new to Mercedes via '83 300SD

[DanHoug]

well, acquired a tow-home '83 300SD w 280k miles... my first Mercedes! price was right, body decent, last ran in 2014. got it to fire up long enough to drive it to the car wash for an engine wash and remove the barnacles. swore off diesels after putting 140k miles on veg oil with a '91 Jetta converted to WVO. got drawn back into them thru this rescue mission on the Mercedes.



Done List:
oil change
air filter
fuse box rehab/cleaning contacts
oil cap jiggle test: passed very nice
checked turbo bearings, just a slight shake, spins nice, no bad intake vanes
odometer gear rebuild
dash dimmer bridge fix
repaint gauge needles neon orange
clean sunroof tracks
remove crumbly hood insulation



To Do List before hitting road:
re-attach vac line to aneroid and check nipple for free flow
Fuel filters
drain tank + filter
adjust valves
rebuild injectors + check timing
get HVAC blower working
get HVAC controls working

To Do as time permits:
Passenger window motor locked
door locks inoperable
change emergency flasher switch (funky now)
reglue peeling wood trim
sagging drivers seat
electric antenna


-dan

[BWhitmore]

Congratulations. Sounds like a nice project car. You will find the members on this forum to be very helpful with technical advice and parts when needed.

[DanHoug]

i've been trying to decide which Mercedes list to spend my time and energy with... i'm active on Samba for VW Vanagons and that list is great with strong technical people and is polite. seems there's a fair bit of technical expertise on peachparts.

-dan

[DanHoug]

made progress on the HVAC today... removed blower and rotor was totally locked up. system still dead with a test fan. removed button climate control and repaired 2 burnt PCB tracts on pin 10, likely toasted due to over-current. test blower now steps thru different speeds and auto ramps up and down. new Bosch blower motor coming ... got last one at ********.

pulled fuel sender, gunked up and no way it would move. cleaned it up, broke the copper ground wire and replaced with a tin coated one. sender and low fuel light now work. tank drain next along with filter changes. smells like varnish and is cloudy.

[WDBCB20]

Originally Posted by DanHoug

removed button climate control and repaired 2 burnt PCB tracts on pin 10, likely toasted due to over-current. ********.

You probably know this already but unplugging the pump (located underneath and to the right if I remember correctly, of the monovalve) which circulates hot water at idle for the heater is recommended to prevent frying the climate control unit.

In the catalog part# A0008352564 was replaced by A0008356964 (still available). Don't know if that corrected the issue.


Thanks for inadvertently answering 2 questions that I had pending!
1. That the 12mm Mcmaster shims "fit just fine".
2. That keys can be had from MB

What size shims thickness did you buy?


.

[DanHoug]

Originally Posted by WDBCB20

You probably know this already but unplugging the pump (located underneath and to the right if I remember correctly, of the monovalve) which circulates hot water at idle for the heater is recommended to prevent frying the climate control unit.

In the catalog part# A0008352564 was replaced by A0008356964 (still available). Don't know if that corrected the issue.


Thanks for inadvertently answering 2 questions that I had pending!
1. That the 12mm Mcmaster shims "fit just fine".
2. That keys can be had from MB

What size shims thickness did you buy?


.

nope, i did NOT know that about the circ pump. i could see smoke come off the board when i turned the test fan (the correct one was on order) on and assumed it was the FAN drawing too much. so then i covered the fan outlet to reduce fan load/amperage and the board did not smoke. bothered me because i know the various speeds go thru the resistor under the brake booster so something wasn't making sense. now if that pump has a locked rotor, that could do that. i took it for one 20 mile drive since then so either the control board is now toast or the pump freed up or fan current somehow IS related. more investigating to do.


i bought 0.1, .2, .3, .4 and 1mm shims. only used the .1 in conjunction with the OEM shim and it raised the pressure about 100psi. the shims are more than just washers... they truly are very flat, die-cut spring steel that give highly repeatable results.



treated the finished injectors with gun bluing just now. gives a bit of a rust resistant coating and looks purrrty.

[WDBCB20]

Originally Posted by DanHoug

nope, i did NOT know that about the circ pump. i could see smoke come off the board when i turned the test fan (the correct one was on order) on and assumed it was the FAN drawing too much. so then i covered the fan outlet to reduce fan load/amperage and the board did not smoke. bothered me because i know the various speeds go thru the resistor under the brake booster so something wasn't making sense. now if that pump has a locked rotor, that could do that. i took it for one 20 mile drive since then so either the control board is now toast or the pump freed up or fan current somehow IS related. more investigating to do.

.

Checklist to comply with (in order not to fry refurb ccu and void warranty) before installing refurb ccu provided by the folks who refurb ccu to verify current draw at the pins per component:

https://www.programainc.com/info/60285/Document/tech-tip.pdf

Apparently Aux Pump is not the only possible culprit: Monovalve and . A.C. Comp relay might also be implicated.

