Oil Seal Leak / Knuckle Centering (1 Viewer)

[motormayhem]

I rebuilt the front axle on my 80 back in 2019 (has a loose wheel bearing so did the whole thing as PM) and about a year later developed minor evidence of birf soup on the drivers side. Its never been leaking a ton, but the grease was clearly oily on that side and normal on the other. I've also noticed grease in the diff oil which I had assumed was coming from the drivers side. Today I confirmed this by tearing it all down and cleaning out the birf soup from the drivers side.

Before removal of the inner oil seal I took a close look to see what its failure was since it was pretty new (and a Toyota seal). It appears the top 1/3 of the seal lip is worn. The lip has little hash marks on it new and they are still present on the lower portion of the lip, but worn away on the top portion. You can also see the bellows / rubber section of the seal has taken a set and is offset towards the top of the steel carrier portion of the seal. Based on this it appears the axle shaft is offset up slightly relative to the seal and wearing it excessively at the top. See my sketch below of the seal.

The trunnion bearings, wheel bearings, and spindles were new when I rebuilt the axle previously so I know those items are tight (spindles have needle bearings for the axle guide). I swapped Birfs left/right last time , but I doubt that threw things off.

Has anyone else experienced this before? I know 9/10 times its not needed, but I am wondering if the knuckle needs to be re-centered relative to the housing to lower the axle shaft a little. Either because something is tweaked or it's just always been off. I'm hesitant to put it back together since it seems to be an alignment issue and not just a random failure.

 

[BILT4ME]

Those are great observations and possibly you are in need of doing a proper trunnion bearings alignment, especially if you don't know the PO service history.

Have you also cleaned the axle housing vent? I had a similar situation after I rebuilt my front axle.

Within 5000 miles I had birf soup. I discovered the fitting was clogged with varnished gear oil and the vent hoses were plugged. I actually drilled out the fitting to remove the crud and open the airway. Then I used about 5 ft of 1/4" fuel hose and a 1/4" inline fuel filter and extended my breather up to the power brake booster. This stopped the birf soup for another 80,000 miles.

 

[Dave 2000]

Looking at the 'rubber and case differences I would go with knuckle alignment.

The only reason that I say that is if the axle shaft was bent then that would be easy to check, and that amount of seal damage would show witness marks on one area of the shaft and very little if any on the other at 180°. The marking should be obvious one area showing a wider band that the other. If the same width of wear on the shaft is all the way around then it can only be alignment.

It would not be the first time someone has 'hot tanked' or cleaned a knuckle assembly without realising there were alignment shims still stuck on the assembly under the grease and gunk. These shims get found long after the customer has left the workshop, so during assembly those shims didn't go back in place and then we have an alignment issue however, looking at those gaps in the seal to shaft though, this is more than a 20 or 30" gap surely?

If there were no real issues before the strip and rebuild I would be inclined to look at the new upper and lower bearing assemblies, wrong bearings, perhaps an installation error and so forth?

Regards

Dave

 

[motormayhem]

Ok, that's along the lines of what I was thinking...either the shimming got messed up at some point or the housing is tweaked a bit and causing the issue. Does anyone have a centering tool? It looks pretty straightforward to machine one, but I think there are a few dims I need to make sure I match to make the calcs work right so I am hoping to get some measurements.

When I first saw the grease in the axle I re-did the breather and ran new hose / removed the check so it wouldn't pull vacuum. So that should all be free flowing. Hard to say what is new/old wear on the axle, but it looks like the main groove / marks on that are wearing pretty evenly around and not a bent shaft.

 

[Broski]

80 axles are not normally centered, there’s no shim’s on the bottom and one or none on the top so not sure you can center it.
You would need shims for the bottom never seen those.
My understanding is the shim is for the proper per load not for centering.
Sounds like you housing is bent

 

[Broski]

Went to my computer so I could see the picture better.
I can say that theirs definitely not enough clearance between the knuckle and the knuckleball to correct that much offset.
It looks like it could be a defective seal, I just can't see the axle moving the seal like that.
The area that makes contact with the axle is very pliable.
Or possibly something went sideways during the install.
When you remove the seal there may be some more clues.

Did you have to remove the knuckle to get the axle out ?

 

[motormayhem]

Pulled the seal and didn’t see too much else. It does seem a little weird the seal is off center so much. The lip portion is pliable, but the other rubber portion of the seal isn’t super pliable at the top part (compared to the bottom). Maybe there was something funny with this seal. It’s a Toyota one though so quality should be pretty good.

Measuring it, it’s probably off center by about 0.5-1mm. I have a 0.25mm shim in the top so that’s as much as I could move it without changing the preload - if l cut out a shim from some stock for the bottom and removed the top one.

The axle did come out by just aligning the flats and pulling it out with the knuckle on. Then I pulled the knuckle after that. So it’s not massively bent if it is.

I did notice the wear band on the axle (where the seal rides normally + when turning) is going right to the edge of the machined surface on the axle. I drove the new seal in the extra 2mm to be sub-flush and center it more on the axle surface/away from the small groove on the axle. Might be good to check the steering stop adjustment as well.

 

[BILT4ME]

Pulled the seal and didn’t see too much else. It does seem a little weird the seal is off center so much. The lip portion is pliable, but the other rubber portion of the seal isn’t super pliable at the top part (compared to the bottom). Maybe there was something funny with this seal. It’s a Toyota one though so quality should be pretty good.

