Install of the ARB Breather Kit for Rear Diff and Rear Locker

I read several threads on multiple forums with regard to how to install an ARB Breather Kit. Most only addressed the rear diff. The ones that did discuss how to handle the rear locker, while somewhat useful, did not provide all the details I would have preferred. So below is my attempt to provide a clean and simple way to install the breather kit when you have both the rear diff breather and the rear locker breather.

I won't post a picture of the ARB breather kit, as there are numerous ones available online.

You will need two additional items to complete this install.
A 3/16" T-connector hose barb (picture provided below)
Waterproof tape (picture provided below)

I obtained both items at Ace Hardware.

Waterproof tape.



The first thing to do is file off the barb on the lower section of the T-connector. I did this with a Dremel tool. The barb needs to be removed in order to attach the rubber hose from the Rear Locker. Forcing the hose over the barb would weaken the hose and eventually cause it to fail.




Now that the T-connector is prepped, it is time to remove the spare tire. This will make access to the breathers much easier. If possible, I recommend you jack up the rear end and place a jack-stand under the frame on each side. This will provide you with much more working room and allow you to sit underneath the vehicle.

Identify where the breathers are, so you know what you will be working on. Note, there is no need to remove the Rear Locker Breather as part of this install. It will be bypassed and can just remain in place.




The next step is to route the ARB breather line. I placed about a 3 ft. piece of PVC pipe down through the engine bay on the passenger side.



View of PVC pipe from underneath 4Runner.




Now insert the ARB line through the pipe from up above. Once you have pushed the line through the pipe, go below and route the line as shown below. Along the way you may add zip ties to hold the line in place, as needed. I only used two zip ties. I did not snug the zip ties too tight, in case the line needed to move a bit.







Continue routing the line to the rear axle. It should pass by the passenger side of the fuel cell and end up above the rear axle.

Once the line is routed, it is now time to prep the line for the Rear Locker. You are going to open up the outer gray conduit and unplug the small rubber hose from the connector as shown below.



You are then going to plug the rubber hose into the lower leg of the plastic T, that you filed down with the Dremel tool.

Next, remove the Rear Diff breather and replace it with one of the ARB breather connectors. This should be straight forward and is explained in the ARB Breather kit.

Now you will cut the ARB line as needed and connect the lines as shown below. Now both the rear diff and rear locker are connected to the ARB breather line. Don't forget to tape the conduit shut that you opened up.



The next step is to place a loop in the line and connect all the lines at the T-connector. Since the barb was filed off to fit the rubber hose, and the other lines were not overly tight, I chose to wrap the whole connection in waterproof tape to ensure it never came apart. The waterproof tape is not sticky like glue, so it won't get all gummy.

When putting the loop in the line to allow for axle travel, be sure to leave the zip tie open somewhat to allow for easy line travel.




The last step is to mount the breather under the hood. This is very easy. Just route the line along the firewall. It should be obvious, but don't forget to remove the PVC pipe at this time.

I placed painter's tape on the back of the breather before mounting. I do this to avoid metal on metal mountings, which may eventually wear the paint away and lead to rust.



I hope you find this method of installation useful.

 

Very good writeup, thanks. Two questions - would heat shrink tubing work as well for the T fitting connections, and how does the ARB breather mount to the fender wall?

 

I suppose heat shrink wrap could work. I don't use shrink wrap very often, so I am not sure if it would have any negative affects on the rubber hose that goes to the rear locker. I would also recommend using the heat gun on a small test piece of the ARB line, which is a hard plastic, to ensure the plastic tubing did not weaken from the heat prior to employing shrink wrap to the connections. Since there is no pressure on the line, I just used some waterproof tape since it was quick and easy.

With regard to the breather filter under the hood, there is already a hole in the hood on the passenger side that accepts a standard mm bolt. The kit comes with self taping screws. I did not need to drill a hole, as I used the available threaded hole that was already there, and used a metric bolt I had that fit perfectly. I think it was a 1" or 1.5' bolt that was 6mm, as I recall.

Hope I answered your questions.

 

Are rear diff and locker the only places that need the breathers extended or are there others as well that sit low?

 

I am not aware of any other items that require a breather hookup of this type. This, of course, does not address a snorkel for the engine air intake.

 

Thanks for the info! I'm aware of the air intake, although I'm not planning to ever go so high for this to be a problem. Snorkel for me would be to avoid dust, not water since the 4Runner cabin isn't properly sealed.

At some point I want to relocate breathers, just collecting info on which ones I need to do. Nothing at the center diff or transmission?

 

Not that I am aware of.

 

This is awesome.

Care to elaborate as to why this is important? Noob here. Watching Aussie 4x4 YouTube videos and one of their "Top 5 Mods" for an off-road truck is proper diff breathers. It's been on my list as something to look into.

So you're saying that the 4Runner already has breathers from the factory? Are "proper diff breathers" just breathers that are routed to a higher elevation? It seemed that the videos I'm referencing recommended breathers for when going through large water passes. I'm wondering if this is something I should bother with, or leave alone.

TIA!

 

If you don’t do water crossings of more than a few inches, than it’s not needed. You need it when the actual breather opening gets submerged and would draw water due to temp differential between hot diff and cold water. The diff is cooled suddenly and will suck in whatever is outside that breather opening to relieve the negative pressure in the diff. If that is water, you’re contaminating the lubricants.

 

Wouldn't?

Thanks for the responses.

 

The front diff breather is extended into the engine bay from the factory. The rear breather is just a fitting on top of the diff housing. I did the rear breather extension, but not the locker. My rear diff breather extension ended up behind the driver's side tail light.

 

I mean't "would" and not "wouldn't" as I was intending for you to test the heat gun on small piece of the tubing. I will edit and clarify my response.

 

I get it now. Sorry, it didn't read that way, but now I see what you meant. I'm thinking the heat gun/shrink wrap wouldn't get hot enough to affect the ARB or oem tubing, but if I get around to a project like that it's not a bad idea to try it on a sample first.

 

Does the transfer case require an extended breather also? Does it have any? Thanks.