Easy 1-person PS Fluid Change DIY - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 06-21-2010, 08:21 PM

Here is a trick to turn the changing of power steering fluid into an easy 1-person job. No more frantic pouring of fluid into the reservoir, trying desperately to keep up with the pump while an assistant turns the steering wheel from side to side. This should work on all PS pumps -- I would like to hear from people whose efforts are in vain.

The procedure is mostly what you've already come to know and hate -- drain the reservoir with the turkey baster, then buy your wife a new one. Remove the filter if there is one. Disconnect the return line and direct it into a drain pan or bottle, then plug the reservoir inlet. Fill the reservoir with fresh power steering fluid. You'll need about two quarts but it won't hurt to have more. It's not necessary to have the fluid in a gallon jug as you won't be adding that much at one time.

Now comes the change. Credit goes to Sixto for making a suggestion that I modified for use with my '87 300D Turbo (W124, OM603). He suggested removing the PS belt or serpentine belt (whichever your engine has) and spinning the PS pump by hand or using an electric drill with a buffing wheel to turn the pump. I modified this suggestion by creating a belt drive from a drill motor, and a homemade pulley and belt.

The belt was made from a length of rubber vacuum hose, a piece of plastic screw to hold the ends together, and some shrink tubing to close the gap. You can use a spare drive belt or a piece of rope -- almost anything will do. I fashioned a pulley from a power drill accessory but a small pulley with a bolt through the center would work -- again, almost anything will work and large diameter is better than small -- it spins the pump faster.

With the reservoir full, use the drill motor to turn the PS pulley clockwise. Fluid should run into the catch bottle and the level in the reservoir should drop. When the level is pretty low, stop the drill motor and refill the reservoir. Get in the car and with the steering lock disengaged, turn the steering wheel all the way to one side.

When you get out, you will see that the fluid in the reservoir has dropped. Fill the reservoir and turn the steering wheel all the way in the other direction. Again refill the reservoir and center the wheel. Refill the reservoir once more and use the drill motor to spin the pump until the reservoir is almost empty.

Put the return hose back on the reservoir inlet and install the new filter, if your PS pump uses one. Fill the reservoir and allow the air in the filter to bubble out. Spin the PS pump with the drill motor to bleed any air bubbles out of the system, adding fresh fluid as necessary. When you stop seeing bubbles, you're finished. Put the belt back on the PS pump and install the cap on the pump.

Finally, run the engine and turn the steering wheel to make sure everything works and you have no leaks. It's Miller time!

Jeremy

strelnik · #2 06-21-2010, 11:35 PM

Quote:

Originally Posted by Jeremy5848

Here is a trick to turn the changing of power steering fluid into an easy 1-person job. No more frantic pouring of fluid into the reservoir, trying desperately to keep up with the pump while an assistant turns the steering wheel from side to side. This should work on all PS pumps -- I would like to hear from people whose efforts are in vain.

The procedure is mostly what you've already come to know and hate -- drain the reservoir with the turkey baster, then buy your wife a new one. Remove the filter if there is one. Disconnect the return line and direct it into a drain pan or bottle, then plug the reservoir inlet. Fill the reservoir with fresh power steering fluid. You'll need about two quarts but it won't hurt to have more. It's not necessary to have the fluid in a gallon jug as you won't be adding that much at one time.

Now comes the change. Credit goes to Sixto for making a suggestion that I modified for use with my '87 300D Turbo (W124, OM603). He suggested removing the PS belt or serpentine belt (whichever your engine has) and spinning the PS pump by hand or using an electric drill with a buffing wheel to turn the pump. I modified this suggestion by creating a belt drive from a drill motor, and a homemade pulley and belt.

The belt was made from a length of rubber vacuum hose, a piece of plastic screw to hold the ends together, and some shrink tubing to close the gap. You can use a spare drive belt or a piece of rope -- almost anything will do. I fashioned a pulley from a power drill accessory but a small pulley with a bolt through the center would work -- again, almost anything will work and large diameter is better than small -- it spins the pump faster.

With the reservoir full, use the drill motor to turn the PS pulley clockwise. Fluid should run into the catch bottle and the level in the reservoir should drop. When the level is pretty low, stop the drill motor and refill the reservoir. Get in the car and with the steering lock disengaged, turn the steering wheel all the way to one side.

When you get out, you will see that the fluid in the reservoir has dropped. Fill the reservoir and turn the steering wheel all the way in the other direction. Again refill the reservoir and center the wheel. Refill the reservoir once more and use the drill motor to spin the pump until the reservoir is almost empty.

Put the return hose back on the reservoir inlet and install the new filter, if your PS pump uses one. Fill the reservoir and allow the air in the filter to bubble out. Spin the PS pump with the drill motor to bleed any air bubbles out of the system, adding fresh fluid as necessary. When you stop seeing bubbles, you're finished. Put the belt back on the PS pump and install the cap on the pump.

Finally, run the engine and turn the steering wheel to make sure everything works and you have no leaks. It's Miller time!

Jeremy

Jeremy,
Great job. I use a pulley+drill combo to run the hydraulic pump on Citroens to pump them up when they have been sitting for years. Easy way to do things

ps2cho · #3 06-22-2010, 12:30 AM

Wow that is genius. Saved the link for future reference!
Thanks!

funola · #4 06-22-2010, 06:55 AM

Is the issue running out of fluid in the PS pump reservoir when filling it after draining? Instead of going through the trouble of removing the belt and rigging up a drill to power the PS pump, How about shutting the engine off before the fluid runs low in the reservoir, top it up, start the engine, repeat untill reservoir does level not drop anymore? Will that work?

funola · #5 06-22-2010, 07:34 AM

Don't forget you have a shutoff lever on the IP so you don't need a helper.

Oldwolf · #6 06-22-2010, 10:16 AM

When the engine is running the oil sucks down so fast you won't believe your eyes.

Kestas · #7 06-22-2010, 11:17 AM

The fluid will see less force if the front wheels are off the ground. It reduces peak pressures when you turn the steering wheel from lock-to-lock.

Jeremy5848 · #8 06-22-2010, 12:00 PM

A remote starter and the STOP lever would indeed allow you to run the engine without a helper. Larry's comment is still true, however -- the pump eats fluid like you wouldn't believe. I didn't have to run the drill motor for more than about ten seconds to drain the reservoir. My concern with running the reservoir empty is not damaging the pump but getting all of the air bubbles purged out afterwards.

I've never had to tighten/loosen the power steering belt on a 61x engine so I don't know how big a job it is. Loosening the serpentine belt on a 60x engine is trivial -- the hardest part is getting the wheel wrench out of the trunk (it acts as a lever).

Another option might be to use the starter motor to turn the pump, as long as you have enough battery, but I'd rather not put that much extra wear on the starter system.

Jeremy

charmalu · #9 06-22-2010, 12:54 PM

Great idea Jeremy. this is a DIY forum, not a ASE certified repair shop. the seasoned mechanic that has done this many times, verses the average DIY guy/gal, can probably do this job w/o any problems.

It is the person that does this for the first time, and not ever that often afterwards that this is helpful for.

I know the profesional shop that changes the oil is going to suck out the reservor, change the filter and top off the fluid w/o flushing the system.

A good time to do this the Jeremy way, is when changing the belts, and these are done every _____ (miles) or ____ years (fill in the blanks.) and these are done right on schedule like oil changes. Right?

Charlie

Kestas · #10 06-22-2010, 03:32 PM

I've exchanged ps fluid from many vehicles and only once had a problem with air entrapment. It was on an '01 Mercury Sable. Never a problem with my E320.