Breather Install
 

Thinking about installing extended breathers myself.

Where did you purchase? How was the install? Any pics you can provide? Where did you put the breather/filter?

Did you put a breather on the front diff?

What about axle bearing seals - do you worry about water getting in the front hubs?

Eric,

First, the 3rd gen 4runner comes from the factory with 2 extended breathers ALREADY installed. One is for the front differential, and the other for either the transmission or transfer case (not sure which). You can see these two breather hose/cap by looking into the engine bay on the driver's side...it is the along the wheel well. You should see two hose with two silver caps side by side.

However, for whatever reason, the rear axle does NOT have an extended breather. Good news is that it is easily done (see below)...it would be very difficult to do the front differential and transfer case. Luckily, Toyota did that for us already.

The rear axle, instead, has a little breather cap (withOUT the hose) on top of the axle. The silver cap acts as a one-way valve. When the axle housing gets hot and pressure builds up, the cap pops open, releasing the gas and then closes down to prevent water from getting in. HOWEVER, in theory, this cap can malfunction, especially when you have mud/dirt sticking to it. This can happen if you off-road often or cross streams often. And if it malfunctions, then water/mud can get into the differential housing. That would be bad. All theory because i have not heard of anyone having problems with it...however, to be on the safe side, read below.

Anatomy of the Land Cruiser breather cap (same for 4runner):
http://www.safari4x4.com.au/80scool/...er/diff_b1.gif

The rear axle breather cap is on TOP of the rear axle housing...to the DRIVER'S side from midline. The breather has a silver cap. I don't think anything else looks close to it on the axle housing.

Some have advised to drop the spare tire to give you more room to work with. My local mechanic was nice enough to let me use his bay! :)

The two main parts from Toyota are:

1. 90404-51319 Union
2. 90930-03136 Plug, breather

Should not cost you more than $15 bucks.

The other parts are from your local Autozone/etc.:

1. 3/8" fuel line hose...about 5-6 ft (i picked 6 ft)
2. 1/4" - 5/8" hose clamps (get a few of them)
3. Cable ties or Zip ties

You can use this link from 4x4Wire's TrailTalk Forums
to do a search on all the discussion on this topic:

http://www.4x4wire.com/cgi-bin/ultim...earch_forum=13

Just type in "diff breather."

For me, i ran the fuel line hose all the way up to the INSIDE of my left (driver) taillight. It goes OVER (on top of) the frame. Run it in front of the rear bumper and into the driver's side taillight housing.

Two important things to remember:

1. Leave enough slack in the fuel line hose for the axle full articulation;

2. BUT, do not leave too much slack that the fuel line hose at ANY POINT dips...that is, the line should not bend down at any point! The fuel line hose should always go UP. This is to prevent any pooling of the differential fluid and cause clogging in cold weather. By running it upwards, if any oil collects in the line, it'll drain back into the diff.

Hope this helps...and enjoy many future water crossings! :D

EDIT: Here is a video to explain why this mod is so important: http://video.google.com/videoplay?do...ta+truck&hl=en

Eric,

The above instructions are for the 3rd gen 4Runner...i have not checked to see if the '03 4Runners are the same.

Therefore, if you have a 3rd gen 4runner, then go for it!:)

If you have a 2003 4Runner, then proceed with caution! :eek:

EDIT: Thanks to Scofco, the 2nd gen 4runner uses the same materials for this modification.

Thanks for the reply. I will be doing this shortly. I have the 2001 4runner Sport.

I'm running the beaches of south Jersey, doing surf fishing. I occasionally have to "cross" a tidal creek.

What about your wheel bearings - any concern for them doing a few water crossings?

i'll be doing this mod this weekend or the next. When I'm done I'll let ya guys know how easy it went on the 4th gen.

GoodTimes,

Great! Tell me if the the breather cap is in the same position, and if it uses the same parts!!

Oh yeah, remember to take some pics.

Worked like a charm!
 

Thai:

I'd like to say that I've successfully done the rear diff breather mod on the new 4th gen 4runner. The existing parts worked as I expected.

Expected time: 1 hr or so including trying to take pix.

