Diff Breather Hoses

I would like to install longer diff breather hoses. Is this hard to do?

What is the max fording depth with stock diff breather hoses?

The safest depth I believe is about 12 inches of water.

The standard breathers have a flap and a spring in them and they can block open. This means that water will enter the diffs and the water in extreme pressure diff oil breaks down the ability of the oil to take the load and the gears actually wear out. (ed - The flap can also snap shut when the diff housing is cooled in water resulting in axle seals popping in and sucking water).

I extended the breathers using normal fuel hose and from the back I ran the hose up to the floor and then along the chassis by zip tying it to other lines (ed - avoid running them along brake lines as they can get caught on branches etc) then up to the top of the engine bay. The front was done likewise. You need about 8 metres of hose (I think, I cant remember exactly). (ed - Don't forget to allow for suspension travel in length of hose at each diff).

I used T fittings into the rear line to also take a breather from the gearbox/transfer. The breather on the gearbox ends at the top of the bell housing at the rear of the engine. Its had to find but you can run your hand along the top and feel it. I unclipped the end from the last fitting on the box and pushed on the new line and joined it into the rear line. Where ever I added the line to I then zip tied the hose to the fitting, although hose clamps could be used.

The T fittings are available from irrigation or auto parts suppliers.

I then installed a small petrol fuel filter in the end of the line in the engine bay with a short length of hose 8 - 10 inches hanging down. The filter is to stop dust entering and the hose hanging down is to provide a u shape to stop water entering if you get it really wet.

Its also worth while changing the diff oil if you even think they might have a bit of water in them as it works quickly to ruin the oil.

If you have an under bonnet compressor, like an ARB one, it is also worth while to provide it with a breather hose as they fill with water/mud through the little bronze filter and they have to be stripped down and the bearings replaced.

The cost all up including a small pack of zip ties and T fittings was under $50 plus a hour or so under the car.

Adrian Salmon

> these 'valves' can block up and cause more problems. Best to toss them and
> use some other filtering arrangement, 'u' tube, petrol filter etc.

These flapper valves are designed to let air out of the housing as it heats up. They snap shut and create a lower pressure in the axle housing when it's cold. Nasty when the axle housing is quenched suddenly when you enter cold water. When installing the extension diff breathers on my latest 80, there was an audible rush of air when I pulled the diff breather hose off the barbed fitting on the housing.

A cheap fuel filter or the filters ARB use on their air compressors are good to use on your extension diff breathers. Especially if you're running air lockers. These will let enough air through in the event that you have a locker piston seal failure and end up pumping 120 psi through your axle housing.

Cheers

gc

just finished installing longer breather hoses on the front and rear diffs yesterday (will install one on the transfer case later this week, ran out of time;-).

after sizing up the situation, i purchased 25' of .250" i.d. fuel line hose, two (2) tee fittings, six (6) hose clamps, a bunch of 10" tie wraps, and went to work.

disconnecting the existing hoses was easy enough, and the front hose yielded a very good filter/baffle to use for the new system. on '97's, the front breather connects to a roto-molded plastic container with a pop filter on the top of it. also, the metal bracket that holds this part to the frame can be used when you reposition the filter under the hood. I do not know if earlier 80 series have this, if not, Dimitry used an in line fuel filter on his setup.

i installed the front diff hose first, which took approx. 1 meter of fuel line to run, allowing enough free play for suspension articulation. two (2) tie wraps held it in place. i ended up running the hose up into the engine compartment, terminating next to the fuse box. the bracket that originally held the plastic filter to the frame, was reshaped and used to attach the filter in its new position (i will take photos of all of this later, and post, as trying to describe exact locations is difficult, at best;-). both ends of the new hose were secured with hose clamps.

the rear diff was even easier to work on, and after allowing enough free play for articulation, and using a hose clamp on the diff breather fitting, it is a straight shot up the frame on the drivers side, using tie wraps to secure the hose in place. i used approx. 4 meters of hose for the rear diff.

i used one of the tee fittings to patch the rear diff hose into the front diff hose, just as the front hose crosses the frame and starts to head into the engine compartment (again, photos will follow).

after testing the hoses today (long on-road, and some off-road driving), i am happy to report all are doing well.

as i mentioned, i will attempt the transfer case breather hose this week, as i ran out of time this weekend, and i really would like to get the cruiser up on a lift, to be able to really see up into the transfer case area. i looked at a shop manual, and saw what i believe to be the breather fitting, located way up on top of the case (this makes sense), and this area only has little more than a hands thickness of clear space to work in.

i hope that this account prompts any other on the list that have been contemplating doing a diff breather mod, to go ahead and do it. the way i rationalized it is as follows:

1. the materials cost less than $40.00 to obtain (you can use less expensive fuel line hose, i suppose, and this would lower cost considerably).