Measuring it, it’s probably off center by about 0.5-1mm. I have a 0.25mm shim in the top so that’s as much as I could move it without changing the preload - if l cut out a shim from some stock for the bottom and removed the top one.

The axle did come out by just aligning the flats and pulling it out with the knuckle on. Then I pulled the knuckle after that. So it’s not massively bent if it is.

I did notice the wear band on the axle (where the seal rides normally + when turning) is going right to the edge of the machined surface on the axle. I drove the new seal in the extra 2mm to be sub-flush and center it more on the axle surface/away from the small groove on the axle. Might be good to check the steering stop adjustment as well.

Is your axle shaft guide still in the interior of the housing, inboard of that seal?

 

[motormayhem]

Is your axle shaft guide still in the interior of the housing, inboard of that seal?

Yup that all looked good

 

[Broski]

Seem like you have a good handle on it,
My guess is there was a issue with the seal.

 

[motormayhem]

For those interested, I turned up an 80 series version of the Toyota alignment tool for the knuckle and it measured pretty much at 0 shim required in the lower as it should be.

 

[Broski]

Thanks for posting

 

[fourtrax]

as mention earlier no shim on bottom.
the upper shim is just for your steering resistance (preload).

 

[1973Guppie]

The housings on these trucks do bend more than people realize. I would pull the housing and take it to be aligned to see if it is fact a bent housing. Hope you figure it out.

 

[motormayhem]

The housings on these trucks do bend more than people realize. I would pull the housing and take it to be aligned to see if it is fact a bent housing. Hope you figure it out.

Ya I suspect something is tweaked…probably upstream of the seal given its always pulled right since I nailed a rut off road a few years back. What kind of shop can check an 80 housing? I kinda assumed that would require a fixture specific to the 80 that most places wouldn’t have.

 

[1973Guppie]

Ya I suspect something is tweaked…probably upstream of the seal given its always pulled right since I nailed a rut off road a few years back. What kind of shop can check an 80 housing? I kinda assumed that would require a fixture specific to the 80 that most places wouldn’t have.

interesting, I was thinking about this while working tonight, did you bottom out your suspension on that side HARD? Yeah it might be hard to find someone to check it out, most likely cheaper to go with a used housing, that's what I would do. I would start with asking if a good machine shop can look at it, might not be worth their fee though.

 

[mudgudgeon]

For those interested, I turned up an 80 series version of the Toyota alignment tool for the knuckle and it measured pretty much at 0 shim required in the lower as it should be.

View attachment 3321372

Can you post some more pics of this tool out of the knuckle?

 

[motormayhem]

Can you post some more pics of this tool out of the knuckle?

Sure, here is a pic. Basically the same as the 60/70 series factory Toyota tool, just sized to fit the 80 dims. So the procedure is similar to the below service manual procedure which isn’t in the 80 fsm since an 80 should only need preload shimming not centering.

 

[motormayhem]

interesting, I was thinking about this while working tonight, did you bottom out your suspension on that side HARD? Yeah it might be hard to find someone to check it out, most likely cheaper to go with a used housing, that's what I would do. I would start with asking if a good machine shop can look at it, might not be worth their fee though.

Ah, having a machine shop inspect it isn’t a bad idea, but I agree by the time it’s torn down to inspect its basically ready to be re-built in another housing so maybe not worth it. I need to run a trip for Memorial Day so planning to throw it back together and see if it leaks again.

The funny thing was I’m pretty sure the hit was on the passenger side, but it was hard to tell. I was going down a ranch road in Mexico at night and a washout came up out of the dark. Slowed down as much as traction would allow, but still nailed a 2ft deep washout at ~15mph. A hard hit for sure (probably the hardest its taken) and probably down to the bump stop, but not something I’d have expected to bend the axle over. Planning to get the camber checked after this side is tightened up and see if it’s off still. If so I’ll probably grab a housing and gusset the balls a bit and keep on trucking.

 

[mudgudgeon]

Ah, having a machine shop inspect it isn’t a bad idea, but I agree by the time it’s torn down to inspect its basically ready to be re-built in another housing so maybe not worth it. I need to run a trip for Memorial Day so planning to throw it back together and see if it leaks again.

The funny thing was I’m pretty sure the hit was on the passenger side, but it was hard to tell. I was going down a ranch road in Mexico at night and a washout came up out of the dark. Slowed down as much as traction would allow, but still nailed a 2ft deep washout at ~15mph. A hard hit for sure (probably the hardest its taken) and probably down to the bump stop, but not something I’d have expected to bend the axle over. Planning to get the camber checked after this side is tightened up and see if it’s off still. If so I’ll probably grab a housing a gusset the balls a bit and keep on trucking.

You could take it for a wheel alignment read out. If camber is out of spec it may indicate a damaged housing.
Or you could set the car up on a flat level garage floor to make sure the axle housing is in a neutral/ level position, remove the top knuckle bearing caps, and set a smart phone with virtual bubble level app on the milled surface on the top of the knuckle to get a caster and camber reading.
Align the centre line of the smart phone parallel with the centre line between bolt holes

Won't be 100% fool proof, but would give you an indication of damage.
I've used smartphone apps at work with good repeatable results to measure pitch angles/deviation from level etc on construction projects.