The penguin's motorcycling and Jeep blog

Friday, December 24, 2010

Motor mount woes

First, let's review what a motor mount does in a Jeep. The job of the motor mount is to a) isolate the engine from the frame so you don't get your teeth vibrated out, and b) hold the engine on top of the frame. There are two motor mounts, one on each side of the engine about 2/3rds of the way towards the front, then the back of the engine is held up by the transmission. The transmission then has a rubber mount at the back of it that holds it to the cross member / belly skid plate that runs across the belly of the Jeep. So there's three pieces of rubber holding the whole engine / transmission / transfer case assembly off the ground, and three points determine a plane so these three pieces of rubber determine the location of the whole assembly.

Here is what the motor mount looks like on my Jeep:

There is a bracket welded to the frame that this mounts to. The part of the bracket closest to the outside of the Jeep has a nut welded into it and you go down from the top through that small hole in the motor mount. On the part of the bracket closest to the Jeep, there's just a hole. A stud comes down from the motor mount that must be pushed through that hole, and then you put a nut on the stud from the bottom. You can't come in from the top because the stud is below that big rubber bushing you see. Then the engine has a forked bracket that comes on either side of that big rubber bushing, and a crossbolt goes through the forked backet and through the big bushing in the middle of the big rubber bushing, and that's what holds the engine up off the frame, nicely isolated by a big rubber donut all around. Here is what it looks like installed in the Jeep (sorry I didn't get a better picture): So anyhow, it's been raining here in the Silly Cone Valley for 40 days and 40 nights, well, feels like it. I decided to take a trip in my Jeep for Christmas. Before taking any trip, I inspect my Jeep to make sure all the fluids are okay, all the bolts are nice and tight, none of the u-joints or tie rods or anything waggle when I whack'em with a rubber mallet, and so forth. And so things were going along fine until I got to the passenger side motor mount on the underside, looked up to where there's supposed to be a stud and a nut holding the engine side of the mount down, and... err. Yeppers, the blasted stud snapped right off at some point in the recent past!

That's from right after I pulled it. To pull it, you first remove the nut from the stud. Well, if there's a stud :). Then you remove the bolt. Then you put your floor jack and a piece of 2x6 under the oil pan skid plate and jack up the engine until the mount is just barely above the frame. Then you remove the crossbolt and the motor mount slides right out.

So anyhow, thanks to Christmas I can't get a new motormount until January (because all the suppliers are on holiday). So I rednecked a temporary fix: I drilled out the remnants of the stud, and jammed a nut on top of it, grinding out just enough so I could tap in the nut with a drift to retain it. This is a flange nut, which has a serrated bottom, so once there's pressure on it from a bolt pulling it towards the frame, it's not going anywhere. But there has to be enough friction to allow it to get pressure on it. Thus why I had to barely grind out enough to be able to force it in there with the drift and 3-pound hammer:

Once I did this, I then had to properly space out a bolt so that it wouldn't bottom out on that bracket part that's above the nut, yet would grab enough threads to not strip out. That required trial and error with various washers and nuts lying around. But I found the right combination, and now it's all installed again, waiting for a new mount but quite usable in the meantime.

As for why the stud broke: It was a metric grade 8.8 bolt welded to the motor mount before the top part of the motor mount was fabricated. Metric grade 8.8 (not to be confused with SAE grade 8, which is the equivalent of metric 10.9) is barely above compressed oatmeal on the hardness scale, but normally won't break in this application. It does bend fairly easily if not fully retained by a torqued nut, however, and also stretches fairly easily if overtorqued or given a sudden shock in the longitudinal direction. What I'm suspecting is that the bolt stretched, perhaps from the oil pan skid plate getting whacked by a rock, letting the motor mount jump around bending the stud back and forth until it work-hardened and finally snapped off. I didn't catch it because I was testing the nut by putting a wrench on it and seeing if it would move, and of course it was corroded in place and wouldn't move -- and unfortunately the place it was corroded into did not put enough pressure on the now-stretched stud to keep the motor mount from moving around.

