Gori

I had the alternator/visit... red light on on a hot summer day. I had to drive home and about after 5o miles, A/C went dead, radio went dead, and temperature rose, and the car stalled... on a highway with no shoulders.

Anyway, I read other threads about DIY alternator replacement, and found several of them on C32 and other cars, but not on C55. Many say voltage regulator is the culprit, so I bought one on line (only 9$). Some say VR can be replaced without removing alternator, I tried from underneath the car, but couldn't.

Now I tired from the top, but there are many things on the way. I had to remove front grill, front crossmember (on top of radiator), serpentine belt, one of the hoe (top) to radiator (to create space to pull out electric fan)electric fan. Remove alternator bolts x 2, but the alternator didn't budge. Tried to pry out, without success.

I don't know what to do at this stage. pay$$$ to dealer or car shop? I can imagine even if it's just RV to replace, labour won't be cheap.

After removing long 2 bolts that hold alternator, there seems to be gold-coloured sleeve inside the bolt-hole that prevents altenator from sliding out, and I don't know how to remove it. Front section of the bracket that holds alternator seems to be part of a water pump assembly, so I should I remove them also? Tha would be a lot of job, removing pulley, etc.? Any advice will be appreciated.

Thanks.

MarcusF

Both having M113s, its not surprising that this sounds like a CLK. If the electrical connections in the rear are unplugged, and both bolts have been removed, then the only thing holding the alternator in place is a pressure fit. You'll need a pry bar. Fortunately, it slips back in a lot easier than it comes out. I think your assumption about the voltage regulator is probably right. It's a normal wear part.

Here's a writeup from when I did mine - http://www.marcusfitzhugh.com/CLK/DIY/alt.html

Gori

Thanks for a quick reply. I saw your thread and the webpage before I tried to do mine, and it was of great help. I think I will try one more time, even though I put everything (fan, belt, etc.) back last weekend.

The pressure fit is the gold thing in the bolt hole that still remain there after removing bolts? It has a slit in the middle, so I guess you should be able to squeeze and pull out. By pry out, you mean prying out the whole aternator (to the left) or the pressure fitting (towards you through bolt hole)?

RedBull

If it is anything like removing the C32 alternator, then you have my condolences. Myself and a friend did mine, and we removed it through the top.....one of the biggest PITA I've had with a car. Good luck!

Gori

I looked up both WSI and AlldataDIY. WSI said remove alternator from engine bay after removing fan ,etc. Alldatadiy said remove VR while aternator is bolted to the engine. So again, I tried both.

1st Alldata method. From underneath the car, remove stabilizer bar. Small space to work on but still OK, but the botles/nuts were torqued too tight and with the difficult angle I have to work with wrenches, I gave up.

Next WIS method. After 2 tries in over a week (see my post above), I was fnally able to remove alternator from its bracket, but removing from the engine bay was difficult, it needs disconnecting a couple of hoses so insetad of that, I decided to work on the alternator removed from bracket but still in engine bay. Extremely small space, but I shifted alternator around several times, and finally found a good position; settle it facing downward and back cover facing up. I attached philips screw to 18 inch breaker bar and tried really hard, finally the nuts and a screw came off from back of alternator. Screws holding VR was also very tight (who torqued such a small screw so tight?)

It took 4 or 5 attempts in over a week, a total of maybe more than 10 hours of work. I am very tired, buit it's done.

colin b

Facing problem with alternator ,when the alternator bolted up all a.c , fan gets off

DG83 C55

Did you guys have to remove anything when you removed the alternator from a C55? It looks like I at least have to take off the radiator fan but am a little unsure.

Damian

DG83 C55

Anyone? I really would feel useless if I end up having to take this to the shop just to replace an alternator since it is very simple and direct. However, getting it out of the engine bay is what has me at a standstill.

Damian

DG83 C55

Everyone, I have searched and searched - even subscribed to StarTek to see if that would offer any solution. Turned out to just be a waste of $18. If anyone can give me any guidance at all it would be great.

Thank you,

Damian

ghiaguy

Looks like a VR and new battery didn't fix my issues..
I will be replacing my alternator this weekend. Anything I should know/ any specialized tools I will need?
Thanks!!

MarcusF

When I've had an alternator actually die, I've taken it to an electronics rebuilder - someone who specializes in rebuilding starters and alternators. The cost is typically around $75 and they do it in a day (within an hour if they're not working on something else). They disassemble the alternator and install a kit that typically includes bearings, brushes, and a diode pack. I find this to be better than buying a rebuilt alternator at a chain store because an individual rebuilder will install the entire kit. Many chain stores use rebuilders who only fix what's wrong. For example, is a 100,000 mile alternator needs a diode pack, that and a coat of paint is all it gets. This allows the rebuilder to save money on parts.

