r500 alternator replacement procedure?
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Joined: Dec 2018
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2006 R500
r500 alternator replacement procedure?
I'm looking for details on how to DIY alternator replacement for the r500. I've seen mention of pulling the radiator fan, but I can't see how to easily detach the front crossmember with the hood latch cables run through it. The service procedure on the WIS/ASRA software that I have are a little sparse on detail where that is concerned.
Can you get it out underneath? Thanks for any help, need to get this back on the road.
Can you get it out underneath? Thanks for any help, need to get this back on the road.
Out Of Control!!
Joined: Sep 2018
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From: unbegrenzt
2017 GLE350 4MATIC
Also not your vehicle, but a V8 M113. Common theme with the above video and this example is removal fo the fan and shroud assembly.
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!
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!
Thread Starter
Newbie
Joined: Dec 2018
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2006 R500
Thanks a ton - the trick is freeing the front crossmember - it has the cables for the hood release captive inside a channel . I guess I'll need to disconnect those cables - I'll look at the latch mechanisms accordingly
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Newbie
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2006 R500
Finally got the old alt out and the new one hung.
I could SWEAR both the black and the red wire were connected to the same post on the alternator I took out, but I didn't take a picture. Does that seem right?
I could SWEAR both the black and the red wire were connected to the same post on the alternator I took out, but I didn't take a picture. Does that seem right?
Thread Starter
Newbie
Joined: Dec 2018
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2006 R500
It didn't to me either - I'm thinking maybe the lead from my alternator to the starter may have been replaced at some point. Regardless, it works with both leads connected to the b+ post on the alternator. The car is back up and running as of this afternoon.
The other post is not used - it doesn't have enough thread to even get a connector/nut on it.
I'll post my findings, unfortunately without pictures - this was a little bit of an ordeal to get done.
The other post is not used - it doesn't have enough thread to even get a connector/nut on it.
I'll post my findings, unfortunately without pictures - this was a little bit of an ordeal to get done.
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Thread Starter
Newbie
Joined: Dec 2018
Posts: 6
Likes: 1
2006 R500
Ultimately, I didn't have to remove the cooling fan. That's a can of worms on the R, at least my R500 - the radiator lines are in the way of extracting the fan - not just for coolant, but the transmission and engine oil lines are in the same unit. You can't take out the fan without disconnecting the oil lines as well.
LONG story short, I was able to get the alternator out after remove the center crossmember, which required disconnecting the passenger side hood latches. The cables for the hood latches are captive inside the crossmember. Once that is loose, the radiator has a LOT of play. After disconnecting the top, bottom, and pump coolant hoses, I had enough play in the radiator to move it forward a couple of inches with a good tug. This was enough to get the alternator out.
Oh, also had to remove the front part of the under-engine cover, and the intake hoses up top.
Getting it loose requires a prybar - the brass sleeves in the bracket will keep it tight even with the bolts out. Once out, those brass sleeves have to be reset. I found this post on a Chrysler crossfire forum - this technique worked:
My wiring to the alternator had so little slack in it that I needed to hang the alternator first and then attach the wiring from underneath the car. I couldn't get it hung from the top with the cables already attached. After I put everything back together, I refilled about a gallon and a half of coolant before it went back to full. I ran it for an hour with the fill cap open and the heater on full, massaging hoses to get the air out.
Also, I never could locate the hole for locking the serpentine tensionser, not with the fan in the way. So I had to put the belt back on while keeping the tensioner loaded with a socket. Not too bad, but a little nervous that something would slip and break a finger.
That's it. If anyone has questions I'll try to clarify. In general - next time I think I'd be willing to pay for 1.5 hours of mechanic labor for this, which is what I was quoted. However, the markup on the part itself was over 2x what I could find it online for the genuine new Bosch part, which is what made me think I would rather do it myself. So I saved some money, but it took me WAY more time than it was worth to figure out the extraction. Reassembly was a lot faster, of course.
LONG story short, I was able to get the alternator out after remove the center crossmember, which required disconnecting the passenger side hood latches. The cables for the hood latches are captive inside the crossmember. Once that is loose, the radiator has a LOT of play. After disconnecting the top, bottom, and pump coolant hoses, I had enough play in the radiator to move it forward a couple of inches with a good tug. This was enough to get the alternator out.
Oh, also had to remove the front part of the under-engine cover, and the intake hoses up top.
Getting it loose requires a prybar - the brass sleeves in the bracket will keep it tight even with the bolts out. Once out, those brass sleeves have to be reset. I found this post on a Chrysler crossfire forum - this technique worked:
I just finished replacing my alternator on a 2004 coupe. Wrestling the old alternator out was quite a struggle due to the brass sleeves in the upper and lower mounting holes in the alternator bracket. It seems that when the alternator is installed, these brass sleeves are pressed into the alternator brackets when the mounting bolts are tightened. This takes up any slack in the area between the front inside and rear inside surfaces of the mounting bracket. It's also the very reason that our alternators are so difficult to remove. Buy a 5/16" carriage bolt x 2-1/2" long, a matching hex nut, and a 5/16" fender washer at your local big box hardware store. Slide the carriage bolt from the inside of the upper / lower alternator mount through the brass sleeve with the bare threads facing the front of the vehicle. Slide a 3/8" socket large enough to pass over the brass sleeve which is protruding towards the front of the vehicle. Slide on the fender washer and thread the hex nut onto the end of the the carriage bolt. Tighten the hex nut with an open end wrench until the brass sleeve has been pressed out of the mounting bracket and is flush with the inside mounting bracket surface. Disassemble the tool, and repeat for the other brass sleeve. Even though you only pressed out the brass sleeves approximately 1/4", that 1/4" of wiggle room that you gained will make installing the replacement alternator into the bracket 10000% easier.
My wiring to the alternator had so little slack in it that I needed to hang the alternator first and then attach the wiring from underneath the car. I couldn't get it hung from the top with the cables already attached. After I put everything back together, I refilled about a gallon and a half of coolant before it went back to full. I ran it for an hour with the fill cap open and the heater on full, massaging hoses to get the air out.
Also, I never could locate the hole for locking the serpentine tensionser, not with the fan in the way. So I had to put the belt back on while keeping the tensioner loaded with a socket. Not too bad, but a little nervous that something would slip and break a finger.
That's it. If anyone has questions I'll try to clarify. In general - next time I think I'd be willing to pay for 1.5 hours of mechanic labor for this, which is what I was quoted. However, the markup on the part itself was over 2x what I could find it online for the genuine new Bosch part, which is what made me think I would rather do it myself. So I saved some money, but it took me WAY more time than it was worth to figure out the extraction. Reassembly was a lot faster, of course.
Last edited by c0re; Sep 3, 2019 at 12:10 AM.