All of this is compounded by the fact that I can't get a torque wrench onto most of these bolts due to lack of access -- all my torque wrenches are too big to fit into these cramped quarters and it's problematic running long extensions thru u-joints and expecting to get the right torque reading on a tork wrench -- so I'm just hoping that I'm putting the right torque on them. It may be that I had already put close to too much torque on the bottom, and whacking my belly pan on a rock was just enough to finish it off.

So anyhow, needless to say I'm not happy here, I think they should have gone with at least a metric 10.9 grade bolt for the stud because they don't stretch as easily, but at least I'm on the road again. And that ends today's adventure in Jeep wrenchin'...

-- Badtux the Wrenchin' Penguin

Sunday, December 5, 2010

Wow, this place has gotten musty...

The latest mod to my Jeep is the Savvy Offroad rocker guards, which are heavy aluminum plate with stainless steel skids. So I took'em out to Death Valley to test'em out in Mengel Pass's rock garden. Naw, dadburned rock garden has gotten as well groomed as Justin Bieber's hair. Still, there was a few mildly interesting spots, and I video'ed them with my new iPhone 4...

I'm being followed by a full-sized F-150 4x4 pickup truck, which is big and wide. I have to wait on him a bit from time to time -- like Marines, we 4x4 types don't leave folks behind.

So now you know what it looks like when I'm out there in the desert...

-- Badtux the Jeepin' Penguin

Sunday, March 21, 2010

The Six Million err Thousand Dollar Jeep

"We have the technology, we can rebuild her."

As readers of my blog know, someone ran a red light in front of me and I t-boned him a couple of weeks ago. The right front corner of my Jeep was a mess and the steering box Pitman shaft sheared right off. But never fear, the Silver Demon is back on the road again:

Because the bumper was toast, I bought a cool Warn bumper. It cost the same amount as the OEM bumper but is much stouter. The fender is a new replacement, but rather than the OEM fender flare I bought some Bushwacker flat fender flares to replace the OEM's, this gives me more clearance under the fender for bigger tires and also some trick side running lights (DOT certified so they're street legal, don't worry). The fog light on that side was toast, so I bought some Hella 500 fog lights rather than an OEM replacement light, they actually use the same reflectors so that wasn't a big deal. I had my mechanic do most of this work because a body shop would have been utterly clueless.

I brought her home Thursday evening, and have spent most of this weekend going over her making sure everything's okay. I swapped out the lower control arms with some new JKS control arms and checked the OEM's to see if the impact had caused damage to the bushings, no, it hadn't. Doesn't appear to have hurt anything else either, the Jeep drives the same as it did before it got whacked. Jeeps are *tough*. Well, except for that OEM steering box, but I'm wondering if that fault line might not have been there on purpose so that if the wheel ever got a whack like that, it wouldn't cause the steering wheel to spin and break my fingers.

The shop mostly did things okay, but two things were wrong -- the wiring for the marker lights was reversed (so it would not blink when the lights were on), and the right marker light was hard-wired rather than having connectors (because the original wiring had been sheered off by the fender when it was crumpled). Easy fix for both. And the alignment shop did not center the steering wheel, grrr, but that was an easy fix too, just grab the spinner near the pitman arm and spin away (it doesn't affect alignment, just the centering of the steering wheel)... took me two tries, the first time was a little too far, the second try was successful, the only way to know whether it's okay is to drive it down the center of a straight road (so the crown doesn't make it want to go one way or another) and see whether the steering is straight, clearly the alignment shop didn't do that. Oh well!

Now to put the new (well, used, bought from someone else) Old Man Emu front springs on her to deal with the sagging front springs... I was going to do that today, but discovered that the new (well, used, being thrown away by work) workbench I'd put in my garage was too big and didn't give me enough room to jack the front of the Jeep up. I remedied that by shifting everything around to put the workbench in the corner, where it's now out of the way... but that ate up a bunch of my time, I have too much junk in my garage (for a definition of "junk" that is "tools and supplies"). And of course once I do that, I'll need to align the Jeep *again* and re-center the steering wheel *again*. Meaning I wasted my time centering it the first time, but what the hey, ain't the first time I've wasted my time ;).

-- Badtux the Wrenchin' Penguin

Monday, March 8, 2010

Toyota is the new Philip-Morris

Philip-Morris, you might recall, is the cigarette company that for years insisted up and down that cigarettes were good to you... all the while knowing, within their labs, that they were addictive and caused cancer. They became the poster child for companies that care more about profits than about the health and safety of their customers, so hated that they had to change their name to "Altria" (I guess if you can't X it out, effin' A it out) to escape their reputation.

