Whats wrong with my front end? (91 FJ80)

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I believe I'm gonna have to do a total front end rebuild. I've never done it before, but I've been researching, and collecting all the necessary tools to do the job. Should I clean and rebuild the entire assembly or get replacement parts (Birfs, inner axle rod, etc). I wanna do this right, so I've added pictures so the more knowledgeable gods of all things Land Cruiser can confirm/deny/advise as they see fit.

***Note: in the middle of applying FF undercoating, which is visible in the pics.***

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ceylonfj40nut

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Great time to replace rotors and pads if worn. Also new brake soft lines if cracked.
 
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the axle nuts are 54mm, if you cat a 2 3/16 in socket that will work as well. get extra hub gaskets, their paper and can tear. small tears you can just put a dab of fipg on the gasket and itll be fine, big tear youll have to replace. i also like having extra hub studs, cone washers and nuts for doing the job. between both sides youll need 3 tubes of grease, about 1 and half per side to fill the knuckle when you done.

i wouldnt worry about replacing the tierod ends unless theres play, their easy enough to do and dont require much prep or disassembly to replace them
 

60wag

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Some of that oil looks to be coming from higher up than the axle. Is the front main seal leaking?
 
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To try to answer the question about what's wrong.

From the pictures I see:
  • Looks like your inner axle seal(s) are leaking and that gear oil has thinned the grease in the knuckles and then leaked out past the wiper seals/etc.. This could just be down to wear of the axle seals, could be the result of a blocked diff breather allowing the axle housing to pressurize and push oil out when heating then suck grease in when cooling, etc.
  • The cover/pan below the radiator and front of the engine appears to be missing.
  • Your springs may have sagged, doesn't look like much room below the bumpstops but that could also be camera angle.
  • I agree that you may have other oil leaks higher up also. Power steering, trans lines, front of engine are all possible sources in those areas. No need to get into that with the knuckle job but you can have your eye out while in there for future work that may be needed.
From experience I would suspect that you need to:
  • Go through a knuckle rebuild as stated above which largely consists of disassembly, cleaning, replacing the seals and re-assembly.
  • Replace the trunion (or kingpin, etc. names) bearings on each knuckle as these are known to wear in their primary position (straight ahead).
  • Order new bushings for the inside of the spindle that the short shafts (outboard of the birf joint) ride on so that you have them on hand and then replace unless the ones in place measure out 100%. If these bushings are excessively worn they can allow too much movement which could be related to your inner axle oil seal leak(s).
  • Be prepared to deal with issues on seal mating surfaces, primarily on the inner axles. Older axles often show a small groove where the seal rides on them which can lead to leaks. Overdriving the seal so that it rides in a new spot, adding a speedi-sleeve or similar, replacing the axle shaft, etc. are all options. The hub outer dust seal surface may need some cleaning and polishing as well as they can get crusty, etc.
  • If the birfs aren't clicking I'd assume they are good for re-use. You can flip them from one side to the other if you want to deal with the hassle and it should move the wear points and help you get more miles out of them.
  • I agree on the brake disc replacement, if they are worn. Unless the hoses are cracked I probably would hold off on getting into more brake work besides maybe pad replacement as the rest (hose replacement included) is easy to do later as a separate job and only the discs are much more easily replaced now vs. later.
 

cruiseroutfit

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the axle nuts are 54mm, if you cat a 2 3/16 in socket that will work as well. get extra hub gaskets, their paper and can tear. small tears you can just put a dab of fipg on the gasket and itll be fine, big tear youll have to replace. i also like having extra hub studs, cone washers and nuts for doing the job. between both sides youll need 3 tubes of grease, about 1 and half per side to fill the knuckle when you done.

i wouldnt worry about replacing the tierod ends unless theres play, their easy enough to do and dont require much prep or disassembly to replace them
Appreciate the detaile
the axle nuts are 54mm, if you cat a 2 3/16 in socket that will work as well. get extra hub gaskets, their paper and can tear. small tears you can just put a dab of fipg on the gasket and itll be fine, big tear youll have to replace. i also like having extra hub studs, cone washers and nuts for doing the job. between both sides youll need 3 tubes of grease, about 1 and half per side to fill the knuckle when you done.

i wouldnt worry about replacing the tierod ends unless theres play, their easy enough to do and dont require much prep or disassembly to replace them
Thanks for the advice! I'll be sure to order extras!
 
Joined
Feb 13, 2020
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Mississippi
Same here.
20221221_201355[1].jpg
Doing gear work and found the same thing, but these axle seals are new. Only about 10,000 on them. I can see nothing wrong with them either. How clogged does the vent need to be to cause this? Is this clogged? I can barely blow "up" through the hose. I think this soup was caused by a clogged vent.
20221221_200641[1].jpg
 
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Olathe, KS, USA
Same here.
View attachment 3198949Doing gear work and found the same thing, but these axle seals are new. Only about 10,000 on them. I can see nothing wrong with them either. How clogged does the vent need to be to cause this? Is this clogged? I can barely blow "up" through the hose. I think this soup was caused by a clogged vent.View attachment 3198948
Yes, that can cause it. I unscrewed that vent, and used a drill bit in my fingers to clean out the build up.

I had the same issue and within 5000 miles I had birf soup. After I cleaned out the vent and installed a hose up over the booster with a fuel filter, the birf soup stopped and I ran another 90k without leaks.
 

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