Adding Grease to Postpone Birf Rebuild?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Oct 20, 2008
Wichita, KS
Disclaimer: I plan to rebuild my birfs this summer, but have other baseline PM tasks to do first. I KNOW I WILL NEED TO REBUILD MY BIRFS. Now that we've gotten that out of the way......:D

At 191k I have no record of a birf rebuild on my new to me FJ80. Records are since new, so I doubt it's been done. No clicking but it does leak, maybe one drip on each side per night. I plan to do the rebuild this summer, but have other baseline powertrain tasks to complete first. The truck is currently a DD, so no hardcore offroad duty.

Per the owner's manual, it shows you can add grease through the plug in the birf housing. The little picture shows a grease gun squirting grease into the housing. Has anyone added grease to their birf through this process? Considering it's probably been leaking for quite some time, how much grease to add? I also plan to service my diff fluid at the same time.

Again, this is simply a stopgap measure to try and prevent damage to the birfs until I can rebuild them this summer.
Yes you can add Moly grease but I don't know what you would accomplish since you have leaking axle seals. The grease is not leaking out. The axle seals are leaking and allowing the 90w in you diff to enter the Birf housing and blend with the grease. This blend is what is leaking past the wiper gasket.

Get the Marlin Crawler HD Axle Seals and the gasket kit.

It really does not take that long to do it right. If you have never done one before, allow 4.5 hours for both sides. Most of that time will be spent cleaning.
My thought was that the slurry is leaking out, therefore the overall quantity of grease in the birf housing is less than it should be. I just don't want to run the damn things dry.

4.5 hrs for both sides?! Is it really that easy? I'm a hardcore DIY type, but most of the write-ups on here seem to present it as a rather daunting task.
If all goes well I guess it would probably take me 4.5 hrs for each side. Those cone washers can be a pain, and I had a spindle bolt that needed to be replaced, so I had to wait for that. Cleaning takes the most time IMO. You could play it safe and start friday night and finish it up over the weekend if you run into any quirks. I'd order a couple outer hub studs and maybe a spindle bolt or two just in case one needs replacing. X2 on the marlin seals. I wish those would have been available back when I did mine.
If someone can do a repack in 9 hours from start to finish, they are humpin and everything goes perfect. Hell, I spent 20 minutes getting on a circlip!! True, cleaning it all out takes the most time, and alot of time can be subtracted if you dont replace the races and bearings, which I think alot of us do.
Yes putting grease in helps, it's a case of some grease is better than none.:hillbilly:

How much is pretty much a guess. My procedure is to clean the plug area, remove it, turn the steering fully towards the side your working on and with a flashlight you can get a pretty good look at how much is in there.

My brother's and mine are due for a repack, didn't have time before the CM trip, so added for good measure. My right side was very low, added a tube, the left side and both of Rob's we added 1/2 tube. If you add too much it will be expelled past the wipers and maybe pushed past the seals into the gear oil, will make a mess, but wont damage anything.
I'd definitely add via the hole, and figure on putting a tube in each side. This will help ensure your birfs are protected until you have time to do the repack. You can also monitor what happens to the grease/oil mix coming out. Obviously if it all drains out in a few nights then you've been running the birfs dangerously low and it's time to repack now. If it stays at the current drip rate then you know they're holding enough grease that your added grease added protection and all's well for a while.


Users who are viewing this thread

Top Bottom