Friday, May 7, 2010
More Parts and Prep for the Accessory Overhaul
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.
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
Thursday, May 27, 2010
Failed Trailing Arm Bushing Leads to Suspension Overhaul
I know, I know. You just read the title of this entry and are now wondering to yourself..."self, is this guy nuts? He was just preparing to do an accessory overhaul and now all of a sudden he's doing a rear suspension overhaul? What the hell happened to the accessory overhaul?" Allow me to explain.
For at least the last couple of years I've noticed a certain sloppiness in the rear end of the car. It hasn't felt as "planted" as it once did. I diagnosed that as worn trailing arm bushings and put those on my list of things to do. Times being what they are and my schedule being what it is, I put the job off and rationalized the delay with my desire to completely overhaul the rear end of the car...eventually. So that brings us to the present day.
While I was washing the car last weekend I sensed something was wrong with the left rear wheel. The ride height seemed lower than normal, almost as if someone had decided to slam it while I wasn't looking. I reached into the space between the top of the tire and the lip of the wheel well to test my theory and found my fingers were a tight fit. I stepped back and walked around the rear of the car to compare it to the other side. That's when I confirmed that the left side of the car was slightly lower than the right. This was made all the more apparent by the fact that BMWs of this vintage are supposed to be slightly HIGHER on the left than the right when the car is unloaded because the vehicle is designed to accommodate the weight of the driver.
I initially concluded that the spring had failed. This is not exactly an uncommon problem here in the northeast states where salt is laid liberally on the roads in the winter. The design of the control arm tends to keep the lower portion of the spring bathed in salt spray, so it's not surprising that the springs eventually corrode and fail, and in doing so, drop the car almost an inch. As I walked back and forth to compare the rear wheels I also realized that, in addition to the usual negative camber apparent on both rear wheels, the left wheel was noticeably toe-in. Since the BMW spec for rear wheel toe is a mere 0.3 degrees positive, I knew something was definitely wrong with the rear suspension.
First thing Monday morning I went to the dealer with a list of parts. I originally thought I'd pick up one M-sport package spring, but as it turns out BMW only sells them in pairs (BMW part number 33-53-9-059-403, $288). A earlier review of my maintenance schedule revealed that the shocks had been in service for exactly 100K miles (10K more than the last time I replaced them), so I added shocks (33-52-1-090-831, $268), shock mounts (33-52-1-092-362, $64), shock tower reinforcement plates (51-71-8-413-359, $41), and all the related hardware to the list before settling up with the parts guys for a cool $805 including a 20% discount and a $52 donation to the government.
If you're wondering why I ordered locally when Tischer would have been able to meet that discount level and help me avoid the tax, the reality is I wanted the option to bitch at someone face to face if the springs turned out to be the wrong version. This was a distinct possibility given that BMW does not publish the spring part numbers in the ETK and therefore make them easy to confirm with the BMW community.
As I left the dealer and drove to work, I thought about my plan of action and figured I'd do the springs and shocks and call it a long day. When I got out of the car at work, I once again attempted to check the gap between tire and wheel well just to make sure it wasn't getting worse. Surprisingly, the gap seemed to be a bit larger and the wheel didn't seem to have as much toe-in. And that's when it hit me. The problem wasn't the spring, but the trailing arm bushing, which was causing the entire arm to pivot left and right.
Since trailing arm bushings are a pain in the ass to replace on the car even if you do have the special pusher/puller tool to get the job done, I quickly found myself on a slippery slope. If the trailing arm bushings are shot, surely the other bushing and ball joint on the trailing arm couldn't be far behind. That and my desire to replace the right wheel bearing (with 193K original miles) would justify pulling the arms and having all new parts pressed in on a bench press rather than use lots of special tools I'd have to source myself or borrow from my technician.
Naturally, I continued, if the bushings on the trailing arm are sloppy no doubt the inner control arm bushings have been taking a beating for the last several years as well. Unfortunately, it's not possible to remove the inner bushings without moving the differential aft a few inches to gain access to the bolts. And if I need to disconnect the differential, I figured I might as well pull it for an overhaul (bearings, seals, reset the lash, repaint). Accelerating down the slope beyond Mach 1, I further rationalized that if the subframe were to be sans differential and control arms, surely it couldn't be that much more of an inconvenience to pull the entire subframe out of the car to clean off all the rust and powder coat it, while at the same time replace the subframe bushings with upgraded M3 parts.
Now beyond the area of maximum aerodynamic pressure at Mach 1.2 or so, I jumped to the conclusion that this would be a perfect opportunity to have a local welder stop by to install the M3 subframe reinforcement plates. I mean, heck...this car might make a mean track rat someday, and it would be stupid of me to track it without those reinforcements. Of course, since mobile welders don't come cheap (and the one closest to me charges a flat rate) I figured I might as well have him weld in both the swaybar tab and RTAB pocket reinforcement plates while he's at it.
I think you can see where this is going. The parts list is long and expensive and most of that list is on its way to me as I write this. The mobile welder is one phone call away. I've spoken to a powder coater about prepping and painting several of the rustier components while they're off the car, and I even managed to convince Dan at diffsonline.com to pick up my differential at the Bedford Airport when I fly it up there in the 172 on a post-annual test flight. There's no stopping now. It's going to be one hell of an adventure and the greatest test of my DIY skillset to date. The plan is to begin disassembly this weekend but holiday plans may have something to say about that. In any case, it appears that the E46 will get to flex its muscles for a couple weeks. I hope the E36 doesn't get jealous. Stay tuned!
Mileage: 193000, Parts $805, Parts Saved: $205