I recently discovered a dreaded gear oil leak on my 4Runner, and knew it meant only one thing - it was time to change the rear axle seals (and bearings and brake shoes since they were now saturated with oil). In addition to the story of the 4Runner repair, and later the Tacoma repair, I figured a detailed set of instructions for anyone wanting to tackle this themselves would be nice to put together, since it's hard to find that written down in one concise place (maybe even impossible before now).

if that grinder got into the axle. yes it will leak axle lube again, and of course the axle lube soaks into the brake linings. I use a Dremel tool with a reinforced disc to cut the retainer ring. being vey careful with the depth. then chisel to crack the ring comes off easily. not a job for rookies or the diy guys. Toyota Master Diagnostic Tech japanwest @ yahoo.com

Glad that the guide could help you! Depending on where the cut with the grinder is, I think I'd replace the entire axle, especially if the vehicle will be used off road or in remote locations where a tow isn't cheap/easy.

This isn't always possible, but if you can understand why the rear axle seals started leaking in the first place, it will make doing the job successfully easier. There are many reasons they could start to leak, but the three "most common" reasons I've seen are:

Sorry if that last answer was unclear (and for that inadvertent "test" email I sent you; I meant to send that to myself!). I'll try again ?...

As you can imagine with a job like this, there are quite a few parts and tools you need to complete it quickly and safely! I've tried to break down what's required vs. optional for you, though of course someone else's situation might mean suggest differently than I have. If in doubt, I'd purchase items in this list and return them, so you aren't stuck in the middle of the fix, waiting for a part or tool you don't have.

P.S.- Got your Tundra brakeline kit and installed with no problems at all per your other tutorial...thanks for that too!

As far as tools go, there are several specialty service tools (SSTs) that you'll need to complete the job. While these tools are technically optional, and you may be able to fabricate some stand-in yourself, I cannot stress enough how much easier they made this job. If you're tackling this yourself, buy all of these tools - especially the Rear Wheel Axle Bearing Puller & Tone Ring Tool/Installer - it is frankly one of the most well-designed tools I've used for its purpose. They will double the cost of the job, but it's still less than half of having Toyota do it, and you have the tools for next time and other jobs!

Axle bearingpuller

Would i need to change the inner axle seals on my truck if I'm going in to replace the third member? I don't have a leak currently, all I need to do is pull out the axels a little to be able to change my third member.

I need your advice on the axle seal/ retainer alignment portion of the process. I had a local machine shop pull old parts, and press all new OEM parts back onto the axle (they said they have done many taco axles) , and I seated the new axle seals myself. I followed your instructions to the letter on that, with freezer, grease and oil etc....They are fully seated, and sit exactly like yours in the picture, but when I performed the sharpie test, both retainers show the witness mark from the sharpie/rubber seal at about 2mm in from the bevel of the retainer.

Therefore, while a conventional driver can be used, a good deal of situational awareness needs to accompany that usage, which may entail modification of the driver to be the correct size.

Hey Trey - I think you might have misunderstood the point of the guide. I lay it out at the top under "Doing the job": This list of steps is just that - a list of steps (which makes it a great resource to print off and reference when you're doing the job).

Also, if the grinder cut is anywhere on the polished portion of the axle shaft, it will prevent the entire shaft from sealing correctly, given that all the retainers (etc.) are pressed on, and rely on that press fit in order to seal.

Rearaxle bearing replacement

And of course, that's where the new one is installed, per the instructions that I previously referenced: Install New Axle Bearing and Dust Seal in Brake Drum. You're looking at steps 7-10 in that section.

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Turbodb, this looks like an adventure! Great pictorial Perhaps I will be one of those taco guys that never need to do this, currently have 218k/25yrs on my old rig But I had a mess of repairs this year of '21 already Crankshaft pulley split whilst on the highway roll Wheel bearing front driver side went after that Then the clutch slave master cylinder The clutch bearings are starting to get sketchy now LOL So yeah hopefully the rear axle seal on the rig stays good, at least until I recover from replacing front steering arm bushings and finally repair the bad frame coating boo!!

Great write up. I have a 2000 tacoma trd without ABS. Just wondering how much different this job will look for me? Looks like it'll be alot easier, is that correct? Any insight is appreciated, thanks man. Been a fan of your write ups for many jobs!

A common statement is "the leaking gear oil has washed the grease out of the bearing and it's no good". Well maybe, maybe not. This comes down to a judgement call that in most cases is way beyond the capability of the average wrench, even pros. A bearing that feels rough is one thing, some degree of wear is another. A bearing that someone insists is still good should at least be repacked with fresh grease. The safe bet is just replace it.

