Post by iluvdrt on Jul 14, 2003 12:13:07 GMT -5
ok i found this on another web site its quite long but good info.On Toyota's with electronic fuel injection (EFI) the engine control unit (ECU) is a critical component of the truck. If it gets wet, it is likely to stop working. The ECU box is not sealed and doing so would be a difficult process. In my '85 4Runner, the ECU is located in the passenger footwell, behind the small kick panel. It is placed just off the floor, so if any water were to enter the cab via the door seals, chances are the ECU would get wet. I decided it might be a good idea to try to raise it up as high as possible using the existing wiring harness. With all the HVAC ductwork and whatnot behind the dash, there is no room to mount the ECU in there, so the next logical place was the glove box.
1. 2.
3. 4.
In picture #1, you can see the ECU fits nicely, I removed the top cover so I could mark for the connector cutout and the mounting holes. In picture #2, you can see the cutout for the connectors, note that the 14P connector is on the left in this picture. When the glove box is ultimately reinstalled, this places it to the right since the 14P cable seems to be the shortest on my truck. In picture #3, you can see the ECU tucked inside the glove box, connectors out the bottom, and the top of the box just protruding above the back of the glove box. Unfortunately, you can't mount the ECU flush to the back of the glove box, since it'll hit some of the ductwork that is just behind the box. I left the ECU standing vertically off the bottom of the glove box and this gives it enough clearance for the duct. FInally, in picture #4, you can see the 3 connectors redy to plug into the ECU.
It t may not seem like much, but this simple relocation raises the ECU a full 12" (one foot!) from the factory location. I found little loss of glove box volume with the ECU in there, still enough room for all the "junk" I had in there before. Now this places my ECU about as high as my engine air intake and differential breathers.
Differential Breathers:
What's a differential breather and what do they do? On most vehicles with axles and differentials, there is a need to vent the axle housing to the atmosphere to allow for the air inside to expand and contract with temperature. If this were not done, the pressure in the axle would build up as it heated up, possibly causing gear oil to be forced past the oil seals. Similarly, when the axle cools, the pressure inside drops and if the axle were in water, this could suck water in past the seals, contaminating the oil.
So correct this potential problem, the factory usually installs a breather to allow the pressures to equalize. The Toyota breather consists of a nipple that threads into the top of the differential housing and a small cap that loosely covers the vent hole. The cap is designed so that as the vehicle moves, the cap jiggles and allows pressure to vent to the atmosphere. When the vehicle stops, it usually seals up to prevent contaminants getting in. One problem can come up with this design that if you suddenly dunk a hot axle into cold water and stop, a fairly strong vacuum is created inside as the air and gear oil cool, and this can cause water to be pulled in. A very common fix for this problem is to replace the stock breather with a fitting to which a hose is attached and run the hose up to a higher point on the vehicle, like the firewall or air cleaner. This allows the axle to breathe freely in or out to prevent pressure differences from occurring.
So, one might be tempted to simply pull off the cap and clamp a hose onto the end. While this will work (for a while) the exposed fitting is very short and irregular and keeping a hose attached is difficult. So, various other types of fittings have been used to replace the stock fitting. One commonly used fitting is a vacuum hose nipple similar to what is used on the engine. Another popular fitting is the Nissan differential breather part # 38323-C6010; cost around $4.50/ea.
However, the threaded hole in the Toyota axle is nothing more than 1/8" NPT:
NOTE:
Officially I would thnk the thread is M10-1.0 but its close enough for gov't work
NPT = National Pipe thread Tapered, and it is 10.2mm OD with 27 TPI (threads per inch)
M10-1.0 is 10mm OD and 1.0 mm thread pitch (or 25.4 TPI)
So you can see the two are VERY close and for the few threads in the housing and the fact that pipe threads are tapered (meaning the male thread starts out small and gets larger in diameter as it threads in, female thread is the opposite) an 1/8NPT thread fits fine for this low pressure, low stress application, YMMV.
For an even better fit, run a 1/8" pipe thread tap down into the hosuing, apply grease to the tap to hold the few metal shavings it'll cut.
A trip to the local hardware store revealed a whole wall full of every conceivable type and style of fitting for 1/8" pipe thread. They have NPT to hose barb fittings, NPT to NPT nipples, elbows of all sorts and they all cost around $1. For the rear axle, a simple NPT to hose barb fitting, sized for the ID of the hose you intend to use is ideal. Up front, I found the use of a close nipple and a 45 degree elbow and a hose barb makes a good combination.
