W115 240D - Covid project





Page 1 of 5 1 2 3 4 5 LastLast
Results 1 to 20 of 82
  1. #1
    Join Date
    Mar 2015
    Location
    Pretoria
    Age
    49
    Posts
    658
    Thanked: 291

    Default W115 240D - Covid project

    My son and I started some work on a 1974 W115 Mercedes 240D. The car hasn't run for a couple of years but it was driven on a regular basis before putting it in storage. It has been in my family for more than 40 years and has more sentimental value than monetary value.

    We try to spend at least 2 hours per day on the project.

    Yesterday it was the fuel system's turn for some much needed tlc. We drained the tank and added around 10 litres of fuel. We also drained all the old diesel from the fuel filter housing and replaced the diesel filter.

    Now the problem. The priming pump seems to be leaking air past it's seal and is not pumping any diesel. With the lockdown I won't be able to get a new one any time soon but I would like to get the car mobile as soon as possible.

    Any tips on getting the fuel lines primed without the priming pump?

    As per advice from contributors on this thread.

    1. OEM oil filter from Mercedes
    2. Upgrade glow plugs
    3. Replace tank filter with in line filter
    4. Lift pump service kit
    5. Replace prime pump - Monark as option
    Last edited by Tom13; 2020/04/01 at 01:18 PM.
    Mitsubishi Pajero 3.2 D-ID GLX LWB

  2. #2
    Join Date
    Nov 2012
    Location
    Kuruman
    Age
    52
    Posts
    59
    Thanked: 17

    Default Re: W115 240D - Covid project

    Put some diesel in an elevated container and flood fed the system.
    If you can do it from the suction pipe on the tank. If you dont have leaks.
    Bleed and start. You have to comprise in these times.
    Enjoy

  3. The Following User Says Thank You to Bere For This Useful Post:


  4. #3
    Join Date
    Jan 2013
    Location
    Friemersheim, Southern Cape
    Posts
    4,286
    Thanked: 3124

    Default Re: W115 240D - Covid project

    Quote Originally Posted by Bere View Post
    Put some diesel in an elevated container and flood fed the system.
    If you can do it from the suction pipe on the tank. If you dont have leaks.
    Bleed and start. You have to comprise in these times.
    Enjoy
    I did this when I fixed up my Rocky.
    Pipe straight onto inlet of diesel filter housing
    Attached Images Attached Images  
    1998 Daihatsu Rocky 'The Kitty'
    2002 Daihatsu Rocky 'The Bully'

    "Socialism only works in two places: Heaven where they don't need it and hell where they already have it." -Ronald Reagan.

  5. #4
    Join Date
    Mar 2008
    Location
    De Wildt
    Age
    57
    Posts
    37,466
    Thanked: 13640

    Default Re: W115 240D - Covid project

    See if you can strip the priming pump, they usually have a rubber diaphragm inside. Bike tube is a good replacement.
    2012 Jeep Sahara Unlimited 3.6 V6
    Percivamus

  6. #5
    Join Date
    Sep 2006
    Location
    Cape Town, Plumstead/The Sea/Franskraal
    Age
    53
    Posts
    2,445
    Thanked: 556

    Default Re: W115 240D - Covid project

    Superb project!!

    Nope, with out that pump you will never prime it. The pump is a fairly high pressure affair so unless you can get pressure to the injector pump, it wont run.

    The primer pump is a bad description, because besides being a primer pump, it is also the main delivery pump.

    It has 2 parts, inlet and outlet(DUH Obviously) Im not sure what you call this pump, alternating, or something like that, one part shuts and then pressures the other side, pressure drops on outlet and inlet opens, outlet closes, fills, inlet closes and outlet opens. wash rinse repeat!! Happens many many times per second so.... you get a hell of a fuel delivery, and plenty of pressure, plenty!! It runs off the cam in the injector pump.

    There is a nut on the top and a BIG nut on the bottom, underneath there is a diaphragm the size of a 50c piece, or just a bit smaller. these may be weak or broken, A replacement at MB is about R150. You give the VIN number and then say primer pump kit. It is the same kit used on VERY current models so they should be in stock. Once you have it in, you will be astonished by the improvement.

