Lupin..the..3rd
09-23-2013, 11:11 AM
This past weekend, I changed out the power steering reservoir in my 2004 325i due to a fluid leak from the old reservoir. In the process, I learned that this reservoir has a filter built into it. The filter is not serviceable on its own; it is built-in, so replacement of the whole reservoir is required. I used a ZF brand replacement reservoir.
To get some working room, you'll want to remove the airbox. Two 10 mm bolts on the driver's fender, and one hose clamp and one electrical connector at the MAF, and the whole box assembly pulls up and out.
You have to drain the reservoir to replace it. I cut the bottom half off a gallon milk jug to catch the fluid in. One 10 mm bolt secures the PS reservoir to its bracket. The hoses are long enough that you can lift it up and out with plenty of working room. The underside of the reservoir has two hoses that need to be secured by clamps. I removed the old factory style clamps by grasping the protrusion on the clamp, with a pliers, and giving it a twist. It popped open and was easily removed. Now holding the reservoir over the milk gallon, slowly work one of the hoses off. Hold it over the milk gallon until all the fluid has drained out. You'll need to move it around, to work all the fluid out of the passages and corners in the reservoir. Now do the same for the other hose.
Once the old reservoir is off, you can toss it in the trash. You'll need some replacement hose clamps to install the new one. Any bolt or worm/roller style will work. Worm/roller are easier to find locally, be sure to get ones that have a cover plate under the worm gear, to prevent it from cutting the hose. Put the clamps over the hoses and slide the hoses onto the new reservoir. Position the reservoir in its bracket, so that you can index the hoses such that they aren't kinked. Tighten down the clamps.
For everything else, "installation is the reverse of removal".
Once the new reservoir is secured, fill it with new clean fluid, checking the fluid level on the dipstick. I don't know what the factory recommended change interval on this fluid is, or even if they specify a change interval, but here's what mine looked like after 112k miles. Pretty dark and nasty.
To get some working room, you'll want to remove the airbox. Two 10 mm bolts on the driver's fender, and one hose clamp and one electrical connector at the MAF, and the whole box assembly pulls up and out.
You have to drain the reservoir to replace it. I cut the bottom half off a gallon milk jug to catch the fluid in. One 10 mm bolt secures the PS reservoir to its bracket. The hoses are long enough that you can lift it up and out with plenty of working room. The underside of the reservoir has two hoses that need to be secured by clamps. I removed the old factory style clamps by grasping the protrusion on the clamp, with a pliers, and giving it a twist. It popped open and was easily removed. Now holding the reservoir over the milk gallon, slowly work one of the hoses off. Hold it over the milk gallon until all the fluid has drained out. You'll need to move it around, to work all the fluid out of the passages and corners in the reservoir. Now do the same for the other hose.
Once the old reservoir is off, you can toss it in the trash. You'll need some replacement hose clamps to install the new one. Any bolt or worm/roller style will work. Worm/roller are easier to find locally, be sure to get ones that have a cover plate under the worm gear, to prevent it from cutting the hose. Put the clamps over the hoses and slide the hoses onto the new reservoir. Position the reservoir in its bracket, so that you can index the hoses such that they aren't kinked. Tighten down the clamps.
For everything else, "installation is the reverse of removal".
Once the new reservoir is secured, fill it with new clean fluid, checking the fluid level on the dipstick. I don't know what the factory recommended change interval on this fluid is, or even if they specify a change interval, but here's what mine looked like after 112k miles. Pretty dark and nasty.