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  #1  
Old 07-03-2019, 09:24 PM
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1985 CA 300D- Newly bought, need help big time

Hello everyone!
So my wife and I decided to get a little project car. I've got a lot of years as a DIY and friend's mechanic so I know my way around a gas engine. Diesel is a whole other story. I'm sure I'll be all over the place and I do have a lot of questions but I'll try to stay somewhat linear.

I'm on mobile so I can't upload images due to size requirements but I will post imgur links if that is allowed; I will delete them if need be.

We scooped up a 1985 California (still got the trap ox) 300D with 177,000 miles. It starts up immediately and runs well. The vacuum was a mess and I am peiceing it back together the best I can. (Didnt even shut off with the key, but i got that!) I've got the transmission shifting better (nothing was connected to the ALDA or the BFS as the elbows were rotted (blue flying saucer???)

So with that, I'll dive right in:

1. There is an inline electric fuel pump scotch-locked under the hood haha. As far as I can tell, there is no pump like that on this vehicle... What would make someone do this? Like what part may have failed? In the past, i have installed one on my old Toyota when my mechanical pump dropped a deuce. Picture link below.

300D https://imgur.com/gallery/MwMG2rI

2. When I inevitabley remove this, as well as replacing a return line that is swollen like all get out, is there a specific priming procedure that needs to be performed? ( this is my first diesel so please bare with me here)

3. I don't think I'm getting any boost pressure.. I believe I hooked the overboost protection valve properly. I want to test this out. Im having trouble understanding the valve.. isot normally open and when too much pressure is induced, does it close and send a signal?? Ive been reading thread after thread but i feel there is so much to do, I dont know where to start! Picture is below (that line that you see going to nothing appears to vent to the cabin so I guess that's nothing)

300D https://imgur.com/gallery/OR5sFQg

Guys, I know this was a book but any and all help you send my way is truly appreciated. My wife and I are excited and love this car and I wanna be able to make it safe and proper for her. Thanks so much!!

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  #2  
Old 07-04-2019, 03:18 PM
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Location: Mount Holly, NC
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Welcome to the forum!
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #3  
Old 07-04-2019, 03:24 PM
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First, open the banjo bolts holding the OBP line to the intake, and the ALDA (careful, here are small washers on both sides of the banjo, and the line is FRAGILE)
Spray brake or carb cleaner through the bolts, and the line, and he valve. Get it all clean.
See if the boost returns.
If not, loosen the nut on the ALDA, 1/4 turn at a time until you have good boost.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #4  
Old 07-04-2019, 04:07 PM
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Location: Alhambra California
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The fuel line that appears the be swollen may be in fact the cigar hose. They appear several open when new .
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  #5  
Old 07-04-2019, 06:19 PM
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1: Some people add an electric pump to help with a weak mechanical lift pump, or to help prime the system after a filter change. I'm in the camp that thinks its entirely unnecessary. If your mechanical lift pump works then it renders the electric pump redundant. It may be a band-aid for a failed hand primer pump, if it's the type with the white or screw down handle, it needs to be replaced with the modern Bosch type replacement, the old ones tend to leak and prevent priming or cause excessive air ingress. The electric pump may also be a band-aid for a weak spring in the overflow pressure valve on the backside of the injection pump.

2: Look for a part number stamped on that "swollen" hose. If one is present, it means it's the "cigar hose" and it's supposed to be swollen. The idea is to damp pulsations in the fuel lines, it's anybody's guess if it does anything noticeable. If you're working on the return side of the fuel system, you don't need to do any sort of priming. If you're working on the suction side or delivery side of the fuel system, you should pump the primer handle until you hear the overflow valve on the injection pump squeal.

3: The line from the manifold should come into the bottom of the overboost valve and the line going to the ALDA on the injection pump should be connected to the middle port on the overboost valve. The valve should be normally open in this configuration, you should be able to blow through it. The valve "switches over" the ALDA line at the middle port to the top port (atmospheric pressure) during an "overboost" condition. The banjo bolt on the manifold often soots up as does the overboost valve. You haven't mentioned if the turbo turns freely or not.

You should consider getting a bypass pipe for the trap oxidizer. It's likely full of soot by this point and killing your power. A forum member here (I think Rollguy) sells a bypass pipe for the '85 California models.

Diesels are deceptively simple, there's a lot more nuance to them than they appear. If you're an avid tinkerer, you'll quickly learn their moods and what's what, but that's the fun of it!
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  #6  
Old 07-04-2019, 07:03 PM
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Is this the converter that the long running federally mandated recall exists?

A worth while free bee as you can even get a new turbo if needed. Worth checking out. If a dealer refuses contact perhaps the classic center.

If this is the part I do not think there is an end point to that free repair as it is federally mandated rather than by Mercedes.
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  #7  
Old 07-04-2019, 10:19 PM
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I doubt that a car with 177,000 miles still has a trap oxidizer. It has probably been replaced with the trap catalyst which, on a W123, is identical to the trap oxidizer, and is supposed to be a lifetime part. As Diseasal suggested, however, it’s probably full of soot and replacing it with a bypass pipe would be a good idea if your state doesn’t have strict emissions inspections for old diesels.

