Rear Axle Seal Leak - Travails and Final Fix (I Hope)

[RC57]

First off I recommend reading the following threads, if you aren't already familiar with leaking seals and repair-

http://www.toyota-4runner.org/3rd-g...e-information-replacement-thread-3rd-gen.html

http://www.toyota-4runner.org/3rd-gen-t4rs/114743-possible-solution-leaking-axle-seals.html

Summary:

Two years ago my 99 Ltd w/ ABS, 170k miles started spraying oil onto the left rear wheel. Inspection of the right side also showed oil starting to leak onto the brake shoes. First I checked to see if the diff vent was plugged (it wasn't). Then I removed the axle shafts and took them to a local axle shop to have replaced all affected parts using Toyota oem stuff. I replaced the seals myself and reassembled the axle.

One month ago, and after 20k miles I'm again getting oil spraying on the wheel. I took the axle shafts out and took them to the same shop. This time I specified that the retainers be sealed to the shaft. So far (1.5k miles) the axle ABS cavity is still dry.


Long story:

When I found my rear axle leaking I referred to the extremely helpful ultimate seal replacement thread. I ordered up the Toyota parts online and found a local shop willing to R&R the bearings on my axle shafts with my supplied parts. A number of shops declined to use my parts and the one accepted the work is a big reputable shop.

After the shop completed the work I glanced over the axles and noticed the placement of the tone ring/bearing retainer and asked if they had been installed in the right location. The shop said they located those parts in the same location as the old parts, by measuring before and after. I also noticed some gouges in the axle shafts and the old retainers that the shop returned to me. When I got the axles home I did a rough measurement and the placement appeared in spec (122.2 +/- 1.0 mm from brake drum flange to top of tone ring ).

I drove in new seals using the appropriate diameter seal driver and assembled the axles. I have to admit I had trouble getting the seals to go in true. I dimpled one seal driving it in crooked and replaced it on the spot. I checked the seals to see if the were in flat and found they had a bit of runout (0.010 - 0.015"). When I installed the axle shafts I noticed the tone rings appeared off center to the ABS sensor port. The ring was inboard to the point where inner edge of the cut gear lined up with the inner edge of the ABS port. At this point I'm wondering if the parts were pressed on far enough.

I drove the truck for a few hundred miles and inspected for leaks by removing the ABS sensors. There was oil showing on the left side. By 1000 miles oil was showing on the right side. After 1400 miles I pulled the axles and replaced the seals. There were witness marks on the retainer rings showing the seals were engaging the retainers properly so I wasn't concerned about the ring placement on the axles.This time I made a seal driver on a lathe that fit the axle bore in order to drive in the seals squarely. Despite this I was never able to drive in a seal to better than about 0.005" runout. I'm guessing the radius at the bottom of the bore allows one side to slip past, but not the entire seal.

After another 1k miles I was still seeing oil get past the seal. I replaced them a third time, this time with permatex red on the seal OD.

I continued to drive the truck and monitor the leak. Oil was again showing up in the ABS cavity, both sides. Each time I cleaned out the oil and replaced the seal, the left side would leak more than the right. l no longer had access to a garage and and could not disassemble the axles myself. I contacted the shop who pressed on the new bearings and they requested I bring in the truck. At this point I suspected the scratched axles were the cause of the leak, and declined to bring the entire truck in. I crossed my fingers the leak was slow enough to be inconsequential. Not so. 15k miles after the third seal replacement there was oil on the left wheel and the right side was drooling onto the brakes. By now however I again had a garage.

