What power steering fluid with PSC Big Bore

LAJK

LAJK

Member
I just received my psc big bore steering gear today and have a question about what fluid to run. I only ordered the steering gear at this time and plan on adding the pump later down the road. I’ve seen some just top off the system with mopar ATF and others who say you need to use the psc swepco fluid. Anyone have any input on what’s the best route to go? Anyone notice any difference in performance between the two fluids?
 
LAJK said:
I just received my psc big bore steering gear today and have a question about what fluid to run. I only ordered the steering gear at this time and plan on adding the pump later down the road. I’ve seen some just top off the system with mopar ATF and others who say you need to use the psc swepco fluid. Anyone have any input on what’s the best route to go? Anyone notice any difference in performance between the two fluids?
Click to expand...
I'm fairly sure that if you're still using the factory pump you need to stay with the ATF+4. If you use their pump, you switch to the Swepco.

--
Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
 
PSC recommends Swepco for either pump. They sell it on their site. If you go that route, order the Flush as well to clean out the old lines and pump prior to putting the new fluid in.

Mines been in for 30k mikes and no issues.
Sent from my iPhone using WAYALIFE mobile app
 
I also switched over to swepco with new box, even though I still run factory pump. Flush the system their flushing fluid as stated, before switching over.
 
Last edited:
VeruGE*144 said:
I also switched over to swepco with new box, even though I still run factory pump. Flush the system their flushing fluid as stated, before switching over.
Click to expand...

Brute said:
Swepco......
Click to expand...

wjtstudios said:
PSC recommends Swepco for either pump. They sell it on their site. If you go that route, order the Flush as well to clean out the old lines and pump prior to putting the new fluid in.

Mines been in for 30k mikes and no issues.
Sent from my iPhone using WAYALIFE mobile app
Click to expand...


Thanks for all the input guys. I’ll order flush kit and some swepco later today.
 
LAJK said:
Thanks for all the input guys. I’ll order flush kit and some swepco later today.
Click to expand...

Check out Summit Racing for the Swepco 715 fluid. Last time I searched I found they were the cheapest and they ship crazy fast. I bought a case to have on hand.
 
I will be installing a Big Bore soon... (non ported - No Ram) on my 17JKU... and using the stock Pump for now.

I just want to confirm the consensus here:

1. Is Swepco 715 necessary for the Big Bore without the Ram & Pump.
2. If yes... Is Swepco 729 Flush really needed or can I just drain old and install the Swepco.

Thx
 
TrailHunter said:
I will be installing a Big Bore soon... (non ported - No Ram) on my 17JKU... and using the stock Pump for now.

I just want to confirm the consensus here:

1. Is Swepco 715 necessary for the Big Bore without the Ram & Pump.
2. If yes... Is Swepco 729 Flush really needed or can I just drain old and install the Swepco.

Thx
Click to expand...

Yes and yes. I believe it has something to do with the compressibility of the fluid. And if you are going to swap, definitely to the flush.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
 
wjtstudios said:
Yes and yes. I believe it has something to do with the compressibility of the fluid. And if you are going to swap, definitely to the flush.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
Click to expand...

How did you flush it? Hook up all the hoses to the new box.... turn the wheel a few times... then drain? Or just keep dumping it into the stock pump with the hoses disconnected and let drain?
 
TrailHunter said:
How did you flush it? Hook up all the hoses to the new box.... turn the wheel a few times... then drain? Or just keep dumping it into the stock pump with the hoses disconnected and let drain?
Click to expand...

Take the supply line off the res, and add a tube down to a gallon jug if some kind. Add the flush into the res and keep turning the steering wheel back and forth then add more fluid. Repeat and repeat until the flush starts going into the jug. You’ll see a difference in color. Then do the same process with the actual swepco fluid and you are good to go.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
 
wjtstudios said:
Take the supply line off the res, and add a tube down to a gallon jug if some kind. Add the flush into the res and keep turning the steering wheel back and forth then add more fluid. Repeat and repeat until the flush starts going into the jug. You’ll see a difference in color. Then do the same process with the actual swepco fluid and you are good to go.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
Click to expand...

Roger That... Thanks!
 
TrailHunter said:
I will be installing a Big Bore soon... (non ported - No Ram) on my 17JKU... and using the stock Pump for now.

I just want to confirm the consensus here:

1. Is Swepco 715 necessary for the Big Bore without the Ram & Pump.
2. If yes... Is Swepco 729 Flush really needed or can I just drain old and install the Swepco.

Thx
Click to expand...

Swepco for the big bore.

I would use the 729 to get a good flush and remove any of the old residual fluid buildup.

When I switched over to Swepco, I called PSC and they told me it was ok to flush my system with the cheap O'Reilly brand power steering fluid; just flush until it came out clean.

I noticed a couple of days after I added the Swepco fluid it was pretty dirty on the bottom of the reservoir, I guess the Swepco loosened up deposits that flushing with regular fluid did not get.