    I would suggest you remove the pump to do this. Taking the pump off is fiddly, 3 nuts on studs, just be patient, you can do it, I did it and have fairly big hands. Cutting a spanner helps. Just crack the nut and then it should come off by hand, do the bottom nut first, then the one closest to the boot and then the front, easiest to get to and the spring pushes it outwards, so bottom and back off, means pressure only on the front one, which is the easiest to get to. Replace the gasket as well with gasket paper and sealant. Have a catch dish for the oil that will run out of the injector pump. This gasket often leaks so a good time to replace the gasket.

    Any questions... ask away
    Mercedes W123 300D, runs on Mother Natures Goodness.
    Powered by the Sun, the Rain and the Earth.
    Have now covered 270 000Km on veg oil.
    Oh, and an Isuzu 280DT, 40 000Km on Bio Diesel
    Rand for Rand gets 33Km/L

  7. The Following 2 Users Say Thank You to ZuluCowboy For This Useful Post:


  8. #6
    Join Date
    Sep 2006
    Location
    Robertson/ Larissa, Greece
    Age
    56
    Posts
    5,443
    Thanked: 3324

    Default Re: W115 240D - Covid project

    Quote Originally Posted by ZuluCowboy View Post
    The primer pump is a bad description, because besides being a primer pump, it is also the main delivery pump.
    Lift pump
    We can't change the wind but we can set our sails

  9. #7
    Join Date
    Mar 2008
    Location
    De Wildt
    Age
    57
    Posts
    37,466
    Thanked: 13640

    Default Re: W115 240D - Covid project

    OK so this is the priming pump on the distribution pump? Then ignore my post. Bigger and more difficult kettle of fish as ZuluCowboy has explained.
    2012 Jeep Sahara Unlimited 3.6 V6
    Percivamus

  10. #8
    Join Date
    Sep 2006
    Location
    Cape Town, Plumstead/The Sea/Franskraal
    Age
    53
    Posts
    2,445
    Thanked: 556

    Default Re: W115 240D - Covid project

    Quote Originally Posted by jelo View Post
    OK so this is the priming pump on the distribution pump? Then ignore my post. Bigger and more difficult kettle of fish as ZuluCowboy has explained.
    Yes, the little one that is on the side of the injector pump. it's a serious little piece of kit, and flipping expensive to replace!
    Mercedes W123 300D, runs on Mother Natures Goodness.
    Powered by the Sun, the Rain and the Earth.
    Have now covered 270 000Km on veg oil.
    Oh, and an Isuzu 280DT, 40 000Km on Bio Diesel
    Rand for Rand gets 33Km/L

  11. #9
    Join Date
    Mar 2015
    Location
    Pretoria
    Age
    49
    Posts
    658
    Thanked: 291

    Default Re: W115 240D - Covid project

    Thanks for the replies Bere, Prof, ZuluCowboy and Jelo.

    If the lift pump (high pressure) is okay but the hand priming pump (low pressure) is shot, will it help to fill the filter housing manually with diesel? This filter housing sits much higher than the dieselpump (as suggested by Prof and Bere).

    My thinking is that if there is enough diesel in the housing to keep the engine running long enough, won't the lift pump have enough time to prime the fuel line from the tank to the filter?
    Mitsubishi Pajero 3.2 D-ID GLX LWB

  12. #10
    Join Date
    Mar 2008
    Location
    De Wildt
    Age
    57
    Posts
    37,466
    Thanked: 13640

    Default Re: W115 240D - Covid project

    Quote Originally Posted by Tom13 View Post
    Thanks for the replies Bere, Prof, ZuluCowboy and Jelo.

    If the lift pump (high pressure) is okay but the hand priming pump (low pressure) is shot, will it help to fill the filter housing manually with diesel? This filter housing sits much higher than the dieselpump (as suggested by Prof and Bere).

