Power steering pump hose

[Tools R Us]

Big tires & rock crawling puts a lot of strain on the PS pump - it has to work hard for extended periods causing the fluid to heat up. Stock cooling tubes might not be able to keep up.

^^^ This. In hot weather (110F ish), playing in the rocks with the '80, I have had the P/S complain/whine, open the hood and have a little fountain of fluid shooting out of the vent hole in the cap, not good, way too hot.

At some point it will affect, ruin the fluid, but most newer fluids take a pretty good beating. Our observation is; ATF gives up easiest/soonest, P/S fluid takes more beating and hydraulic fluid takes the most beating, especially a good one like Mobil DTE.

Switching from a "it will work fluid" like ATF, to something better like DTE solves the fluid problem for most. The fluid maybe OK with the high temps, but, the system is sealed by "rubbers", they start giving up at ~250F ish range. Time operating at elevated temps accelerates the hardening, cracking, of the seals, hoses, etc. causing them leak, fail sooner.

Tools,
What's the issue if the cooler is too large ?

I am guessing the fluid doesn't heat up...but is that harmful ?
...

That said, it's likely even worse to run it too cool. The #1 degrading contaminant is moisture. It's driven off by heat, the cooler it runs, the more builds up in the system.

Also the system is spec to run a certain viscosity fluid, in this case ~5cst and the spec is at 100C/212F. Most have started a rig on a very cold morning and has the P/S complain/whine, this is why: A fluid that is say 5cst at 212F, will be about ~6cst at 180F, ~8cst at 160F, ~11cst at 140F, ~17 at 120F, ~26 at 100F, ~44 at 80F, ~84cst at 60F ,,,, ~250cst at 32F, etc. It's easy to see why most oil systems are designed to run in the 180F range, from 160-212F the viscosity doesn't significantly change, but at just 100F it's 9 times spec. Cool, thick fluid is difficult to pump, doesn't provide the intended amount of assist, can cause destructive cavitation (even if you cant hear it), etc.

The P/S system doesn't need much cooling, even when pushed hard. Most typical sedans don't have a cooler or a very rudimentary one and this is sound design. It's way easy to over cool, so it takes a bit of tuning to correctly add a cooler without causing more problems that you fix.

We have put the above cooler on several FJ40's, they are likely too big. Have been watching the temps and they run somewhat cooler than I would prefer, but they fit nice! These are "nice day" rigs, wheelers not DD, much more likely to be run at 100F+ than below 50F and likely never at 32F, so in this application, can get away with it.

This is another one that we run, it's simply copper tube. Works great most of the time, but can be less than needed when playing in the rocks at high temps.

https://forum.ih8mud.com/attachment.php?attachmentid=663952&stc=1&d=1344838833

 

[BrownDog1]

I know that this is an old thread but I'm having issues with a FJ60 power steering gearbox return connection leaking. I tried both a 16mm and a 5/8 connection at the port in the power steering box with no luck. The threads in that port seem to be in good shape and the brass insert is still in place - I believe you can see that in the photo. Any suggestions would be appreciated. Was there a larger sized connection at some point for these return ports? OD on each threaded connector was .620" or 15.75mm on the first connector and .628" or 16mm on the second. Was the OEM connector the same as either of these?

 

[BrownDog1]

For anyone else looking for this same part.
The size is 17 mm and the thread pitch is 1.5
I looked high and low for this since it's a little unusual.
Matt @ CuiserMatts let me know the size, the fact that it's an unusual size and he sold me the part.