Early vs. Late W126 models

I like to get my information first-hand since I’ve seen some impressively glaring omissions (or worse) in supposed-to-be-reliable sources. Not that I totally ignore that; I reconcile all my sources and try to make sense of it all.

I’ve been trying to get a handle on when the W126 range split. My 1984 W126 4-door is significantly different (as to a great many little things) from my 1989 W126 4-door, and I’ve been trying to find the exact cut-off when the “significantly revised” range was introduced.

At this point, my conclusions match what Wikipedia implies: the 1986 model year was the first of the revised models.

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Door Window Lift Issues: Front Window

On my 1991 300SE, I can make the driver side front window slide up or down by putting my palms on either side of the glass and pushing up or down. Not that I need to do much pushing down … gravity does that gradually, as I drive.

Today, I analyzed a parts donor car, so as to learn more about likely causes of the problem, and how to get access to the relevant parts.

The first step was to open the door. No problem there.

I removed the seat control switches. I pulled the little black plastic miniature-seat pieces away from the door to remove them. Then, I pried away the plastic cover just below that. One side has three fairly flexible tabs, and the other side has one large tab. I broke one of the tabs on one side.  With the cover out of the way, two small yellow Phillips screws become visible, and with them removed, the switch base could be accessed and removed. I also pulled the wiring plug away from each switch.

I removed the door handle. With the window switch base out of the way, a large yellow Phillips screw becomes visible. I removed that, and two similar screws in recesses in the door handle. With the three screws removed, the door handle can be lifted free.

I removed the door lock knob, by turning it counter-clockwise and then lifting it away.

I pulled the door trim away from the metal of the door; I own a tool for that but I hadn’t brought it along. Girl arm muscles worked well enough, as did digging in my nails around the edges to pry the panel away.

I removed several (non-identical) 10mm bolts and one or two 10mm nutes, and the window winder mechanism came loose. I chased its wires. Two of them can be loosened by removing two Phillips screws, but there’s another three-wire harness for which I couldn’t find an easy disconnect point, so I cut the wires.

I could maneuver the mechanism downward but not free of the two metal guides at the bottom of the window glass, until I removed a 10mm bolt that was clamping the mechanism to the guide.

I’m not sure that I needed to get the window out, or remove parts in order to get the window out, but I did anyway.

The two vertical guides for the glass are non-detachable as far as I can tell.

 

Door Window Lift Issues: Rear Window

On my 1991 300SE, I can make any either of the rear windows slide up or down by putting my palms on either side of the glass and pushing up or down. Not that I need to do much pushing down … gravity does that gradually, as I drive.

Today, I analyzed a parts donor car, so as to learn more about likely causes of the problem, and how to get access to the relevant parts.

The first step was to open the door. No problem there.

I removed the door switches. The donor car was a 560 SE or SEL, so the door switches have more features than on my humble 300SE, which doesn’t offer heated or adjustable rear seats.  Even so, I pried the switch surround off with a flat screwdriver. One side has three fairly flexible tabs, and the other side has one large tab. I broke one tab on each side.  With the switch surround out of the way, the switches could be accessed and removed, by pressing their catches inward with a flat screwdriver, and pulling the wiring plug away from each switch. I bought the two window switches; I plan to see if they’re the same as in the center console. If so, they’re probably less-worn.

I removed the door handle. With the window switches out of the way, a large yellow Phillips screw becomes visible. I removed that, and two similar screws in recesses in the door handle. With the three screws removed, the door handle can be lifted free.

I removed the door lock knob, by turning it counter-clockwise and then lifting it away.

I pulled the door trim away from the metal of the door; I own a tool for that but I hadn’t brought it along. Girl arm muscles worked well enough, as did digging in my nails around the edges to pry the panel away.

I removed several (non-identical) 10mm bolts and one or two 10mm nutes, and the window winder mechanism came loose. I chased its wires but couldn’t find an easy disconnect point, so I cut the wires.

I could maneuver the mechanism downward and then free of the single metal guide at the bottom of the window glass.

I’m not sure that I needed to get the window out, or remove parts in order to get the window out, but I did anyway.

I used a flat screwdriver to lift the flat, black horizontal door weatherstripping rubber that runs alongside the bottom of the door-and-window opening, on the inside of the car.

I used a flat screwdriver to lift the chromed horizontal door weatherstripping rubber that runs alongside the bottom of the door-and-window opening, on the outside of the car.

I pulled the window rubber surrounding the glass out of the car.

The rear window glass has two pieces: a rectangular piece and a somewhat triangular piece, to the rear of that. Separating them is a vertical metal pillar, part of which is painted body color. With the door rubber removed, a small Phillips screw is visible at the top of the pillar.  After that screw has been removed, the pillar can be maneuvered free and out.

