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Tuesday, September 16, 2014

Doug's Domain

Doug Vetter, ATP/CFI

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Friday, May 7, 2010

More Parts and Prep for the Accessory Overhaul

(Image: Closeup of metal water pump pulley and OE plastic power steering pulley)BMP Design finally came through with the aluminum water pump pulley. As you can see from the top half of the photo to the right, it's a good looking, sturdy piece. Unfortunately, they were not able to provide the aluminum power steering pulley so today I picked up an OE plastic pulley at the dealer while I was picking up some other parts including some fasteners for the under-hood insulation (a leftover from my windshield washer system overhaul) and the two M6 bolts needed to extract the water pump during the upcoming accessory overhaul. I've been in touch with a couple shops about machining a custom power steering pulley out of billet aluminum and black anodizing it, but it appears my installation timeframe may not permit me to install one. Since it's relatively easy to install the pulley later, however, I haven't ruled it out.

While my technician was busy running around handling the crisis of the minute, one of the other techs I chat with, "K", helped answer a few questions while he munched on a bagel and gathered tools to start work on a nice blue 335i in his bay. The first question had to do with the water pump itself and the aforementioned extraction bolts. He knew what I was looking for and managed to coerce another tech there to grab a couple of them for me out of his stash. He then pointed out that while the bolts were good to have on hand if the pump didn't want to budge, I probably wouldn't need them because in his experience most pumps come out pretty easily. His technique to extract the pump is to put a piece of cardboard between the radiator and the pump to protect the radiator, and then with both hands around the pump, rock it back and forth while pulling at the same time. I intend to do it this way initially and resort to the bolts only if necessary.

I then asked about the oil filter housing installation procedures. I noticed that the new gasket has two different faces -- one flat and one pointy. I naturally assumed the pointy end would mate with the groove machined into the housing but when I asked about the correct orientation he pointed out that it can only be installed in one way. Simple enough.

(Image: Closeup of M52 filter housing gasket)Another question related to reports online of housings continuing to leak even after the gasket was replaced. He said that's usually caused by the housing loosening up a bit, perhaps due to the gasket shrinking over time in combination with the stress created by the attached accessories. This results in the housing moving in relation to the block, which wears the surface and prevents it from sealing properly. This explains why some people wind up buying a new housing for around $300. Fortunately, given one experienced technician's appraisal online that this affects perhaps 5% of all installations, I won't be buying the part unless absolutely necessary. I'll risk a few days of downtime to save that money.

This led to a discussion on torque values of the housing bolts -- he said he did it all by feel. For a DIYer doing this for the first time on a cast iron block M52 that's probably acceptable, but I would be nervous to do try that on the M54's aluminum block, fearing I'd pull threads. The consensus online seems to be 21 ft pounds, which is openly suggested as a compromise between the maximum torque recommended for the bolt size and the desire to protect the threads and prevent wracking of the housing due to accessory load. I'll likely fine tune that number with additional research so if you're about to do this work don't take this at face value. Make sure you come up with the right torque spec for your application.

The only remaining parts to order are the power steering pump, alternator and some miscellaneous hardware. I'm waiting to purchase these parts based on the result of the airplane's annual inspection. A chat with my FAA-certified mechanic today revealed no surprises, thankfully, but the work isn't done until it's invoiced.

The OE power steering pulley lists for an astounding $59 (guess someone at BMW missed the memo that this is made out of plastic) so the parts guys took pity on me and gave me a slightly higher discount level than normal. They also discounted the hood insulation fasteners by a similar amount. The result? $20 in parts savings after tax is taken into account. After all, another Jackson in my pocket isn't a bad thing.

Trivia: While looking under the hood of that 335i, K told me that BMW is now using an expensive ($35/quart) power steering fluid in the latest cars. One can only wonder what the hell BMW's engineers are smoking lately. Surely if ATF did the job for years it could continue to serve that role, right? Oh wait...then BMW can't make $33 on a quart of proprietary fluid. But hey, it's "lifetime fluid", right, so we won't ever need to replace it! Problem solved! It's crap like this that makes me wonder if I'll ever buy another BMW, even if the 1 series M car recently spied in testing does eventually make it to our shores. I think someone at BMW needs to re-learn the engineer's mantra: keep it simple, stupid.

Mileage: 192050, Parts $80, Parts Saved: $20