV joints and wheel bearings. The reason was customer perception (one less thing to leak).
The results were awful, wheel bearings would last about 80,000km max. Usually due to water/mud getting in through the hub seal. Because these didn't have their own breather, when dunked in water the air inside contracts and pulls in whatever is on the outside of the seal.

Luckily for owners of these vehicles, it was easy to go back. Simply fit the earlier style oil seals to your hubs, remove/damage the inner axle seal and let the oil flow.
And instantly you are back to wheel bearings that last.

For your cruiser, it all depends on getting appropriate seals. I tried conventional rotating oil seals on landrover axles and the life was short (and brakes lubed when they gave up). The seals are also intolerant of bad bearing adjustment. If you have a locknut back off (like I did a few weeks back, my own fault) then you'll get seal leaking as a result.

 

[crushers]

actually, the idea that "if a seal keeps oil in then it will keep water out" is pure rubbish.
if you take a look at a normal oil seal used to keep oil in then you will see that it is designed for force from inside and not from the outside (taper). if you are in deep water, you have pressure pushing in with the rake of the seal. as the diff contacts with the colder water the pressure from the heated air cools and a vacuum occures. the difference allows the pressure of the water to bypass the seal and enter the object, be it axles, t/case, etc.


you really need to think your plan through a lot more before trying it.

the semi floater, which is lubricated by the axle fluid, the bearing is a different design than the bearing and race design for the full floater. the semi floater is designed to run on the thinner fluid. the FF taper bearing is designed to have the heavier grease in there to keep the bearings in proper function.

lets think this through a bit more,
the bearings fail and eventually one of two things will happen. the rear wheel will lock up and react like a one wheel brake system shooting you out of your lane and either into the ditch (which in this case is a bonus since you kill only yourself and your passengers) or into the other lane (which could kill or maim innoccent individuals that are just trying to enjoy their petty little lives).

IF the bearings don't fail quickly then you WILL end up with fluid on the brake linings (drum or pad) which will lead to brakes that grab badly when applied. of course gear lube and heat (heat will be created when the brakes are applied) and you could end up with a fire under your ass. this will be a good thing since it will get a fool and his truck off the road. BUT. it could also cause loss of control while braking and if it happens only on one wheel the result will be the same as losing a wheel bearing, you either hit the ditch/curb or you go into oncoming traffice where you could be responsible for the pain and suffering of others.

 

[Dougal]

actually, the idea that "if a seal keeps oil in then it will keep water out" is pure rubbish.
if you take a look at a normal oil seal used to keep oil in then you will see that it is designed for force from inside and not from the outside (taper). if you are in deep water, you have pressure pushing in with the rake of the seal. as the diff contacts with the colder water the pressure from the heated air cools and a vacuum occures. the difference allows the pressure of the water to bypass the seal and enter the object, be it axles, t/case, etc.

Have you never seen a dual lip seal? They have one tensioned lip to keep the insides in and another to keep the outsides out. They are used on oil filled hubs.

Further, if a hub is oil-filled from the axle housing it benefits from the axle housings breather. When it cools and the air inside contracts, it pulls air through the breather instead of pulling a vacuum.

See landrover had this stuff down over 50 years ago. It's one of the things they really nailed.

lets think this through a bit more,
the bearings fail and eventually one of two things will happen. the rear wheel will lock up and react like a one wheel brake system shooting you out of your lane and either into the ditch (which in this case is a bonus since you kill only yourself and your passengers) or into the other lane (which could kill or maim innoccent individuals that are just trying to enjoy their petty little lives).

IF the bearings don't fail quickly then you WILL end up with fluid on the brake linings (drum or pad) which will lead to brakes that grab badly when applied. of course gear lube and heat (heat will be created when the brakes are applied) and you could end up with a fire under your ass. this will be a good thing since it will get a fool and his truck off the road. BUT. it could also cause loss of control while braking and if it happens only on one wheel the result will be the same as losing a wheel bearing, you either hit the ditch/curb or you go into oncoming traffice where you could be responsible for the pain and suffering of others.

now, of course when dealing with individuals that try such ideas there is little conscience of others lives so should the worst happen, you will probably ***** more about the loss of your hunk of metal than the injury to others.

very stupid idea ...

How does better lubrication cause a bearing to sieze on the highway?
Oil is a far better lubricant than grease. It just requires better containment. Which is why all heavy machinery and pretty much all heavy truck and trailers use it.

It's pretty hard to create enough heat with an oil-soaked brake to set the oil on fire. It's been tried many times on machinery ranging for sport motorbikes on upwards. The oil starts producing heaps of smoke when you get it hot enough (which is hard, because the brakes don't work that well). But never seen fire.

Last I checked, greased wheel bearings have been known to fail and lockup wheels. To be really safe, don't drive or be driven anywhere.

 

[crushers]

umm, so you are saying that all seals on land cruiser axles and t/case are double lipped?

so, if you are right, then why did toyota bother to make the FF use grease rather than oil? on the rear FF it would have been easy enough to design a better seal to keep the oil in ...
maybe they know something you are missing ...

 

[Dougal]

umm, so you are saying that all seals on land cruiser axles and t/case are double lipped?

Nope.
I specifically said above that it all depends on finding the appropriate seals.

so, if you are right, then why did toyota bother to make the FF use grease rather than oil? on the rear FF it would have been easy enough to design a better seal to keep the oil in ...
maybe they know something you are missing ...

Ask Toyota.

it does sound like you are encouraging this idiot, sad really.

Astr is not an idiot by any definition. Take a look at his projects here.
Then send him an apology.

 

[roscoFJ73]

Landrover used to run oil-bath wheel bearings, with the result that wheel bearings would last the life of the vehicle. The oil bath as well as lubricating and cooling better, ensures you've got a good enough seal to keep water out in river crossings.
Put simply if your seals can keep the oil in, they keep the water out. If not you should notice the oil drips on the inside edge of your tyres.

Grease can do a pretty good job of keeping water out

In the early-mid 90's landrover/rangerover went from oil bath bearings to grease lubed CV joints and wheel bearings. The reason was customer perception (one less thing to leak).

If LR are so attune to customer perceptions ,why dont they fix up the rest of their horrible problems?
Last time I looked they were the only 4wd maker that had 2 sites dedicated to airing grievenances about poor quality and servce.

The results were awful, wheel bearings would last about 80,000km max. Usually due to water/mud getting in through the hub seal. Because these didn't have their own breather, when dunked in water the air inside contracts and pulls in whatever is on the outside of the seal.

Just because Landrover did a half assed job ,it doesnt mean Toyota did. Who cares if they only got 80000klms from a bearing,what happened to Landrover is completley irrelevant..

 

[Dougal]