I ordered another round of Toyota parts and again pulled the axle shafts. Before I brought the axles back to the shop, I measured how far the retainers were pressed onto the axle. The left side showed 3.5mm of machined axle, the right side 3.0mm. Compare that with 5mm shown in the first picture of the possible solution thread. Close inspection showed the right side retainer ring was making contact with the axle housing. The witness marks on the retainers showed 2.5 - 3.0 mm of seal engagement from the inboard ege of the polished surface of the retainer. I took the axle shafts back to the same shop as before and had them press on the new parts. This time I had them press the retainer on to show 4.0mm of machined axle. That is slightly outboard of where the shop had placed them before, and only enough to clear the housing by 1mm. I also had them put sealant under the retainer. They chose to use Loctite 648. They also welded up some deep scratches. I installed new seals and checked them with grease (bolt the axles in without the oring) and got witness marks ~1.5 - 2.0 mm of engagement on the ring. That's a _very_ narrow sweet spot. I did not reverse the retainer like Drcoffee and the seal still hits the retainer, but barely.

I've been inspecting the ABS cavities for leaks and so far so good. 1.5k miles on the new seals and still dry. I'm confident at this point that the main issue for me was scratches on the axle shafts allowing oil to leak under the retainer. Sealing the retainer to the shaft to begin with would have saved me quite a bit of labor and hundreds of dollars. In hindsight I can't believe I allowed the leak to continue until the new bearings had been contaminated with oil and required replacing. (There were other problems that went along with lack of a garage, but still...) A second issue was retainer placement. The right side had 3.0mm machined axle showing and it was hitting the housing. The gouge in the housing was noticeable.

Bottom line:

Be very careful where you locate your retainer on the axle shaft. Check it with grease to determine the seal is engaging properly before final installation. Make sure the retainer is sealed onto the shaft.

 

[Drcoffee]

This time I had them press the retainer on to show 4.0mm of machined axle. That is slightly outboard of where the shop had placed them before, and only enough to clear the housing by 1mm. I also had them put sealant under the retainer. They chose to use Loctite 648.

Good job. I just want to re-state from my thread above, by reversing the retainer and leaving 4mm of polished axle inboard of the retainer, the seal will ride dead center on the retainer. Adding sealant between the axle and retainer is a good idea as well as between the seal and axle housing. Two other places the oil can leak from. I still wonder if yours will leak under severe driving condtions like offroading or hard cornering with only 1.5mm of seat on the retainer. Time will tell.

Please post periodic updates over time. All too often we get one post and never a long term follow up. I updated my thread from May thru Oct and when the temps warm, I'll check them again.

:snacker:

 

[RC57]

I still wonder if yours will leak under severe driving condtions like offroading or hard cornering with only 1.5mm of seat on the retainer. Time will tell.
:snacker:

The Toyota spec for maximum axial end play is 0.70mm. The 1.5mm engagement is with the axle pushed all the way in by hand. There's considerable axial play even for a new bearing, and all that play goes outboard, reducing seal engagement. Increase the load from hand loading to hard cornering and the axial play is going to increase. I can't say how much. At least if the retainer is pulling out of the seal the oil should be sloshing to the other end of the housing.

I'll be performing regular inspections. If I see oil you'll hear about it.

 

[Tucson Mike]

I just change my passenger rear axle seal and bearings this past Xmas. I read the same info. and followed Dr. Coffee's suggestion of reversing the retainer. I left about 4.5mm of polished surface on my axle shaft and the seal was close to center. Mine is a daily driver and I have driven over 500miles and so far so good.

 

[RC57]

Here's some pics from my repair. Theses are all of the right side, where there was contact with the retainer and axle housing.



Above is the old retainer that was leaking. There is ~3.0mm of machined axle showing inboard of the retainer. Note the deep gouges in the axle from the shop R&R'ing the parts. Also can be seen at the inboard edge of the retainer is damage due to contact with the axle housing. The contact was heavy enough to raise a 1/2mm lip inward on the retainer. The seal witness mark on the retainer is ~2.5mm from the inboard edge of the polished surface. The witness mark is broadened for two reasons. 1) The axle bearing has play- up to 0.70mm according to spec. 2) The knife edge of the seal has already worn to ~0.5mm width after 15k miles.




Here's a shot of the damage to the housing. The gouge is about 1mm deep.




