Changing power steering fluid in 1984 300DT, how do I plug return line?

[HuskyMan]

I've drained as much of the PS fluid as I can using a turkey baster. I go to loosen the return line and power steering fluid gushes out. What can I use to plug the return inlet in the power steering reservoir so I can continue to flush and fill the power steering system?

[Charlie Foxtrot]

I usually put on the return inlet a piece of scrap fuel line w/bolt in the end, and use worm drive clamps to snug up fit & hold in place.

[HuskyMan]

That sounds like a good idea; I was wondering if an oil drain plug would work. Does anyone know the diameter of the threads for it?

[Mxfrank]

I use my vacuum tank (I assume everyone changes their oil by vacuum). I just insert the tube directly into the return line and start the engine. Pumps the PS system clean in a few seconds.

[toomany MBZ]

When I do this, I send the return line to a container to catch the fluid poured into the pump when running, my helper turns the engine on and off.

[cooljjay]

Why not just undo the drain bolt....turn the wheel from one side to the next....and be done??

[toomany MBZ]

Maybe he wants to flush the system.

[cooljjay]

Originally Posted by toomany MBZ

Maybe he wants to flush the system.

Well if he wants to flush the system....advice is against that...I would replace both the high pressure hose and low pressure hose as well as rebuild the power steering pump....

Like using ATF in the power steering system....it is highly advised to "not" use ATF....because 98% of these cars are still running the OEM fluid....and well this "stuff" is know to clean the system way to well....aka leak central...

The reason why I say replace both hoses is because they are breaking down internally hints to why the power steering fluid darkens very fast...the rubber is disintegrating...

[HuskyMan]

I'm thinking the bolt size is either an M14 or M16. What say you??

[sleepstar]

put the return line into a large container... run the engine, keep adding fluid into the PS pump until it runs clear from the return line. replace the filter.

[Ceristimo]

Isn't it going to be really hard to keep adding fluid fast enough?

here's how I did it:
1) Undo the drain plug on the steering box and drain all the black crud.
2) Fill back up with fresh fluid
3) Jack front-end of car up so the front wheels are hanging free and turn steering wheel from full-lock to full-lock a bunch of time.
4) Rinse and repeat all of the above until the fluid stays clean.

You don't even have to run your engine...

[toomany MBZ]

Originally Posted by sleepstar

put the return line into a large container... run the engine, keep adding fluid into the PS pump until it runs clear from the return line. replace the filter.

Yes and have a helper add fluid as the engine runs and pumps out the old fluid.

[Stretch]

Originally Posted by Ceristimo

Isn't it going to be really hard to keep adding fluid fast enough?

here's how I did it:
1) Undo the drain plug on the steering box and drain all the black crud.
2) Fill back up with fresh fluid
3) Jack front-end of car up so the front wheels are hanging free and turn steering wheel from full-lock to full-lock a bunch of time.
4) Rinse and repeat all of the above until the fluid stays clean.

You don't even have to run your engine...

This is exactly what I do.

There is just no need for turkey basters - messing about with a running engine catching fluid and involving half of the local community with buckets!

Pedantic me needs to point out that the "drain plug" isn't really a drain plug but a covering bolt for fitting a centring pin on installation (could also be used during alignment) - still remove the bolt and turn the steering to the left hand side lock and the fluid will exit in an orderly manner...