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Car Forum / Mercedes-Benz Cars / August 2005Help a newbie '77 123 Starter motor
Hey guys, I have recently been given a MB for the tidy sum of $0. It's a '77 280E (123 Chassis) Yes I'm stoked. Can't wait to drive it . I've been poking around under the bonnet for a few days now. Boy am I impressed by the degree of engineering on these things! How ahead of there time are they ! Ok the car has been sitting untouched for about 9 months. I've replaced the battery.( It was dead ) The starter motor does not want to respond when Turning the ignition key over to start. The motor turns over fine Manually (with a ratchet on the front of the engine).So it's not ceased or anything.I Managed to loosen the starter up a bit by tapping the Body and the solenoid. I now have made a bit of progress and I'm actually hearing a faint Click every now and then. I've cleaned the battery terminals and also the ground from the battery to the body. Is there an earth strap going from the Engine block to the Chassis anywhere? My main questions is how to go about pulling the Starter motor. The lower bolt is hard to access via socket or open wrench and ring spanner. The upper bolt looks to be an allen/Hex key? Do I need any special tools at all. Also I can't access the Connectors on the soleniod. Do I have to remove the rear exhuast manifold and heat shield? Thanks for any help. Jeremy Miller >Hey guys, > [quoted text clipped - 42 lines] > >Jeremy Miller I am not familiar with your particular model but I am familiar with cars in general (Jaguar). When an old car is parked for a long time, it's not unusual for the starter brushes to fail from making a good contact. If you can move the position of the brushes by a minute amount you may solve your problem Tapping the Body and the solenoid as you have done sometimes works. Try again with a piece of wood. A piece of wood was part of the tool box on my wife's Mustang . It was used more then a dozen times. If the car is manual, there are ways of forcing the starter to rotate a little, but they are too dangerous for people without experience. If you can try the following: Connect a voltmeter between the heavy wire that goes to the starter, from the starting relay and the starter body (not the car's body) Try starting the car. If you have voltage (+12) and the starter doesn't run the problem is with the starter If you don't have voltage, measure between the same heavy wire and the chassis ground . Try starting the car. If you have voltage the problem is a bad ground. Confirm by connecting between the starter ground and the car chassis. If there is voltage you have a bad ground. A friend of mine wants to give me a 1978 450SL. Vlad "Give" you a 1978 450SL, as a gift? Can you introduce me to your friend? >>Hey guys, >> [quoted text clipped - 72 lines] > > Vlad >"Give" you a 1978 450SL, as a gift? Can you introduce me to your friend? No way. He mention 2 conditions: a) His wife approval ( she is a good friend ) b) I have to pick it up (about 2000 miles from my place) The car has 180.000 miles By the way... I am not gay. Vlad >>>Hey guys, >>> [quoted text clipped - 72 lines] >> >> Vlad Out of caution I'd suggest you first convince yourself that the starter is, in fact, the problem. It may very well be given the car's age, but you'd be crestfallen if you replaced the starter only to find no change. Have you confirmed 12V at the starter when the key is turned to START? If not, then the other possibilities are: ignition switch, neutral start safety switch, etc. I'd suspect this car wasn't driven for nine months because nobody could solve the problem. There's a lot of knowledge in this group, most of it good, so come back with your questions. There is a ground strap that runs above the battery tray on the firewall to the transmission linkage/dipstick area.Also the ground wire from battery to the fender is suspectable to corrosion. To remove starter,go under the W123 and use 2 long 3/8 extensions with a 17mm socket and another ratchet or box wrench and remove bottom bolt and then the top.After the starter comes down,you can then remove the wires.Pay close attention when you reinstall the starter and avoid the wiring touching the shield or manifold. One last thing to consider is checking the connections for corrosion on the little junction that is located on the frame near the alternator and AC. > Hey guys, > [quoted text clipped - 38 lines] > > Do I have to remove the rear exhuast manifold and heat shield? Almost sure the problem will be the starter relay sitting on top of the starter. Give it a blow with a hammer while someone else holds the starter key. Demount the starter and grease the ralay bolt. IIRC you can pull out the starter from downside with some twists around the exhaust manifold. At least that was the case with a /8 300D. My 280E never had any problem with starter.  SignatureRoland Franzius Oh yeah I forgot to add that the hex is a 8mm if I am not mistaking but not 100% sure.If you do not have a socket/hex,you can make one by using a cutoff tool(dremel) and cut off the right angle off of allen wrench and stick the straight piece in a 3/8" deep well socket. Thanks for all the help! Ok I've had the Starter Tested and the Brushes were stuffed! The Soleniod (Starter relay?) tested fine. I reinstalled the starter and Finally have her cranking. Cleaned all the grounds.Checked for corrosion on the power distribution block, cables and wiring The Fuel pump was also dead! So I Popped a new one of them in too. I can now hear the fuel pump pressursing the system when turning the key on. She fired straight away and idled perfectly for about 40 seconds!!! Then died. I tried starting it again straight away. But she wouldn't fire! And I couldn't hear the fuel pump running??? Had a bit of a read through the online MB manuals. And found that the fuel pump relay is located behind the Glovebox. I disconnected that and tried to start it. The fuel pump worked but she didn't want to crank!! Reconnected it and the same thing again. Fuel pump on but no crank. There is 12V at the starter Soleniod (main terminal). I'm getting a faint click from the small Square relays mounted next to the fuse box Is one of these another relay for the starting system? Where is the safety switch located? Thanks for all the help again( I'm so close). My plans for the car are new Black paint a nice set of Polished wheels 17 or 18 inch. > Hey guys, > [quoted text clipped - 43 lines] > > Jeremy Miller The fuel pump safety switch is located in the airflow sensor.If you look at the top of this sensor,you will see an electrical connection(blue) and to change,sadly you have to disassemble but is fairly easy.The 10mm bolts that go around are all that holds the two halves together.The hard part is removing the fuel lines from the fuel distributor. To prevent kinking them,loosen at the injector also! If time and money allow,replace the injector O-rings and sleeves. Forgot to add:possible causes Jammed or sticking airflow sensor Auxiliary air valve sticking Cols start injector not opening Defective thermo-time switch Sticking control plunger Restricted injectors Do a volume and pressure test after you get the fuel pump to behave! 75 to 84 psi on the fuel pressure. Fuel pump relay specs: Place an 8 amp fused jumper between fuel pump relay(on top of front fender under black cover,and is the one closest to the engine and firewall)sockets terminals 30/51 and 87. If you are interested,I have a W123 forum at yahoo to help you out on top of here; http://autos.groups.yahoo.com/group/mercedesW123Forum/ 74 members and there is one also at msn W123Club@groups.msn.com 1400 members Thankyou for the help Captain. At the moment the fuel pump is working. But she doesn't want to Crank. I'm just getting a faint click? > Forgot to add:possible causes > [quoted text clipped - 17 lines] > fender under black cover,and is the one closest to the engine and > firewall)sockets terminals 30/51 and 87. > Thanks for all the help! > [quoted text clipped - 88 lines] >> >> Jeremy Miller |
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