If you read another sentence there, it tells you where the photos are: If you're curious about what a step looks like, I suggest reading the story of my shop day.

The drivers in the OTC 4507 Seal Driver Kit (and others) are often made of aluminum and can be turned down - with a lathe or drill and sandpaper - to be the perfect size to drive in the seal.

When a driver that is too small is used, the seal can deformed. Here is a photo of what appears to be extreme inward bending/deformation of the face of the seal.

Thanks Jeni. Just did a quick lookup, and those part numbers that you listed are the "old" part numbers, replaced by the ones I've got in the writeup.

Of course, in addition to SSTs, you'll need a reasonably well-equipped shop to tackle this job. Here's the additional list of tools that I used to complete the job, as well as having additional tools at my disposal in case I needed them.

Is it as simple as taking the axles back to the shop and show them the witness marks, so they can adjust the retainer to contact the seal at about 4.5mm, or center-ish? I am unsure because both axles sharpie tested/witness marked so evenly at that same measurement/position on each retainer....

Frontaxle bearing replacement

well thank you very much, just by notating the orientation of the retainer after Toyota did the seal upgrade is a huge plus. thank you for taking the time for helping out even for shops like ours that want to do things the right way. have a blessed day. overall the best step by step there is out there. My situation is that after i removed everything with tools I've notice a significant cut with a grinder and everything looks new but it came to our shop because it still leaking. should i replace the axle. Thats going to be our recommendation but would like to know your opinion its an expensive one.

There, you'll find pictures of basically every step. But you probably don't want all those in a print out, so that's why they aren't in the printable list.

Thanks so much for putting this together, so incredibly helpful. I recently followed your write up on rebooting CV axles and made the job so easy, though quite messy. Was trying to figure out why I was getting a squeal from rear brakes, so pulled the drums and one side was coated in oil. Found this article and read through it numerous times and figured with the right tools it was doable for this 70 yr old . Buddy offered me use of his shop and shop press so that eliminated one major expense. A few thoughts why still fresh in my mind. 1) Ordered all OEM parts from PartSouq. About a 40% savings over any online Toyota dealer. 4 day delivery from Dubai to CA and no sales tax. 2) Rear axle bearing puller from Duane was amazing and with the things in the kit, I found no need for the 5/8" socket or 4x4 plate you mentioned. 3) Since I recently changed the rear diff fluid, I didn't want to drain it again. Found by the raising the side I was working on, no fluid leaked out other than what little there was on the axle shaft. 4) I capped off the disconnected brake line and also plugged the hole. Just to make sure nothing got in there. 5) Toyota says if you just disconnect one brake line you only need to bleed that one brake, so when I finished one side, I did the one man bleed job. A 3/16" ID vinyl hose fit perfect with no leaks. 6) Debated if I needed to do the other side but when I pulled the ABS sensor I could see oil in there. So only a matter of time before it got on brake shoes and went ahead and did 2nd axle. 7) Buddy had a 3/4" large socket that fit perfect for new oil seal, so eliminated need for seal driver kit. 8) Followed your write up on rear drum brake replacement too. Big thanks!!!

EDiT: to my post about the part numbers. I just talked to the parts dept at the dealership and he verified that 90310-50001 has been updated to -50006.

In general, it should be as simple as taking the axles back to the shop and having them move the inner retainer the appropriate amount (and, that's pretty normal - I had to move my retainer a couple millimeters one direction or the other the first time I tested the fit).

Because it is difficult to find a perfectly sized seal driver, and because a slightly-to-large driver will not fit in the axle housing, it is common for a too-small driver to be used, deforming the seal.

Thank you again for replying and keeping in touch. Here is a link of the cut in the axle. Please let me know what you think, I'm trying to get this out of the shop but in the right way. Thank you for the work you do and the knowledge you share with us. I'll wait for your final verdict in this crucial case.

Though there are only a few steps here, this is the most important part of this entire job, and the most common place that mistakes are made because it's easy to deform the seal during installation.

After Toyota adopted the new seal there were still numerous cases of repeat leaking so they came up with a special seal driver SST and a service bulletin.

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Thanks for getting back to me so quickly, excellent write up by the way. Part number 90313-54001 I see it listed at the beginning of the article but then never shown in the article, unless I missed it. Does that dust seal go in the brake plate ?

One of best website for 1st Gen Tacomas around. I tow a boat (about 2200lbs), very short distances, and occasional loads. On average, how often can i expext to replace these seals? Its a very expensive job where I live and I just did one last year! Thanks!

