diff breather extension

mtxride · 10-09-2004, 02:44 PM

Couldn't find this in earlier posts so... when doing the rear differential breather extension mod, does the breather need to be mounted in an upright position, like it is on the differential??

Also, has anybody mounted their breathers any where else besides near the fuel filler door?? I don't think I need to go that high with my driving style.

thanks everyone!!

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4Crawler · 10-09-2004, 05:13 PM

No need for it to be vertical, the stock breather fitting must be vertical since it relies on gravity to close the cap off to seal the axle. With a raised breather, you want to use an open filter of some sort on the end, orientation is not an issue, *but* make darn sure the vent lines runs up all the way to the end, you don't want any dips in the line. I did this on mine (tried running the rear line to the front) and found that oil mist pooled in the low spots in the line. Come winter and cold weather, 90W gear oil turns thick, enough to plug the line, pressure builds in the axle from heating and pushes oil out past the seals.

I run my rear vent into the space behind the taillight:

http://www.4crawler.com/4x4/CheapTri...html#Breathers

4RunnerKid · 10-09-2004, 06:18 PM

I mounted mine under the hood. Pretty easy to route the hose... Just took a bit more.

lal357 · 10-10-2004, 09:04 AM

where did ya get those filters and what type are they i tried looking for some and didnt have much luck i ran mine front by the battery with opening facing rear and the rear up thru whats left of my bed to just behind the tail light facing rearwards i did leave some slack in the lines for flexing

4Crawler · 10-10-2004, 09:13 AM

Mine is asmall K&N filterm probably a valve cover breather or something like that. A small VW air cooled fuel filter works well, or any of the small filters at the local auto parts stores will work. The filter is mainly there to keep small critters (spiders and other bugs) from crawling down the hose and plugging it up.

4RunnerKid · 10-10-2004, 11:58 AM

Mine are APCs from WalMart. $8 or so a piece, I think...

mtxride · 10-10-2004, 12:41 PM

hmm, from all of the write ups I've seen for extending the breathers, they still use a breather similar to the factory one.
example: http://www.yotatech.com/~corey/tech/...r/breather.htm

so would you guys recommend a small air filter over this breather??
and, 4crawler, I take it this breather would also have to be in an upright position since it's similar to the factory one??

thanks again everyone

4Crawler · 10-10-2004, 12:48 PM

Read my page for a full explanantion, but one of the reasons for extending the breather tube is to get rid of the stock breather, as it is part of the problem. Why? Stop in deep water with a hot axle full of hot air and guess what happens? The axle and air inside it cools. Cool air has a lower pressure (i.e. partial vacuum) and ideally you want to be able to pull outside air in via the breather tube to equalize the pressure inside the axle. Why? Because there is a chance of differential pressure sucking water in past the axle and pinion seals into the partial vacuum inside the axle. Stock breather is designed to close off and seal the vent when you stop, in case you are in water. If it remained open, water would pour in the open hole. But its the very design of the stock breather that can lead to the secondary problem of the partial vacuum. Normally when you are moving, the cap on the stock breather jiggles and allows air to move in and out, but stopped it seals off. So if you want to use a stock breather on the end of the tube, mount it upside down in order to let the cap hang free and not seal. A filter is a better option as it'll also help to keep out dirt and also filter the oil mist out of the escaping air.

mtxride · 10-11-2004, 11:53 AM

Quote:

Originally Posted by 4Crawler

Read my page for a full explanantion, but one of the reasons for extending the breather tube is to get rid of the stock breather, as it is part of the problem. Why? Stop in deep water with a hot axle full of hot air and guess what happens? The axle and air inside it cools. Cool air has a lower pressure (i.e. partial vacuum) and ideally you want to be able to pull outside air in via the breather tube to equalize the pressure inside the axle. Why? Because there is a chance of differential pressure sucking water in past the axle and pinion seals into the partial vacuum inside the axle. Stock breather is designed to close off and seal the vent when you stop, in case you are in water. If it remained open, water would pour in the open hole. But its the very design of the stock breather that can lead to the secondary problem of the partial vacuum. Normally when you are moving, the cap on the stock breather jiggles and allows air to move in and out, but stopped it seals off. So if you want to use a stock breather on the end of the tube, mount it upside down in order to let the cap hang free and not seal. A filter is a better option as it'll also help to keep out dirt and also filter the oil mist out of the escaping air.

i see your point there, makes sense. How often do you change the filter??

4Crawler · 10-11-2004, 12:02 PM

Quote:

Originally Posted by mtxride

i see your point there, makes sense. How often do you change the filter??

Never, its a K&N, I think I've washed it once in 7 years.

mtxride · 10-11-2004, 08:29 PM

Quote:

Originally Posted by 4Crawler

Never, its a K&N, I think I've washed it once in 7 years.

Nice. Well I think I'm gonna go with a filter over the breather, then.

Thanks for the help everyone!!

