R" Extended Rear Differential Breather
Toyota Union Fitting- #90404-51319 (~$6.00)
Toyota Breather Plug- # 90930-03136 (~$3.00)
Fuel Hose Line (5 to 6 feet; ID 3/8", OD 1/2")
1/4" - 5/8" Hose Clamp (2)
14mm rachet socket
12mm rachet socket
Pipe Thread tape
Large Cable Ties (2)
I am providing this write up for illustrative purposes
only. Perform at your own risk. Any mods (including this one) you perform
on your vehicle is your responsibility. Furthermore, commercial use of
this write up is prohibited---all images and text are property of 4Runners.org.
Linking or copying any portion of this write up will result in legal action.
If you plan on or anticipating off-roading in fairly deep water, extending
your rear differential will help you prevent damage to it. The stock rear
differential breather plug only extends about an inch above the differential
itself. When fording deep water, the cool water has a high probability
of being sucked into the differential through the stock plug and as you
know, "oil and water don't mix." The key to this installation
is to basically raise the breather plug higher than what you anticipate
most mods, there's always room for improvement either in the process or
the parts used. Thanks to some rather specious sources, I acquired a very
"special" differential plug that allowed my differential to
breathe easier and amazingly add an additional 50 rear wheel horsepower!
Skeptical? Read on! And of note, thanks to Jalaber's excellent write up
on his website,
which I used as a reference to perform mine.
Step 1: Removing the Spare Tire
You'll need some room down there to work so it's best to remove the spare
tire. The spare tire is removed by using the supplied tire tool to lower
it from its mount. The tire tool is located under the rear seat. After
removing it from its plastic clips, insert it into the hole located in
the rear cargo area and turn counter clockwise. You will see the tire
up the passenger seats and you'll see the tire tool
the tire tool in this hole, make the connection and turn counter clockwise
to lower the tire
is completely lowered, slip the plate out of the tire, roll the tire in
a safe location and then pull the tire wire up.
Step 2: Removing the Rear Differential Breather Plug
As you can see here, the rear differential breather plug is located on
the left side of the rear axle.
axle view from the back. The stock plug is shown as (D)
up of the stock breather plug
breather plug with a long 14mm rachet socket. Be forewarned, it will hiss
as the gas pressure escapes from it. I got a bit startled and hit my head.
Ok, back to the write up: After removing the plug, tape some thread tape
on the new union fitting and use a long 12mm rachet socket to fasten it
onto the rear differential.
Stock breather plug (O); New "special" breather plug
the new union fitting with thread tape and fasten w/ a 12mm rachet
Step 3: Threading the Fuel Line
Here's where I did things a bit differently from others. First,
I removed a plug that holds the gas line cover to the body. You really
only need remove one single plug (pic below). Wedge some paper in between
the body and the gas line cover to allow the fuel line to slip through.
from underneath: (G) is the gas line cover and (P) is the location
of the single plug you need to remove. After removing the plug, wedge
some paper to create a gap
is the plug you need to remove. The plug has two tabs (T) that you
must push in to remove the plug. Use a flat bladed screwdriver
your Xacto knive and cut an "X" shape in your gas filler gasket.
I cut mine on the right side, but in retrospect, it might have been better
to cut it a little higher and to the left.
an "X" shaped hole in the rubber gasket and feed the tube
downwards. If I were to do it again, I'd cut the hole a little higher
and to the left
the differential fuel line coming through the gap you created (G).
As you can see, the plug (P) is removed
tube downwards and it should go through the gap. Note: it took me a few
tries to successfully thread the tube through so don't give up after the
first try. You'll notice that there is enough space for the new fuel line
to peacefully co-exist with the existing fuel line. You can now insert
the plug back into the gas cover.
Step 4: Connecting the New Fuel Line to the New Union Fitting
Once you've finished threading the fuel line down, run the fuel
line as shown across to the right and down to the new union fitting. Leave
some slack for suspension articulation. Next, take your Xacto knife and
make sure that the fuel line end is cut straight. Fasten the hose clamp
onto the end about a 1/4" from the bottom. Moisten the union fitting
w/ a little water or saliva, push the fuel line/pipe clamp onto it and
then tighten the hose clamp.
the new fuel line (G, marked with yellow) threaded from the gas line
cover and running to the new union fitting.
the new fuel line, hose clamped onto the new union fitting
Step 5: Type R Power!
Go back to your gas filler nozzle area and cut the new fuel line
tube to length. As you can see, I purchased 6 feet and I have quite a
bit left. Now, insert a hose clamp to this end of the fuel line and then
(drum roll, please) insert the "special" Type R breather plug.
Yes, you heard it first here at 4Runners.org---a Type R breather plug!
See the pic below.
the new fuel line. Cut to length. In this pic, I prematurely put on
the hose clamp so I wouldn't lose it.
first! If it works for the slammed Honda crowd, why shouldn't it work
your spare tire back. After final fitment, I took a little drive. I immediately
noticed that at WOT, I was just moving as if someone dropped in an LT1
engine---Good lawd! I can wholeheartedly say that the Type R breather
plug is responsible for this massive increase in horsepower!
or feedback? Email me and I'll try to get back to you. If this article
helped you save time, money or just made things more convenient for
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