Re: [MBZ] Vacuum shutoff saga

[Marshall Booth]

Peter Frederick wrote:

Marshall:

The servo was a very tight fit in the cover, so we may have distorted 
it a bit going it.  I think I checked it for proper operation before 
installing it, but don't remember, and I fumbled the cover putting it 
on so it dropped down to the floor -- not much room back there on a 
W115.


On the 601 you must have had it hooked on the front side of the lever 
instead of pin-through-hole -- at least I seem to remember a pin and a 
hole on that servo.


Thanks for the insight.

Marshall

--
  Marshall Booth (who doesn't respond to unsigned questions)
  "der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 182Kmi, '84 190D 2.2 229Kmi, '85 190D 2.0 161Kmi, '87 190D 2.5 
turbo 237kmi

Re: [MBZ] Vacuum shutoff saga

[Peter Frederick]

Marshall:

The servo was a very tight fit in the cover, so we may have distorted 
it a bit going it.  I think I checked it for proper operation before 
installing it, but don't remember, and I fumbled the cover putting it 
on so it dropped down to the floor -- not much room back there on a 
W115.


At any rate, it was bent enough to pull down but not spring back!  Easy 
fix, just tweaked it a bit and it was fine.


This servo has a tripod flange on the bottom, it was only used on the 
MW pump in the W115, on the W123 it's held down by a clamp ring and is 
MUCH easier to replace.


If anyone has to do this job, it's very easy to get the servo "hooked" 
in right -- it just sits in front of the rack operating lever.  You can 
pull the top cover off the governor to make sure, but it's almost 
impossible to install incorrectly unless you floor the acclerator while 
putting it on.


On the 601 you must have had it hooked on the front side of the lever 
instead of pin-through-hole -- at least I seem to remember a pin and a 
hole on that servo.


Peter

[MBZ] Vacuum shutoff saga

[Peter Frederick]

My brother and I finally got around to replacing the shutoff solenoid 
in his 75 300D (W115 chassis).  This is an MW pump with manual altitude 
correction.


To change the solenoid, you must remove the rear cover of the pump 
(five screws) since the solenoid is held in place by two screws from 
the inside and the top screw for the cover (through which you can 
measure the pump rack travel).


Hans laughed at us and said " have fun, that one is a real pain" when 
we bought the solenoid from him.  He's right, it is.


First "fun" part was getting to the back of the IP -- not much room in 
that car.  Had to remove the rear pair of injection lines, drain the 
rad, and drain the head by removing the heater supply hose, then 
removing the last two glow plugs (only the rear one really needs to 
come out, but Sam has burned out two rear GP in the last month, and I 
wanted to check the next plug up for shorts).  Also pulled the main vac 
line off the booster to get it out of the way too.


Next PITA is getting.the slotted head screws out -- this particular job 
has been done before on this car, so all the heads have huge burrs from 
sloppy work.  Sam has a wonderful "sideways" screwdriver made by 
Miller's Falls he got with some machinist tools some years back.  With 
it, we got all the screws out, some from underneath as there isn't room 
up top.


We bought new cap screws and ditched the old slot heads.

After juggling around a while, we got the new servo installed in what 
we though was the correct location (it's actually easy on this pump, as 
the hook is just behind the rack lever, no slot or anything, but we 
didn't know that and opened up the top cover anyway), and proceded to 
replace the vac pump diaphram.  Glad we did, but that meant pulling the 
engine fan and upper radiator hose, too.


Got everything correctly installed again and tried to start it.  No go 
-- cranks fine, but no start.  Not even any diesel smoke.  Big bummer, 
did we wreck the IP?


Pulled the top cover off, solenoid lever looks wrong, decided it was 
dragging on the rack lever instead of in front of it as the rack could 
be shoved forward with a screwdriver, so we messed around a little and 
then applied vac to the shutoff with the MitiVac again.


Ha, it's stuck, so off the cover comes again (after removing the 
injection lines, glow plug, and vac line again).


This time we actually found the problem.  The servo was sticking down 
when vac was applied, so the rack was in the stop position all the 
time.  Easy fix, the actuating arm was slightly bent.  Straightened 
that out and everything works fine.


Took almost 5 hours, though

Peter