So why bring up Toyota and Philip-Morris in the same breath? Well... it's because of the testimony of David Gilbert, an automotive technology professor who demonstrates a fault condition that Toyota's electronic throttle control software doesn't detect. Note that Mr. Gilbert does not say -- or prove -- that this particular error condition is the cause of Toyota's problem. Rather, he shows that there is a condition that Toyota's throttle control should detect -- two shorted wires to the throttle position sensors, which are supposed to have different voltages on them because they go to different resistor packs -- which it does not, in fact, detect, and therefore there is at least one bug in Toyota's throttle control software. And software bugs are like cockroaches -- if you can see one wandering around on your kitchen counter in broad daylight, likely enough there's a thousand more in the wall behind the counter hidden from view.

Toyota can try to spin this all they want, but as someone who has an EE+software engineering background, I agree with Gilbert that this seems to indicate that Toyota's throttle control software is not as robust as they claimed and thus cannot be eliminated as a possible cause of the problem. So what's Toyota's response? A) say that Gilbert was paid by trial lawyers (true, but so what? The software problem doesn't go away just because of who Gilbert is paid by), and B), to hold a dog and pony show claiming that Gilbert's *SPECIFIC* bug is not the cause of the acceleration problem. Uhm, okay, but Gilbert himself did not say his bug was *THE* cause, just that it indicated a problem with the software.

All Toyota is accomplishing is making themselves look like the cigarette companies -- i.e., a bunch of lying bastards more concerned about the bottom line than about the health and safety of their customers. This points to a problem in the Japanese psyche that has been sort of shoveled under the covers since WWII -- the Japanese unwillingness to ever admit that they made a mistake or are not perfect. The Japanese refused to believe that their codes had been broken for years after Pearl Harbor, allowing the U.S. to know exactly what they were doing at all times, and even when things happened that should have just blatantly told them "our codes are broken" (like American carriers appearing off of Midway Island *just in time* to sink their own carriers) they refused to believe that any mere American could ever do such a thing to their "perfect" codes. I'm seeing the same mentality at work on the part of Toyota right now... and it ain't pretty, ain't pretty at all.

-- Badtux the Car Penguin

Sunday, March 7, 2010

Gimme heat!

I'm not sure when the low speed on my Jeep's heater quit working, but I noticed it one day while driving down the street -- no hot air blowing out of my vents. WTF? I checked the next three speeds up, and they all worked. So it wasn't the motor, and given that my Jeep has less than 40,000 miles on it, it didn't seem likely to be the switch. At that point, it clicked: Heater resistor.

To understand what I'm talking about, here's the deal. Your heater blower motor takes 12 volts. The way pretty much all American cars are wired, it takes that 12 volts straight from the fuse box, through a relay controlled by the "Hi" setting on the air conditioner/heater fan control. If you want the motor to run slower, you have to feed it less voltage. The way that American cars do that is to have a resistor network, where each resistor gives you a progressively lower voltage, and use the heater control switch to switch which pin of the resistor network gets sent to the blower motor. The higher the resistance, the lower the voltage, and the lower the fan.

Checking out my handy dandy factory service manual, I decided to pull the resistor out and test it. The problem was, where is the blasted thing? Finally after sufficient digging around I found where it is: mounted right above the passenger side footwell light. So I unbolted the light and unplugged it and put it aside, unplugged a bunch of wires under there and moved them aside, and there we were, two 8mm bolts holding this thing in so that it sticks into the airflow where it can get cooled down while the heater is operating. So I removed it and it turns out to be a flat circuit board with resistive traces on it. I take my ohm meter, and yeppers, the connection between the last two pins (the smallest one is the low speed pin) is gone, and a glance at the circuit board shows that the trace apparently exploded where the connector's pin attaches to it, probably due to a manufacturing defect that allowed moisture to get into the circuit board.