 

 

 

Easy Access to Fuel Level Sending Unit

I recently bought a 1989 300SE that had been sitting for long enough that the fuel tank was all gunked up. I removed the tank, washed it out with some impressive solvent, then paid someone a few bucks to pressure-wash it inside. Back into the car it went, and it’s now living happily there, and the car starts and runs.

However, in the process of taking the tank out and putting it in, I damaged the fuel level sending unit at the top of the tank.  It’s still out of the car. Today, I know exactly how much fuel is in the tank because I personally poured in a couple of gallons, but once I start driving the car, it’d be nice to be able to rely on the fuel gauge.  Besides, a big, gaping hole atop the fuel tank probably will make anything in the trunk (and maybe the cabin too) smell like fuel.

Now that the car starts, I’m focusing on the sending unit. I spent some time on a donor car today, trying to get a sending unit removed. I failed as to the sending unit itself, because I needed to rotate the entire unit, and for that I needed either an adjustable wrench or a massive socket (more than 40mm, I’m guessing) or a huge wrench — none of which I’d brought along.

However, I learned a lot, and I did get the wiring, which is part of the problem; I’d crushed the black plug at the top.

I’d feared that I’d have to remove the entire fuel tank to work on the sending unit, but, today I learned that I don’t have to do so. After I remove the rear seat back, I can see a shallow, black, plastic plug, and when that’s been pried up and removed, the top of the sending unit is easily accessible.

I love how logically these cars are designed!

Kickdown Once, Fine — but not Twice

Today I was cruising at (very approximately) 65 mph and 3500 rpm in top gear in my 1991 300SE. I decided to stomp on the accelerator, and the transmission downshifted and the rpm went up to 5000 or more, good. Zoom, off we went, fast — but I kept the pedal on the floor and then the transmission downshifted again … NOT good.

I saw the rpm needle swing high, way deep into the red-line; if not to 7000 rpm then darn close to it. The engine was surging too; presumably trying to limit the engine speed by doing so.

I backed off and drove normally, listening for obvious sounds of engine damage. It all sounded normal.

After a while, I tried the downshift again, but this time I used the shift lever. Starting today, that has become my preferred way of downshifting.

I’m worried about engine damage. I plan to do a compression test soon, to check.

Door Window Lift Issues: The Competition

Two of the three windows on my 1991 300SE no longer open or close electrically, and I can make any one of these windows slide up or down by putting my palms on either side of the glass and pushing up or down. Not that I need to do much pushing down … gravity does that gradually, as I drive. I haven’t found out how to get a window up if it’s ever all the way down. I might not like the answer.

I’m getting pretty tired of the hassle. Also, drive-through ordering is a pain due to a window that I can’t open while I’m sitting in the car.

So, today, I went to an auto glass shop whose owners I like and trust, and whose prices are typically low. Their price: $150 per fix per door, $450 total. Whoa! That would be with new parts; they don’t have any used parts on hand. Wow! Good thing I’m in the used-parts business.

So one more item on my task list is to immerse myself into the world of W126 window winders….

Trunk Lid Badge Removal

I have mangled many W126 trunk lid badges while trying to gently remove them from cars at junkyards. I finally gave up on it and I delegated the work to my competent assistant. She worked a serrated bread knife gently underneath the chromed plastic, and gently carved and leveraged the badge from the trunk lid. Success!

Soon my 560 SEC will not longer have a badge with the “C” broken off so that it reads “560 SE.” Better …

Gasoline Shower, Best Avoided

When you remove the fuel pumps from a 560 SEC, you have the opportunity to have a gasoline shower, with the fuel running down your arm and thoroughly soaking you, clothing and all.  I don’t recommend you pursue this particular style of self-destruction.

IMAG8728The alternative I choose is to jack up the passenger side rear wheel, way high, and to place an axle stand under the suspension component close to the wheel.  Then, I place a container underneath the fuel pumps, and then slightly loosen a connection so that the fuel drips into the container, thus emptying the tank.  That way, I don’t have to deal with as much of a gasoline mess, when you take the pumps out. There will still be some gasoline and pressure, but it’ll be a better situation than if the tank contained a large amount of gasoline.

I suspect that I could also have used the drain plug at the bottom of the tank, but draining it at the hose I’m supposed to work with tends to make that critical area better-drained.

Gasoline and static electricity tend to make for a big fire. And, gasoline being drained does, according to one story I’ve read, build up a static charge that can trigger a static spark that can burn down a building.  So, I ground the car with a steel cable from the negative battery post to the floor.

No-Start True Story About Dead Fuel Pump

I recently bought a lovely 1988 Mercedes-Benz 560 SEC from a nice gentleman. The car had been sitting for years. The fuel distributor was so gunked-up that when I jabbed at the air flow plate with my finger, the plate stayed in whatever position I left it at. It’s supposed to bounce back.

