help w/taking glow plug out - PeachParts Mercedes-Benz Forum

lws1 · #1 10-20-2007, 01:02 PM

Trying to take a glow plug out and can't get it out with a simple wrench. The former owner overtightened everything on this car that it's next to impossible to loosen. Any recommendations on what I can use to get this thing out of there? the wrench has come off a few times, so I'm limited on my tries here before I really have problems... I'm going to have to make a run to Craftsman and just need to know what I can get the best torque with and fit into that tiny space. I am refraining from taking the fuels lines off.

Thanks, Lance

TMAllison · #2 10-20-2007, 01:11 PM

Go slow first off. Start using some penetrating oil such as PB Blaster and let it soak a day or two. Remove anything in the way preventing you from getting a good bite with a socket.

If it starts getting serious, you can heat the cyl head up and then hit the GP with a spray "freeze" product to contract/shrink it.

TheDon · #3 10-20-2007, 01:48 PM

It is alot easier working on that issue with the engine hot.

Sbean · #4 10-20-2007, 03:05 PM

Maybe you should take off the injector lines this time-at least the ones that are in the way- to have the best chance of success. Don't forget to use some Nevr-seez or the like when installing new plugs. Steve

pjc · #5 10-20-2007, 03:29 PM

When you say "the wrench has come off a few times," do you mean it has just slipped off, or are you rounding over the corners of the hexagonal GP? Best to use a 6-point socket on these, not a 12-point. If it's rounded to point where a 6-point socket slips, you can buy a fluted "grip" socket from Snap On or some other sources. They're not cheap ($15-20), and they can chew up the hex head, but in some cases they're the only option.

toomany MBZ · #6 10-20-2007, 04:53 PM

A flare wrench won't hurt, (I get 'em from Sears, pricey) once "broken" loose, a gear wrench makes things go faster. Removing fuel lines will give you more room, I didn't need to, but mine were not so tight as yours seems to be. I did have to remove some throttle linkage to access the rear most GP.

lws1 · #7 10-20-2007, 05:00 PM

I get the feeling these are original. How long do glow plugs usually last? My car has 133, 000 miles. I tried taking out the second one and it's the same thing. I am going to try when engine is hot next.

Cervan · #8 10-20-2007, 05:43 PM

i would say a propane torch... before i try to freeze it off.

junqueyardjim · #9 10-20-2007, 05:48 PM

It is not only difficult to get them out between the hard lines, it is very difficult to get them back in also. Man, I sure would recommend taking the no more then 30 minutes to pop those injector lines off, top and bottom in one piece with a 17mm open end. To get them back on, start all of them on the bottom but not very much. Then start all the tops. It is very easy to do and gives you a lot of access on the glow plugs. I would pull the hard lines to replace just one glow plug.

300SDog · #10 10-20-2007, 06:32 PM

Try 2-3' steel pipe that fits over handle end of wrench. And if you use box end on the bolt then open end can interlock with another box end to gain leverage ending the handle length of wrench.

toomany MBZ · #11 10-21-2007, 07:11 AM

Removing the fuel lines results in cranking the engine to prime after you've pumped and pumped and pumped, on mine anyway, fast way to burn out your starter, they ain't cheap.

lws1 · #12 10-21-2007, 12:05 PM

Quote:

Originally Posted by junqueyardjim

It is not only difficult to get them out between the hard lines, it is very difficult to get them back in also. Man, I sure would recommend taking the no more then 30 minutes to pop those injector lines off, top and bottom in one piece with a 17mm open end. To get them back on, start all of them on the bottom but not very much. Then start all the tops. It is very easy to do and gives you a lot of access on the glow plugs. I would pull the hard lines to replace just one glow plug.

I guess I'm getting to the point of taking off the injector lines. I thought it was only the first one that was going to give me a hard time. I guess I'm going to have to struggle with them all and this is probably the best way to go at it. Is there a lot of fuel loss onto the floor? I just try to do everything as simply as I can because I'm not a mechanic. Of course, nothing is easy when you don't know what you're doing.

so all I have to do is take the injector lines out, bottom and then top and the whole line comes out?

Stevo · #13 10-21-2007, 12:18 PM

Quote:

Originally Posted by lws1

I guess I'm getting to the point of taking off the injector lines. I thought it was only the first one that was going to give me a hard time. I guess I'm going to have to struggle with them all and this is probably the best way to go at it. Is there a lot of fuel loss onto the floor? I just try to do everything as simply as I can because I'm not a mechanic. Of course, nothing is easy when you don't know what you're doing.

so all I have to do is take the injector lines out, bottom and then top and the whole line comes out?

Taking off the fuel lines as one unit is really the easiest and fastest way to get at the GPs. A couple drops of fuel may come out but not much. Do it with the engine hot and it will start easier.

junqueyardjim · #14 10-21-2007, 01:09 PM

For doing the compression test with the fuel lines off you can do it with very little fuel flying around and none on the floor. Do the test using the terminal block on the passenger side fender. I use a needle nose plier to jump the little screw to the middle screw. Get it all set up and have the gauge in a position where you can read it. Then insert one prong of the needle nose into the center of one screw, then when ready move the plier enough so the other prong will stick the center of the other screw. Try it once or twice before the test to get the feel of it, (and yes you might see a couple of sparks jump also). But by doing it that way (with the ignition off) your fuel shut off remains closed and no new fuel comes into the IP. So only the very small amount of fuel in the cell in the IP jump out and just put a shop towel over it and you will have no fuel. That terminal box is right behind the radiator overflow bottle and it is about three quarters of an inch wide and about 2 inches long and has a big X across the top. It has a pop open lid on it. Try it, you'll like it!

Stevo · #15 10-21-2007, 01:33 PM

Quote:

Originally Posted by junqueyardjim

For doing the compression test with the fuel lines off you can do it with very little fuel flying around and none on the floor. Do the test using the terminal block on the passenger side fender. I use a needle nose plier to jump the little screw to the middle screw. Get it all set up and have the gauge in a position where you can read it. Then insert one prong of the needle nose into the center of one screw, then when ready move the plier enough so the other prong will stick the center of the other screw. Try it once or twice before the test to get the feel of it, (and yes you might see a couple of sparks jump also). But by doing it that way (with the ignition off) your fuel shut off remains closed and no new fuel comes into the IP. So only the very small amount of fuel in the cell in the IP jump out and just put a shop towel over it and you will have no fuel. That terminal box is right behind the radiator overflow bottle and it is about three quarters of an inch wide and about 2 inches long and has a big X across the top. It has a pop open lid on it. Try it, you'll like it!

HUH

Never tried that