Please help with power steering box flush

[Mark80K15]

Hi all. 1980 GMC K15, 350. I am replacing the power steering pump and both lines. I have removed the old pump and lines. Can you please confirm if I should flush the old fluid from the steering box? If so can you please tell me the procedure? Do I need to install my new pump first? I saw a video where the return line was disconnected from the pump and the system flushed by raising the truck and turning the wheels many times. The old fluid was flushed out of the return line, and new fluid was added to the pump until the old fluid was gone. Is that the correct procedure? Is that the only procedure, or can I do a flush with no pump installed? Thanks, Mark

 

[Originalthor]

That would be the correct procedure.
You just got to cap the return inlet on the pump if its pretty low on the tank or put a hose on it so its above the fill line.

Its a good idea to flush fluid for warranty purposes and keep the receipt of the fluid.

Also who knows what crap or how old it is in there and if you have a cooler its will hold alot of oil aswell.

 

[Mark80K15]

Ok, cool, thx for the quick reply. Any idea what is the total fluid capacity of the whole system (pump, box, lines, no cooler)?

 

[Originalthor]

Probably a liter. I would get two to be sure. Not much to flush since your doing lines and have no cooler.

 

[fast 99]

We do it running with 2 people. One person to fill the pump other person to start/shut off the vehicle and turn the wheel. Return outlet to a drain pan with rubber hose, it's messy. Those pumps have A LOT of volume. Usually takes 2-3 quarts and less than a 1/2 minute. Need to have ducks in a row before starting the operation.

 

[idahovette]

And maybe a half a bag of floor dry.......

 

[Mark80K15]

Ok, gotcha, thanks everyone!

 

[CalSgt]

Good time to just remove the pump for an inspection & rebuild unless its been done in recent history. Check the frame for cracks while it's off of there. Then just spend the time you would be flushing to bleed the PS system.

 

[75gmck25]

Also, once you get it flushed and refilled you need to purge air out of the system. The GM procedure in my book is to lift the front wheels off the ground, top off the reservoir, start up the engine so the pump is running, and then turn the wheels slowly, lock to lock for 10 cycles. It definitely got my steering working smoothly after a pump replacement.

 

[CalSgt]

Good time to just remove the pump for an inspection & rebuild unless its been done in recent history. Check the frame for cracks while it's off of there. Then just spend the time you would be flushing to bleed the PS system.

Just realized I said pump instead of box... I was recommending the gear box be rebuilt while everything else is apart.

 

[fast 99]

Just realized I said pump instead of box... I was recommending the gear box be rebuilt while everything else is apart.

Don't know where you are getting those but we have had a lot of issues with rebuilt boxes.

Unless there is a problem we don't replace them. Biggest issue we have seen on rebuilts is loose pitman shafts, sometimes worse than the box we are taking off.

 

[Originalthor]

Don't know where you are getting those but we have had a lot of issues with rebuilt boxes.

Unless there is a problem we don't replace them. Biggest issue we have seen on rebuilts is loose pitman shafts, sometimes worse than the box we are taking off.

I would have to agree. Unless its a red head. I've had to change out 2 reman boxes and now my pump is going out on the wife's escalade. They don't make stuff like they use to anymore.

 

[Grit dog]

And maybe a half a bag of floor dry.......

I try to perform these types of tasks in the gravel side driveway or the neighbors yard!

 

[CalSgt]

Don't know where you are getting those but we have had a lot of issues with rebuilt boxes.

Unless there is a problem we don't replace them. Biggest issue we have seen on rebuilts is loose pitman shafts, sometimes worse than the box we are taking off.

I would have to agree. Unless its a red head. I've had to change out 2 reman boxes and now my pump is going out on the wife's escalade. They don't make stuff like they use to anymore.

I think you are misunderstanding me, I was recommending he rebuild the box himself not to go get a remanufactured box.


You're right the remanned boxes are trash, I think they throw all of the parts in a big pile and reassemble them with Chinese o-rings, using a hammer & five thumbs.

 

[fast 99]

I assumed you were referring to a rebuilt unit. Rebuilding boxes is a little beyond a DIY repair. Reseal, yes. Rebuild no.