Reoccurring Rear Axle Seal Leaks

Is there a common mistake/cause for leaking rear axle seals after replacing seals & bearing? Besides rear diff breather

History:
2020 passenger rear axle slinging oil all over wheelwell. Had one shop replace the seals and bearing.
2021 (less than 1 yr later) same problem. Brought back to same shop for warranty on service/parts. Immediately (same day) after 2nd replacement, gear oil still slinging. Was given a refund and brought my truck to a different shop.

The 2nd shop replaced seals & bearing for the 3rd* time. This shop said the previous shop never replaced the old bearing. I don't know who the believe.

2023: driver side rear seal starts leaking. Brought truck back to 2nd shop for the repair.

2024: brought truck to a 3rd shop for unrelated repair. They did an inspection and say BOTH sides are currently leaking into my brakes and that it's the axle seals

Could there be an underlying problem getting overlooked? Or just bad work? How can I make sure this 3rd shop gets it right?

Thanks y'all!

 

The retainer position matters and you cant simply install it in the same position every time, the depth has to be set to the seal.

Hard to explain, but most techs just measure the seal retainer/abs tone and send it. But in reality, I go shallow and test the seal depth with grease to see how far the seal is contacting.

Those tacomas have stupid axle seal designs due to abs, but a lot of techs dont understand how it works. So very little seal to retainer contact is made.

 

@turbodb Do you have a write up on this?

 

Yes, as has been mentioned, they can be challenging to do correctly. I've even had a Toyota dealership fuck it up this job.

Have any of these 3 shops you've been to ever verified the straightness of your axle shafts before slapping on new bearings and seals. Any runout at the flanges?

One thing you can carefully do at home is to put your rear axle up on jack stands so both rear wheels are off the ground. Start the truck and gently put it into drive. This way you can visually see any wheel wobble.

 

I ended up just using a shit ton of rtv around my axles and diff when I couldn’t get them to stop leaking. But mine was only a weep or drip at most. Not flung everywhere.

 

I followed Timmy's YouTube video to a T and got it right on both my '03 Tacoma and '98 4Runner, neither have leaked and it's been over a year. Maybe the first shop damaged the inner lip of the axle housing where the seal sits when they removed the old seals, and no seal will seal properly now.

 

It’s very common. I had an axle bearing go out (so far the only time my truck has stranded me on the side of the road), got it towed to a shop and had them do both bearings and seals. Same deal. Leaking a month later. Brought it back, had it fixed. Leaking again two weeks later. Finally brought it to my preferred mechanic in another town. Going four years now with no leaks. They’re temperamental to begin with, then over time, where the seal sits wears, making a leak even more likely. Then you need a specialty tool to press things off correctly and if they don’t have it at the shop you get a hack job.

 

Yeah, he does

https://adventuretaco.com/guide/ste...ring-w-abs-1st-gen-tacoma-or-3rd-gen-4runner/

 

Without knowing what parts they used (OEM vs aftermarket) it's hard to say. Way back in the day when these trucks were new, the rear seals were a big problem, to the point where the seal design was updated in the mid 2000s. Those of us who frequented the trails were replacing the seals (and usually the oil coated brake shoes) on a near-yearly basis. It was a pain. Then the new design seal came out, and that solved most of our problems. It wasn't an issue with the bearings, cause they were all still new at this point. That all being said, seal design and manufacturer is important here- if the original design OEM seals were prone to leaking, lower quality aftermarket seals don't stand a chance. The point of all that back story is, if the 1st, 2nd, and 3rd shop aren't using OEM parts, and they just keep using whatever seal they source from their preferred distributor, I wouldn't expect them to last more than a year.

Once people started to replace their bearings along with the seals (late 2000s), they started to invert the seal ring/race. I've done this myself when I did my bearings, but I am not convinced it's necessary, as the new design seals held for many years without altering the orientation of the race- YMMV.

As others have mentioned, it's a temperamental process. It's easy not to seat the new seal correctly or damage the seal if you don't have a seal driver. It's easy to drag the axle shaft over the seal while inserting the axle shaft assembly.

 

Axle shaft/s possibly have a groove worn into them at the seal lip causing the leakage.

 

There is a ton of subtle little things/techniques that apply to this specific job. Separately, some are relatively inconsequential while several cumulative botched/skipped steps can cause problems.
No single video, write up, thread or post including any of mine detail everything that should be considered with this job. So it's understandable that shops/dealerships screw it up, all the time.

 

It's a finicky job to get the retainers in the right place once you've pulled them off to replace the bearing (but it's exactly the same location from axle housing to axle housing - that is you can swap a fully assembled axle from housing to housing without any work).

Here's the step-by-step on how to do it, with photos of figuring out the positioning of the retainers (and everything else):

Step-by-Step Replacing Rear Axle Seal & Bearing

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I'd love to know what's missing from the write-up above, if you have feedback, so I can update it.

 

@turbodb
Your write up is great, maybe the best.
Since I have opened my mouth i will have to go over it with as detailed and constructive an approach as you did and that will take some time. I will put it together and PM you to use or not as you see fit.

Here are a couple examples.
The first task out of the gate should be to check the axle shaft for run out with a dial indicator, no sense working with a bent axle.

Below is a witness mark from the redesigned seal on a "not flipped" retainer. Also note the witness mark from the original retainer position on the shaft. Knowing what you know, it should open up a small can of worms.

 

It's really amazing how helpful everyone is and it's greatly appreciated, so thank you all again! Beyond researching and learning the mechanics I ultimately have to choose who to let help me fix it. This one isn't a diy for me. If anyone still cares to read, below is what the 2nd shop said when I reached out to them.

I called the 2nd shop, told them the problem is back and verified by a 3rd shop. Understandably the 2nd shop wants to see for themselves and says "it's probably just residue from before, bring it in, we'll clean it up and check in a week".

Well, the 3rd shop had already cleaned & adjusted my brakes, but took a video of how saturated my shoe was before they did it.

I went to talk with the 2nd shop in person, showed him the video, told him the brakes were just cleaned and went over a few possibly causes. He confirmed retainer position is important, said he's sure my axle isn't bent otherwise I'd feel a wobble (though he didn't test for any runout at the flanges), he's sure the inner lip is not damaged. When it came to OEM vs non, he said "no, I probably didn't use OEM".

I told him what y'all have mentioned: it's a common issue especially with aftermarket seals and that Toyota changed the design in the late 2000s.

He said to bring it back to him and he'll put OEM seals in. He said he's *never* had this job come back to him in the time he's been doing it. That statement seemed a bit of a red flag since this mechanic has had his own shop for over 20 years, is 4x4 specific, and one of his techs has a heavily modified 1st gen. This sounds like too common of a problem to have never seen a failed aftermarket seal...

 

Did he offer to put the OEM seals in for free to warranty his previous repair?

Good luck and hope you get this figured out once and for all.

 

Thanks! I will eventually. He didn't specify and I didn't ask. He said to call him next week. I might or I might not

 

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My 02 3.4L is slinging gear oil all around as well, but on the driver side rear.
Just ordered the rear wheel bearing & seal kit from eBay
https://www.ebay.com/itm/2854753785...EQLsq2pTpS&var=&widget_ver=artemis&media=COPY