Congratulations on your purchase and I hope you have fun working on the car. I’ve always found this forum to be very helpful and responsive.
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Christopher
'06 Mercedes E350 station wagon (silver/black)
'85 Mercedes 300D (black pearl/palomino)
'85 Mercedes 300SD (smoke silver/burgundy)
'79 Cadillac Sedan DeVille

'05 Toyota Camry (because always running is nice)

'85 Mercedes 300D sold back to orig. owner 8-1-06
'84 Volvo 264GL Diesel, owned 2000-2013
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  #8  
Old 07-04-2019, 10:47 PM
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Quote:
Originally Posted by Volvo Diesel View Post
I doubt that a car with 177,000 miles still has a trap oxidizer. It has probably been replaced with the trap catalyst which, on a W123, is identical to the trap oxidizer, and is supposed to be a lifetime part. As Diseasal suggested, however, it’s probably full of soot and replacing it with a bypass pipe would be a good idea if your state doesn’t have strict emissions inspections for old diesels.

Congratulations on your purchase and I hope you have fun working on the car. I’ve always found this forum to be very helpful and responsive.
Is there a way he can easily tell if Trap-Ox was replaced with the trap catalyst?
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Old 07-04-2019, 10:56 PM
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My cautions are going to be about the Rubber Parts.

Inspect the Oil Cooler Hoses. If they are seeping replace them. If someone has replaced them with hose and hose clamps deside if you want to replace them or re-hose them. There is threads on that.

People have lost Engines when the bought a used Mercedes and drove around without inspecting the Oil Cooler Hoses.

Look at the Drivers Side Motor Mount and see if the Power Steering Belt is getting close to one of the Oil Cooler Hoses as with a collapsed mount the Belt has been know to cut into the Hose.

The Drive Shaft has rubber Flex Discs one on each end. Look at them carefully for cracking. If the one on the Transmission end comes a part it has been known to tear the tail off of the transmission.

Tire Tilt Tire wear due to more rubber parts rotting out.
Sagging upper control arm bushings will cause the camber to become negative, resulting in inner edge tire wear.
Barring some catastrophic failure due to rust, the most common cause of the front wheel tilting inward at the top is failure of the upper control arm's inner bushing, where it's bolted to the inner fender.
Rotted out Lower Control Arm Bushings will cause outer edge Tire Wear and unless they are extremely bad you cannot see the Bushings are no good.

Repair Links
Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

Former owners seldom adjust the valves if it was something they could not do themselves. In use the valve clearances get tighter.
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Old 07-04-2019, 11:23 PM
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Cracked Flex Disc pics. The 2 with the drawing on they were mine. The really bad one is pic from another member.

The on the Transmission end is hard to inspect because it is hard to see it. You may have to remove some stuff to see it.

Good idea to look at the drive shaft support also.
Attached Thumbnails
1985 CA 300D- Newly bought, need help big time-my-cracked-flex-disc-1.jpg   1985 CA 300D- Newly bought, need help big time-my-cracked-flex-disc-2.jpg   1985 CA 300D- Newly bought, need help big time-my-cracked-flex-disc-3.jpg  
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  #11  
Old 07-04-2019, 11:30 PM
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Quote:
Originally Posted by Diesel911 View Post
Is there a way he can easily tell if Trap-Ox was replaced with the trap catalyst?
It’s always been my understanding that you can go to a dealership with the VIN and they will tell you. I got a letter from MB sometime in 1996 telling me to bring the car in because they had developed a replacement for the trap oxidizer called a trap catalyst that did not need periodic replacement.
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Christopher
'06 Mercedes E350 station wagon (silver/black)
'85 Mercedes 300D (black pearl/palomino)
'85 Mercedes 300SD (smoke silver/burgundy)
'79 Cadillac Sedan DeVille

'05 Toyota Camry (because always running is nice)

'85 Mercedes 300D sold back to orig. owner 8-1-06
'84 Volvo 264GL Diesel, owned 2000-2013
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Old 07-04-2019, 11:43 PM
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Vacuum Diagram from one of our members.
Attached Thumbnails
1985 CA 300D- Newly bought, need help big time-vacuum-diagram-85-300d-cali.jpg  
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  #13  
Old 07-05-2019, 02:51 PM
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Quote:
Originally Posted by Volvo Diesel View Post
It’s always been my understanding that you can go to a dealership with the VIN and they will tell you. I got a letter from MB sometime in 1996 telling me to bring the car in because they had developed a replacement for the trap oxidizer called a trap catalyst that did not need periodic replacement.


"Is there a way he can easily tell if Trap-Ox was replaced with the trap catalyst?"


So was there enough visual difference that someone looking at it could tell if it had been replaced?
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  #14  
Old 07-05-2019, 05:18 PM
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Quote:
Originally Posted by Diesel911 View Post
So was there enough visual difference that someone looking at it could tell if it had been replaced?
No. It looks the same. There is a part number on the side of it. Perhaps you could tell that way. Don’t really know, however, why you’d need to try if you can just call a dealership and find out...
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Christopher
'06 Mercedes E350 station wagon (silver/black)
'85 Mercedes 300D (black pearl/palomino)
'85 Mercedes 300SD (smoke silver/burgundy)
'79 Cadillac Sedan DeVille

'05 Toyota Camry (because always running is nice)

'85 Mercedes 300D sold back to orig. owner 8-1-06
'84 Volvo 264GL Diesel, owned 2000-2013
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  #15  
Old 07-05-2019, 06:57 PM
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Since you are new to these cars. Some of the aftermarket parts are not very good. Postings on this site can identify the poorest brands.

URO is about the worse brand currently I think.

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