The issue is the flat vertical metal portion of the seal (yellow line) can easily be bent inward and deformed (red line) if the outer diameter of the seal driver does not press of the outer diameter of the seal.

Hey Kerry, Glad to hear the tutorials have been helpful! I've gotten a ton of help from folks over the years, so it's always nice to be able to provide a bit of the same.

With all the parts and tools gathered, it's time to get to work. Perhaps obviously, the job is mostly a bunch of removal of parts, and then a bunch of installation of those same parts - or rather, installation of replacement parts. This list of steps is just that - a list of steps (which makes it a great resource to print off and reference when you're doing the job). If you're curious about what a step looks like, I suggest reading the story of my shop day, or watching this video to see how something is done.

Awesome Don! So glad the guide was useful for you, and thanks for all the notes you've added. I really like the "top the axle housing" trick (#3) to save yourself from draining the rear diff. I think I might have been in a similar situation (it was long ago now that I don't totally remember), and I might have drained the gear oil into an old milk jug and then re-used it when refilling the diff.

That link (which I have deleted) was to a local file on your computer, and not in the correct format for a photo. Feel free to upload the photo to a photo hosting site like imgur.com, and then post a link to it here and I'm happy to take a look.

The dust seal you are wondering about is what I'd previously mixed references to (seal/shield), so that was a good catch. It is a seal that goes on the brake side of the assembly, prior to reinstallation of the axle shaft.

Nope, no need to change the rear axle seals when you pull the axles, just be careful when you pull them so you don't damage the seals. Are you changing your gear ratio, or just swapping in a new third? Good luck!

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In general, continual leaking usually is an indicator of a bent axle or improper placement of that retainer, so that's where I'd start! ?

With the seal redesign, flipping the inboard retainer is probably not necessary, but it does no harm and could cover for a degree of seal deformation.

Axle bearing replacementcost

I don't have a picture of that seal - either the removal or installation - as part of the process, but the old one was removed from the center of the hole in this photo:

This is of course based on two amazing resources - first and foremost are some videos by Timmy, which are great. Second, is the Factory Service Manual (FSM) description, but varies slightly (to make things easier) and doesn't require flipping back and forth between many different sections.

Hi Noni, Assuming that your axles and axle housings are in good shape, and the job is done correctly, you shouldn't have to replace the axle seals very often - they should last over 100K miles, easily. Many owners never have to replace them. When you have to do one however, it's generally a good idea to do both - they are usually subject to the same stresses, etc. Hope that helps!

One other thing I should note: some trucks that don't have functioning ABS, still have ABS axles. I'm pretty sure that all 1st gen Tacomas with e-lockers also have ABS axles (and bearings, etc.), regardless of whether the "feature" is enabled on the truck.

Brake shoe kit 04495-35151 was replaced by/with 04495-35230 Inner Seals for Axle Housing 90310-50001 was replace by/with 90310-50006

If you'd like, shoot me an email (just reply to this email that you're receiving about my comment reply) with a photo of the witness mark on the retainer and I'm happy to take a look. ?

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Hi Bruce, Looks like I called them "Dust Seals" in the parts list and on removal and "Dust Shields" on installation; thanks for pointing it out! I've updated the entire post to use "Dust Seal," and you can find the installation section entitled: Install New Axle Bearing and Dust Seal in Brake Drum. Hope that helps! Did you have a specific question about the seals?

All Toyota said was that a conventional seal driver could damage the seal. I have never seen one of these SST drivers but the issue it addresses is real.

Yes, the Branick was a nice splurge. I got after picking up the ADS shocks, since I knew I'd eventually want to rebuild them. Turns out that having it meant that I could do my own assembly of the OME coilovers that I purchased for our (short-lived) 3rd gen 4Runner, and I've since used it for shock rebuilds on my - and several of my buddies - trucks. Love that thing, and it makes a job that is seriously terrifying, a walk in the park. I love it.

At first was trying to figure out what was to the right of your 20ton. Then discovering it was a Branick Strut Spring Compressor. Wow that is the gold standard. Very smart, not overkill as some would say. Having friends try to make do with Harbor Freight or similar compressors, and seeing them bend and groan, they stopped and headed to the nearest shop.

Hey Cully, the process will be conceptually the same, so if you're just following the flow of the process, you should be good to go.

OTC 4579 Seal Puller Kit - this slide hammer makes pulling the old seals easy and prevents any damage to your axle housings. It feels expensive, but is worth it (and versitile for other projects).