Failing Already? Front Inner Axle Seals (2 Viewers)

[scottcb]

About 5 years and 3,000 miles ago I did a knuckle rebuild using the kit with the heavy duty seals from @cruiseroutfit . I was underneath recently and noticed there is some fluid on both sides on the four studs under the knuckle. Not horrible yet, but definitely there. So my question, is it normal for those seals to fail or start leaking this soon? Or would there be some other reason for the leaks? I’ll refill the front diff but I’m fairly certain not much has leaked out. From what I’ve read around, this seems like a fairly regular maintenance item, but because of the low miles driven, I was surprised.

 

[3_puppies]

are you sure it is gear oil?
dino grease will separate and you will get some liquid out of it

 

[cruiseroutfit]

5yrs/3000 miles is certainly premature for an inner axle seal failure, particularly on a part-time 4WD setup. Failure modes could be seal failure, inner axle seal groove, damage during install, over-pressure of the differential housing (poor venting), etc. As @3_puppies mentioned, gear lube will separate, make sure you're seeing a drop in gear lube at the diff before you get too alarmed.

 

[kevin in okinawa]

About 5 years and 3,000 miles ago I did a knuckle rebuild using the kit with the heavy duty seals from @cruiseroutfit . I was underneath recently and noticed there is some fluid on both sides on the four studs under the knuckle. Not horrible yet, but definitely there. So my question, is it normal for those seals to fail or start leaking this soon? Or would there be some other reason for the leaks? I’ll refill the front diff but I’m fairly certain not much has leaked out. From what I’ve read around, this seems like a fairly regular maintenance item, but because of the low miles driven, I was surprised.

did you retorque the nuts and clean the area to see if it continues?

 

[Spike Strip]

You didn't say if you used the Centering SST when you did the rebuild, so If the axles aren't centered (SST) or the shims are re-installed incorrectly making the axle out of center, the seals will wear quickly.

Also, even if you don't drive much, you need to engage 4wd and lock axle once-in-a-while, to keep everything lubed and churned in the front axle and transfer case. Try to do on dirt or anywhere but pavement.

 

[scottcb]

Good comments and tips. I have not retorqued the nuts - happen to know the torque spec? I don't remember if we used the Centering SST when we did it. I'll check the fluid level today and attach a couple of pics of what I'm seeing.

 

[BGarcia88FJ62]

As long as you put the Top and Bottom shims back on the knuckle in the same order the SST isn't necessary.

 

[scottcb]

Checked the fluid level which seems fine because when I opened the top of the diff some fluid came out, so that makes me think the level is ok. Here are some pics of what I am seeing and the color of fluid at the end of the studs. No drips , just getting messy. Just thinking, if fluid came out the top so easily, could it be overfilled? I don’t know how I would overfill it though?

 

[gt7058a]

over-pressure of the differential housing (poor venting), etc.

You should check the axle breather vent cap to see if it’s stuck. Look for a tube running up to the frame rail. There’s a spring loaded vent inserted in the end and they can get clogged up, which allows pressure to build up and gear oil to push through seals. I think it’s on driver side of the axle.

Pull out the vent valve and try blowing air through it.

 

[scottcb]

I will definitely check that breather later today. That might explain why fluid start pushing out so easily. Really appreciate all the ideas to help chase it down.

 

[3_puppies]

as clear as the oil is on the wipe, my WAG is oil is separating out of the grease

for the oil to be low in the diff, you would need to lose quite a large amount

 

[scottcb]

So here’s what I did tonight…found the breather valve and it was a bit crusty. Pull it off the hose cleaned it out good and it seems to be functioning; I can blow air through it when I press down on it, air is obstructed. Interestingly, enough, as I was working on the breather, the hose was dangling down, pointing down. When I came back, there’s a little bit of diff oil coming out of the hose. That told me that there may have been some pressure in the diff. So I pulled the whole hose off, cleaned it out, real good and reinstalled everything. I decided to check the diff fluid level to see what was going on. again, it started leaking oil out, so I just let it drain to the proper level. Here’s a picture of how much ended up coming out. So I’m wondering if whenever I filled it last, if I somehow overfilled it? The only way I could’ve possibly done that was if it were up on the jackstand or the car was not level. I don’t remember for years back, but anything is possible. So I’ll clean things up, and see if the oil starts to come back again. Let me know if anyone has any better logic than mine to think through this. So if it were, indeed, overfilled, and that breather valve wasn’t functioning correctly, is it feasible that there would’ve been pressure pushing oil from the diff out of the axle seals?

 

[gt7058a]

I think the leakage was definitely caused by pressure due to vent being clogged. It’s likely you may still have a leak because now the seals are compromised. The drainage you’re seeing from the full plug could be related to temperature. Do you recall if you filled it in winter?

 

[samc2447]

Checked the fluid level which seems fine because when I opened the top of the diff some fluid came out, so that makes me think the level is ok. Here are some pics of what I am seeing and the color of fluid at the end of the studs. No drips , just getting messy. Just thinking, if fluid came out the top so easily, could it be overfilled? I don’t know how I would overfill it though?

View attachment 3308530

Post a better picture of the knuckles. There is a lot of grease getting past the wiper. Are you sure you put them back together properly?

 

[scottcb]

I think the leakage was definitely caused by pressure due to vent being clogged. It’s likely you may still have a leak because now the seals are compromised. The drainage you’re seeing from the full plug could be related to temperature. Do you recall if you filled it in winter?

I wish my memory was that good. I’m in Arizona so I’m sure I did it before it was too hot here, it wouldn’t have been cold. Cruiser is garaged and the garage in the summer is extremely hot.

 

[scottcb]

Post a better picture of the knuckles. There is a lot of grease getting past the wiper. Are you sure you put them back together properly?

View attachment 3309376

Anything is possible as it was a first time job, but having said that I did things slow, following instructions closely while also watching videos and was meticulous about the torque on every nut. I cleaned them up last night and will pay attention to see if I start seeing fluid. In my opinion the oil sealing out was consistent with the gear oil in color, texture and smell.

 

[scottcb]

Replying to myself
Been a while and the evening temps have broken below 90. I pulled out the cruiser and more grease on the floor. It’s kinda got a pinkish hue which makes me wonder if it’s the grease in the knuckle. The picture doesn’t show the color well. I cannot imagine that the grease is separating in there…anyone seen that before? I may open that side back up and see what’s going on.

 

[WILLD420]

Grease will separate above 90 degrees. Just hang a grease gun up with the pull bar pointed down and leave it there for a couple of summers above a drip pan. You'll be shocked how much oil comes out of that grease. Tucson temps are certainly hot enough, especially after the July and August you had this year...

 

[cruisermatt]

I agree it is oil separating out of the grease, we have big 5-gallon Moly grease pails here and pools of oil will form in the middle of them. Have had several customers ask about mild oil just like this after knuckle jobs in the last year.
If it was a actual seal failure there would be a lot more and your oil level would be low.

 

[scottcb]

That makes sense. I’ll retorque things up and watch it during the winter and see if anything improves. As always, thanks for the collective feedback and experience.