Does anyone have a visual writeup on how to change the ignition cables on a 90 e300? I am hoping to do a general tune-up this weekend and could use all the advice that i can get! Things on the list include:

-Ignition cables
-Spark plugs
-Brake pads
-Oil change
-air filter change

for the pads, i just unbolt the calipers and pop the pads out and put the new ones back in with a clamp right?

If anyone has any suggestions about procedures for any of these, your help is appreciated!


Thanks,
-MaloventEvil from BF.c

 

By ignition cables you mean spark plug wires? If so, they are easy as can be really. You have to carefully remove the plastic cover over the distributor, which is located on the top front of the motor, at the end of the head. Then carefully pop out the cover that runs down the middle top of the valve cover. All of the spark plug wires are routed in here. Your new wires should be labled 1 through 6. I suggest you start at either end of the motor and work your way across the motor replacing one wire at a time. The book calls for using a special pair of pliers to remove the wire from the spark plug, but I have found it to be just as easy to do it by hand, carefully grabbing the wire at the end, where the base snaps over the plug. I would replace the sparkplug at that time too. Before you unscrew the sparkplug out, give the recessed hole that the plug is down in a good blast of compressed air. If there is any loose dirt or dust down there it should get blown out and not enter the cylinder that way. Check your plug gap on the new spark plug, apply an anti-seize to the plug threads (I just give the threads a small squirt of WD-40), and then CAREFULLY start the plug in the spark plug hole threads BY HAND. Do not cross thread these threads! If you are unsure at all, immediately stop and back out. They should start in easy as can be. I slip the spark plug into my spark plug socket that has a rubber insert that holds the plug in place, and with a short extension inserted in the socket I hand tighten the plugs in. Believe me, cross threaded spark plugs are probably the most common and easiest way that heads get damaged. Anyway, after hand tightening it down until the metal plug gasket contacts the head, I then put the ratchet on and tighten it about 1/4 turn further, no more. Kind of depends on the plug gasket design used, but just enough to compress it. Again, here it is very easy to tighten those aluminum threads too much and strip them. I don't recall a torque off the top of my head, but I'd say probably no more than 10 - 12 ft./lbs.

Oil change. You want to change it while its hot (and often), but not so hot it'll burn you. I prefer using a topsider suction system for most oil changes, but about every 4th or 5th change I drain the oil through the pan drain bolt. To change the oil filter, you need either the filter tool that slips over the end and lets you use a ratchet on it, or a strap wrench like I use. I have to remove the air filter housing to get enough room to get at the filter, but if you had the end cap type filter tool you might not need to.

On the air filter, it is really easy to take the top of the filter housing off. Four 10 mm nuts on the top, and 8? latches around it. The rubber hose from the valve cover to the air filter top just pops off. To remove the rest of the air filter housing there are three more 10 mm nuts. Two are in between the filter housing and motor, pointing up, and the third is on the driver's side, in the middle, pointing towards the driver's side. You should then be able to pull it off, slipping it carefully off the intake and out of the cold air intake. While you have it off, lubricate the accelerator and cruise control linkages and cables. While you got the lube out, lubricate the hood hinge pins and latch too, and clean the cabin air intake screen right under the windshield wiper. Check your battery terminals and ensure they are free of corrosion. I have had far less problems on my 300E with this than on any other car I've owned, due to how the battery is situated and protected, but it's still worth checking. If you see any white corrosion, then clean it off with a tooth brush and a paste of baking soda and water.

While you're at it, I would recommend changing your coolant too, if it hasn't been recently done, making sure to only use the MB coolant or its equivalent (NO GREEN STUFF). Tranny fluid and power steering fluid changes are good cheap insurance too. Both of those have filters as well.

Brake pad change: Yeah, pretty much like you said, but be sure to replace the front brake wear sensors, and use the MB brake grease on the pad backsides/ edges to prevent squeaking. Also, inspect the rotor surfaces for flaws, and a dial gage to check for runout is also very good, as well as a micrometer to check the disk thickness and make sure its still in specs. (Looking for warpage) Also, since you are doing the brake pads, be sure to flush and bleed your brake lines, starting at the passenger side rear brake. Remember that the brake resevoir is open to the atmosphere, and that brake fluid will draw moisture right out of the air and get contaminated, and water in the brake fluid boils and causes mushy brakes. Flushing the brake lines every two years is very good preventative maintenance. I have had zero problems with any brake components, and I attribute this to flushing the fluid every two years.

I think that the first components to usually fail on these motors, is the water pump which is what I am currently replacing on my motor. While I'm in there I'm replacing the belt, tensioner, tensioner damper, tensioner adjuster, idler pully, and am going to try and refurbish my viscous fan clutch. (it currently has marginal performance, keeps spinning after shutting the motor off when hot, spins the fan when the motor is running, but doesn't every really engage.) If the refurb doesn't work, I will just replace it later. With winter here now, and the majority of my driving on the highway, I'm not too worried about the marginal fan clutch right now.

 

spark plug wire removal can often be easier said than done. Mine were on the spark plugs so tight that i had to take a set of needle nose vicegrips and clamp them down on the plug wire socket, then clamp another set of vice grips to the needlnose at a right angle and pull, lever off. I hope yours are easier to remove. If you're going to replace the old wires then you can be more aggressive in yanking the old ones off and not worry about damaging them.
Be sure you replace the brake pad caliper screw, a new one should come with your pads.

 

Just a tip to male things easoer for you..use Beru spark plug wires....About $125 for the SL320 6 cyl..they are top quality,east to snap on and off,and fir perfectly.I replaced my Bosch plugs and pit on mew wires and the car runs like it is brand new.Make sure that you don't ovetighten the plug cover nolts.Check your battery output and your alternator output and the condition of the voltage regulator.If needed replace them with a rebuilt unit

 

You might also want to do your cap and rotor while you're replacing the plug and wires, it's pretty much a unbolt and replace w/ new item procedure. As far as the brakes, don't for get to bleed them properly w/ the correct bleeding tool. Pumping the brakes to bleed them can cause your ABS to get all screwing. Using the correct bleeding tool (cost about $50) will save you from future trouble.