Here's the axle shaft after pressing on new parts. There's now 4.0mm of machined axle showing. That's 1mm more than before. Note the grease line indicating how far the new seal is engaging. That's still >2mm.




Here's another view of the axle housing scores. This time I put a dab of grease on the score to make sure the new retainer is clearing the housing. It does, barely.

If I had reversed the retainer, the clearance would have decreased due to curvature of the housing surface. I would definitely go to 5mm if installing the retainer reversed.

As is, there's very little wiggle room with the new design Toyota seal. The retainer is barely clearing the housing, and barely engaging the seal. IMO there's less than a 2.0mm tolerance for positioning the retainer (FSM spec) and I suspect the 122.2mm distance is off too.

 

[RC57]

I said if I saw oil I'd say so, so-

I'm seeing more oil on the right side. After 1500mi the ABS sensor has oil on the lower half when removed. No oil was visible on the tone ring. (A bigger leak or after more time the sensor would be totally covered and the tone ring will show oil.)

The right side continues to leak oil, although it appears to be at a slower rate. For review, the retainer was pressed on with 4.0mm machined surface showing on the axle, bevel inward. The axle had previously been scored badly and the shop had welded up the worst scratches and ground them down. The shop put bearing retainer and sealer on the axle before pressing on the retainer. The type used can fill gaps up to 0.005" and is oil resistant.

I pulled the axle and found about 1/4 tsp of oil in the cavity. 1/2 tsp at the most. That's not enough to contaminate the bearing imo. So I cleaned things up and applied a fillet of Permatex ultra-grey on the inboard side of the retainer. After 24hr I reassembled the axle and crossed my fingers.

Before assembly I inspected the seal closely and could see no nicks. I left it in place. If this continues to leak I'll pull the axle again and focus on the seal placement. The witness mark after 1500mi is _very_ close to the inboard edge of the retainer. The mark itself is about 0.6mm wide and is ~0.5mm from the retainer edge. That's very close. We'll see if that's too close.

I'm getting pretty good at r&r'ing this axle.

The other axle (left) was done the same way 3000mi ago and the cavity is still dry. The scratches on that side were not nearly as bad as the right side, however it was leaking worse before this second bearing replacement.

Verdict is still out on the right side. If it still leaks, it's definitely the seal. Even if it doesn't leak, the seal/retainer engagement is way too finicky. With 4mm of machined axle showing, the retainer barely engages the seal. At about 3.5mm the retainer was hitting the housing. I'd be more comfortable with 5mm of machined axle showing and the retainer reversed. I should know in a month or two if the rtv sealant fixed it or not. For the record I don't take this 4Runner wheeling, so it experiences less sideloads on the axle than most of the people on this list. No idea if that would move the axle enough to disengage the seal from the retainer.

 

[Drcoffee]

I still believe that reversing the retainer is the best option. Theres just too much force being applied to the axles to think a .5mm - 1mm seal seat is enough to seal under hard corning and off road use. If you have to R&R the seals, give it a try. Please take pictures. A visual thread helps everyone.

Good luck

 

[RC57]

Toyota allows for up to 0.70mm axial play before replacing the bearings. My witness mark is already 0.6mm width, although I haven't check the actual axial play on that new bearing. Imagine how much those balls and races in the bearing would have to distort to add even 0.1mm of extra axial motion.

 

[Drcoffee]

Imagine how much those balls and races in the bearing would have to distort to add even 0.1mm of extra axial motion.

Yep. There's textbook and then there's real life. I don't think you could measure the strain to the bearings on the bench like it is experiencing in real life.

I don't know if you remember me saying in my thread that it wasn't possible to insert the retainer the way you have it to seat correctly on the seal and Not hit the axle housing. This kind of proves my point. It wouldn't have to be set in so deep with the retainer reversed. And again, each axle needs to be measured before doing the work. There is so little room inside of the seal that you need to be spot on.

 

[BrianSD_42]

BTW, if anyone is in San Diego and wants this done professionally, I was quoted about $650 for a full replacement will all OEM parts by the Toyota Shop I go to. 12 mo full warranty.

