Power steering cooler question

[Javin]

i have an 1981 gmc 3/4 4x4 and the previous owner put a tranny cooler on it and used it for he power steering. I have replaced the fluid and belt and still have a nasty squeal and at a dead stop she doesn’t like to turn a whole lot. Should I remove the cooler and see if that makes a difference or should I keep it and replace the pump?

 

[shiftpro]

Which side is the cooler on? Pressure or return? I would hope it's on the return side.

You have air in the system. Jack up front wheels off the ground and with the engine OFF rotate the steering wheel to the stops and back about... 25 times. Check oil level. Start engine and do the same thing again.

Did you drain the steering box too? That's where all the crud hangs out. If you drained the steering box it will take some patience to get all the air out.

 

[shiftpro]

Actually I don't know which side (pressure or return) is best for a cooler. Hopefully someone will comment on this... me too lazy to search this answer.

 

[Javin]

I’ll check in a little bit here which side it’s on I believe the return side, would it be a good idea to eliminate the cooler? And how would I go about cleaning out the power steering box?

 

[skysurfer]

Keep the cooler, it's not the cause of the noise and some aftermarket pumps require them.

 

[1987 GMC Jimmy]

I don’t see why it’d be necessary to have the cooler there in the first place unless an aftermarket pump calls for it as aforementioned. Maybe an in-line filter to help the Saginaw box, but that’s all I’d do. You may want to flush the system, too with the less viscous Prestone type PS fluid that all the stores sell and refill with that. I don’t have an exact procedure on the flush, though, and would be interested to see how people go about that.

 

[shiftpro]

I’ll check in a little bit here which side it’s on I believe the return side, would it be a good idea to eliminate the cooler? And how would I go about cleaning out the power steering box?

Disconnect the return line from the pump. Start engine... look out! The oil will be flowing out the line making a mess.
This is how you get all the crap out. Keep an eye on the tank, fill it and let it flush out the box. I use tranny fluid for
flushing out the box, then switch to power steering fluid. Keep adding steering oil and flushing until all the red tranny fluid
is gone.

Tranny fluid will work fine for PS, but I don't like it because if the oil in the tank gets foamed up (from air) it takes a few hours before the air bubbles lift out of the oil. PS fluid doesn't froth up like tranny oil.
I have added tranny fluid to a PS system, and it was fine... but I never have been able to properly bleed the system trying
with tranny fluid.

 

[Blue Ox]

Point of information: If you have hydroboost brakes DO NOT put transmission fluid in your power steering system. Ask me how I know.

 

[shiftpro]

If you're trying to play in the rocks with tires 35" and up, the pump can get pretty hot...
but if you're at this point in your off road enthusiasm, best to go with aftermarket hydraulic
steering ram in conjunction with the stock pump and steering box.

So the moral of the story, to reiterate, is that if you need a cooler on the PS system you really need to upgrade.

 

[Javin]

Yeah the cooler is on the return side, so just to confirm I should disconnect the return line and start it up and let it run out of the line, and just keep filling it up till it looks clean? Then switch to proper ps fluid? While I’m doing this should I have the front in the air and be going left to right?

 

[Snoots]

Yes.
Yes.
And yes.
Heed what Blue Ox and shiftpro have posted.
And KEEP the cooler.

 

[shiftpro]

Yeah the cooler is on the return side, so just to confirm I should disconnect the return line and start it up and let it run out of the line, and just keep filling it up till it looks clean? Then switch to proper ps fluid? While I’m doing this should I have the front in the air and be going left to right?

Yes you understand with one exception... cranking the steering stop to stop isn't necessary at the purge process (but it wouldn't hurt, might even help move some crud out of the box/pump). And as you are purging the engine needs to be running, of course.
After all the old oil is gone and replaced with PS oil go ahead with bleeding the air out. Turn engine OFF for some 25 cranks lock to lock, and THEN you can start the engine and do it some more.

 

[shiftpro]

Point of information: If you have hydroboost brakes DO NOT put transmission fluid in your power steering system. Ask me how I know.

Oh wow good point. I forgot about this as I haven't touched one ton juice brakes for some years. I'll have to get brushed up on hydroboost as my current project is 1 ton fun.

 

[shiftpro]

Yes.
Yes.
And yes.
Heed what Blue Ox and shiftpro have posted.
And KEEP the cooler.

I doesn't hurt to keep the cooler... if it doesn't leak and provided you are able to get all the air out of it.

 

[Javin]

Ok sounds good guys thanks for the info, and yes it isn’t hydro boost so I should be good to go, which ps fluid would you guys suggest?