Even with fuel in the tank, and a good battery, and compression, and spark, the car wouldn’t start, even though it cranked over nicely.

I wanted to rule out the fuel distributor. I could hypothetically remove it and soak it in solvent, but instead I got another unit from another 560 SEC, and I cleaned that and installed it.

IMAG8604

Still … no start. These cars are relatively simple as to fuel delivery. The “E” in Bosch KE Jetronic means that the fuel distributor optimizes the mix based on electrical input, but even without that, it basically works — mechanically, and for that it needs fuel pressure. To be precise: it needs A LOT of fuel pressure. It expects the fuel pumps to deliver more than 84 psi, and then a regulator right by the fuel distributor limits that to 84 psi. That’s very high, about double what a BMW of the same era would run, as fuel pressure.

To generate that much pressure, the car uses two fuel pumps, in series. When I cranked the motor, both fuel pumps got power, and there was the sort of hissing sound you’d expect from a functioning-fuel-pump situation. Still, no start. So, I suspected one of the fuel pumps was bad.

I removed the cradle in which the fuel pumps are housed, and tested each one individually. Sure enough … one was bad. That explains the no-start situation. We replaced the bad pump with a good used pump, and did a pressure test. Together, the pumps put out more than 84 psi. Yay! So, now they are ready to go back into the car — and now I suspect it will start.

I want Empathy when I Buy Parts, Dammit

New-parts counter guys for exotic cars have a rough life. I can guess why. Day after day, he deals with the following two sorts of dialog, many times a day:

“Hey, I’m looking for a fuel distributor for a 1986 560 SEC.”
“What’s the VIN?”
“I don’t know. I don’t have it with me. I’m at work. The car’s at home.”
“I need the VIN to look up the parts.”
“Seriously?”
“Yes.”
“Well, I don’t have it.”
… and it doesn’t get better after that.

Assuming the person does have the VIN, the next conversation goes something like this:

“How much for the fuel distributor?”
“$714.34.”
“Say, what?”
“$714.34.”
“For the fuel distributor?!”
“Yes.”
“Wow! The entire car cost me maybe $3K and that had a working fuel distributor. That’s crazy.”
… and it doesn’t get better after that.

Aftermarket prices are often better, and sometimes not by much. Sometimes, when I heard the price, I thought “Forget that,” or some less-polite variant.

Seems to me that whoever comes up with these prices has no idea of the basic viability of someone who’s not made of money, trying to keep their 126 Series car. There seems to be a basic disconnect when the parts prices are so high that a customer reacts with incredulity. Basically, the vendor and the customer don’t relate to each other. They’re are not on the same page. There’s no empathy.

* * *

New Mercedes-Benz parts prices can suck, but there’s a parallel to that: software.

How often have you used software that sucks, because regardless of how technically cool it might be, it sucks for you because it doesn’t work for you? Whoever made it didn’t empathize. As to whatever your situation was, they didn’t “get it.”

There is a better way. In the software industry, it’s called “Eat your own dog food.” Wikipedia defines it as: Eating your own dog food, also called dogfooding, is a slang term used to reference a scenario in which a company (usually, a computer software company) uses its own product to demonstrate the quality and capabilities of the product.”

It’s a great idea.

That might be the best reason to buy your used parts from my little company. What’s in it for you? You’re understood. That’s it. We also drive old 126 series cars and we’re trying to keep them going, with a tight budget. We empathize.

For a while, I’ve driven a 1986 560 SEC whose engine was leaking coolant. And, I survived. I didn’t have money for the “new parts” solution. I just kept pouring in coolant, before every trip.

My little used parts business is not the world’s smartest when it comes to 126 series cars. We haven’t been in business the longest. We don’t have massive depths of technical insight. We don’t have a huge inventory. We often mis-estimate the time it’ll take to get a part into inventory.

But, dammit, we relate. We have our own little sad fleet of several floundering old 126 series cars, and we struggle to keep them going on a tight budget that includes wondering how we’re gonna pay the rent this month. We get personally stranded when a main fuel pump dies, and we have to walk home and figure out what’s wrong, how to remove the bad part without causing a fire, and how to replace it without paying three figures.

This struggle makes us relate to customers who struggle, just like us.

We need to buy food, pay the rent and somehow keep viable, as transportation, an almost-30-year old car that most people have given up on, long ago.

We tenaciously refuse to let these cars die. We make plans, we find money, and we pull through — so that we can keep driving these magnificent pieces of engineering, even if the dash lights don’t work and the heater fan is broken. At some point the way we’d start one the company 560 SEC cars was to hot-wire the fuel pump. But, dammit, we kept it going until we could figure out a better way. We’re still in the game. We’re fighting and if driving the car one more day is victory, then we’re winning.

If you like that mindset, buy your stuff from 126seriesparts.com because you’re dealing with someone who “gets” you.