 

[RC57]

With ABS? $650 is a great deal for all Toyota parts if done right.

Mine didn't start showing external signs of leakage until 18mo/20k miles. If done properly they won't leak for at least 100k miles.

 

[Drcoffee]

BTW, if anyone is in San Diego and wants this done professionally, I was quoted about $650 for a full replacement will all OEM parts by the Toyota Shop I go to. 12 mo full warranty.

Is that $650 for just seals or bearings too? For seals alone, that is way too much. For the whole shebang, thats a good price.

 

[blizz86]

BTW, if anyone is in San Diego and wants this done professionally, I was quoted about $650 for a full replacement will all OEM parts by the Toyota Shop I go to. 12 mo full warranty.

Just wondering for information, is this both sides or only one?

 

[RC57]

I don't know if you remember me saying in my thread that it wasn't possible to insert the retainer the way you have it to seat correctly on the seal and Not hit the axle housing. This kind of proves my point.

Agreed. Next time (if there is one) I'm flipping the retainer and pressing on for 5mm machined axle showing. The shop did not want to do it that way this time around.

If I pull this axle again I'm going to measure the retainer placement compared to factory spec. Going by the inboard machine marks on the axle is dicey. After scratching my head on this one for a while I think I have an easy way to measure it (using two precision rules, a straightedge and an assistant).

 

[Drcoffee]

If I pull this axle again I'm going to measure the retainer placement compared to factory spec. Going by the inboard machine marks on the axle is dicey. After scratching my head on this one for a while I think I have an easy way to measure it (using two precision rules, a straightedge and an assistant).

You already have a reference mark on your axle. Just measure from the seal mark on the retainer to the edge of the polished axle. Then situate the new retainer accordingly so the seal hits in the middle of the shoulder. Why make it any more difficult than that?

 

[RC57]

You already have a reference mark on your axle. Just measure from the seal mark on the retainer to the edge of the polished axle. Then situate the new retainer accordingly so the seal hits in the middle of the shoulder. Why make it any more difficult than that?

That's what I did this time around. I'm thinking for future reference for those going from an old style seal to new, or replacing an axle shaft.

 

[Drcoffee]

That's what I did this time around. I'm thinking for future reference for those going from an old style seal to new, or replacing an axle shaft.

That makes sense to me. What I have suggested was to yank the axle and install the new seal. Then re-insert the axle and find out exactly where the new seal resides on the old retainer. It should take the guess work out of positioning the new retainer on the axle.

 

[RC57]

To tidy up one loose end, I checked axial play on the right axle. It's 0.016" or 0.4 mm. That's on a new bearing that has been run in 1500 miles. 0.4mm axial play is close to the ~0.6mm witness mark I measured on the retainer. The seal still has close to the original knife edge when new. For comparison, the seal with 20k miles had worn to an edge with about 1/2mm edge width (new seal design).

So Toyota's axial play spec of 0.7mm allows for about 1/4mm or 0.010" increase in axial play. That's even closer to the hairy edge of seal/retainer engagement.

I definitely endorse Drcoffee's method of flipping the retainer to increase engagement.

 

[Drcoffee]

I definitely endorse Drcoffee's method of flipping the retainer to increase engagement.

Thank you.

This is a rhetorical question. Why would you knowingly put the seal on the edge of the retainer when a method exists to place it in the center?

 

[RC57]

Thank you.

This is a rhetorical question. Why would you knowingly put the seal on the edge of the retainer when a method exists to place it in the center?

Er, because as I stated above, the shop pressing on the retainer was unwilling to reverse it's orientation. According to my calculations, it would still work, barely. So far it looks like it will, _barely_. I _used_ to have a garage where I could do everything myself. I'm temporarily in an apartment and must rely on local businesses to get some things done. This particular shop was the only one I could find willing to let me bring in my axles and Toyota parts I had purchased online, and had the tools to do the job. Alternatives, such as the dealer, were considerably higher cost.