Rear Differential Breather Extension 2007 FJ Cruiser

***Corey*** · 11-19-2006, 06:09 AM

Article by:
OlyWaFJ

So we have all heard that the FJC will ford 27.5” of water thanks to the high point of the air intake and rubber sealed electrical connections.
One area that isn’t well protected is the height of the rear differential breather.
The breather provides a pressure release valve that springs to life when a heated diff meets cool water.

Now if that meeting takes place and the breather is submerged in water it may actually suck in water while the valve is open releasing the pressure. Water & oil obviously don’t mix especially when the oil is lubricating the gearing of your new FJC!
A breather extended to height that water can’t touch is what this write up is all about…

Parts needed
You will need a few things, the most difficult to obtain is the Union which needs to be ordered or if you are lucky, picked up from your local Toyota dealer.
The Toyota part number for the Union is 90404-51026, remove the dash if they have trouble identifying the part.
Next head to your local auto parts store and pickup 8 feet of 1/4” rubber fuel line, two 1/4” to 3/8” small hose clamps, and a small handful of zip ties.

Tools needed
A few common tools are required: a couple box/open wrenches both 10mm & 14mm, Phillips or slotted screw driver for the hose clamps, something to cut the fuel line (I used a razor blade) and a cup of boiling water.

The stock breather is located on the top of the rear differential “pumpkin”. You need to clean the area around the breather before removing it to prevent small particle from dropping into the exposed hole and contaminating your differential.
I learned this after I put mine in, I don’t think anything fell it but just in case I flushed and changed the diff oil.
Once the breather is removed install the new union using the smaller 10mm wrench, tighten it down until there is about one thread left exposed.

Start your water boiling and once rolling place one end of your fuel line hose into the water for 30 seconds.
This softens the rubber allowing for easier insertion of the stock breather. Make sure you are able get the hose all the way up to the base of the breather, no threads are exposed here.
Tighten the hose clamp down around the breather.

At this point I ran the breather up to my gas tank fill; initially I stuck it into the drain hole of the tank fill I have since moved to one side after cutting a small hole. To get the hose up to the tank fill I had to loosen the fender well cover by removing the bottom two screws.

Once the breather is stuck up into the tank fill area I loosely attached the breather fuel line hose with the zip ties to one of the other hoses and continue on down to the location of the union.
As you lay the hose out on its way to the union be sure to keep it up above the frame and out of the way of stray sticks looking to tear it free.

Keep everything loose for now as we are about to cut the hose to attach to the Union.
Measure twice cut once right?
Do NOT pull the hose tight, in fact leave a loose bend in it to allow the suspension to flex without ripping the hose right out of the union in the middle of the trail.
If your are planning on lifting the rear leave even more tubing so you don’t have to come back later and replace the hose with something longer.

When you feel you have the right length cut the hose slip the hose clamp on and press onto the union. Once you tighten the clamp, and all the zip ties you’re done! Simple huh?

Any questions about this article, please contact OlyWaFJ

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