GregMN's 1991 W126 350SDL Has A New Home - Page 5 - PeachParts Mercedes-Benz Forum

Squiggle Dog · #61 09-30-2018, 12:12 PM

Quote:

Originally Posted by Mike D

It's too late now but for future repairs take a look at Diseasel300's replacement sliders. He had some made up but he might be sold out now. He was talking about making some more.

The "Diseasel" - '86 300SDL

Another way to go which eases replacement. Thanks, Warren!

W126 rear window won't go up

Both of these repairs have the added advantage of not having to remove the regulator assembly if future replacement is required.

I saw those replacement sliders. They look clever. The clevis pin idea is smart, too. My roommate bought a pack of four of the stock sliders a while back, so I guess I have to use those ones up.

But, if this same left rear window slider breaks again, then it warrants heavier duty sliders. I can see why it broke the last two times, because the window was very hard to slide due to the tracks being too close together, but if it happens again, then obviously the stock sliders are just not up to the task. It seems that the newer the car, the more ridiculous it is in design.

vwnate1 · #62 09-30-2018, 12:15 PM

Often the vertical tracks are the problem, you've adjusted them so the window slides easier by hand, that's (IMO) the #1 thing .

Most other cars don't have the ability to adjust the tracks .

Squiggle Dog · #63 09-30-2018, 12:31 PM

Quote:

Originally Posted by vwnate1

? Is this a replacement part from where and what P/N please ? .

I'm amazed that Dorman, Champ items Et. Al. don't make a simple kit for this, they used to specialize in this sort of thing .

The ones my roommate got were part number 126 720 01 42, unknown aftermarket brand, purchased in a set of four on eBay.

Squiggle Dog · #64 09-30-2018, 01:25 PM

One of the rubber buffers that secures an air conditioning line to the side of the radiator core support has been broken for a while, and I got a new one in.

It was very difficult to install the new one. I had to remove the clamp securing the hard line to the condenser and had to bend the hard line away and pry and push the new buffer into place.

One of the rear license plate lights hasn't worked since we got the car, so I jumped it with a wire from the other side so it would come on. The high beam indicator has been stuck on for a while, and the high beams don't work. Replacing the combination switch didn't fix it.

I wasn't sure what to do until I read about something called a light module control unit. Apparently all the exterior light wiring on the car passes through it so the driver can be notified if a light bulb burns out. As nice as that sounds, it means that it makes the car much less reliable and as the solder connections deteriorate from engine heat, it can cause problems with lights.

The light control unit can be taken apart for inspection by sliding credit cards in each side and then prying on each end with a very thin flat blade screwdriver.

Wow, look how complicated this part is. No wonder it can fail and cause problems with the lights. This is over-engineering in my opinion. I didn't see anything obviously wrong with regards to soldered joints, but I did see a problem. One of the flat pieces of metal had melted like a fuse.

My roommate ordered a used light control unit on eBay, so we'll see if it fixes the problem. What's interesting is that after I put this one back together, reinstalled it, and turned on the lights, the high beam indicator light was no longer stuck on, and the high beams worked again. Strange. Simply removing and then reinstalling the control unit seemed to fix the high beams.

The power steering isn't working at low speed, so maybe the steering box needs to be rebuilt. I already rebuilt the tandem power steering pump and installed new hoses.

The ASD light on the instrument panel has been on for a while, so I will have to run a diagnostic. I know it needs the accumulator sphere replaced as I can hear it hissing every few seconds and the hose going back to the differential keeps slapping against the oil pan.

Despite all the problems with the car, we're grateful to have acquired it for my roommate. It's just illustrates the saying, "There is nothing as expensive as a cheap Mercedes." In this case, the car was free, so it holds even truer. Eventually it will have so many new parts on it that it will be almost like having a new car.

vwnate1 · #65 09-30-2018, 01:52 PM

"Keep brotherhood until die"

.

Diseasel300 · #66 09-30-2018, 03:04 PM

Quote:

Originally Posted by vwnate1

Often the vertical tracks are the problem, you've adjusted them so the window slides easier by hand, that's (IMO) the #1 thing .

Most other cars don't have the ability to adjust the tracks .

The biggest issue is the fact that they used the standard SWB mechanism in the LWB car. The window is longer, heavier, and easier to skew in the tracks. Couple that with a poor design that has the entire weight of the window resting on a (somewhat) flexible arm that has to both rotate AND slide while moving and it's a recipe for disaster. The SWB cars have failures far less often than the LWB cars do but it's still a sorry design. The OEM slides are relatively fragile and will fracture the first time they bind or chatter in their slide. From there it's a matter of time before it breaks and leaves your window stuck down.

