Power Steering Flush
12-20-2007 | 09:49 AM
#21
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Joined: Jan 2007
Posts: 564
Likes: 2
From: Kingston, WA
there is a write up on here about doing the rebuild on the pump, had lots of pics too if I remember right, just look into it and see if it looks like something you would be comfortable doing, if you don't want to "risk" messing it up or something, then get a rebuilt one and put it in yourself, still do lots of research before (again, search and you'll find tons of info here)
if you rebuilt one, you would definately have to buy more tools, but that's always the case with most projects, and it gives you an excuse to spend money on things you might want anyways
if you want to make a learning experience out of it, then get one out of the junkyard to rebuild (saves you from worring about getting it done quickly so you can drive your truck to work on Monday or whatever) the rebuild kit is going to be $35-$50 and the pump from the yard maybe $40-$100, depending on where you go and if they are scam artists, worst case you'll still spend less than or close to getting one from a parts store, and you'll have an extra pump you can sell or whatever
if you rebuilt one, you would definately have to buy more tools, but that's always the case with most projects, and it gives you an excuse to spend money on things you might want anyways
if you want to make a learning experience out of it, then get one out of the junkyard to rebuild (saves you from worring about getting it done quickly so you can drive your truck to work on Monday or whatever) the rebuild kit is going to be $35-$50 and the pump from the yard maybe $40-$100, depending on where you go and if they are scam artists, worst case you'll still spend less than or close to getting one from a parts store, and you'll have an extra pump you can sell or whatever
12-20-2007 | 02:33 PM
#23
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Joined: Nov 2002
Posts: 1,651
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From: Yavapai County, Arizona
You can disconnect the return line as previously stated in this thread, or if you don't care to do that, there is the turkey baster method....
You can get a turkey baster and suck the fluid out, dump in fresh atf and repeat, a lot. Cranking the wheel back an forth several times in between to circulate the fluid. You may want some flex tubing to stick in the end of the baster so it'll reach to the screen at the bottom, be careful not to damabe it in the process.
You can get a turkey baster and suck the fluid out, dump in fresh atf and repeat, a lot. Cranking the wheel back an forth several times in between to circulate the fluid. You may want some flex tubing to stick in the end of the baster so it'll reach to the screen at the bottom, be careful not to damabe it in the process.
12-20-2007 | 05:10 PM
#24
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Joined: Nov 2007
Posts: 141
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SOB just noticed this thread and realized i did the same crap. i just got my runner and the previous owner has a gerneric cap on the pwr steering i guess cuz it says power steering fluid only. i did end up driving around like this for about 4 days am i going to have to repack the pump soon?
12-20-2007 | 07:59 PM
#25
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Joined: Jan 2007
Posts: 6,106
Likes: 26
I rebuilt my pump and have been using PS fluid exclusively since doing so. No troubles after 8 months with it in there. Seems to work fine. At least, that's what I thought...
BUT, I just found this information.
from http://www.thefreelibrary.com/Effect.....-a0159789946
I guess Toyota already knows what I just learned.
I'll be flushing and replacing the PS fluid in my system with ATF, ASAP.
Silly me...
Why do I keep doing such things?
The
made me do it. Yeah...that's the ticket!
BUT, I just found this information.
Automatic transmission fluids (ATF)
Automatic transmission fluids (ATF) are engineering fluids that are designed specifically for transmission gears. The history of the development of manual or automatic transmission gears and the associated fluids is briefly described in reference 9. Most ATF fluids are derived from petroleum base stock with additional modifying formulations for specific gear and functional applications. This requires careful and balanced additives and ingredients to ensure its performance. ATF fluids are formulated to be resistant to service-induced oxidation and sludge formation (ref. 10), to provide sufficient friction for locomotion and to maintain long-term thermal stability (ref. 11).