Other than that, the alternator in an M113 powered CLK comes off just as I said in the second post. It may differ sightly on a W203, but it's undo the drive belt, disconnect the power, remove two bolts, and slide it out with a pry bar.

ghiaguy

Fantastic! Thanks very much for the prompt reply.
I got a replacement that doesn't require a core return, so I will take your advice and rebuilt the original alternator to have as a spare!
I took a look at that writeup last night and was shocked to see only two bolts. Thanks for confirming that I won't need the fan clutch tool!
Happy New Year!!

betrezra

I bought the rebuilt alt from mb and it was over 500$. Def get your local shop to rebuild.


I thought I was getting new when I bought mine. New was over 1000$

ghiaguy

Ouch! I picked up one from a California Alternator to throw in while I rebuild the OEM one. I'm tackling this tomorrow and hoping it all goes to plan. I can't wait to be able to go WOT with the car again!

ghiaguy

Job done- My experiences changing the alternator on my C55 over this last weekend are as follows…

There are clearance issues with the removal of the alternator in the V8 w203. I contemplated several different solutions including removal of the water pump, raising the engine, and removing the fan shroud assembly. The water pump would solve the interference directly, but be a total pain in the ***. A quick trip to Mercedes taught me that my car may have two different pumps (with differing gaskets) and both gaskets had to be ordered. I needed the car for work at 6 am Monday morning so that would leave me channeling my inner MacGyver. The thought of attempting the salvation of the present gasket while removing all those little bolts was frightening so I shelved that idea. Next thing considered was raising the engine to allow the alternator to snake underneath the water pump bracket. I didn’t do this because I had just invested in fresh motor mounts and didn’t want to upset their seating. I would be lying if I didn’t say lifting the engine was also imposing enough to scrap it right away.



The solution I settled on was one that I found mentioned with regards to the w210 E55 guys. The removal of the fan and fan shroud allows acceptable room to maneuver the alternator out of the engine compartment. Also, a benefit over the w210s, the C55 doesn’t require any specialized tools for removing the fan. Unfortunately, I didn’t take more pictures as this was a ‘learn as you go’ operation.



With the serpentine belt and all coolant lines in the way removed (it pays to siphon off some coolant first), you can remove the fan itself. It was held on with four Torx bolts; small, T-25 if I remember correctly. Maneuver it slowly up and out of the engine compartment. The water pump pulley is the only really tight squeeze here. Next, you are on to the fan shroud which is a bit more of a pain.

My method was a little shade tree with regards to loosening and flexing the front engine compartment sill to allow the fan shroud to be removed. You do this by removing two silver bolts on either side, pictured:


Then I took off two little 8mm bolts in the center to minimize undue stress on the grill. These circular black plastic plungers hold the radiator centered, I removed these and unhooked the little arms to keep the radiator from working against us. Here’s where another pair of hands is quite helpful, I was lucky enough to have my Dad give me time away from his ’41 Chevy project.



There is a large electrical plug at the bottom driver’s side, extremely accessible from under the chin of the car. Remove that first then look for clips on either side of the fan shroud that will release it from your radiator. With it disconnected, carefully walk it up and out of the engine compartment making sure not to get stuck on wiring on the driver’s side and AC lines on the passenger side. The engine compartment sill does need to be pulled against- do so carefully and evenly. There are some very close clearance spots around the water pump pulley and the oil filter area. Be sure to come up with it evenly to avoid getting caught up. Patience and good light are important to avoid any unnecessary collateral damage.



Above is a picture of the cavernous room you have with the fan shroud out. Do be mindful of the exposed radiator! There is zero protection and the alternator is quite heavy. The room made from the fan shroud removal is enough to get the alternator out without removing the VR and cover from the back. I would leave all that intact on the alternator to protect it for a later rebuild.

*Remember to move the small sleeves in the upper and lower alternator mounting points to allow for the new alternator to slide in easily. These little golden sleeves, not witchcraft, were why the old alternator needed prying out once you removed the two bolts.

Good luck and safe travels!

gnma

Thanks for the pics and write-up Ghiaguy, and thanks to MarcusF - your website is of great help!

cblue55

Thanks ghiaguy, this was massive help for my first alternator change. The only thing I'd do different next time (which I hope is not for quite some time) is actually drain a considerable amount of coolant from the bottom of the radiator first.

ghiaguy

Glad to hear it worked out well for you guys! Hope you enjoyed a beer once the job was done or during

Juho

Hi Marcus, do you have a version of your write up posted somewhere else nowadays? The link above goes to a 404 page. Thanks!