Squiggle Dog · #67 09-30-2018, 07:59 PM

Today I tried swapping the connectors for the washer motors, and it solved the problem. Now the windshield washer works without the lights on, and when the lights are turned on, then the headlight washer works. Yay!

Here are some current pictures of the car.

Squiggle Dog · #68 09-30-2018, 08:04 PM

Here's the engine compartment as it looks now.

This is what the turbo looks like, if it helps any to tell what type it is.

Diseasel300 · #69 09-30-2018, 08:20 PM

That "thing" on the turbo looks like an air recirculation valve. Is your turbo a Garrett or a KKK? I don't see the boost actuator is why I ask. The 126FSM shows the ARV for 1987+ vehicles but doesn't show a vacuum wastegate. Mine's an '86 Federal with the Garrett turbo, so no emissions equipment and not a good comparison.

Squiggle Dog · #70 09-30-2018, 09:26 PM

Quote:

Originally Posted by Diseasel300

That "thing" on the turbo looks like an air recirculation valve. Is your turbo a Garrett or a KKK? I don't see the boost actuator is why I ask. The 126FSM shows the ARV for 1987+ vehicles but doesn't show a vacuum wastegate. Mine's an '86 Federal with the Garrett turbo, so no emissions equipment and not a good comparison.

I don't know. I can't even see the turbo much at all, but it looks different than the Garrett T3 that's on my car.

vwnate1 · #71 10-01-2018, 09:43 AM

I can't see the wastegate either so crowded in there but I'm betting that's your power problem .

You alls keep saying "vacuum" when talking about the wastegate, it works off _PRESSURE_, completely different .

? Have you yet tried a small, cheapo boost gauge to see what the actual boost levels and RPM's are ? .

I bought a 1" 'Mr Gasket' (cheapo Chinese brand) $20 fuel pressure gauge for boost testing my my grey market 300TD, it only goes to 15# so it's very sensitive, easy to connect using simple vacuum hose and a plastic 'T' , it would let you know what's going on in your engine boost wise right away ....

I'm trying to remember what FLAPS I bought the gauge at, prolly an O'Rielly as they're my go to place for cheaper filters and basics .

Diseasel300 · #72 10-01-2018, 09:50 AM

Quote:

Originally Posted by vwnate1

You alls keep saying "vacuum" when talking about the wastegate, it works off _PRESSURE_, completely different .

In a normal world, yes. In the 90s German car world, no. At some point in the early 90s, they migrated to a VACUUM operated wastegate actuator that's controlled by the ECU instead of the pressure operated wastegate that is passively operated off the intake manifold pressure. The 124's got it for sure, the 140's had it, but not sure if it was ever fitted to the 126 (hopefully not).

The ARV should be disabled when vacuum is not applied to it, but it could possibly be stuck partially open. If so, boost is bleeding off back into the atmospheric side of the compressor housing, more or less defeating the purpose of the turbo. Checking boost pressure will tell you a lot real fast. Put a T on the ALDA sense line and tie in a pressure gauge and go for a ride.

vwnate1 · #73 10-01-2018, 09:55 AM

Thank you ! .

As I said I work on the older MB's .

Why/how is vacuum possibly used to measure and correct too much boost ? .

jay_bob · #74 10-01-2018, 01:50 PM

I thought the US market W124 and S124 (1987 only) were fitted with a 6 cyl OM603 up until 1989. From 1990-1994 they got the 5 cyl OM602 and were badged 300D-2.5.
In 1995 they got the N/A OM606 engine that was then used in the W210.

From what I have learned the OM603s had the EDS but it only worked on the ARF valve on the turbo. The wastegate was pressure operated. They had a pressure switch in the manifold that opened a switchover valve in the manifold to ALDA line that dumped the boost if it became excessive.

Starting in 1990 with the 2.5 liter/5 cylinder OM602 they expanded the electronic controls by adding a MAP sensor and vacuum operated wastegate.

So chances are if the OP has a transplanted engine from a W124 it is likely from an 87 to 89 model with the pressure operated wastegate. If the person doing the swap was diligent they would have brought over the EDS computer from the W124 donor along with all the associated control hardware.

Squiggle Dog · #75 10-01-2018, 02:16 PM

I have a boost gauge, but I remember looking for a spot on the manifold to hook it up (years ago?) and couldn't find one, so I started working on something else--and here we are. I just have to find where I can attach the boost gauge and go from there.