2. the whole job took me less than 3 hours total (this with LOTS of rerouting hose, to obtain maximum safe routing). i am sure it can be done in less time than this.

3. the cost of rebuilding a diff that has sucked water is considerably more than the material cost, and my labour for three hours (even though i do charge a lot for my consulting time;-).

cheers,

johnc

Instructions: How to Install Gearbox & Differential Breathers

The Test Vehicle

• 1FZ-FE engine
• manual 5 speed transmission
• mechanical centre diff (same transfer case housing as viscous coupled)
• no diff locks
• ARB side steps (mounting hardware seen in picture)

Background Details

The front diff breather enters the axle housing about 25mm above the axle centreline. The rear breather is connected to the top of the rear axle housing. It is interesting to note that the 60 series Land Cruiser had the breather entry at the top of both axle housings.

When the axle housing breather hoses were removed there was a noticeable induction of air into the axle housing, which had been under vacuum.

A number of small modifications have been made to (hopefully) resolve the discharge of front diff breather, and prevent the breather or seals from sucking in water or dirt during river/creek/mud hole crossing.

Options

• use a 60 series breather valve instead of modifying an existing valve
• incorporate the main gearbox,
• use a garden variety fuel filter on the combined breather line,
• pressurise the combined breather line to a low pressure (1-2psi ??)

Modifications

• modify the breather valve
• relocate the breather valves higher
• connect all breather lines
• possibility of pressurising the diff & transfer case

The Breather Valve

The breather valves are designed to permit gas (and liquid) exit the axle or transfer case housings. A modification needs to be carried out on only one valve.
Below is a cross section of the original breather valve. The valve body is brass, with a steel cap, spring, and rubber flapper.  

The 60 series Land Cruiser used a plastic body and cap, without either the spring or rubber flapper. You may wish to purchase one of these if you do not wish to modify one of the original breather valves.

The 80 series breather valve after modification is shown below;

Tools

• 12mm combination spanner
• 12mm socket
• 14mm socket (from memory)
• ratchet and extension
• sharp knife
• flat blade screw driver
• pointy nose pliers
• multi-grip pliers
• side cutters
• safety glasses
• ramps, or jack and jack stands

Parts

• 7 metres of 1/4" hose (rubber fuel line)
• 10 "P" clamps to suit above hose (with 10mm mounting holes)
• 10 hose clamps to suit rubber fuel line above
• 3 1/4" brass "T" pieces (the ones with barbs)
• 1 3/8" rubber blanking cap
• 8 7" long cable ties (BLACK only)
• 8mm bolt - optional
• hand cleaner
• rags

Modification Procedure

Overview

Then new breather line will run from the rear axle housing, to the inner rear cross member, along the inside of the left chassis rail to the transfercase cross member. From there it will split to run up the side of the transfer case to the transfer case breather outlet, and forward along the chassis rail to front axle house breather valve hose mounting point on the chassis.

At this point the new breather line will split to connect to, the front axle housing breather outlet, and the other remaining leg will run up into the engine bay.

The new breather line will be secured to the chassis with P clamps, and cable ties were access to the bolt onto the chassis is extremely difficult (like behind the fuel tank).

Brass "T" pieces are used at the transfer case cross member, and just forward of the left engine mount. Hose clamps are used at each breather outlet and each "T" piece.

Work is commenced from the rear axle housing towards the from of the car. Breather lines are always mounted above the brake lines.

Please read ALL of the modification details before commencing. There are a lot of steps involved, but most are just reasonable engineering practice.

This procedure has worked fine for me, on 1FZ-FE engined '94 model. Your mileage may vary, so use these instructions as a guide.
  

Detail

Rear Axle

1. cap one end of the new breather line
2. feed the breather line (capped end first) rearwards from the transfercase crossmember along the inside of the chassis rails, above the brake lines) past the main fuel tank
3. slip one P clamp (tail pointing rearwards on the right side) over the new breather line
4. slip one hose clamp over the new breather line
5. remove the original rear axle housing breather hose (completely)
6. remove the cap in the new breather line
7. push the new breather line onto the rear axle housing breather outlet, and secure with the hose clamp
8. ensure that there is sufficient hose to allow full articulation of the suspension without fouling or rubbing
9. secure the new breather line to the fuel tank cross member using the existing parking brake cable guide bolt
10. remove the bolt holding the brake lines to the chassis at the rear of the fuel tank
11. install a P clamp over the new breather line, tail outer most and pointing down
12. loom the new breather line neatly across the rear of the fuel tank, and secure with cable ties
13. secure the P clamp and brake lines with the original bolt
14. remove the bolt holding the brake lines to the chassis at the front of the fuel tank (and behind the transfercase crossmember)
15. pull any excess new breather line forward from in front of the fuel tank
16. install two P clamps over the new breather line, tail outer most and pointing down, just forward of the fuel tank
17. secure the new breather line to the brake lines behind the fuel tank with cable ties at each brake line clip
18. secure the rear most P clamp and brake lines with the original bolt