[Diesel911]

Originally Posted by DanHoug

well, acquired a tow-home '83 300SD w 280k miles... my first Mercedes! price was right, body decent, last ran in 2014. got it to fire up long enough to drive it to the car wash for an engine wash and remove the barnacles. swore off diesels after putting 140k miles on veg oil with a '91 Jetta converted to WVO. got drawn back into them thru this rescue mission on the Mercedes.



Done List:
oil change
air filter
fuse box rehab/cleaning contacts
oil cap jiggle test: passed very nice
checked turbo bearings, just a slight shake, spins nice, no bad intake vanes
odometer gear rebuild
dash dimmer bridge fix
repaint gauge needles neon orange
clean sunroof tracks
remove crumbly hood insulation



To Do List before hitting road:
re-attach vac line to aneroid and check nipple for free flow
Fuel filters
drain tank + filter
adjust valves
rebuild injectors + check timing
get HVAC blower working
get HVAC controls working

To Do as time permits:
Passenger window motor locked
door locks inoperable
change emergency flasher switch (funky now)
reglue peeling wood trim
sagging drivers seat
electric antenna


-dan

It could just be that the window switch contacts need to be cleaned (switch comes apart don't loose the ball bearings, springs and rockers). I scrape them with a small pocket knife. Others say not to do that and use some other cleaning method. Your choice.

I don't know if the SD front doors are the same as W123 doors in that the W123 doors have a terminal/junction block where the Motor Wires connect held in with screws. I had both of the 2 screws back out and tightening them returned fixed the no go issue.
It is also a convenient place to test the front window motors. because the wires are right there. Not hard to connect some jumper wires to the motor wires and apply them to a Battery and see if the Motor itself and the regulator are working.

Unfortunately the read doors don't have any terminal blocks on the W123.

[DanHoug]

Originally Posted by Diesel911

It could just be that the window switch contacts need to be cleaned (switch comes apart don't loose the ball bearings, springs and rockers).

the dome light dims when working the window switch so at this point i'm assuming a locked motor.

[83w126]

Check the oil cooler lines too. On the sagging seat, the base is interchangeable with the later ones (89-91 I think) but those have an extra spring so they are way more durable. They are not too hard to take apart once you seen how they are assembled.

[Diesel911]

When I had the locked motor it was because the bearing at the rear of the motor had stuck onto the shaft.

Unfortunately due to the bearing retainer being staked in to the bottom of the housing I had to pull the shaft and bearing through the spring tabs of the bearing retainer bending some.

I had to then pull out the bearing retainer and bend it back into shape the best I could.

Now I know that I could likely have avoided that by spraying penetrating oil down where the bearing is and simply waiting to see of it worked to the out I could pull the shaft out of the bearing and leave the bearing in place.

I don't have a picture of it but there is actually a hole on the bottom side of the bearing area in the motor housing were spray the lube in behind the bearing.

But, of course your issue may be different.

There is several motor take a parts and window regulator issues in the Repair Links
Fast navigation Fast navigation Do It Yourself Links

[DanHoug]

Originally Posted by Diesel911

When I had the locked motor it was because the bearing at the rear of the motor had stuck onto the shaft.

Unfortunately due to the bearing retainer being staked in to the bottom of the housing I had to pull the shaft and bearing through the spring tabs of the bearing retainer bending some.

I had to then pull out the bearing retainer and bend it back into shape the best I could.

that was exactly the issue on mine... had to use a small puller and heat to remove the round bushing from the shaft. tried to remove that finger clip so i could re-insert it over the bushing but it wouldn't budge so i just bent the fingers back over with a socket. they are loose but time will tell if that is an issue. that window is now the fastest, smoothest window of the 4.


-dan

[DanHoug]

thanks for the fast nav links... hadn't come across those!! very useful.

tank drain tomorrow! i think i'll suck it out from the fuel sender which i just had out for rehab. there was enough gunk in there to make me think the tank screen will be sludged up and hold back some diesel. Question... is the sludge in the interior of the sender correlated with the amount in the tank? or does it somehow accumulate more than the tank (hope hope).

-dan

[Mxfrank]

Don't forget a transmission fluid & filter change. Differential, too.

[Diesel911]

"last ran in 2014" it is entirely possible the sludge is from stuff growing inside of the Fuel Tank.
The stuff can be killed with a biocide. Not sure I am spelling it correctly Biobor can kill it and stuff like Startron (startron makes more then one product so you need to sure you get they correct one) uses an enzyme which is supposed to break up the organisms into small enough parts that they safely pass through the Filters.

Note even if you removed the Fuel Tank and cleaned as is often done you still need to treat the infection (so to speak) because it is still in the fuel lines going from back to front.

From my notes (more on the subject would be in the repair links):
STARTRON
Algae Clogged Filter Pic StarTron WORKS !

Biocides Startron, BioBor, BIO KLEEN
Diesel Power "Diesel Clear" or Starton diesel fuel treatment are the best products to use.
Biobor will CLEAN the tank, but not reconstitute it into the fuel for burning, and WILL plug up your tank filters/screen/etc
http://mydieseldoctor.com/FAQ.html
http://www.thedieselpageforums.com/tdpforum/showthread.php?t=23293&page=2