Tools required:
13mm and 14mm Box/Open wrenches
Screwdriver
Wire Cutter
hot water

Image of the stock rear diff (looks the same like any toyota!)
http://kashusales.com/good_times/rear-diff-1.jpg

Use a 14mm wrench to remove the stock breather. Before removing the breather completely make sure to clean around the breather so you don't get anything side.
http://kashusales.com/good_times/rear-diff-2.jpg

Should look like this when you remove the breather..
http://kashusales.com/good_times/rear-diff-3.jpg

Add the union into the differential housing. Should tighten down but will have a thread or two shown. (Use 13mm wrench)
http://kashusales.com/good_times/rear-diff-4.jpg

Attach the hose. Make sure you have enough slack so when the diff is at it's lowest point you still have enough hose for it to move.
http://kashusales.com/good_times/rear-diff-5.jpg

Run the hose along any route to a higher point in the vehicle. I chose to run it into the gas cap area which is pretty darn high. If the water goes that high I'm already in trouble anyway! :D
http://kashusales.com/good_times/rear-diff-7.jpg
http://kashusales.com/good_times/rear-diff-6.jpg

Dip the other end of the hose in hot water to let the rubber hose expand. Then insert the new breather and clamp it down. Find a place to secure it and you're done!

GoodTimes,

Great pics!! Good job! Cool, both 3rd gen and 4th gen uses the same parts for the breather modification.

Good job!

GoodTimes -

Comments and questions:

First of all, your post took the job and made it less than 30 minutes for me. That's the first time in a long time that a job took less time than budgeted. My wife routinely doubles the amount of time I tell her. ;) Thanks!!

I used 5/16" fuel line -- 3/8" seemed a little loose. Getting the hose over the union was a bit difficult. However, instead of using hot water to expand the hose, you can put WD-40 on a paper towel or a rag, carefully wipe it on the union, and the hose slips right on. Then just clamp as usual. Much easier than hot water.

Questions:

1. You mention leaving enough slack for full articulation. About how much room should I allow? It looks like the wheels can go down 8" or so before the hose is taut.

2. Where in the gas fill area did you put the breather element? I poked it between the rubber grommet and the fuel filler pipe, then used a zip tie to hold the hose and filler pipe together. That avoided making any custs whatsoever.

3. When I unscrewed the original breather, it obviously had pressure because it hissed. Did you find the same thing?

Again, thanks for the pics and the write-up. You made it very easy.

John:

30 min sounds about right... just takes abit longer when you try and take some pix... esp taking gloves off so your camera doesn't get dirty :p

well i did think about using wd-40 but i just didn't want any unkonwn fluids to get inside the hose. figure if i used hot water, the water will evaporate whereas the wd-40 will stay on the hose for a long time... hence might mix w/ the oil inside... so i figure ehe hot water should do the trick :)

actually the 3/8" was fine for me. dunno but hey if it works, it works!

1> the entire length of my hose was about 5 ft and 2 inches or so... i think if you have 18" of space hose you're okay... (don't rem exactly but i did read somewhere that if you have about 5-6ft of hose from the diff to the gas cap then you're fine...

2> i put the breather to the 8 o'clock area. i made a hole about 1/2 the size of the hose and just forced it in there. i purposely left alot of slack in the gas cap area because i didn't want the breather to get stuck on the wall of the gas cap. that breather has to be able to move (i.e. spring inside to let air out) so make sure it's free to move around. (hence the question 1... have extra )..

3> yeah the hissing was normal... nothing to be worried about :)

no prob on the write up. actually it's very similar to everyone else's write up! hehe gen 1-2-3... all the same pretty much

Lance

Sorry to sound ignorant, but what does this mod do to my car ? Does this increase power ?

Thanks

Doesn't increase power. Instead, it prevents a potential problem.

Thai said it best in his earlier post:

So look at this as preventative, and worth the $15 and 30 minutes to be on the safe side.

I'm new to this forum. You did the write for gen3 and gen4, what about us gen2 guys. I noticed that almost all of the members have at least a gen3 truck. Am I in the wrong forum?

Andy

hey man, i have a 2nd gen. hah, i agree with you on the fact that all i see are 3rd and 4th gen. here, but its cool. you can do the breather mod for the 2nd generation too, its easy..even I could do it:eek:

:chnsw: :chnsw: i know i aM ABOUT TO GET CHEWED UP HERE AND SPIT RIGHT back out but what g eneration is my four runner it is a 1992 and what is a generation? that you all are talking about