A quick trip to my local Jeep dealer and $25 later, and I have a new resistor, and have all fan speeds going again. And yeah, this was probably caused by a manufacturing defect of this Hecho en Mexico hunk of junk, but my OEM warranty ran out at 36,000 miles, so fat chance of getting reimbursed. WTF, it's just $25. So anyhow, if you ever run into this with your own car, it might be as simple as that: a $25 resistor panel might be blown. It's a cheap and easy first thing to check anyhow, and it's not as if they're (usually) expensive...

-- Badtux the Now-Warm Penguin

Tuesday, February 9, 2010

What the fuck is the matter with cars?

Toyotas that accelerate because they feel like it or won't brake because they don't feel like it. Hondas whose airbags deploy with the force of a stick of dynamite. This shit that just came out where all the Jap cars seem broken is just crazy. But you know what? I ain't surprised, because the Japs have gone for that electronic shit big-time -- electric steering, electric brakes, electric throttles, electric everything. And when electronics go wrong, they fucking GO WRONG, unlike old-school shit.

My Jeep is old-school. The cable from the throttle goes to an air flap at the throttle body. I open the throttle, the flap opens. I close the throttle, the flap closes. A throttle position sensor, a mass air sensor in the air intake and two oxygen sensors on the exhaust manifolds send signals to a small computer that adjusts how much fuel gets injected by the injector. If the computer goes out, my engine don't run -- it doesn't suddenly decide to go zooming across the freeway at nine bajillion miles per hour. Same deal with my brakes. The brake pedal attaches to a hydraulic plunger. The hydraulic plunger pushes brake fluid into brake lines and forces the brake pads towards the disk. There's actually two plungers attached to my brake pedal (one in front of the other, one for the front brakes and one for the back brakes) so that if one of the brake lines gets busted, there's still two wheels that have brakes and will stop me.

All these new cars, though, they don't have that kind of old school setup. What they have at the top end of the accelerator pedal is a sensor that tells the computer how much you've pushed down the throttle. Then a motor under the hood opens or closes the throttle flap appropriately to make the car go slower or faster in the most efficient way that the computer has calculated. So if the computer decides that this flap thingy needs to be all the way open even though you've let up on the gas pedal, well, it'll do it.

Same deal with the brakes on the Prius, the Toyota that's been having the problems with braking. The Prius cars that have been having stopping problems, they don't got that old-school piston shit. They got *electric* brakes. You push on the brake pedal, and it signals a computer to start reverse-charging your battery, using the electric motor in reverse as a generator and incidentally slowing the car down. You push even harder, and an electric pump starts squirting brake fluid into the lines until the car stops. If the electric pump decides it's tired and doesn't feel like pumping, or if the computer decides the electric pump doesn't need to pump, you're fucking *screwed*.

Now, I've thought about upgrading to one of those new-school Jeeps with the electric throttle and shit. They get better gas mileage and you can fit bigger tires to them without worrying about breaking shit, because their wheel wells are bigger and their axles are sturdier. But I tell ya, there's something to be said for old school. I can't think of a damned thing that'd make the throttle stick on my hoary old Jeep, and same deal with the brakes -- yeah, old-school master cylinders wear out over time, but they fucking *give you warning* that they're going out, the brake pedal starts going down closer to the floorboard and you might have to pump the brakes, and that's when you know it's time to put another master cylinder in. But that electronic shit... when it decides it ain't gonna work, it just don't fucking *work*. Which is a big-ass problem if you're talking about *stopping*.

What we have here, ladies and gents, is a case where the geeks who programmed these cars have forgotten what the wrenches knew years before the geeks finished kindergarten: cars ain't a place to experiment with shit that could kill people if it goes wrong. I'm stickin' with my old school Jeep. Yeah, it's crude and ugly as shit, but you can fix the goddamned thing with a big fucking hammer and a pair of pliers, and it don't decide it's going to go galumphing down the freeway at a bazillion miles per hour just because some goddamned computer geek forgot to carry a digit somewhere in his code. As someone who programs computers for a living, I'm happy as a clam that the only computer in my Jeep is the one that handles the fuel squirters and spark plug sparkers. If they quit squirting and sparking, all that happens is that the Jeep stops going. Which sure the fuck is preferable to what those goddamned Toyotas with their little electric-motor-controlled throttle thingies have been doing, yessiree.

-- Badtux the Old-school Penguin