THIS IS YOUR LUCKY DAY

I just signed a deal with the south’s largest Mercedes Diesel Collector. The Helping Hands Network Charity I am the director for, now has access to below market priced parts for pre-millennium DIESEL Mercedes’!  Just email me a question about what part you are looking for and I will get you a price. I am at the parts yard often and am helping inventory his 3 barns and over 200+ vehicles!

tfrentz@hotmail.com

Mercedes Benz Turbo Diesel TD300

MANUAL: http://www.toddcomputer.com/Mercedez-manual/300D-repair-manual.html

Donate $5 to our Charity and I’ll get you a ZIP file with the full manual to view offline.

RESOURCES:

http://dieselgiant.com/mercedes_diesel_maintenance_tips.htm  (dieselworld@bellsouth.net)

peachparts.com ; benzworld ; mercedesdieselguy.blogspot.com ; mbca.org

PARTS:

http://www.benzcostless.com

Car-Stuff.com

 

Problem: Grinding in wheel gears.

Cause: Torn boots, dry axle gears, bad bearing.

Solution: Check all lubrication. Jack up wheels and hand turn them and listen or feel for problems. IN MY CASE, the grinding only starts in the rear passenger side after driving at least 40 mph for 20 miles consecutively. I am still testing to identify the exact cause and solution.

 

Problem: Broken Accelerator pedal

Cause: Damaged AC condensation drain tube allowing water to settle at the pedal base plate which then rots the floor out.

Pedal damageAC drain foam

 

 

 

 

Solution:  Replace the damaged foam AC drain tube with a rubber and duct tape tube. Then weld a new pedal connector in place with seam sealant, rust inhibiting paint spray and rubber coating. Also spray the bottom of the car. I riveted my pedal plate in place because I didn’t make the plate large enough to weld to solid floor metal.

AC drainAC drain linePedal repair close

 

 

 

Pedal new holder Pedal new

 

Problem: RUST! ARE YOU IN AN ICY CLIMATE? If you are in 80% of the USA your vehicle is at risk. Some of the main places and parts to keep protected include the fender well cover along the floor support & the independent suspension. A hole will rust out in the fender along the frame support and moisture will get into the lower frame and find it’s way down on to the suspension parts.

Mercedes Shock RustRear PAssenger Quarter

Solutions: Re-coat your fender wells with truck liner as needed. IF it is too late you will find that the rear shock mounts sit in a bowl made to support the spring and that will rust out. To get that replaced is a major job as the spring support and the wheel base and axle are ALL attached to this suspension arm and they will need to be removed. The main suspension arm will likely be rusted and you will have to cut off the bolt head and cut out the support tube away from the rubber bushing because it is usually rusted to the bolt.

Suspension Bolt Grinding Suspension Bolt

REMOVE your suspension arm bolts right now and go grease them if it is not too late!!! Make sure you jack the arm up and keep it in place while removing the bolt because if you let it tweek out of place it is a pain in the ass to get the freshly greased bolt to start threading.

 

Problem: Floor Board and trunk rust rot (usually due to failing door/trunk seals)

Solutions: Replace or repair seals. Treat them often with rubber conditioner.

Door Seal b4Door Seals

 

Problem: Window switch is not working. The rear window switch on the rear door works but not the front control switch. (The switches get goo in them over time and the contacts arc and burn out.)

Solutions: Disassemble the switch and clean the contacts and other parts with a razor blade and rotate them before reassembling.

Switch Cleaning 1 Switch Cleaning

 

 

Problem: Transmission or drive shaft allows the vehicle to role about 2 inches when put into park.

Solutions: The main issue is likely that the bushing between the two pieces of the axle is getting worn out. This is very common and is not known to brake completely so there is little risk of being stranded. The drive shaft joint fingers also are very flexible and the give increases with ware.

 

Problem: Transmission shifts hard and horse power seams weak.

Solutions: *LATE ’84 or newer models have a unique shifting vacuum pressure line out of the banjo bolt found on the drivers side of the valve cover. Test by removing the vacuum filter line for the shifting and bypass it by plugging it up. It shifts smoother and increased my horsepower because the extra shifting filter really is not necessary and decreases the pressure too much. This is also a way to test if your turbo is working by unplugging it while vehicle is running to see how much pressure is coming through the banjo.

 

Problem: Concerned how good my engine seals are and if they are causing too much blow by and oil leaking.

