So Sunday I decided to flush the power steering system, change the reservoir and hose clamps. The reservoir should be replaced from time to time because it has a filter built inside of it. I heard the factory hose clamps can leak from the reservoir and my lines were pretty nasty. Only problem, the clamps had already been replaced. :(
There are a couple ways to flush the P/S fluid. You can simply use a turkey baster or suction gun to suck out whatever fluid is in the reservoir and then replace it with new fluid and repeat. Or you can remove the hose from the pump and turn the steering wheel from lock to lock until most of the fluid has been drained. I used the "optimal method" described below.
This was the DIY I used: http://www.dvatp.com/bmw/diy/power_steering_flush/
You can see the 22mm banjo bolt here that you have to remove. Once you bust it loose ATF should start coming out. The more you suck out of the reservoir the less is going to come out. I didn't really bother sucking any out. You can already see in this pic that fluid looks like it's dripping from behind the fitting.
You can see the system draining here. At least the PO used ATF like the system calls for instead of regular P/S fluid. The return line was held to the cooling pipe with a hose clamp. This is not the original part. There is supposed to be a hard clamp here. You would have to remove the clamp on the bottom of the reservoir to change the reservoir. I was able to pull the reservoir out with the two lines attached.
You can see the intake and return line are all gunked up. I didn't take a picture but there was a date of 1.18.2000 on the intake hose. It sucks that it has already been replaced and now it's failing again. Also the previous owner used fuel injection hose for the return line instead of P/S line. Not sure what the difference is but the P/S system is rated 1,000,000 PSI. I don't know what it is but it's not 40 psi like a fuel hose. Also like I already said, there is a reducer in the return line which helps with that pressure. If you don't have that you're return lines might leak. I assessed all of this once everything was out and decided to order a new intake and return line from the P/S reservoir.
While I had the P/S reservoir and lines out I decided to dig in there and clean out the Idle Control Valve. My idle has been surging with pretty poor drivability when the car is cold. The RPMs drop and bounce between shifts. When I come to a stop the RPMs would drop low and then bounce between 500-1100. Just down right annoying. I also read that the ICV is pretty difficult to remove without first removing the intake manifold. Eh, forget that, it's not like this is the first time I've tried to get my hands into a cramped German engine bay.
I should mention that to remove and replace the P/S reservoir on the 1995 e36 m3 you'll have to remove the intake box and MAF. No big deal. It's two 10mm bolts holding the cruise control module on and some hose clamps. Don't rip the box out, there is a temp sensor attached with at 10mm bolt.
Here you can see the cradle for the P/S reservoir. Underneath the manifold is the ICV. You'll have to remove that alternator cooling snorkel thingy as well. Mine was taped up. Yay!
You still can't really see the ICV in this picture but go ahead and remove that front intake manifold bracket. It's held on by one 10mm and one 13mm. The 13mm is a little deep and tight, but just be a man and break it free.
Alright, there's ICV all nestled in there. First thing to do is unplug it. After that there is a rubber ring holding it to a clamp. The ICV has to move parallel to the ground towards the fire wall to remove it from that ring. Before doing that try to loosen the two hose clamps on the inlet and outlet of the ICV. I was able to loosen the clamps all the way but the ICV had never been removed and I was unable to pry the hoses off of it. I ended up pulling the whole ICV out with hoses attached. The hose came off the intake manifold as I was trying to remove the hoses off the ICV so I figured, what the hell, I'm pulling this bitch out. There is a good chance of ripping the vacuum hoses this way so be prepared to replace them. There is also a possibility that they are hard and cracked anyway. I would've replaced them, but I didn't have the parts and there were no rips so they were reusable.
There is a direction to the air flow. There is a fat and skinny side. Remember which way the hoses go. It's not really possible to switch it around.
I cleaned out the ICV with some STP throttle body cleaner and some blue shop towels. Mine was disgusting! I mean it was pretty dirty. I don't think the valve inside was even moving. Once I had cleaned it out a bit I could feel the valve inside breaking free from all the dirt. If you whip it with your wrist, which you might do, the valve clinks against the side. I read it was fragile so don't whip that bitch around to dry it. The TB cleaner evaporates almost immediately.
I sprayed a bunch of cleaner inside the boot and cleaned that out. I also hit up the TB plate which had some gunk in it as well.
I put everything back together reverse of the way it came out. The hoses weren't totally hardened so I was able to reuse them. I also attached the hoses back to the ICV and wrangled that thing back into place. I don't really have any advice on how to do that. It wasn't exactly easy, but wasn't harder than changing the temp sensors on a Corrado VR6 or let alone anything on an Audi TT. The claim that you can't get to it without the removal of the intake manifold is overstated. At least on the s50. There might be a whole bunch of other shit in the way on other e36's.
Once the ICV was all cleaned up and back into position I put the P/S reservoir and lines back in.
I knew the lines were leaking and hardened into shape from the old hose clamps, but I didn't have anything to replace them with at the time. I cleaned them up to see if I could notice where the leaking was occurring.
I also cleaned up the cradle since that thing was covered in gunk as well.
Don't forget the new crush washers on the banjo fitting of the intake hose. Torque the 22mm bolt down to 30ftlbs if you can get a torque wrench in there.
The Bentley or that DIY calls for Dexron III on the e36. It was 1995 and I guess that's what they engineered the system to run on. I mean it's just Power Steering. You could probably get away with anything higher than Deron III, or synthetic, but who cares. The Castrol DEX/MERC was Dexron III rated and $3.99. When I flush the tranny with synthetic ATF, I might change the rack and use this to see if there is a difference. I'm not expecting any.
Fill up the reservoir and start the car. You'll have to attach the MAF and box in a way so the car doesn't stall. You can try to crank it to spin the pump and move the fluid through if that works. If the reservoir wasn't in such a tight spot you would put everything back together and just run the car with the cap off and add fluid as necessary as the P/S fluid gets into the rack. I added too much and had to draw it out. I used this suction gun that I use for tranny flushes.
Changing the clamps, washers and reservoir didn't fix the leak as the lines were bad. I decided to just order a new intake line and return line with cooling pipe as this car is more of a restoration/mod more than just a throw it together beater/track car. I don't think there is anything wrong with using a P/S hose for a return hose with a reducer and clamp in the middle. I just wanted to make absolutely sure the parts were correct and didn't want to cheap out on something that might still leak later down the road.
Cleaning out the ICV worked wonders! My idle no longer bobs up and down. Drivability on cold start-ups is much better. Overall acceleration has improved as well. It honestly feels like a mod. Sad to say that, but I really felt a difference. I didn't feel much of a difference when I changed the fuel filter, but cleaning the ICV was definitely made a noticeable overall improvement.
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