front axle inner seal help

[landshark1]

About 6 weeks ago, I did a front axle/birf rebuild on my 96 LC with 196,000 miles on it. Things looked surprisingly good inside, original inner seals not leaking. The job went smoothly as I took it nice and slow. Getting to the point, now my newlt installed OEM inner seal on the passenger side is leaking. I feel like I did everything right when installing the new seal: checked for burrs, made sure spring stayed in place, used the proper install tool(and diff breather tube is functioning btw). The drive axle slid back in and splines engaged effortlessly. So...my question is, when I go back in(sigh...) to replace the seal(again) what do I need to do/check for that I am missing so as to avoid the leaking? I am going with another OEM seal as it seems most prefer this on the 80's unless someone convinces me otherwise. Would very much appreciate you guy's help!
Chris

 

[Rifleman]

One of the things you can look at is the surface of the axle shaft where that seal rides. It's not uncommon for an old seal to wear a grove in the axle shaft, causing your new seal to leak. Your idea to stay with a factory seal is a good one, most members, if not all, agree that the factory seals are the best. If you do have a groove in your axle shaft, you can replace it with a new shaft, or you can repair your old one using a Speedi sleeve. One other thing i would do when you replace that seal. Before you slide the axle shaft back through your new seal, i like to pack the back side of the seal with the same grease i used on the CV joint. The reason i do that, i think it helps to hold the seal's garter spring in place.

 

[landshark1]

One of the things you can look at is the surface of the axle shaft where that seal rides. It's not uncommon for an old seal to wear a grove in the axle shaft, causing your new seal to leak. Your idea to stay with a factory seal is a good one, most members, if not all, agree that the factory seals are the best. If you do have a groove in your axle shaft, you can replace it with a new shaft, or you can repair your old one using a Speedi sleeve. One other thing i would do when you replace that seal. Before you slide the axle shaft back through your new seal, i like to pack the back side of the seal with the same grease i used on the CV joint. The reason i do that, i think it helps to hold the seal's garter spring in place.

Thanks rifleman. I did pack grease on the back side of the seal, and I did inspect the axle for wear. Looked OK, but maybe I need to look closer. I need to check out the Speedi sleeve.

 

[midfat]

Same happened on mine. Fresh seal started leaking within a few months. Had to go back in and install a second seal. Just be really sensitive when you drive in the new seal to keep it going straight. Go slow, tap gently and don't drive it in past flush to the machined surface. I didn't see any grooving on my axle shaft, but I did clean it up with a little emery cloth just in case. Been several thousand miles now and all is good. No axle oil commingling with birf grease.

 

[LINUS]

If you do find a groove on the shaft, the Marlin seals could be an answer too - they are a good 'last time' seal to run on inner shafts that otherwise grooved since they ride in a slightly different spot due to thickness.

But yes, if given a choice of OE seals & Marlins, if the inner shaft has a decent sealing surface I'd go back with OE's.

The last time I did a FAS memory the RH shaft (long side) was ~$100 / @cruiserdan price - I needed the shaft as I'd bent the shell, cracked parts (female side driven cuff the shaft rides in) -in the 3rd & those parts destroyed the splines on the 3rd member end of inner shaft. Needless to say I had birf soup on that side, but surprisingly less than you'd expect.

And I drove a good month on all that jumble in the axle, as it surprisingly didn't act like it had been beaten to any degree. Biggest symptom was a failed gasket between the axle shell & 3rd, so I was dripping diff fluid everywhere I parked.

 

[LandCruiserPhil]

If grooved you dont need to drive the seal in all the way getting away from an axle groove. Marlin seal is a good seal but not ideal for a FT 80 series IMO. The Marlin is not a suspension seal like OEM making it more forgiving than a fixed seal like Marlins.

 

[NLXTACY]

If the seal is riding in a valley on the axle shaft then the best option is to overdrive the seal onto a untouched portion of the shaft. If doing this sounds like something that sounds scary enough doing it flat, much less further in and at the right depth, fear not. I have it on good authority there is a solution in the works

 

[Nostradamus]

When I did this on my 60, I used the Marlin seals, and used emory cloth on the shafts at the point of contact (seal/shaft), and left the seal face about a "zillimeter" proud of how the OEM sat in the hopes of having the new seal meeting a part of the shaft that was not where the old seal sat.

It's been about 2.5 years and 7500 miles (my 60 is not my DD) w no issues.

 

[BILT4ME]

One thing that NO ONE has addressed is the axle vent.

I rebuilt my front axle and within 12K I had birf soup. I KNEW I had done everything correctly, but I did NOT clean and rebuild my front axle housing vent.