10-09-2004, 05:13 PM	#2 (permalink)
4Crawler Contributing Member Join Date: Jun 2002 Location: SF Bay Area, CA Posts: 7,829	No need for it to be vertical, the stock breather fitting must be vertical since it relies on gravity to close the cap off to seal the axle. With a raised breather, you want to use an open filter of some sort on the end, orientation is not an issue, but make darn sure the vent lines runs up all the way to the end, you don't want any dips in the line. I did this on mine (tried running the rear line to the front) and found that oil mist pooled in the low spots in the line. Come winter and cold weather, 90W gear oil turns thick, enough to plug the line, pressure builds in the axle from heating and pushes oil out past the seals. I run my rear vent into the space behind the taillight: http://www.4crawler.com/4x4/CheapTri...html#Breathers __________________ 1985 Toyota 4Runner SR-5, 22REC engine, dual t-cases, 4.88 gears, dual ARBs, 33x10.50 BFGs or 35x12.50 MTRs r.c.brown@ieee.org TruckEditor@tlca.org Project: 4Crawler 4Crawler OffRoad Gettin'Off 4WD Club

10-09-2004, 06:18 PM	#3 (permalink)
4RunnerKid Registered User Join Date: Aug 2004 Location: Sac + SLO, CA Posts: 1,033	I mounted mine under the hood. Pretty easy to route the hose... Just took a bit more. __________________ -Mikey- 1993 4Runner ~ TG HD/RUF front \| All Pro rear \| 37" Krawlers \| Marlin UM06s \| 12" King 2.5s \| 2" air bumps \| 12" Fox 2.0s \| Aussie front \| Lock-Right rear \| 5-speed swap \| TG 4.7s \| 5.29s \| 4xInnovations cage \| bumpers \| sliders \| t-case skid \| K&N intake \| Flowmaster 40 \| Optima red top \| clear lenses \| PIAA 1400s \| LED rock lights \| PIAA superwhites \| stereo Polygoats 4-Wheel Drive Club Poly Performance

10-10-2004, 09:04 AM	#4 (permalink)
lal357 Registered User Join Date: Sep 2003 Location: alabama Posts: 30	where did ya get those filters and what type are they i tried looking for some and didnt have much luck i ran mine front by the battery with opening facing rear and the rear up thru whats left of my bed to just behind the tail light facing rearwards i did leave some slack in the lines for flexing __________________ 80 toyota flatbed 22r ,headman header,weber 32/36,8" lift,3612.5015 swampers,4.88, aussie locker in front yukon spool in rear,co2,full cage

10-10-2004, 09:13 AM	#5 (permalink)
4Crawler Contributing Member Join Date: Jun 2002 Location: SF Bay Area, CA Posts: 7,829	Mine is asmall K&N filterm probably a valve cover breather or something like that. A small VW air cooled fuel filter works well, or any of the small filters at the local auto parts stores will work. The filter is mainly there to keep small critters (spiders and other bugs) from crawling down the hose and plugging it up. __________________ 1985 Toyota 4Runner SR-5, 22REC engine, dual t-cases, 4.88 gears, dual ARBs, 33x10.50 BFGs or 35x12.50 MTRs r.c.brown@ieee.org TruckEditor@tlca.org Project: 4Crawler 4Crawler OffRoad Gettin'Off 4WD Club

10-10-2004, 11:58 AM	#6 (permalink)
4RunnerKid Registered User Join Date: Aug 2004 Location: Sac + SLO, CA Posts: 1,033	Mine are APCs from WalMart. $8 or so a piece, I think... __________________ -Mikey- 1993 4Runner ~ TG HD/RUF front \| All Pro rear \| 37" Krawlers \| Marlin UM06s \| 12" King 2.5s \| 2" air bumps \| 12" Fox 2.0s \| Aussie front \| Lock-Right rear \| 5-speed swap \| TG 4.7s \| 5.29s \| 4xInnovations cage \| bumpers \| sliders \| t-case skid \| K&N intake \| Flowmaster 40 \| Optima red top \| clear lenses \| PIAA 1400s \| LED rock lights \| PIAA superwhites \| stereo Polygoats 4-Wheel Drive Club Poly Performance

10-10-2004, 12:41 PM	#7 (permalink)
mtxride Registered User Join Date: Jul 2004 Location: san antonio, tx Posts: 132	hmm, from all of the write ups I've seen for extending the breathers, they still use a breather similar to the factory one. example: http://www.yotatech.com/~corey/tech/...r/breather.htm so would you guys recommend a small air filter over this breather?? and, 4crawler, I take it this breather would also have to be in an upright position since it's similar to the factory one?? thanks again everyone __________________ -chad- 2000 4runner SR5 4wd 5sp \| 1" lift pp coils \| ARB bumper \| 265/75/16 MT's on american racing wheels \| detroit locker \| deckplate, MIT and AMSOIL \| magnaflow exhaust \| Lars's discos \| extended diff breather \| yakima roof rack \|

10-10-2004, 12:48 PM	#8 (permalink)
4Crawler Contributing Member Join Date: Jun 2002 Location: SF Bay Area, CA Posts: 7,829	Read my page for a full explanantion, but one of the reasons for extending the breather tube is to get rid of the stock breather, as it is part of the problem. Why? Stop in deep water with a hot axle full of hot air and guess what happens? The axle and air inside it cools. Cool air has a lower pressure (i.e. partial vacuum) and ideally you want to be able to pull outside air in via the breather tube to equalize the pressure inside the axle. Why? Because there is a chance of differential pressure sucking water in past the axle and pinion seals into the partial vacuum inside the axle. Stock breather is designed to close off and seal the vent when you stop, in case you are in water. If it remained open, water would pour in the open hole. But its the very design of the stock breather that can lead to the secondary problem of the partial vacuum. Normally when you are moving, the cap on the stock breather jiggles and allows air to move in and out, but stopped it seals off. So if you want to use a stock breather on the end of the tube, mount it upside down in order to let the cap hang free and not seal. A filter is a better option as it'll also help to keep out dirt and also filter the oil mist out of the escaping air. __________________ 1985 Toyota 4Runner SR-5, 22REC engine, dual t-cases, 4.88 gears, dual ARBs, 33x10.50 BFGs or 35x12.50 MTRs r.c.brown@ieee.org TruckEditor@tlca.org Project: 4Crawler 4Crawler OffRoad Gettin'Off 4WD Club

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