ATF fluids have good anti-wear and corrosion resistance. They are thermally stable and can conduct heat away from metal parts, in addition to serving as lubricant to hot metal parts, without degrading. Performance additives in engineering fluids, however, can be detrimental to rubber seals. When properly formulated, ATF can provide its services without significant adverse effect on rubber or thermoplastic compounds and seals that are integral to gears. Due to these and other desirable properties, ATF is the hydraulic fluid of choice for use in hydraulic or power assist steering systems for mobility vehicles. A typical ATF is Dexron, which is widely used in many platforms (figure 1a).
Discussion
...
The ultimate test for sealability is the sealing force or lip load. It is a measure of the grip of the seal lip on the shaft. Figure 11 shows the change in the sealing force for pinion seals that have been soaked in Dexron and 15W40 fluids at the temperature and time indicated. For each fluid, the temperature effect is obvious. With increases in temperature and time of exposure, the hardness of the lip increases. A combination of long exposure time and high temperature has a detrimental effect on seal performance, particularly when non-ATF fluid is used. However, it could be seen that when the ATF is used, the combination of long time and high temperature exposure may not totally degrade the seal performance to the level that can cause failure. This is the result of the difference between the ATF and non-ATF abilities to conduct heat away from the seal and metal surroundings. Figure 11 shows that soaking a seal in Dexron fluid for 1,000 hours at 121[degrees]C is not as detrimental as soaking in 15W40 fluid at 93[degrees]C for the same period of time. The significantly higher lip load values for the seals soaked and heated in 15W40 fluid could be attributed to the hardening of the seals and by shrinkage. Hardening increases the modulus and degrades the flexibility and the ability of the lip to seal properly.
...
We have further measured how the physical properties of seals were affected when heated in air, and compared the results to when heated in the two fluids. As expected, figures 12-14 show the adverse effect of increasing temperature on the physical properties of seals. At 121[degrees]C, the seals that were heated in 15W40 fluid became harder than those heated in air or ATF fluid. Again, the effect of heating is minimal on the seals heated in ATF. It is important to note, too, that all the tests were conducted in static conditions. The combined effect of time, temperature and dynamic articulation is a subject for future consideration. We, however, have produced road data from returned seals that were suspected of losing seal capabilities because non-ATF fluid was used in the gears. Figure 15 shows the relevant physical data (ID, hardness and sealing force) that were measured on the returned seals in a case-by-case basis and compared with that of a new seal. In all cases, the use of non-ATF fluid had significant detrimental effect on all indicators of good sealing properties of seals.
Conclusions
The safe and satisfactory performance of most power assist vehicular steering systems for mobility vehicles depends on using the recommended power steering fluid in the gear. This is because the rubber seals that are integral to the inner working of gears can be adversely affected if the power steering fluid is not compatible with the seals.In the working conditions of a typical steering gear, rubber seals can swell or shrink excessively, or can be in other ways degraded by the contacting fluid. Hydrogenated nitrile (HNBR) rubber compounds and seals were studied in this work. HNBR was chosen because of its being a choice elastomer for making PS gear seals.
The ATF fluids were less destructive with the two seal compounds at the temperatures investigated. The non-ATF fluid tended to extract unattached and un-bonded compounding ingredients from the rubber matrix. This leads to excessive shrinkage, increasing hardness, reduced lip flexibility, reduced interference and seal leakage.
Automatic transmission fluids (ATF) are engineering fluids that are designed specifically for transmission gears. The history of the development of manual or automatic transmission gears and the associated fluids is briefly described in reference 9. Most ATF fluids are derived from petroleum base stock with additional modifying formulations for specific gear and functional applications. This requires careful and balanced additives and ingredients to ensure its performance. ATF fluids are formulated to be resistant to service-induced oxidation and sludge formation (ref. 10), to provide sufficient friction for locomotion and to maintain long-term thermal stability (ref. 11).
