By request I have combined & condensed several posts by myself and others into this one.
Why change it? Power steering fluid is usually an ignored fluid, but over time and especially if overheated it can break down, oxidize, change viscosity, consume its additives, be contaminated with solids such as grit from the environment and wear metals from the pump and box, having no filtration these contaminants circulate endlessly causing more wear.
It is a good idea to occasionally change out the fluid to get rid of old fluid and the contaminants it carries. Although color is not the best indicator of fluid condition it is the easiest to check, if your fluid is looks considerably darker than new you should consider changing it to be safe. It is also a good thing to baseline this fluid after purchasing a 100K+ mile used 80 series as it has likely never been done before.
The classic method of changing PSF is to disconnect the return line, start the engine and turn the wheels lock to lock wile someone attempts to keep the reservoir full. The pump pushes the old fluid out the return line, wile this does work it is messy and almost impossible to keep up with the pump, an uncontrolled hectic and possibly pump damaging process,
I prefer a more leisurely controlled method
Supplies:
3 or 4 quarts of fluid
3/8" double barb
6' or longer of 3/8" tubing, clear vinyl “fish tank” tubing makes it easier to see what is going on.
3/8” hose clamps, these may not be needed if everything fits tightly, the pressure during this process will be low.
Cap for return port, I had a plastic shipping cap from a master cylinder that fit. You can also make one using a short section of hose and a bolt with a 3/8” shank. Or use a foam ear plug or just put a length of tube and lift the end above the reservoir.
Procedure:
1. Set parking brake.
2. Lock CDL so that park “gear” is still effective with only one axle on the ground. (put in low or set CDL switch with key on, then turn key off)
3. Block rear tires.
4. Lift front axle so the tires clear the ground,
5. Set the axle on jack stands being careful they will not interfere with the travel of the tires when turning, removing the front tires may be needed for clearance depending on your stands.
6. Enjoy the cold beverage of your choice.
7. Remove return line from the reservoir, it is the upper and smaller of the two hoses on the reservoir, it is a slip fit with a clamp. It comes in mid height on the side to an “L” shaped metal tube.
8. Catch the ~1/2 quart of fluid that drains from the return tube in the reservoir, Alternately you can take fluid out of the reservoir before hand so there is much less mess. plug the opening so the reservoir can hold fluid again.
9. Slide the barb into the return line you disconnected, slide the clear tubing on the other end of the barb, clamp joints as needed. Route the tube into a container or drain pan.
10. Fill reservoir with new fluid
11. Turn the key to acc to unlock the steering wheel but do not start engine, also do not leave in the "on" position for any length of time.
12. Slowly turn the steering wheel lock to lock.
As the wheel turns a large piston in the steering box will draw fluid from the reservoir through the pump, into the box, out to the cooler and out the return line to your drain pan, valves in the box keeps the fluid going in the same direction no matter witch way the piston is moving.
Keep the reservoir from emptying if air gets in it breaks the prime and it will take a bit to get going again, this will also form foam witch may lengthen the process.
13. When clean looking fluid starts coming out of the line reconnect the return line the reservoir, cycle lock to lock until the fluid level in the reservoir does not drop, you can get all/most of the air out by cycling the wheel lock to lock with the engine off, let it settle for a few minutes between cycling or the tiny bubbles/foam if present will just get reintroduced, repeat until air bubbles are cleared out
14. Start engine cycle lock to lock, check for leaks.
15. Return to your 80 to normal condition and wipe up any spilled fluid under the hood.
This was specifically written for 93-97 FZJ80s, but I think the system on the 91-92 FJ80s is close enough that these instructions will work.
I prefer this engine off method to the engine on method as with the engine running things happen very fast and it is almost impossible to keep the pump fed. Although running the pump dry for a short period is not likely to kill it, it is still counter productive IMHO.
Another simpler method is to remove the fluid from the reservoir with a turkey baster and fill the reservoir with new fluid, you are only getting a portion of the total fluid in the system This way so it will take many of these drain and fills (with driving in-between) to get the majority of the fluid replaced. Also the new fluid is mixed with the old each time so you will eventually run into diminishing returns. This is the method I use on my transmission, from time to time I drain the transmission pan and fill with new fluid, and this keeps the fluid in good overall condition.
Several have tried Mobil 1 ATF in the power steering system, many report they have groaning afterward, it may not be a good match for this application.
I had Originally used chevron fluid Dextron III and I do not remember any noise, about a year ago I did it again with some left over Transynd (A group III Castrol/Allison Dex III compatible fluid) and I do get light groaning when cold.
Downey has been reported to quiet Groaning by putting a teaspoon or two in the system.
I have yet to try it for myself.
More reading
https://forum.ih8mud.com/showthread.php?t=30395
https://forum.ih8mud.com/showthread.php?t=77585
I think this is going into the FAQ, if you have anything to add or correct please post up.