Solution: You can put your thumb over the vent hole on the top of the valve cover to get a good idea how healthy your ring seals are. The longer the engine continues to run, the better the seals. 3 seconds means run away from that engine while 6 seconds is average and 9 or more is like new! Mine is 7ish  🙂

 

Problem: Transmission shifts hard, then sometimes it stops and has no power and no acceleration?

Solutions:

1. Check the Tranny Levers/Valves and throttle linkage. http://dieselgiant.com/trannyleverreplace.htm

In my case, the throttle pivot bushing connecting the pedal arm to the accelerator linkage connected to the firewall was broke. (see pictures below)

This part is $54+ from PeachParts: http://tinyurl.com/7nwjhdf

$41+ from Car-Stuff.com : http://tinyurl.com/6wst7cc

A: 1984+ has a metal tranny valve  lever on top of the engine

B: <1983 has (2) plastic levers

2. Clean the Banjo-bolt and LINE located on back of engine, near transmission fluid dip stick at rear of exhaust manifold. (*Need cleaning agent and wire brush) Remove line from firewall switch-over valve.

A: 1984+

B: <1983

Switch-over valve line to banjo bolt cleaned? (if you by-pass the switch over, your engine can not prevent over fueling from over boost! This will ruin the engine by ______ ?

3. Clean Fuel and air system (filters, sea foam etc.)

4. check vacuum system (adjust tranny linkage) The 5 way connector by the throttle linkage on pre 1983’s or the 4 ways on 1984+ is usually swollen from oil vapors and heat.

http://dieselgiant.com/mercedesvacuumtroubleshooting.htm

http://www.youtube.com/watch?v=Wlg7mZffni8

Start at the ALDA with vacuum tester, and if the pressure is not making it that far, then you’ll need to investigate to figure out what is the source of the problem.  Make sure you’ve got the ALDA – there are also vacuum fittings connected to the vacuum shut-off valve on the injection pump,

You can modify the vacuum lines. Remove all lines to the head valve cover. The main vacuum supply goes to a single T as seen in the photo. One end of the T goes to the vacuum control valve (via the green dampener) and the remaining end goes off to the transmission. Note the restriction orifice remains in the line to the vacuum control valve.

One T is completely eliminated……..the line to the black box on top of the valve cover is eliminated. The vent line goes directly to the vacuum control valve. Second T is completely eliminated. The return vent line to the black box on top of the valve cover is eliminated. Remove the line from the black box to the temperature switch on the thermostat housing. Finally, the line from the temperature switch to the EGR valve is eliminated. Opened up the black box and pull out the remains of the 3-2 switches. The IP linkage works a bit smoother when you don’t need to force the cam.

*By removing the EGR vacuum lines connected to the Switchover (3/2) valves and temperature switch, you improve mileage and power but lose first gear and increase carbon blow back. (The 3/2 valves activate the transmission’s 1st gear).

BEFORE PICT:

AFTER PICT:

5. check kickdown solenoid performance

Check that the kickdown solenoid isn’t stuck. A simple test you could do is turn the key on and have a helper press the go pedal to kickdown a couple times. You should be able to feel or hear the solenoid click. If it is stuck, pressing the pedal to kickdown quite a few times may free it up.

There is a button under the pedal connected to a cable to the solenoid in the rear of the transmission.

6. check/adjust throttle linkage

Adjustment Of Cable Control For Control Pressure. Vehicles with engine 617.95.

  1. Push off ball socket (19).
  2. Push ball socket (19) first to the rear (opposite to direction of arrow), then pull carefully forward (direction of arrow) until a slight resistance is felt.
  3. In this position, hold ball socket (19) above ball head ; drag lever (13) should rest against stop (14).
  4. Adjust control pressure cable control at adjusting screw (15) in such a manner that the ball socket (19) can be pushed free of tension on ball head.

Mercedes Benz 300D Shifting Problem

7. Check/Replace change-over valve.

The vacuum line from the rear of the intake manifold goes to the changeover valve which is operated by DC power.  From the changeover valve the line goes on the the ALDA. A new Changeover valve has returned the engine back to it original power at all speeds according to some. This is located next to the brake booster.

