Can rear axel seals fix themselves? Unique situation...

Jason B

Jason B

Official Vendor
So, you guys might think this is crazy, but as I mentioned in another post, my axel seals were leaking for the past few years. Don't drive the truck that much right now. I filled the rear pumpkin over 3 months ago and was able to add about 22 ounces of diff fluid until it became full again (diff holds 96 ounces total when full, 3 quarts about). It's been 2 months and NO MORE LEAKING. Can this somehow fix itself?
 
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Sometimes it's just the breather stuck shut.

If you've been taking shorter trips since then, maybe it's not warming up enough to make pressure to push oil out past the seals (even good seals can't hold back pressure like that). Or maybe you freed up the breather somehow (even if you just bumped it). Tired seals that are leaking even with the breather venting properly aren't really going to fix themselves though.

Well, on second thought perhaps the new oil had some of that 'high mileage' additive which swells up the rubber in the seals?
 
JohnMc said:
Sometimes it's just the breather stuck shut.

If you've been taking shorter trips since then, maybe it's not warming up enough to make pressure to push oil out past the seals (even good seals can't hold back pressure like that). Or maybe you freed up the breather somehow (even if you just bumped it). Tired seals that are leaking even with the breather venting properly aren't really going to fix themselves though.

Well, on second thought perhaps the new oil had some of that 'high mileage' additive which swells up the rubber in the seals?
Click to expand...

Interesting... Somehow it fixed itself.
 
It could, depending on humidity and other factors. But it is only temporary, not a permanent fix. Have you bothered to look inside your drums?

If you do nothing else, change the breather on the axle for peace of mind.
 
Are you pulling the ABS sensor to check the leak? Looking at the drum itself is not a good indication for smaller, slow leaks.
 
Probably a stuck breather as another mentioned. The breather IMO is serviceable in many cases and acts as a check valve. Remove it - use an air nozzle off a compressor to blow air through it. If it un-sticks or allows air through it / re-seals then do the following....
- first spray a bit of lectra motive contact cleaner inside (made for electronics but...) this will remove most oxidation and nastyness / flush it out.
- Once dry, then spray some silicone lubricant inside.
- Last, blow compressed air through it again several times in short bursts. If it opens and closes nicely - you are set. Re-install and check again in another 60K miles.
 
I've had this truck for 17 years, no trolling :) It may be a rare case, but there could be a chance that fixing a clogged breather stops leaking, or maybe the gear oil that could have been thicker that was mentioned... Something stopped it, and level is full in the diff.... It's now been 6 months and counting and a few decent trips.

So, for the heck of it. Anyone who starts noticing some leaking, remove and clear out the breather, clean out your drums (which I did 6 months ago), and wait and see if it stops before you spend all the money and time to fix it. I fixed the seals many years ago, but makes me wonder if it was just a clogged breather, which I'll never know.
 
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I side swiped a lamp post last winter and my passenger side rear wheel took the brunt of the impact (broke a chunk off of the rim, had to trash it).

I've been nervously keeping an eye for a leak as I have no clue if the impact screwed up a bearing or bent a seal or something. So far, no leaks or rear brake problems that I can see, but man it makes me nervous.

When I left for work this morning (in my wife's car), I noticed some wet lines on the inner side of the rear driver's side tire. My heart jumped in my throat, but just drove off to get to work. Now I'm anxiously awaiting to get back home so I can have a closer look. I'm hoping it was just my imagination, but it still makes me nervous.

If I had one complaint about owning an almost 20 year old vehicle and knowing what I know about the common issues with 3rd Gen 4Runners, is that I feel like I can never truly enjoy it because I'm always nervous about the next thing that's gonna break.

Other people beat the crap out of their vehicles and never worry about a thing until they need a tow truck, I'm not like that. I don't think I'm made to own an old vehicle as it always has me on edge. I never stray too far from home with my 4Runner as I never wanna be left stranded and having to fork over gobs of cash for repairs all the time.

I bought a 3rd gen because of its "reliability", but I just haven't felt the peace of mind that I thought I would and my wife gives me the evil eye because as soon as I do preventative maintenance on one thing, I'm looking at the next. This is supposed to just be a second vehicle (I've put less than 4K miles on it and just as much money into it in 2 years of ownership), not a money pit.

Anywho, lately the axle seals and rear bearings have been a concern for me, even though the previous owner said he had them replaced about 4-5 years ago. But hitting that lamp post has made me vigilant.

I need to learn to just drive the thing until it actually breaks.

unfortunately, for now though, I'll have to take a look at the diff breather and inspect for leaks again. :moping:
 
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Jason B said:
I've had this truck for 17 years, no trolling :) It may be a rare, case, but there could be a chance that fixing a clogged breather stops leaking, or maybe the gear oil that could have been thicker that was mentioned... Something stopped it, and level is full in the diff.... It's now been 6 months and counting and a few decent trips.