Why change it? Power steering fluid is usually an ignored fluid, but over time and especially if overheated it can break down, oxidize, change viscosity, consume its additives, be contaminated with solids such as grit from the environment and wear metals from the pump and box, having no filtration these contaminants circulate endlessly causing more wear.
It is a good idea to occasionally change out the fluid to get rid of old fluid and the contaminants it carries. Although color is not the best indicator of fluid condition it is the easiest to check, if your fluid is looks considerably darker than new you should consider changing it to be safe. It is also a good thing to baseline this fluid after purchasing a 100K+ mile used 80 series as it has likely never been done before.
The classic method of changing PSF is to disconnect the return line, start the engine and turn the wheels lock to lock wile someone attempts to keep the reservoir full. The pump pushes the old fluid out the return line, wile this does work it is messy and almost impossible to keep up with the pump, an uncontrolled hectic and possibly pump damaging process,
I prefer a more leisurely controlled method
Supplies:
3 or 4 quarts of fluid
3/8" double barb
6' or longer of 3/8" tubing, clear vinyl “fish tank” tubing makes it easier to see what is going on.
3/8” hose clamps, these may not be needed if everything fits tightly, the pressure during this process will be low.
Cap for return port, I had a plastic shipping cap from a master cylinder that fit. You can also make one using a short section of hose and a bolt with a 3/8” shank. Or use a foam ear plug or just put a length of tube and lift the end above the reservoir.
Procedure:
1. Set parking brake.
2. Lock CDL so that park “gear” is still effective with only one axle on the ground. (put in low or set CDL switch with key on, then turn key off)
3. Block rear tires.
4. Lift front axle so the tires clear the ground,
5. Set the axle on jack stands being careful they will not interfere with the travel of the tires when turning, removing the front tires may be needed for clearance depending on your stands.
6. Enjoy the cold beverage of your choice.
7. Remove return line from the reservoir, it is the upper and smaller of the two hoses on the reservoir, it is a slip fit with a clamp. It comes in mid height on the side to an “L” shaped metal tube.
8. Catch the ~1/2 quart of fluid that drains from the return tube in the reservoir, Alternately you can take fluid out of the reservoir before hand so there is much less mess. plug the opening so the reservoir can hold fluid again.
9. Slide the barb into the return line you disconnected, slide the clear tubing on the other end of the barb, clamp joints as needed. Route the tube into a container or drain pan.
10. Fill reservoir with new fluid
11. Turn the key to acc to unlock the steering wheel but do not start engine, also do not leave in the "on" position for any length of time.
12. Slowly turn the steering wheel lock to lock.
As the wheel turns a large piston in the steering box will draw fluid from the reservoir through the pump, into the box, out to the cooler and out the return line to your drain pan, valves in the box keeps the fluid going in the same direction no matter witch way the piston is moving.
Keep the reservoir from emptying if air gets in it breaks the prime and it will take a bit to get going again, this will also form foam witch may lengthen the process.
13. When clean looking fluid starts coming out of the line reconnect the return line the reservoir, cycle lock to lock until the fluid level in the reservoir does not drop, you can get all/most of the air out by cycling the wheel lock to lock with the engine off, let it settle for a few minutes between cycling or the tiny bubbles/foam if present will just get reintroduced, repeat until air bubbles are cleared out
14. Start engine cycle lock to lock, check for leaks.
15. Return to your 80 to normal condition and wipe up any spilled fluid under the hood.
This was specifically written for 93-97 FZJ80s, but I think the system on the 91-92 FJ80s is close enough that these instructions will work.
I prefer this engine off method to the engine on method as with the engine running things happen very fast and it is almost impossible to keep the pump fed. Although running the pump dry for a short period is not likely to kill it, it is still counter productive IMHO.
Another simpler method is to remove the fluid from the reservoir with a turkey baster and fill the reservoir with new fluid, you are only getting a portion of the total fluid in the system This way so it will take many of these drain and fills (with driving in-between) to get the majority of the fluid replaced. Also the new fluid is mixed with the old each time so you will eventually run into diminishing returns. This is the method I use on my transmission, from time to time I drain the transmission pan and fill with new fluid, and this keeps the fluid in good overall condition.
Several have tried Mobil 1 ATF in the power steering system, many report they have groaning afterward, it may not be a good match for this application.
I had Originally used chevron fluid Dextron III and I do not remember any noise, about a year ago I did it again with some left over Transynd (A group III Castrol/Allison Dex III compatible fluid) and I do get light groaning when cold.
Downey has been reported to quiet Groaning by putting a teaspoon or two in the system.
I have yet to try it for myself.
More reading
https://forum.ih8mud.com/showthread.php?t=30395
https://forum.ih8mud.com/showthread.php?t=77585
I think this is going into the FAQ, if you have anything to add or correct please post up.
Last edited:
. Nice work as always RT.