After I had the Birf soup, I did a drain and refill of diff, then removed the vent hose, the vent elbow, and cleaned it all out. Make sure you actually UNSCREW the elbow on the axle housing and clean it out as well as the hole in the housing. Mine was so caked with gunk that I had to soak it in brake cleaner to then icepick it out. I then added about 48" of 1/4" ID fuel hose, and a fuel filter, ran it up over the brake booster, and clipped it on. Make sure you install the fuel filter in the VERTICAL line before it goes over the booster. Otherwise, it may burp gear oil up there and then the filter will get clogged and it cannot drain back again.

What caused it is the heat of driving warms up and causes pressure in the housing. It chooses the weakest seal to vent through, so it pushes oil into the birf. When it cools back down, the vacuum sucks in the grease from the birf, contaminating BOTH sides. Once the vent is open, the housing is allowed to vent both directions and the problem goes away.

I never replaced my seals a second time. I have NOT continued to have the problem after fixing the vent.

 

[landshark1]

So it sounds like when I install the new one to not quite tap it in all the way. It is still odd to me that the old seal was not leaking, but the new one is leaking unless I did not install it perfectly.

NLXTACY, I would love to know what you are talking about

 

[Malleus]

You could have a bad seal. It's rare, but it does happen. The best you can do is the best you can do. That's all that was done when it was built.

 

[landshark1]

One thing that NO ONE has addressed is the axle vent.

I rebuilt my front axle and within 12K I had birf soup. I KNEW I had done everything correctly, but I did NOT clean and rebuild my front axle housing vent.

After I had the Birf soup, I did a drain and refill of diff, then removed the vent hose, the vent elbow, and cleaned it all out. Make sure you actually UNSCREW the elbow on the axle housing and clean it out as well as the hole in the housing. Mine was so caked with gunk that I had to soak it in brake cleaner to then icepick it out. I then added about 48" of 1/4" ID fuel hose, and a fuel filter, ran it up over the brake booster, and clipped it on. Make sure you install the fuel filter in the VERTICAL line before it goes over the booster. Otherwise, it may burp gear oil up there and then the filter will get clogged and it cannot drain back again.

What caused it is the heat of driving warms up and causes pressure in the housing. It chooses the weakest seal to vent through, so it pushes oil into the birf. When it cools back down, the vacuum sucks in the grease from the birf, contaminating BOTH sides. Once the vent is open, the housing is allowed to vent both directions and the problem goes away.

I never replaced my seals a second time. I have NOT continued to have the problem after fixing the vent.

If the vent were clogged, then why had it never been an issue with the old seal when I changed diff oil? Just trying to understand...

 

[Dave 2000]

I am a time served mechanic and rebuilt my own axle. Despite OE seals and correct tools and procedures, one side did leak a short while later, why I have no idea? I fitted another OE seal and has been good for around 6 years and around 80,000 miles. Recently seen some oily discharge from the knuckles, two Marlin seals sitting on the shelf, just need the tiiiiiiiiiiiiime!

Regards

Dave

 

[BILT4ME]

If the vent were clogged, then why had it never been an issue with the old seal when I changed diff oil? Just trying to understand...

Because the old seals did not hold as tight and allowed more free air flow between the birfs and the housing and possibly through worn wheel seals. As a whole, ALL the seals allowed air to pass more freely, whereas NEW seals all fit much tighter and thus, hold more pressure or vacuum.

 

[landshark1]

You all are awesome! Thanks are all of the info. Truly appreciate the collective wisdom of this forum.

 

[2fpower]

Because the old seals did not hold as tight and allowed more free air flow between the birfs and the housing and possibly through worn wheel seals. As a whole, ALL the seals allowed air to pass more freely, whereas NEW seals all fit much tighter and thus, hold more pressure or vacuum.

I agree with @BILT4ME

The prior owner of my 97' (Boost) solved the risk of water coming down the vent by sealing it with marine silicone. Yeah!

 

[inkpot]

If the seal is riding in a valley on the axle shaft then the best option is to overdrive the seal onto a untouched portion of the shaft. If doing this sounds like something that sounds scary enough doing it flat, much less further in and at the right depth, fear not. I have it on good authority there is a solution in the works

Whoda thought?

 

[NLXTACY]

Whoda thought?

It’s partly your fault

 

[86tuning]

You could have a bad seal. It's rare, but it does happen. The best you can do is the best you can do. That's all that was done when it was built.

Years ago, I had a leaky Toyota axle seal on a different application (rear of a 4Runner). When inspected upon removal, it wasn't leaking from the seal/axle interface, but rather from the outside of the seal between the seal and the housing. This was due to installation error on my part. The outer portion of the seal was damaged and was no longer a tight fit with the housing. Had this been at 12 o'clock position it would have been fine, but at 6 o'clock position it seeped enough to wet the brake shoes on the 4Runner.

Get a new inner axle seal. Remove the old seal and inspect, then install the new one. Check for evidence of leaks next week.

 

[landshark1]

Spent 5 hours on Sat redoing the seal. Good times..... I really hope it does not leak.