I'm trying to check my glow plugs but i couldn't pull off the electrical leads. The connectors are long cylntrical plastic and appear to pull sriaght up and off but i can't pull them by hand and don't want to break them. any tips will be greatly appreciated.

 

They do pull straight off; they may break in the process if they are really old and corroded.
Try pulling with a pair of pliers.

All you need to do to replace them is use a bullet-style crimp connector of the right size and crimp it onto the end of the wire.
I once used a large female spade connector that had the "loops" on the sides large enough that it fit nicely over the GP male.

 

<p>welcome to FTE.</p><p>as said above, use a pair of pliers to get a good grip on the plug. if the plug breaks bullet style crimp connectors work perfect, and i then use heat shrink tubing over the connectors to seal them .</p><p>what symtoms are you having that you want to test the glow plugs?</p><p>&nbsp;</p><p>if you get the connector off and see they are autolite, wellman, bosch, diesel rx, champion, or any other type of glow plug, don't even bother testing them,. just do yourself a favor and buy a set of motorcraft/beru ZD-9 glow plugs and put them in.</p><p>motorcraft glow plugs are the only ones that work properly in our engines. most of the other brands will burn out soon after they are put in,</p><p>and some, like the autolites that most parts stores sell will burn out after the first start.</p>

 

If you haven't pulled the glow plug wire connectors off yet STOP RIGHT NOW!
After much thought I figured out a way to remove old connectors weakened by age/heat/oxidation/exposure to hydrocarbons or chemicals, etc., with far less risk of damaging them. I've partially tested his idea without actually pulling any connectors and I think this method may be good enough to put in a Read First article with photos. It is very simple. !

I can't post the method at this moment because I have to make an important phone call and finish a cup of coffee because I just woke up. I'll be back within an hour to describe this method. Maybe I can take some photos to make it perfectly clear.

 

Here is the method I mentioned in my previous post- no photographs yet. Sorry this is so long, I am very detail-accuracy oriented.

First, the damage is most often caused by the compression forces (pressures) placed on the weakened connector by the jaws of a pliers type removal tool which are most often serrated as well (serrations cut into the surface of the weakened connector and in a very technical view would make it weaker and more subject to breakage under these forces).

This is what you will need:

ITEM 1) Most importantly: One, approx 6 inch long piece of one of the following:

a. One 6 inch long 5/16 inch (inside diameter) length of fiber reinforced rubber transmission cooling line. In metric measure 8mm (inside diameter) is perfect. This fiber reinforced rubber line, or hose, cut properly, is stiff enough to resist compression forces placed upon the old weakened connector during the removal process and will protect your old connectors from damage during the removal process. Note: 5/16 in. (8mm) Auxiliary Transmission Cooler Hose is essentially the same (if you have some extra) but it is normally not available in small pieces cut from bulk rolls.

OR
b. One 5/16 in.(or 8mm) piece of old used reinforced rubber transmission line is even better because it is stiffer than new line offering better resistance against compression forces from the jaws of a removal tool. Clean it to remove any transmission fluid from the surfaces.

OR
c. 5/16 (8mm) fiber reinforced rubber Fuel Line will probably work equally as well.

OR
d. Perhaps this is the best because it is the stiffest: One piece of 5/16* (8mm) inside diameter, clear vinyl or clear PVC tubing available on bulk rolls at hardware stores and cut to the length you need. *Note: 5/16 inch i.d. diameter tubing in these materials is almost impossible to find so you will likely have to get the next size bigger = 3/8 in. (9.5-10mm metric) and the last step in making your device will be trimming approx 1/16 inch from one edge to make it a perfect fit. (you'll understand what I mean further below)

Procedure to make the rubber fitting from the tubing:

A) The length of the glow plug connector that you will be using to grab the connector is all of the connector that is below the ridge at the top. This section is 7/8 inch long. This is how long your finished rubber tubing part will be after the final cut. Slightly less then 7/8 in. long by as much as -1/16 in. is just fine, no problem but more than 7/8 in. long is to be avoided. In metrics, 22mm length is fine. The ridge below the larger diameter part of the connector at the top is going to serve us perfectly!

B) Hold your piece of tubing down on a work bench or other stable cutting surface with one hand. Use your other hand to cut one slit all the way through a single wall of the tubing at the free end in the direction of it's length, not across. The length of this slit needs to be longer than 7/8 in. (22mm)

I used a sharp razor blade style utility or 'box' knife. BE SURE to cut in a direction or manner that is safe so you wont accidentally cut yourself! This fiber reinforced rubber tubing is difficult to cut though and requires more applied pressure and motion of this type of cutting tool than for a non-reinforced rubber tube so there is no concern about cutting through the opposite side . You can use any other type/style of sharp cutting tool that does the job. This cut does not have to be exactly straight. If the cut is jagged or at a slight angle from straight, that is OK

C) Now cut this slit end of your tubing off at 7/8- inch (22mm)

This is your finished piece! Hooray! You can spread it apart at the slit and install it over your connector right under the ridge!

ITEM 2) ONE inexpensive spark plug wire boot removal tool (pliers) which has a soft rubber-like coating at the grabbing end and no serrations on the jaws that could damage a delicate part - but a rubber coating doesn't matter in this process. These are often shaped with an angle of 20-30 degrees (mine are buried in tools somewhere so I can't check).

OR ANY appropriately shaped metal pliers tool should work just fine to accomplish the job, such as a needle-nose or other pliers that were made with a 15, 30, 45 or 90 degree angle. A straight pliers tool or a narrow 'needle nose' 'Vice Grip' style tool will work fine.

You may find that using a small block of any suitable material and size to use as a fulcrum point to pry with your tool, like a lever, to remove a particular connector close to straight up off the GP terminal will help.

Now you can grab this covered and protected part of the old connector and pull it off with substantially less risk of damaging it.

IMPORTANT NOTE: This stiff rubber protector will provide the most resistance to compression forces if the slit is facing 90 degrees away from the 2 locations where your tool makes contact with each side of the rubber protector.

In other words, DO NOT grab the rubber protector with one of the jaws on top of the slit! This will substantially reduce the resistance of the rubber protector to the compression forces of the jaws of your tool. Position the rubber protector with the slit anywhere close to 90 degrees from the location where the jaws of your tool make contact with the rubber protector.

This way the edges of the slit will be pushed together as the protector is grabbed and the resistance to compression of the tubing and possible compression of the connector are substantially increased.

If you like this method and especially if you try it and it works well for you, and if others think this should be written up, with photos, for a Read First article I can re-write it "fine tuned" with photos. I really don't want to mess with my own old and weak connectors to prove this method, especially the difficult to access ones, but when time permits during the next few days I will pull a couple of the front ones to prove the concept. I did cut and test fit a 5/16 in piece of reinforced rubber tubing and it looks like this will work very very well.

 

Great unintentional pun! ....any tips will be greatly appreciated...