Need Help Replacing Injector seals - PeachParts Mercedes-Benz Forum

EricSilver · #1 08-02-2003, 02:01 AM

Car: 1989 260E

I purchased a set of new injector seals. I wanted to replace them today, but encountered some problems:

1.) After removing the hex bolt on that metal bracket it which secures the injector to the engine, does tne bracket slide off somehow?

2.) The top part of the injector assembly, attached to the fuel line, is hexagonal metal. Do I use a wrench to unscrew this? Do I hold the lower plastic hexagonal part still while doing that, or to they turn together?

Any help would be appreciated.

sbourg · #2 08-02-2003, 02:19 AM

The bracket is all that retains the injectors - however, you must disconnect the injector fuel lines to slip the bracket off. You use two wrenches, one for the fuel line compression fitting, and another on the injector directly below, to keep it from turning. Best is to place the wrenches so the handles form a small angle to each other. Then grasp both and squeeze to loosen the compression nut. Then use only the wrench on the nut to remove the line. Once the injectors are out, you may have to carefully cut the old, hardened seals to get them off. The new ones should pop on easily.

I also found it best to remove both ends of the injector lines - at the fuel distributor too. Take a picture if necessary to get the routing right on reassembly.

Steve

mike690003 · #3 08-02-2003, 02:31 AM

Tools needed:
2 13mm open end wrenches.
5mm allen Hex
10 mm open end wrench

Steps
- Remove air filter
-Loosen gas cap(to remove pressure)
-look closely at injector holders. there is the 5mm allen hex hole.
if you have a 5mm hex ratchet. that is a lot better, you need a lot of pressure to loosen the hex.
-After that loosen the bolt on the fuel distrubutor that corresponds with the injector(those thin metal fuel lines, the are 10mm)
-after removed, put the 13mm wrench on one end of the injector connector, and the other wrench on the metal fuel line connector. Hold one and turn the other, in order to loosen that injector.
-replace injectors, and the injector seals. A shortcut to remove the seals is to slice them off with a razor blade or knife. and slide the injector seals onto the injector.
-reverse the steps to reinstall the injectors and fuel lines
Takes 1-2 hours(for a first timer)

any more questions, or if the directions seem too fuzzy,Please PM me!! I will gladly respond ASAP.

EricSilver · #4 08-02-2003, 10:07 AM

Steve & Mike,

Thank you both.

Just so I am clear: After removing the hex bolt on the bracket, I loosen & remove the fuel line at the fuel distrributor, then twist the hexagonal metal part of the fuel line where it meets the injector while holding the yellowish looking injector in place?

Sounds easy enough. I plan to remove and replace one seal at a time before proceeding to the next, so I can avoid mixing the fuel lines up when it is time to reassemble.

I am glad I chose to stop what I was doing last night and seek help here. I hate to think of what trouble I'd be in right now had I just gone ahead and tried to guess what to do

Thomaspin · #5 08-02-2003, 11:54 AM

Eric -

When I did the intake manifold work on our 380SLC I also replaced the seals, holders and O rings, and illustrated the job here. Some of these pix may help - similar on your engine.

With abundant respect to Mike690003, I would not use a knife to remove the old seals as you risk scoring the injector body and creating a leak. Your choice, however. Slide on the new ones after oiling the injector shaft, like the factory manual says.

Also, I would loosen and remove the fuel lines (you may have to completely take them off if too much bending is involved - meaning undoing them carefully at the fuel distributor, using a brake line wrench if possible - see my pix) before undoing the 5mm Allen bolt retaining the injector retaining plate/spring - less stress on the line that way.

The injector line is 14mm and the fuel distributor line 12mm on the M116. Not sure of your sizes.

sbourg · #6 08-04-2003, 10:22 AM

Since each pair of injectors is retained with one bracket, they are best worked on as a pair - i.e. remove a pair of injector lines at both ends at a time. Whatever your procedure, do NOT bend the lines at all! It will be difficult to reattach them without crossthreading if you do. Also, the reason for squeezing both wrenches in one hand is it prevents inadvertantly putting undue force on the retaining bracket and damaging it.

Using a single edge razor blade to slice the old seal should be fine, using safety precautions and cutting only far enough to insert a flat-edge screwdriver tip. That you twist to propagate the cut until the seal is separated.