So, what do you do with them once installed? Up front, hook up a length of hose and terminate it at a filter on the firewall, as high up as you can get it. In back, I first ran up to the front line and filter, but found in cold weather that gear oil collected in any low points of the line, and essentially plugged the vent, letting pressure build up in the axle and forcing oil out past the seals. Then I routed it to the rear and up onto my rear tire carrier, as pictured here.
After selling the rear bumper, I had to find a new location for the filter. I found that if I pushed the hose up inside the rear tail light housing, I could re-install the filter (pictured above). No drilling or cutting required. Now that's a really cheap trick! I've found the tail light housing seems to stay very dry, just a little dist inside. With the filter pushed clear to the underside of the bed rail, I would have to be in some deep water to submerge the vent line.
NOTE:
The following mental experiment should help see if your vent line run is proper. Imagine you will try to fill the axle with gear oil by pouring it into the end of the hose where you have the filter. If you feel that you could fill the axle with oil from the end, that is it would run downhill all the way from the filter to the axle, then its probably OK. If there are any points in the line run where you have a dip in the run (such as wires between power poles) then oil can pool there. Gear oil is thick and when cold it is VERY THICK and doesn't flow well at all. While the oil in the axle will heat up with use and flow easily, any oil pooled in the vent line won't heat up if its cold outside. I found when my line plugged up with oil in cold weather, pulling the vent line off the axle and blowing into it took a pretty strong puff or air to blow the line clear (like blowing into a straw in a thick milk shake). That much pressure buildup can force oil out past the axle and pinion seals.
The idea behind the breather is to place the end of the line as high as you can get it, in a protected location where its not going to get pelted with mud, dust and water. Some folks carry this to an extreme and route the breeather lines as well as the vehicles air intake up to a snorkle. This, in theory, would let the rig ford water up to the point the top of the snorkle went under water. This assumes you have EVERY OTHER water-sensitive part of the rig waterproofed in some fashion. In fact, there are some folks who have done all this and find that doing so creates a secondary problem, that being that the vent is so high up, that you get significant water pressure buildup (1/2 psi per foot of water depth) that water gets into the axles, despite the vent. So what then? You need to run the axle with a slight positive pressure maintained with a small on-board air source. Certain military vehicles are so equipped.
So where does it all stop? It all depends on how much time and work you want to put into it and how much you need to run in water. Do as much as you can, based on what sort of conditions you drive in. I don't purposely drive my truck in mud or water, but if a water or mud crossing blocks the trail and is the only way across, then I have to go in. In many years of 4-wheeling, I've never had water get in my axles, never had to change gear oil because it got contaminated, so I think a simple vent like I have works good enough.
Cost:
About $1 per axle
all these tips were found at 4crawler.cruiserpages.com/4x4/CheapTricks/WaterProofing.shtml#ECU
1. 2.
3. 4.
In picture #1, you can see the ECU fits nicely, I removed the top cover so I could mark for the connector cutout and the mounting holes. In picture #2, you can see the cutout for the connectors, note that the 14P connector is on the left in this picture. When the glove box is ultimately reinstalled, this places it to the right since the 14P cable seems to be the shortest on my truck. In picture #3, you can see the ECU tucked inside the glove box, connectors out the bottom, and the top of the box just protruding above the back of the glove box. Unfortunately, you can't mount the ECU flush to the back of the glove box, since it'll hit some of the ductwork that is just behind the box. I left the ECU standing vertically off the bottom of the glove box and this gives it enough clearance for the duct. FInally, in picture #4, you can see the 3 connectors redy to plug into the ECU.
It t may not seem like much, but this simple relocation raises the ECU a full 12" (one foot!) from the factory location. I found little loss of glove box volume with the ECU in there, still enough room for all the "junk" I had in there before. Now this places my ECU about as high as my engine air intake and differential breathers.
Differential Breathers:
What's a differential breather and what do they do? On most vehicles with axles and differentials, there is a need to vent the axle housing to the atmosphere to allow for the air inside to expand and contract with temperature. If this were not done, the pressure in the axle would build up as it heated up, possibly causing gear oil to be forced past the oil seals. Similarly, when the axle cools, the pressure inside drops and if the axle were in water, this could suck water in past the seals, contaminating the oil.
So correct this potential problem, the factory usually installs a breather to allow the pressures to equalize. The Toyota breather consists of a nipple that threads into the top of the differential housing and a small cap that loosely covers the vent hole. The cap is designed so that as the vehicle moves, the cap jiggles and allows pressure to vent to the atmosphere. When the vehicle stops, it usually seals up to prevent contaminants getting in. One problem can come up with this design that if you suddenly dunk a hot axle into cold water and stop, a fairly strong vacuum is created inside as the air and gear oil cool, and this can cause water to be pulled in. A very common fix for this problem is to replace the stock breather with a fitting to which a hose is attached and run the hose up to a higher point on the vehicle, like the firewall or air cleaner. This allows the axle to breathe freely in or out to prevent pressure differences from occurring.