Transfer Case

22. slip one P clamp (tail down and forward most), and one hose clamp over the unused end of the new breather line
23. secure the new breather line to the  T piece on top of the gearbox using the hose clamp
24. route the new breather line down the left side of the transfer case
25. remove the second lowest transfer case housing bolt
26. secure the new transfer case breather line with the P clamp against the transfer case using the bolt just removed
27. loom the new transfer case breather line along the transfer case cross member, and up to the top of the chassis rail
28. cut the new transfer case breather line at the top of the chassis rail
29. cut the rear axle housing breather line just forward of the transfer case cross member
30. slip one hose clamp over each of the new rear axle housing breather and new transfer case breather lines
31. trim each new breather line to permit a tidy fit of one brass T piece
32. secure the new breather lines to the brass T piece with the hose clamps, with the new transfer case breather line connecting to the terminating portion of the brass T piece
33. slip one hose clamp over a the remaining section of new breather line
34. secure the remaining section of new breather line to the remaining unused portion of the brass T piece
35. secure the rear axle housing breather line to the chassis using the mounted P clamp and bolt from the original rear axle housing breather support

Front Axle

36. slip all but one of the remaining P clamps over the new breather line
37. route the new breather line forward from the T piece, under the engine mount, to the front axle housing breather support
38. secure the new breather line to the chassis using bolts from the brake line mounts and P clamps
39. use cable ties were appropriate
40. cut the new breather line approximately 15cm forward of the left front engine mount
41. remove the front axle breather hose from the front axle, and chassis rail. Listen for the suction!
42. slip a hose clamp over the unused section of new breather line
43. install this section of new breather line onto the front axle breather outlet, and secure with the hose clamp
44. allow sufficient breather line for full front axle articulation from the front axle housing to meet up with the breather line from the rear axle and transfer case.
45. cut the new front axle housing breather line at this point
46. slip one hose clamp over each of the the new front axle housing breather line, and rear axle/transfer case breather line
47. clamp the rear axle/transfer case breather line to the terminated part of the remaining brass T piece with the hose clamp
48. clamp the new front axle housing breather line to the brass T piece using the hose clamp
49. route the remaining section of new breather hose down along the left inner guard in just in front of the left engine mount
50. slide one P clamp and one hose clamp over this section of breather line
51. secure the breather line to the remaining outlet of the brass T piece using the hose clamp
52. secure the P clamp using the original front axle breather hose support bolt and chassis mounting hole

Engine Bay

53. route the section of breather hose to a convenient location in the engine bay which has an 8mm bolt hole. This will depend on the extra equipment installed on your car
54. rework either the front or rear breather hose support bracket to hold the new breather line
55. mount the breather line support bracket
56. install the breather line into the support and secure by compressing the metal loop slightly
57. cut the breather line, leaving sufficient to install an original breather valve
58. slip a hose clamp over the end of the new breather line

Breather Outlet

59. non destructively remove one of the original breather valve caps
60. re-assemble the breather valve without either the rubber flapper or spring, as per the modified 80 series breather valve drawing
61. remove the breather valve from the original breather hose
62. install the modified breather valve into the open end of the new breather line in the engine bay
63. secure the modified breather valve onto the new breather line using the hose clamp

Completion

64. ensure all clamps are tight
65. inspect brake lines for any damage
66. account for all unused clamps and hose
67. account for all tools used
68. clean the tools
69. clean thy self
70. remove the car from the ramps or jack stands

Pictures of the Installation

The following photo shows a view forward from the transfer case cross member to the front brass T piece, were the breather line splits to go down to the front diff, and up into the engine bay. The hydraulic line seen in the picture is the clutch line. The white object on the right is the engine sump.

The second photo shows details of the area around the transfer case T piece. You will notice the P clamps using the same bolts as the new breather line, and the support U bolt for the ARB side steps (left of the picture) routed under the brake lines and new breather lines. Fuel lines can be seen on their way to/from the engine in the centre of the photo.