ATF fluids have good anti-wear and corrosion resistance. They are thermally stable and can conduct heat away from metal parts, in addition to serving as lubricant to hot metal parts, without degrading. Performance additives in engineering fluids, however, can be detrimental to rubber seals. When properly formulated, ATF can provide its services without significant adverse effect on rubber or thermoplastic compounds and seals that are integral to gears. Due to these and other desirable properties, ATF is the hydraulic fluid of choice for use in hydraulic or power assist steering systems for mobility vehicles. A typical ATF is Dexron, which is widely used in many platforms (figure 1a).
Discussion
...
The ultimate test for sealability is the sealing force or lip load. It is a measure of the grip of the seal lip on the shaft. Figure 11 shows the change in the sealing force for pinion seals that have been soaked in Dexron and 15W40 fluids at the temperature and time indicated. For each fluid, the temperature effect is obvious. With increases in temperature and time of exposure, the hardness of the lip increases. A combination of long exposure time and high temperature has a detrimental effect on seal performance, particularly when non-ATF fluid is used. However, it could be seen that when the ATF is used, the combination of long time and high temperature exposure may not totally degrade the seal performance to the level that can cause failure. This is the result of the difference between the ATF and non-ATF abilities to conduct heat away from the seal and metal surroundings. Figure 11 shows that soaking a seal in Dexron fluid for 1,000 hours at 121[degrees]C is not as detrimental as soaking in 15W40 fluid at 93[degrees]C for the same period of time. The significantly higher lip load values for the seals soaked and heated in 15W40 fluid could be attributed to the hardening of the seals and by shrinkage. Hardening increases the modulus and degrades the flexibility and the ability of the lip to seal properly.
...
We have further measured how the physical properties of seals were affected when heated in air, and compared the results to when heated in the two fluids. As expected, figures 12-14 show the adverse effect of increasing temperature on the physical properties of seals. At 121[degrees]C, the seals that were heated in 15W40 fluid became harder than those heated in air or ATF fluid. Again, the effect of heating is minimal on the seals heated in ATF. It is important to note, too, that all the tests were conducted in static conditions. The combined effect of time, temperature and dynamic articulation is a subject for future consideration. We, however, have produced road data from returned seals that were suspected of losing seal capabilities because non-ATF fluid was used in the gears. Figure 15 shows the relevant physical data (ID, hardness and sealing force) that were measured on the returned seals in a case-by-case basis and compared with that of a new seal. In all cases, the use of non-ATF fluid had significant detrimental effect on all indicators of good sealing properties of seals.
Conclusions
The safe and satisfactory performance of most power assist vehicular steering systems for mobility vehicles depends on using the recommended power steering fluid in the gear. This is because the rubber seals that are integral to the inner working of gears can be adversely affected if the power steering fluid is not compatible with the seals.In the working conditions of a typical steering gear, rubber seals can swell or shrink excessively, or can be in other ways degraded by the contacting fluid. Hydrogenated nitrile (HNBR) rubber compounds and seals were studied in this work. HNBR was chosen because of its being a choice elastomer for making PS gear seals.
The ATF fluids were less destructive with the two seal compounds at the temperatures investigated. The non-ATF fluid tended to extract unattached and un-bonded compounding ingredients from the rubber matrix. This leads to excessive shrinkage, increasing hardness, reduced lip flexibility, reduced interference and seal leakage.
I guess Toyota already knows what I just learned.
I'll be flushing and replacing the PS fluid in my system with ATF, ASAP.
Silly me...
Why do I keep doing such things?
The
made me do it. Yeah...that's the ticket!
Last edited by MudHippy; 12-20-2007 at 09:04 PM.
12-22-2007 | 09:32 AM
#29
Registered User
Joined: Jul 2007
Posts: 738
Likes: 2
From: Vancouver, BC
A thorough flush will take at least a couple quarts.
I'd just buy a 4L (1 gallon) jug of DexronIII from your local retailer. Any brand will work fine. Pennzoil or other 'name brands' won't work any better than the house brand, or Esso/Exxon or Shell brands. Saving a buck or five here on a gallon of ATF will make no difference to the end result. No need for synthetics either.