    My thinking is that if there is enough diesel in the housing to keep the engine running long enough, won't the lift pump have enough time to prime the fuel line from the tank to the filter?
    use a gravity feed as per Prof's pic
    2012 Jeep Sahara Unlimited 3.6 V6
    Percivamus

  13. #11
    Join Date
    Sep 2006
    Location
    Cape Town, Plumstead/The Sea/Franskraal
    Age
    53
    Posts
    2,445
    Thanked: 556

    Default Re: W115 240D - Covid project

    Quote Originally Posted by jelo View Post
    use a gravity feed as per Prof's pic
    If you have diesel in the line, it may work.

    There is only one pump, lift pump. Its is mechanical high pressure. (note, not high in the normal sense) and high delivery. At the back of the injector pump, between the injector pump and the engine, is the return line, it has a ball and spring valve, if that valve isn't getting forced open, you don't have enough pressure and volume inside the injector pump. If you have air in the injector pump, it can be hard to get out, I have found towing is the easiest. Remember the fuel doesn't lubricate the injector pump, the engine's oil system lubricates the pump.

    What will work, is.... and this is a bit Mad Max.... somehow do as in the pic, but close the bonnet onto the first click, put the outlet directly into the injector pump and tow the car till it starts, if it is manual. Auto is more difficult but can be done. Swinging the car will cause a hell of a lot of stress on the starter, and that's another kettle of fish to fix. doable, but rather don't stress it.

    The lift pump may work once the car is running but starting may be a problem due to it not delivering enough fuel to open the delivery valves on the top of the injector pump, and then not pushing enough fuel up the steel injector lines. But, once running, it will.
    Mercedes W123 300D, runs on Mother Natures Goodness.
    Powered by the Sun, the Rain and the Earth.
    Have now covered 270 000Km on veg oil.
    Oh, and an Isuzu 280DT, 40 000Km on Bio Diesel
    Rand for Rand gets 33Km/L

  14. #12
    Join Date
    Mar 2015
    Location
    Pretoria
    Age
    49
    Posts
    658
    Thanked: 291

    Default Re: W115 240D - Covid project

    Thanks for the feedback. I will try a couple of the suggestions this afternoon and report back.
    Mitsubishi Pajero 3.2 D-ID GLX LWB

  15. #13
    Join Date
    Sep 2006
    Location
    Cape Town, Plumstead/The Sea/Franskraal
    Age
    53
    Posts
    2,445
    Thanked: 556

    Default Re: W115 240D - Covid project

    Another thing, glow plugs, they are long lasting, but are not great, it took MB 20 years to sort this out. This motor WILL not start if the glow plugs don't work.(WD40, Doom, Quick Start aside)

    The later model engines had the glowplugs replaced with pencil type, Early 123 models still had the type that you have and i believe this was the death of the engine. As compression dropped, these engines were scrapped, when all that was needed was better glowplugs.

    The later models had a glowplug with a single wire to each plug, operated by a relay behind the left headlight. 12mm spanner to remove with an 8mm net to keep the wire in place.

    Earlier models had 1.5 volt BIG glow plugs,(19mm spanner i think, if i remember correctly) with an 8mm nut holding the resistor wires in place with ceramic isolators. Get rid of these and go to Masterparts and get the hybrid, big screw with pencil point, connected via a single wire to the power. You can set up a switch supplying power to the 4 wires going to the glowplugs. Starting will improve dramatically on the Highveld.

    This was the biggest failing of these engines. Your motor is old, so compression will be down and will need all the help it can get with starting.
    Mercedes W123 300D, runs on Mother Natures Goodness.
    Powered by the Sun, the Rain and the Earth.
    Have now covered 270 000Km on veg oil.
    Oh, and an Isuzu 280DT, 40 000Km on Bio Diesel
    Rand for Rand gets 33Km/L

  16. The Following User Says Thank You to ZuluCowboy For This Useful Post:


  17. #14
    Join Date
    Sep 2006
    Location
    Cape Town, Plumstead/The Sea/Franskraal
    Age
    53
    Posts
    2,445
    Thanked: 556

    Default Re: W115 240D - Covid project

    Another thing, there is a filter in the tank, if this is clogged(actually, it probably is clogged, (cock on a block) you can also have poor performance, due to fuel starvation, take out the tank drain, about a 37mm with a 19/17 in the middle, put an inline filter in the line instead of that filter in the tank. Here are 2 pics of a special tool to get that thing out of the tank.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Special tool 1.jpg 
Views:	114 
Size:	404.2 KB 
ID:	564352   Click image for larger version. 