So, for the heck of it. Anyone who starts noticing some leaking, remove and clear out the breather, clean out their drums (which I did 6 months ago), and wait and see if it stops before you spend all the money and time to fix it. I fixed the seals many years ago, but makes me wonder if it was just a clogged breather, which I'll never know.
Click to expand...

For the hell of it, what fluid did you use?
 
Sorry, don't mean to hijack thread, but I have a rear diff leak and need some help ASAP!! I just joined yesterday and can't post a new thread. Can I post a question on this one? I'd really appreciate it.
 
Here's my story with my 97 with 207k miles

I changed the rear diff fluid (standard cheap ass fluid) when I first got the car from my brother. I also did the extended rear diff breather mod shortly after the fluid change. After weeks of reading on this forum about various things (axle seals come up often), I decided to check mine even though I had no indication they were failing (no wet drums ect).

I opened up the abs sensor port and inspected for any gear oil and sure enough, I found trace amounts of old dark diff fluid on the ABS gear. If I would spin the wheel, every 4th or 5th tooth had some oil on it. I also stuck my inspection camera in the opening to see if there was a pool of oil and there really wasn't, just a trace amount on the bottom.

I used pipe cleaners and long Q tips and cleaned it up the best I could. The amount of oil in there was so low that I doubt it was even high enough to be at the level of grease seal on the bearing.

Checked the other side and it was exactly the same, so I did the exact same thing. I cleaned it up and called it a day.

A couple months later I checked to see if I had nice new clean oil in there (since the oil in the diff was now new) and I effectively found no new oil.

Can the seals fix themselves, probably not. Can you fix the problem that is most likely causing the seals to fail (totally clogged diff breather like mine), YES!

Btw, I checked my bearing and they have virtually no play in them.

I'll continue to monitor for leaks but its been months now and I've towed some heavy boats and driven 4 hours up north and even did some moderate wheeling, no new leaks...

Whenever a new "just bought a 4runner, what maintenance things should I do" post shows up, I now always tell them to do the extended diff breather mod. It is the cheapest insurance you can buy in helping to prevent axle seal failure.
 
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I had a slow rear left axle leak after an offroad trip. I did a breather mod and no leak so far. I'm just hoping it was a clogged breather. I'll keep an eye on it but got the rebuild parts just in case.
 
thegipper said:
Fire away! What's up?
Click to expand...

Thanks! Sorry, I am slow to react. Getting used to this site.

I have a 2001 SR5 4x4. I have a rear diff leak. It has gotten worse over the last week or so. Back story... noticed oil coming from rear end back in July. It was dropping oil on driveway. Husband looked and confirmed it was coming from rear diff. He did the best he could to plug it with that JB Weld stuff. It held for a few weeks, but then started leaking again. At first, it would drop a tablespoon or so after it was parked then stop. Now, over the last week or so, it seems to drip a little at a time, all the time. My husband says there is a broken bolt where the leak is coming from. The car is not showing any other evidence of this aside from what I see underneath the car. No noise, etc. My question is... to the best of your knowledge, is this something that would require the entire rear axle to be replaced, or is there some way we can fix the bolt to stop the leak? And, where do I get this done? Am NOT going to dealership!! I am so worried about this, and we are so broke right now, and this is our only car. LOL, and, we are moving 1100 miles away in the spring and I need this car to last for that move.
 
Is the leak coming from where the brake cable bracket is? That is a common area for leaks.

When you did the jb weld repair, did you first drain the diff and clean up the area? If not, it won't seal it very good.

Post some pictures of the leak, that will give us a better understanding if/how it can be fixed.

Worst case scenario would be a new cover, if that is where it's leaking from. Generally, you would remove the carrier (3rd member) and have a shop cut out the old cover and weld in a replacement.

Sent from my SM-N910V using Tapatalk
 
thegipper said:
Is the leak coming from where the brake cable bracket is? That is a common area for leaks.

When you did the jb weld repair, did you first drain the diff and clean up the area? If not, it won't seal it very good.

Post some pictures of the leak, that will give us a better understanding if/how it can be fixed.

Worst case scenario would be a new cover, if that is where it's leaking from. Generally, you would remove the carrier (3rd member) and have a shop cut out the old cover and weld in a replacement.

Sent from my SM-N910V using Tapatalk
Click to expand...

When my husband did the weld plug, it didn't 100% seal it. He described that there was a pinhole still open? If that makes sense. No, we did not drain the fluid first. After his attempt at sealing, at a routine oil change, he had the shop do a diff service where they drained and replaced the fluid.

As far as the brake cable bracket, my husband says it's not coming from there.

I am happy to provide pictures. Husband has car so it will be later today. What specifically would you need a picture of?
 
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