Mercedes-Benz Forum banner

1 - 3 of 3 Posts

Mercedes 420 SEL
617 Posts
Discussion Starter #1 (Edited)
I have to say for two bolts and a couple of shims, what a major pain - literally and figuratively. I"m recovering from a torn rotator cuff, so being under the car was a bit awkward, but I digress.


3/8 inch 18 inch extension
Swivel head extension for the socket
Breaker bar
18 inches of plumbing pipe (not too big, enough to fit over an allen key)
10 mm allen key
Stubby flat head screwdriver
Stubby phillips head screwdriver
13mm wrench
assorted metric sockets
Super Glue
short handled (stubby) flex-head ratchet
3 ton jack
jack stands


Impact gun w/ assorted sockets.


Step 1: Put car in Park, and chocked driver side rear wheel so car wouldn't roll. Remove negative ground from the battery.

Step 2: Jacked up car. I first put it on a support beam under the car, but noticed I was crushing that beam, so I found the jack hole and put the jack under that spot, worked great. Placed Jackstands under car for safety

Step 3: Looking at space, you can't get to the bolts without removing the beam that protects the transmission, it looks like some sort of brace. There are six bolts that attach it to the control arms (?). They are easy enough to remove, and the brace comes right off.

Step 3a: Using your stubby head phillips screwdriver, remove the wire coming from the battery that attaches to the starter. Then unbolt the small nut on top of the starter--I think its a ground of some sorts, but I don't know.

Step 4: Using the 10mm allen key, took off the bottom bolt. It wouldn't come off with just that, so I used an extension, which was simply a cheap piece of metal pipe about 18 inches long. Inserted the key into the pipe, then the key into the allen head bolt. (if you put the allen key on the bolt first, then you won't have enough space to slide the pipe onto the allen key.

I would advise against using PB blaster, WD-40, etc with an allen head bolt. I've seen them cause the key to slip and then strip the bolt--which would be disastrous. Avoid it if possible.

Step 5: Big step 5 - The Top Bolt. Fortunately, somebody had taken the starter off before and replaced the allen head bolt with a regular hex head bolt. Either way, the following steps are the same, just substitute a 10mm hex head socket for the six point socket I used. (They make a 10mm allen key type socket, but its an actual socket you can put on a ratchet.) I'm pretty sure Sears sells it individually, but if not you can buy it as a set, which is quite handy.)

Place the flex-head adapter onto the 10mm hex socket. Attach the flex-head adapter to the 18 inch 3/8 inch extension.

I wouldn't use a 1/2 inch, as I doubt it would fit between the exhaust and the body of the car.

I didn't remove the 02 sensor nor did I remove or loosen the exhaust. There was a hangar that looks like it should have been bolted down to something, but this wasn't. Looks like a transmission oil cooler line or something--if it is attached, I'd remove it so you can reach that top bolt.

Step 6: Find the top bolt. This is kind of tricky, actually. How I eventually figured it out was by looking at the new starter and getting a feel for where it should be. The easiest wasy is to follow the "round bulge" from the bottom bolt, glide your hand over the circumference and follow the round bulge over and up until you can feel it. Its a bit rearward (rearward being in the direction towars the back end of the car)

Note: Make sure the allen head bolt is clean and free of debris so you get them maximum insertion--if not, you risk the possibility of slipping and stripping it.

Step 7: Slide the extension, hex head socket, and swivel head up by the exhaust while reaching around with your right hand (in front of the tie rod) and reaching up over the starter--feeling for the extension which you are working up with your left hand--and guiding the socket into (or onto) the bolt head.

You can actually get a pretty straight shot this way without too much angle.

Step 8: Attach the breaker bar to the extension--while maintaining pressure on the extension so it doesn't slip off. An extra set of hands would be extremely helpful here, but not necessary. (I did this by myself....with a bad shoulder.

Step 9:

Very carefully press (push?) against the extension while turning with the breaker bar (regular ratchet would work, but I like the breaker bar because it has no flex in it). Apply pressure so the socket doesn't pop off the bolt and stripping it. Work carefully, but be prepared to put some muscle into it to break the bolt free.

Note: Use a quality extension so it doens't torque and twist--thus losing all your power to break the bolt free.

Step 10: Remove top bolt. Versus trying to unthread it with your bare hands- which will be impossible, just use the extension and back it out.

Keep all bolts, nuts, washers in one place. I find a magnetic dish is quite helpful.

The starter should now just slide out. Be careful, its heavy.


Step 1: Have patience, lots of it.

Step 2: My starter plate had two metal gaskets and a metal gasket with a tab for the slot/very small dowel on the bell housing--so three metal spacers/gaskets.

The one with the tab was easy, because it slipped onto the dowel, the other two, not so easy.

I ended up just super gluing the two without tabs onto the one 'gasket' with the tab, so all three would line up, stay together, and not fall off while trying to install the starter.

Step 3: Thread top bolt and bottom bolt through their respective holes. Line up the gaskets onto the bolts then insert the starter.

Step 4: I started with the bottom bolt. While holdilng up the starter, I hand threaded the bottom bolt onto the starter, then let it rest on that little dowel that sticks out--while still pressing the starter up against the bell housing so it wouldn't slip off and fall down. Trust me it slipped off and fell down a ton of times--I'm not really sure I needed those metal spacers, but I wasn't about to second guess something.

Once you get the bottom bolt started, then work on the top. I was able to turn the top bolt by hand. Instead of grabbing the head, I grabbed the center part of the bolt and turned it that way--because I don't think you can get your hand back that far...I kind of also used my index finger alone and "spun" the bolt to get it started.

Step 5: Hand tightened the bottom bolt--not quite all the way. Hand tightened top bolt via the extension and swivel head. Then tightened down bottom bolt and then tightened top bolt.

Those five steps probably took me a good 2 hours--to get the bolts started, the starter lined-up properly, etc. :rolleyes:

Step 6: Tighten up both bolts, re-attach power wire. I noticed my starter had two attachment points, its the bottom of the two (in my case). The starter had a flat head screw instead of a phillips.

Step 7: Check all bolts to make sure they are secure, then re-attach brace.

Step 8: Remove jackstands, lower jack, and you're done.... (oh yeah, reattach negative ground to battery).

Well, there you go. I hope this was helpful, sorry I didn't take pictures. This job is straightforward, it just takes time, dexterity, patience, and a bit of strength.


Premium Member
1973 450SL 2004 E320 4Matic Wagon 2019 Jeep Grand Cherokee
3,199 Posts
Great write-up

Thanks for taking the time to walk us through this along with your helpful hints.
1 - 3 of 3 Posts