Name:	Special tool 2.jpg 
Views:	104 
Size:	373.2 KB 
ID:	564353  
    Mercedes W123 300D, runs on Mother Natures Goodness.
    Powered by the Sun, the Rain and the Earth.
    Have now covered 270 000Km on veg oil.
    Oh, and an Isuzu 280DT, 40 000Km on Bio Diesel
    Rand for Rand gets 33Km/L

  18. #15
    Join Date
    Sep 2006
    Location
    Cape Town, Plumstead/The Sea/Franskraal
    Age
    53
    Posts
    2,445
    Thanked: 556

    Default Re: W115 240D - Covid project

    Yet another thing, only buy the oil filter from Mercedes, don't use the filter from Midas or any other after market, only MB OEM.
    Mercedes W123 300D, runs on Mother Natures Goodness.
    Powered by the Sun, the Rain and the Earth.
    Have now covered 270 000Km on veg oil.
    Oh, and an Isuzu 280DT, 40 000Km on Bio Diesel
    Rand for Rand gets 33Km/L

  19. #16
    Join Date
    Jan 2012
    Location
    Langs die rivier, op n berg
    Posts
    13,849
    Thanked: 2987

    Default Re: W115 240D - Covid project

    Wat is fout met n GUD filter? Hardloop al my merc engined vragmotors op gud.
    Vrywaring: Niks wat ek hier kwyt raak moet hoegenaamd as feite beskou word nie.

  20. #17
    Join Date
    Sep 2006
    Location
    Cape Town, Plumstead/The Sea/Franskraal
    Age
    53
    Posts
    2,445
    Thanked: 556

    Default Re: W115 240D - Covid project

    Dis 'n twee stage filter. Midas filters nie twee stage nie.
    Mercedes W123 300D, runs on Mother Natures Goodness.
    Powered by the Sun, the Rain and the Earth.
    Have now covered 270 000Km on veg oil.
    Oh, and an Isuzu 280DT, 40 000Km on Bio Diesel
    Rand for Rand gets 33Km/L

  21. The Following User Says Thank You to ZuluCowboy For This Useful Post:


  22. #18
    Join Date
    Mar 2015
    Location
    Pretoria
    Age
    49
    Posts
    658
    Thanked: 291

    Default Re: W115 240D - Covid project

    I will add parts and advice to my to do list in my first post. Sadly most of the parts will have to wait until after lockdown.

    I will add some pics of the progress later.

    Voel vry om in Afrikaans raad te gee, ek skryf net Engels vir 'n groter gehoor. Hoe meer siele hoe meer vreugde.
    Last edited by Tom13; 2020/04/01 at 01:26 PM.
    Mitsubishi Pajero 3.2 D-ID GLX LWB

  23. #19
    Join Date
    Oct 2017
    Location
    Vereeniging
    Age
    57
    Posts
    129
    Thanked: 85

    Cool Re: W115 240D - Covid project

    Can someone respectfully ask the president if Zulucowboy can sanitize himself and travel to Tom13's place? The Merc will run sommer gou-gou.

  24. The Following User Says Thank You to EtienneB For This Useful Post:


  25. #20
    Join Date
    Mar 2015
    Location
    Pretoria
    Age
    49
    Posts
    658
    Thanked: 291

    Default Re: W115 240D - Covid project

    Fresh diesel on the left and the stuff I drained from the tank on the right (at least 5 years old).Click image for larger version. 

Name:	IMG_20200401_170357.jpg 
Views:	93 
Size:	15.0 KB 
ID:	564406
    Mitsubishi Pajero 3.2 D-ID GLX LWB

Page 1 of 5 1 2 3 4 5 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •