Rear Axle Breather Extension - Routing (1 Viewer)

[RWBeringer4x4]

Hey all,

I'm contemplating extending my axle/differential breathers to keep water/crud out of them. There's plenty of "how to's" surrounding the extension, so I think I have that covered. My question pertains to routing the rear.

I was planning to route the front axle breather up into the engine bay, and terminate it with an air filter. Where have folks routed the rears? It seems like an awful lot of hose to lay down to bring a rear axle breather all the way up into the engine bay. Do most folks terminate it somewhere under the tub in the rear? If so, what is the best option? I was thinking, potentially, the rear frame crossmember...thoughts?

 

[subzali]

Took mine up to the engine as well. FJ40s really aren't that long, so the hose isn't as long as you might think.

 

[RWBeringer4x4]

Took mine up to the engine as well. FJ40s really aren't that long, so the hose isn't as long as you might think.

Where did you route it, along the passenger frame rail? did you use any hold-downs/clamps?

 

[subzali]

I think I just zip-tied it to the rear wiring harness running along the passenger rail.

 

[Coolerman]

Gives me an idea: When I build a new rear harness I could bundle a differential vent hose in with the wiring like the washer motor hose on 78 and later trucks...

 

[franklin40]

that's a great idea cooler man. I routed mine along the brake hose so it had some flex. I then zip tied it along the brake hard lines on he passenger side. a t hose connector brought the front and tears together and then routed it up to the engine compartment. I used pvc on my 40 and rubber fuel line on my 62. I like the rubber better as it stays more flexible in the cold. it only cost $15 for the hose and a 40 will require less yet

 

[darwink1]

I ran mine inside the frame rail and followed my fuel line to the ps fire wall. My wiring harness runs through there as well. May as well do the transfer case while youre messin around.

D

 

[RWBeringer4x4]

I ran mine inside the frame rail and followed my fuel line to the ps fire wall. My wiring harness runs through there as well. May as well do the transfer case while youre messin around.

D

@darwink1 - Transfercase will come later. The next major project on this truck is the clutch, during which time the T-case and transmission will be coming down. When that happens, I'll handle the T-case breather.

 

[Living in the Past]

Personally not a fan of running soft tubing horizontally drain of vent. Any type of liquid gets in a low spot and it will no longer be a vent, drain will air lock. I like the idea of running a line in 1/4" rigid copper that is wrapped in 40 mil tape. May make a manifold adding the transmission and transfer case vent to the line or just run three separate lines. Thought about terminating them in the air cleaner but with a dirty filter and gas butterfly valves open in the carburetor the vent would become a vacuum line and not a vent. Not sure it would create a large enough vacuum to pull anything past the oil seals but why risk it.

 

[Tools R Us]

We just run them into the passenger rear corner of the tub, through one of the holes in the top of the fender well.

 

[RWBeringer4x4]

We just run them into the passenger rear corner of the tub, through one of the holes in the top of the fender well.

This is more along the lines of what I was thinking - I guess it would depend on how deep the water is you're planning to drive your truck through. In my case, extending the breathers is probably overkill as it is. I doubt I'd ever get "tub deep." My only concern with putting anything in or near the fender wells would be the the tires kicking mud up into the breathers. My guess is there is something back there blocking this, but I'd have to take a look.

 

[Tools R Us]

Indoors, like this.

 

[Living in the Past]

That is fine with a open top vehicle but if you run a hard top in a cold climate wouldn't want smell gear oil in the cab if I don't have to.

 

[RWBeringer4x4]

I guess I never noticed a hole back there...

My truck smells like worse than gear oil...with the massive open hole in my tranny cover for the "modified" shifter and no boot of the T-case (not to mention missing bolts/grommets in the firewall) my bigger concern is the truck filling with exhaust fumes.

@Tools R Us solution might work, in this case. Not even sure the breathers "breathe" enough to really make the gear oil smell a problem - I guess there's one way to find out!

Maybe I'll try this (shorter) route first, and if the smell is rough, I'll run it up to the engine bay.

Again, I think I could also probably terminate over the frame crossmember, under the tub, too. Really doubt I'll be sinking my truck that deep.

 

[Living in the Past]

on a 75 that hole in the passenger's side is for the wiring for side marker and license plate lights.

once running and the oil heats up things expand. Colder it is to start with the more it expands. If that wasn't the case there wouldn't be a need for the vent to begin with.

 

[RWBeringer4x4]

on a 75 that hole in the passenger's side is for the wiring for side marker and license plate lights.

once running and the oil heats up things expand. Colder it is to start with the more it expands. If that wasn't the case there wouldn't be a need for the vent to begin with.

I understand the need for a breather, and how things heat up as they expand, etc. and force air out (and pull it in). Radiators/overflow bottles work in very much the same way.

I was just implying that the amount of air pushed out as the diff heats up (to me) doesn't seem ultra significant, and probably not enough to gas me out of the 40! The gear oil smell would just add to the truck's natural "musk."

 

[BANDICOOTII]

I just clamped it up against bottom side of the floor pan on my 60. No loops or horizontal runs to trap water. Are you planning to ford rivers door deep? You know 40's float once the water is push'n up on the body pan..... unless you open the doors

 

[RWBeringer4x4]

I just clamped it up against bottom side of the floor pan on my 60. No loops or horizontal runs to trap water. Are you planning to ford rivers door deep? You know 40's float once the water is push'n up on the body pan..... unless you open the doors

Right now (mostly due to the mechanically unsound nature of the truck) it is a glorified grocery-getter. Sometime down the road I plan to use it offroad, but probably won't be fording any rivers. As I've mentioned previously, extending the breathers at all is probably overkill - but I just can't leave well enough alone.

 

[DickM]

My 40 has the rear axle breather t'd to the TC breather and run to a small air filter located in the fuel/vapor separator housing on the passenger side.
The front is similar but comes up by the air filter intake. Short hose runs and well protected.

 

[BANDICOOTII]

Right now (mostly due to the mechanically unsound nature of the truck) it is a glorified grocery-getter. Sometime down the road I plan to use it offroad, but probably won't be fording any rivers. As I've mentioned previously, extending the breathers at all is probably overkill - but I just can't leave well enough alone.

No worries, just takn a friendly jab at you. I got ADDS worse than anyone! Adds this adds that