Walmart, Canadian Tire, etc all have it for around $12-15. Get a long skinny funnel too. Kitty litter is handy for sopping up the mess, and brake parts cleaner "brake cleaner" is handy for degreasing stuff.
Buy some tygon or similar clear tubing from any hardware store. Home Depot etc have it for a good price.
Disconnect the return hose on the reservoir and cap the reservoir port. Extend the return hose with your clear hose, and put the end in a large bucket. Hint: the larger hose is the pump suction/feed hose, the skinny one is the return hose. Instead of capping the reservoir port, you can sometimes remove the pump suction hose and put the tip of your funnel in that. Then fill the funnel to the top.
Fill up the reservoir to the top using the funnel. Have a helper start the engine, ready to shut it off when you scream
Pour fluid into the reservoir, watch the outlet hose and when it starts to run red, you're done. If you hear the pump whining, shut the engine off.While it's flushing, you should slowly cycle the steering lock to lock in both directions to get all the old oil out of the system.
Have fun making a mess!
12-22-2007 | 07:20 PM
#30
Registered User
Joined: Jan 2007
Posts: 6,106
Likes: 26
Rebuild kits are cheap. At least I didn't waste too much money there. Rebuilding the pump again here soon won't be fun though...DOH!
Last edited by MudHippy; 12-22-2007 at 07:25 PM.
01-13-2008 | 10:33 AM
#33
Registered User
Joined: Feb 2007
Posts: 18
Likes: 0
From: IN
i have a leaking rack since puttin in psf into my reservoir. i'm going to attempt to flush my system today and see if the leak will disappear.... a new rack isnt a cheap deal either. ran my pump dry on the way home from work only to discover my leak. hopefully i'm not replacing both.
02-08-2008 | 02:44 PM
#36
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Joined: Feb 2007
Posts: 1,267
Likes: 1
From: Searcy, Arkansas
LOL...mine had a slight leak & I let my wife drive it to deliver the mail for a day.....I even told her specifically to use automatic transmission fluid DexronIII. Well, she came home & the next morning I started my 4Runner & it was moaning like crazy; I put in some ATF & it quieted down, but by the time I had driven the few miles to my kids school & back home it was moaning again. I called her cell & asked her what the blankety-blank she did & she replied as calm as you please: "Nothing! I just added some power steering fluid like you said to do! There's still some left in the back...maybe you just didn't add enough to it!"
Well, that was my cue to see what she used & sure enough power steering fluid. It caused a slight leak to become a massive leak in no time flat.
Do not use power steering fluid if you value your P/S pump seals!!
Well, that was my cue to see what she used & sure enough power steering fluid. It caused a slight leak to become a massive leak in no time flat.
Do not use power steering fluid if you value your P/S pump seals!!
02-08-2008 | 11:56 PM
#37
Registered User
Joined: Jan 2007
Posts: 564
Likes: 2
From: Kingston, WA
This should be a stick or faq or something, just so people won't have to go through the same crap as the rest of us
(I know that it does say in the owner's manual to use ATF and not PS fluid, but not many 10-20 year old pickups and 4runners still have these. And how many people who buy used Toyota's bother to read it if they do have it, not too many I would guess. I know that I didn't know about the atf until I had read it here when doing research before replacing my pump because it was groaning (I don't know if the PO put ps fluid in it or not, I just know it made enough noise to annoy me)
(I know that it does say in the owner's manual to use ATF and not PS fluid, but not many 10-20 year old pickups and 4runners still have these. And how many people who buy used Toyota's bother to read it if they do have it, not too many I would guess. I know that I didn't know about the atf until I had read it here when doing research before replacing my pump because it was groaning (I don't know if the PO put ps fluid in it or not, I just know it made enough noise to annoy me)
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