[hamsanwich81]

I have replaced my 1978 300cd glow plugs and now I do not know the correct sequence to replace the electrodes and insulators. I have looked and can not find a good picture or diagram of the system. I am sure that needs to go back together just right. Your help is appreciated.

 

[Rmac58]

I thought they were one piece, do you have the series unit? The wavy wire thing.

 

[79Mercy]

Okay, the insulators are the little white ceramic pieces.

Starting from GP # 5. Put on the solid metal bar, then slide on the insulator then connect the 12V supply wire and put on the nut.

Now to GP # 4 Slide on one of the wavy metal lines, put on a insulator, and then the other bar that comes from GP #5 and tighten the nut.

now GP #3. The wavy bar should already be on it, slide on a insulator, slide on a solid bar and put the nut on.

Now GP #2, slide on a wavy bar, slide on a insulator, put on the solid bar that comes from GP # 3 and put the nut on.

Now GP#1, the wavy line should already be on it, now slide on a insulator, put the ground strap on and put on the nut.

Thats about as clear as I can make this, I hope it helps.

 

[akimball442]

Step 2) Throw wrench in anger and replace GPs with updated parallel wiring kit.

Step 3) Start engine effortlessly in the cold.

It would be the easiest method. The series wired plugs are much less efficient, although your profile says you live in GA so it shouldn't be really that big of a deal.

The 'Wavy line' parts are actually resistors, so power is being wasted as heat into the atmosphere, which in no way helps start the engine.

 

[abgwin]

Okay, the insulators are the little white ceramic pieces.

Starting from GP # 5. Put on the solid metal bar, then slide on the insulator then connect the 12V supply wire and put on the nut.

Now to GP # 4 Slide on one of the wavy metal lines, put on a insulator, and then the other bar that comes from GP #5 and tighten the nut.

now GP #3. The wavy bar should already be on it, slide on a insulator, slide on a solid bar and put the nut on.

Now GP #2, slide on a wavy bar, slide on a insulator, put on the solid bar that comes from GP # 3 and put the nut on.

Now GP#1, the wavy line should already be on it, now slide on a insulator, put the ground strap on and put on the nut.

Thats about as clear as I can make this, I hope it helps.

Hello, thanks for this post and the very clear instruction. Just replaced the glow plugs on our 1978 300CD.

I am struggling to understand if I reinstalled the contact bars correctly. I took a photo but after I took the first link off (GP 3 to GP 4). I have two solid bars. One has a large loop end and small loop end; that was from GP 5 to GP 4. The other solid is not straight; it has a angled bend to avoid something. I installed it pointing down (potato masher ones pointing up, as originally found) but it seems really close to the sensor between 2 and 3.

Is this correct? These get hot, so worried it’s going to fry the sensor.

Thanks in advance for input!