Steve

EricSilver · #7 08-04-2003, 11:18 AM

Thomaspin - that is an incredible collection of DIY procedures you have amassed -- a definite public service. I will be using them as a resource for future projects. Thanks for the help.

Steve -- I am confused now. What bracket do you refer to -- as far as holding a pair of injectors -- the one with the hex bolt?

What I had planned to do was remove and replace one injector at a time: remove fuel line from injector and distributor; remove injector, replace seal, replace injector, reattach fuel line to injector and distributor, proceed to next injector.

In my aborted attempt last Friday, injector #1 (at the front of the engine) could be lifted halfway out with the seal attached. I assume that is normal, and only after the injector & seal are out will I have to cut the seal away, and attach the new seal and reseat it?

I can be pretty clumsy with a knife or razor blade on small objects (and really don't enjoy cutting myself) so I'll probably use a small pair of nippers to cut the old seal away, with minimal risk to the injector.

I will most likely do this job mid-week, so if I mess something up I can get to my mechanic's with no weekend delay. But so far it seems straightforward.

sbourg · #8 08-04-2003, 11:53 AM

"Steve -- I am confused now. What bracket do you refer to -- as far as holding a pair of injectors -- the one with the hex bolt?"

Yes. On our 2.3, that is the only bracket that is involved, and it retains 2 injectors. I cannot remove the bracket to get the injector out without disconnecting the lines to both. I suppose it might be different on the 2.6.

Steve

EricSilver · #9 08-04-2003, 12:29 PM

The 2.6 has one hex bolt bracket per injector. The one I removed actually came out without too much trouble (they are in very tight) but I nonetheless intend to get a hex socket wrench to make it easier.

nthach · #10 08-04-2003, 03:04 PM

Thomaspin, you have bigger versions of the reference pics?

Thomaspin · #11 08-04-2003, 03:33 PM

Nope. That's as big as they get. You can print them to a larger size but definition will suffer - originals are only 640x480 for the most part. That's the lowest definition setting on a 1.3mp digital camera. I keep them small to allow fast loading.

If you are concerned about the mating of the two part seal, don't be. It's shipped mated, so just note how it goes together and also take a look at the old one before pulling it off. All the other parts fit one way only. Make sure the two parts mate on the injector shank. They tend to separate when you slip the seal on - a bit of light oil helps.

EricSilver · #12 08-08-2003, 10:42 AM

It’s done! I finished the job yesterday.

Took about 3 hours – but would have been a 45-60 minute job if I had better access to the injector hex bolts. I urge anyone doing this work to buy either a rounded end 5MM hex wrench, or a bendable, narrow ratchet with a 5MM hex bit. (The toughest ones were injectors 3 and 4. One and two (in front of engine) were OK, and 5 & 6 were a breeze.) Also, replacing the fuel lines at the distributor took time. If the bolt is not perfectly aligned, it will not screw in.

I did this work in hopes of correcting some stumbling and hesitation at idle, which appears to have been somewhat accomplished. The roughness is significantly less noticeable and more consistent, like a sine wave that has been flattened. Instead of periods of smoothness interrupted by roughness, I now am experiencing smoothness with occasional undercurrents of mild roughness. In truth, this is fine for an almost 15 year old car, but at times my idle is so smooth I cannot tell that the engine is on, and I want it to be that way all the time. (Or am I asking too much?)

I still need to have my fuel/air mixture readjusted, which should help even more. For now, I at least know the occasional roughness is not electrical (replaced plugs, wires, distributor and rotor a few weeks ago) and not because of leaky injectors. The (brass) injectors themselves looked clean, but that really tells me nothing. I may run some Techron through the system and perhaps do an Italian tune up. After that, my areas of focus are the fuel filter and air filter. I hear things about the air mass sensor, but I will not be messing with that.

EricSilver · #13 08-08-2003, 10:47 AM

Oh - forgot to mention that the wiring harness had to be unbolted to easily remove the fuel lines. Appears to be just the one bolt next to the engine. Of course, I dropped this bolt and hope to find it on the belly pan, wedged under the sway bar.

EricSilver · #14 08-08-2003, 01:58 PM

Also,

It was no necessary to remove the fuel line at the injector. Once the line is unbolted from the distributor, the whole fuel line/injector assembly can be lifted out in one piece, the old seals cut away, and the new ones slipped on.

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