I haven't changed it (3yrs ago) and it's working fine but I'm sure I'm not getting the full benefit of the Swepco fluid.

I need to change the lines and plan to flush with the 729 this time.
 
jeeeep said:
Swepco for the big bore.

I would use the 729 to get a good flush and remove any of the old residual fluid buildup.

When I switched over to Swepco, I called PSC and they told me it was ok to flush my system with the cheap O'Reilly brand power steering fluid; just flush until it came out clean.

I noticed a couple of days after I added the Swepco fluid it was pretty dirty on the bottom of the reservoir, I guess the Swepco loosened up deposits that flushing with regular fluid did not get.

I haven't changed it (3yrs ago) and it's working fine but I'm sure I'm not getting the full benefit of the Swepco fluid.

I need to change the lines and plan to flush with the 729 this time.
Click to expand...

Good info... thanks!
 
So, my question is what is so special about the super expensive Swepco fluid?

My very expensive heavy equipment, some of it running near 6000 psi, runs on normal, easy to find, relatively cheap hydraulic oil.

All this is is a hydraulic pump and gear box, and if normal oil can't be compressed at 6000 psi, it sure won't at the meager pressure the steering pump puts out.

People selling the high end fluid seem to be the same ones recommending it 🤷

I would like to see an actual technical reason why this special fluid is the only? one that can be used. Can anyone educate me, other than "it's recommended by....."?
 
jdofmemi said:
So, my question is what is so special about the super expensive Swepco fluid?

My very expensive heavy equipment, some of it running near 6000 psi, runs on normal, easy to find, relatively cheap hydraulic oil.

All this is is a hydraulic pump and gear box, and if normal oil can't be compressed at 6000 psi, it sure won't at the meager pressure the steering pump puts out.

People selling the high end fluid seem to be the same ones recommending it 🤷

I would like to see an actual technical reason why this special fluid is the only? one that can be used. Can anyone educate me, other than "it's recommended by....."?
Click to expand...

I don't have technical knowledge but i slept 8 hours last night lol
My guess is heavy equipment fluid does not require the additives that are in the fluids used in vehicles. Most have mineral oil or synthetic with anti-foam, anti-squeal and secret formulas but each auto manufacturer has it's own recommended fluid. I do know from experience, if you don't use Honda specific power steering fluid in a Honda, it will ruin the seals.

BaddestCross said:
My RNR runs off the ATF+4 like factory. [emoji848]
--
Build Thread - Adventures of Fiona - https://wayalife.com/showthread.php?t=47407
Click to expand...

This is true, I used ATF+4 for the 1st year of my PSC system, it worked fine.
I did notice when wheeling all day and in hot weather, the fluid would spew from the breather line quit a bit and I'd have to add fluid after a few days of all day wheeling; it would also at times squeal when holding a hard left or right turn. When daily driving on really hot summer days 100*+ fluid would spew from the breather hose on occasion.

With the Swepco I haven't had any of those issues.
 
jdofmemi said:
So, my question is what is so special about the super expensive Swepco fluid?

My very expensive heavy equipment, some of it running near 6000 psi, runs on normal, easy to find, relatively cheap hydraulic oil.

All this is is a hydraulic pump and gear box, and if normal oil can't be compressed at 6000 psi, it sure won't at the meager pressure the steering pump puts out.

People selling the high end fluid seem to be the same ones recommending it 🤷

I would like to see an actual technical reason why this special fluid is the only? one that can be used. Can anyone educate me, other than "it's recommended by....."?
Click to expand...

I’m with you as far as specifically Swepco fluid. I did do some digging about atf-4 vs power steering fluid when I got the big bore box and power steering fluid is better for power steering (go figure). I had a jug of BG power steering fluid laying around so I used that and haven’t had any problems. As far as flushing goes. Emptied the reservoir and lines when I replaced the box. Can’t be much left of whatever was in it. Added a cooler and called it good. Stock reservoir doesn’t overflow and the wheels turn so must be ok. Eventually if I switch to high pressure pump I will get the kit that includes the reservoir. For now it ain’t broke so....


Sent from my iPhone using WAYALIFE mobile app
 
A.J. said:
I’m with you as far as specifically Swepco fluid. I did do some digging about atf-4 vs power steering fluid when I got the big bore box and power steering fluid is better for power steering (go figure). I had a jug of BG power steering fluid laying around so I used that and haven’t had any problems. As far as flushing goes. Emptied the reservoir and lines when I replaced the box. Can’t be much left of whatever was in it. Added a cooler and called it good. Stock reservoir doesn’t overflow and the wheels turn so must be ok. Eventually if I switch to high pressure pump I will get the kit that includes the reservoir. For now it ain’t broke so....


Sent from my iPhone using WAYALIFE mobile app
Click to expand...
I was looking into the same thing and the biggest difference I could find is that the ATF doesn't have any anti-foaming agents in it, which is probably why it would be coming out the overflow after hard use.

Sent from my Pixel 2 XL using WAYALIFE mobile app
 
You must log in or register to reply here.
Top Bottom