Diff breather blow-by?

[ToyBarn]

The front diff breather on my 1993 80 has started dripping diff fluid again. Cleaned out the diff breather while performing r&r on the front axle late last winter (R&R: birf repack, new grease, new seals, and synthetic diff fluid). I used cleaning fluids and compressed air on the breather tube and breather to clean it. Any suggestions or just replace with new one?
Thanks, Bryan 1993 Toyota 80-no airbags, no lockers, and sf rear axle--- wife's DD.

 

[landtoy80]

Get a clear hose (one for chemicals) and a small fuel filter. Run the hose up to the brake master cylinder and put the filter on the end.
Remove the factory hose and junk it.
Put the new hose on, give it enough slack to move up and down with the suspension. Tie strap the hose down. You have now an extended breather hose. You can go in deep water now (with the front end, that is) do the rear and both can go swimming.

I use a clear hose to see if oil is being pushed up the hose.

It looks like you are new,
WELCOME TO THE MUD


What oil is in the diff?
I had a pickup that would spray out oil from the rear breather after I put syn oil in it.
Put dino oil back in it and never leaked/sprayed again.

 

[concretejungle]

welcome

 

[Beowulf]

We've reached a new milestone in MUDDING. Kurt has finally found and used the Edit Post button.

HOOOOOOORaaaaaaay!

-B-

 

[landtoy80]

We've reached a new milestone in MUDDING. Kurt has finally found and used the Edit Post button.

HOOOOOOORaaaaaaay!

-B-

A first and last.

 

[IdahoDoug]

Bryan,

To clarify, did you replace the INNER axle seal?

DougM

 

[ToyBarn]

Reply: Synthetic gear oil in front differential now, previously unknown except it was coming out prior to be changed & cleaned. I have been using this site for almost 1 year gathering info prior to purchase of Toyota at the end of 2003. Also a CDan customer!

 

[landtoy80]

-B- Now if I make one of my GREAT replys and the topic started reads my GREAT post and then I have a "more better" GREAT post, how will the post starter or other replyer know to reread my "more better" GREAT reply post edit???

 

[landtoy80]

Reply: Synthetic gear oil in front differential now, previously unknown except it was coming out prior to be changed & cleaned. I have been using this site for almost 1 year gathering info prior to purchase of Toyota at the end of 2003. Also a CDan customer!

Why so shy, ALL are welcome to join it mo mater what JUNK says.


OOOOOPPPPPPPSSSSSSS did it again. You knew it was to ggooooodddd to be true.

 

[ToyBarn]

Doug,
Replaced inner & outer axle seal during birf repack; no leakage at the pinion.
Thanks, Bryan

 

[landtoy80]

What brand syn oil and weight. 80w90?

 

[Beowulf]

>> and then I have a "more better" GREAT post <<

The odds on this are infinitesmally small.

-B-

 

[landtoy80]

<>> and then I have a "more better" GREAT post <<

The odds on this are insestious small. >

True, my first GREAT post reply says it all.

 

[IdahoDoug]

Bryan,

I asked the question for a reason and your reply was only 75% of what I'd hoped as you mention the "inner and outer" and the "pinion" seal. So, not sure still. At any rate, I was slyly making sure you or whomever worked on the job replaced a commonly overlooked seal known as the inner axle seal where the axle shaft exits the tip of the axle housing. It's inboard of the birfield and even Toyota dealers routinely miss it.

The reason I asked is because barring water intrusion, the only way front diff gear oil volume can be increased enough to start burping oil out the breather is if the birfield grease is getting sucked into the diff through that seal. To solve the mystery, the first thing I'd do is drain the front diff and look at the color. Expect a lot of discoloration as the pre-repack grease contamination is still being dissolved into the diff oil. Check the level in the fill plug FIRST, and let us know if it is so high it freely flows out of the fill hole vs just a few drops (normal full condition).

DougM

 

[landtoy80]

A plugged breather could maybe do it too. THe valve maybe sticking as pressure builds up, it then releaces out the breather.

 

[ToyBarn]

Reply #3;
Amsoil 80/90 gear oil gl-5, again both inner & outer axle seals were replaced at birf servicing, diff breather was dripping when toyota was purchased last year, diff breather was cleaned during bird service, dripping resumed again after another 30 days. Truck has not been in deep water yet!

Breather re-routing to under the hood be done soon. thanks

 

[landtoy80]

When you remove the fill plug or the breather hose do you notice any pressure?
When you remove the fill plug does oil run out?
Your oil is good.

 

[IdahoDoug]

Bryan,

Hope you've got a good sense of humor, cause if not I'm going to reach the end of your good nature with this comment. There is no "outer" axle seal that I'm aware of and I've personally done my own axle rebuild. If you didn't personally do it yourself and are using this terminology, then my concern is STILL that someone replaced their version of the "inner" seal (the rubber seal on the axle housing) and the "outer" seal (the felt seal at the same location) and the real inner seal is still leaking. They told you (as many dealers/mechanics have with many 80 owners) that they replaced "all the axle seals". This is quite common and your symptoms mesh perfectly with the description of what's going on. Naturally there are a raft of other scenarios such as the axle tore the seal when it was reinstalled, the seal was not OEM and isn't a good fit, or the installer forgot to put the shims on the axle housing back on and the axle is distorting the seal as it runs in it. But for my money, and analyzing your issue from across the country, I'd say you've got an inner axle seal issue. The burping breather is a symptom of the problem, NOT the problem itself.

Having said all that (whew), you should definitely perform the breather mod as it will help reduce the front axle contamination even if everything's right with the inner axle seal work. Hope you still love me.........heh.

DougM

 

[lovetoski]

Hi Doug,

Question regarding your comment...

Bryan,

Having said all that (whew), you should definitely perform the breather mod as it will help reduce the front axle contamination even if everything's right with the inner axle seal work. Hope you still love me.........heh.

DougM

I rebuilt the front axle on my 80 last winter, and modified the OEM axle breathers by removing the spring so that they "breath" more easily. (Read about this mod on this board.) However, I didn't go for the full breather extension mod as the 80 will never see deep water service. However, I don't want the inner seals to fail too quickly...

Will the inner seals last longer if I replace the OEM breathers with an extended tube and filter?

Thanks for your help.

Best Regards,

 

[IdahoDoug]

Doug,

Nope. They'll last the same length of time in terms of their wear which is unchanged. However, they will be able to do their job longer of preventing cross contamination between the different lubes they separate. This is simply because there will no longer be a strong vacuum forming on the diff side every time the vehicle is driven (heating, then cooling is source). Having said that, you've already achieved this by removing the device that caused the vacuum issue. However I'd still elevate the breather by adding hose up and away from road spray (especially if you're in the salt belt).

In the later stages of wear on the axle seal, enough axle grease has been drawn into the diff housing and thrown up into the breather tube (the burping we see) that it starts to completely block the tube as the grease dries and thickens. Then the diff housing begins to generate pressure (vs a vacuum) and force diff oil out into the birfields - eventually washing them clear of grease.

DougM