So, one might be tempted to simply pull off the cap and clamp a hose onto the end. While this will work (for a while) the exposed fitting is very short and irregular and keeping a hose attached is difficult. So, various other types of fittings have been used to replace the stock fitting. One commonly used fitting is a vacuum hose nipple similar to what is used on the engine. Another popular fitting is the Nissan differential breather part # 38323-C6010; cost around $4.50/ea.
However, the threaded hole in the Toyota axle is nothing more than 1/8" NPT:
NOTE:
Officially I would thnk the thread is M10-1.0 but its close enough for gov't work
NPT = National Pipe thread Tapered, and it is 10.2mm OD with 27 TPI (threads per inch)
M10-1.0 is 10mm OD and 1.0 mm thread pitch (or 25.4 TPI)
So you can see the two are VERY close and for the few threads in the housing and the fact that pipe threads are tapered (meaning the male thread starts out small and gets larger in diameter as it threads in, female thread is the opposite) an 1/8NPT thread fits fine for this low pressure, low stress application, YMMV.
For an even better fit, run a 1/8" pipe thread tap down into the hosuing, apply grease to the tap to hold the few metal shavings it'll cut.
A trip to the local hardware store revealed a whole wall full of every conceivable type and style of fitting for 1/8" pipe thread. They have NPT to hose barb fittings, NPT to NPT nipples, elbows of all sorts and they all cost around $1. For the rear axle, a simple NPT to hose barb fitting, sized for the ID of the hose you intend to use is ideal. Up front, I found the use of a close nipple and a 45 degree elbow and a hose barb makes a good combination.
So, what do you do with them once installed? Up front, hook up a length of hose and terminate it at a filter on the firewall, as high up as you can get it. In back, I first ran up to the front line and filter, but found in cold weather that gear oil collected in any low points of the line, and essentially plugged the vent, letting pressure build up in the axle and forcing oil out past the seals. Then I routed it to the rear and up onto my rear tire carrier, as pictured here.
After selling the rear bumper, I had to find a new location for the filter. I found that if I pushed the hose up inside the rear tail light housing, I could re-install the filter (pictured above). No drilling or cutting required. Now that's a really cheap trick! I've found the tail light housing seems to stay very dry, just a little dist inside. With the filter pushed clear to the underside of the bed rail, I would have to be in some deep water to submerge the vent line.
NOTE:
The following mental experiment should help see if your vent line run is proper. Imagine you will try to fill the axle with gear oil by pouring it into the end of the hose where you have the filter. If you feel that you could fill the axle with oil from the end, that is it would run downhill all the way from the filter to the axle, then its probably OK. If there are any points in the line run where you have a dip in the run (such as wires between power poles) then oil can pool there. Gear oil is thick and when cold it is VERY THICK and doesn't flow well at all. While the oil in the axle will heat up with use and flow easily, any oil pooled in the vent line won't heat up if its cold outside. I found when my line plugged up with oil in cold weather, pulling the vent line off the axle and blowing into it took a pretty strong puff or air to blow the line clear (like blowing into a straw in a thick milk shake). That much pressure buildup can force oil out past the axle and pinion seals.
The idea behind the breather is to place the end of the line as high as you can get it, in a protected location where its not going to get pelted with mud, dust and water. Some folks carry this to an extreme and route the breeather lines as well as the vehicles air intake up to a snorkle. This, in theory, would let the rig ford water up to the point the top of the snorkle went under water. This assumes you have EVERY OTHER water-sensitive part of the rig waterproofed in some fashion. In fact, there are some folks who have done all this and find that doing so creates a secondary problem, that being that the vent is so high up, that you get significant water pressure buildup (1/2 psi per foot of water depth) that water gets into the axles, despite the vent. So what then? You need to run the axle with a slight positive pressure maintained with a small on-board air source. Certain military vehicles are so equipped.
So where does it all stop? It all depends on how much time and work you want to put into it and how much you need to run in water. Do as much as you can, based on what sort of conditions you drive in. I don't purposely drive my truck in mud or water, but if a water or mud crossing blocks the trail and is the only way across, then I have to go in. In many years of 4-wheeling, I've never had water get in my axles, never had to change gear oil because it got contaminated, so I think a simple vent like I have works good enough.
Cost:
About $1 per axle
all these tips were found at 4crawler.cruiserpages.com/4x4/CheapTricks/WaterProofing.shtml#ECU