8. Adjust ENGINE valves (*Need 13mm torque wrench for header bolts, new Gasket maybe, MM feeler gauge, 27mm socket, 2 angled 17mm wrenches (tightner wrench needs to be skinny to fit on tightner nut under adjuster nut, baggies for parts, paper and marker to label parts and mark rocker arm as completed)

http://www.youtube.com/watch?v=3LzJsD6gc4E

http://youtube.com/jpiTfk6Z3n8

http://www.youtube.com/watch?v=fcsgyPGgaxg

http://www.youtube.com/watch?v=kkzz-8YJOp4

A. put 27mm socket on crank pulley to turn engine

B. loosen air breather tube from base but leave attached to head plate or you will break it and need to replace. Remove header bolts a turn each at a time to prevent header warping. Gently shimmy header loose to protect gasket and avoid replacing.

C. Crank engine with 27mm on pulley until valve #1 cam rocker arm is straight up. Loosen lock nut on bottom, move adjuster on top to desired spacing. Tighten lock nut.

D. set intake valves at .004 inch (drivers side), exhaust/out take valves to .012 inches (passenger side)

E. repeat for each valve and reconnect header with 2 or 3 torque clicks of pressure (aprox. 15lbs. of pressure?) and breather tube

9. adjust ALDA  (Automatische Lade Druck Anreicherung – Automatic load pressure enrichment) Adjusting may not do anything? 1/2 turn counter clockwise should result in light smoke from exhaust which signifies more fuel being processed by engine and increased power. BE CAREFULL, the screw is easy to break!

In a nut shell the ALDA unit sits on top of the fuel injection pump and contains 2 aneroid capsules and some internal linkage, that enriches the fuel deliver in response to altitude and intake manifold pressure.  When the turbo charger starts making boost the small banjo bolt  and accompanying plastic line, transmits this pressure signal to the switchover valve on the firewall.

http://dieselgiant.com/mercedesaldaboostsystemservi.htm

http://www.youtube.com/watch?v=yyYAMpuqRwg&feature=related

IF YOU REMOVE the ALDA …. BE VERY CAREFUL ABOUT FULL THROTTLE TAKE OFFS, don’t do them. It will run very rich under acceleration but OK under cruising, watch your temp. If you leave it off you’ll need a manifold boost gauge and pyrometer to avoid overheating pistons

10. EGR VALVE plugged or plated off with steel

Unplug the vacuum line going to the EGR valve (in front of the air cleaner)  IF there is a power increase service the EGR Valve. IF you leave it blocked, it is recommended to use Bio Diesel as much as possible to minimize exhaust carbon from breaking down the vacuum rubber components and causing build up on other parts.

11. Check the timing

Check the timing marks on the cam gear and tower with the crank pulley at TDC. IF off/retarded by more than 5 degrees replace the timing chain which brings the timing to 2.5 degrees retarded. Offset woodruff keys are available to further correct timing.

12. Replacing the injectors will improve starting, performance, and limit exhaust smoke. http://dieselgiant.com/mercedesinjectornozzlereplace.htm

Mercedes late OM-616, -617 nozzle
Refer to MB part number 001 017 29 12
For later (~1980-’85) Mercedes-Benz applications OM617, OM616, and OM601.921
Sold as each, specify quantity needed.

Price: $43.00 at http://www.kermatdi.com

13. Check Fuel Rack Damper Bolt

Replacing or adjusting fuel rack damper bolt improves idle and smoothes the engine shake.

Loosen the lock nut and screw the bolt in until the engine smooths out and then back it out and go in again, just to make sure it’s in the right place. Tighten lock nut.

You really only want it screwed in as far as you need to stop the wild side to side rocking. Once that stops, screwing it in further is not going to make it smoother. These engines shake and that’s all there is too it. If it’s screwed in too far it will mostly likely stall and be difficult to start.

http://articles.mbz.org/engine/diesel/rackbolt/

 

 

OTHER FUN NOTES ON THE 300td:

Run the Engine Cooler by drilling holes in the Thermostat! http://dieselgiant.com/thermostatreplacementandmodif.htm

DO A CITRUS FLUSH every year for 3 years then every other year to clean rust build up off components!

http://dieselgiant.com/mercedes_citrus_flush.htm

AC TROUBLE SHOOTING

http://dieselgiant.com/repairyourac.htm

HONDA cb750 1980 4b DOHC

http://wp.me/p13eVj-qj

DODGE 1995 6L Mark250 VAN

http://wp.me/p13eVj-qY

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Comments
  1. The images in this post illustrate this diesel repair in great way.

  2. stefnaad says:

    Hey T. I just noticed the date on this blog. I sent you an e-mail any way. Stay safe!! xo . s

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