220d generator brushes - PeachParts Mercedes-Benz Forum

pdxwaker · #1 10-26-2006, 05:42 PM

I'm suspecting bad brushes on my 220d generator... looking for help/tips on brush replacement for this model. It isn't obvious to me how to replace the brushes looking at the generator. Note that this model has the voltage regulator separate from the generator and is not like the w123/w126 alternator where brush replacement is part of the voltage regulator.

Please reply with any tips/suggestions if you've done this before...

t walgamuth · #2 10-26-2006, 11:40 PM

it is a simple job. first take the generator off the car. there will be a band around the end where the brushes are located. this keeps dirt out of them. remove the band. remove the screws securing the brush wire. pry the clip away from the end of the brush and install the new brushes in the slot and secure the screws holding the wires.

on my 74 bavaria the brushes on the starter were soldered in. it might be soldered in your gen too. but if it is it isnt hard to solder the new wires on. but if you dont have the skill or the soldering iron you can prob take it somewhere and have that part done.

i dont think i have done a mb gen of that era but they are all very very similar.

good luck

tom w

Lycoming-8 · #3 10-27-2006, 01:11 AM

This seems a little strange to me, as my 1968 220D originally had an alternator. It lost a diode or two at one point, so I stole the generator off of the 190Db and kept on driving the 220D. Now that generator sounds a lot like what you are talking about, but it was not orig equipment for the 1968. Brushes for the generator were cheap and fairly easy to obtain back in the 80's, and that is why I made the swap.

One interesting feature on the MB generators is that the brushes have a travel limiter so the brushes don't just keep wearing down till the springs contact the commutator. You completely loose charging capability, but once it happens you will always know what is going on! Some of these springs are pretty stout, so I usually pry them up and tie them off or use a part of a tooth pic to keep them from ramming the new brushes too tightly to the commutator while you slip the whole end fixture back over the commutator. You may also have to polarize the generator once it is reassembled, before it is ready to use again.

t walgamuth · #4 10-27-2006, 07:15 AM

really? you can just sup a gen for an alt?

you didnt have to change anything else?

tom w

Lycoming-8 · #5 10-27-2006, 10:36 AM

Well I had to do a tiny bit of rigging so the main mount bolt fit correctly, and that the pulleys aligned. Also the regulator for the generator had to be incorporated into the wiring along with the generator; but that was only one connection that was different, I believe. Had an old hardback book that showed the wiring for both the Pontons and the '68 style electrical systems, and it seemed like an easy swap. Turned out it was, after the monster York compressor was out of the way!!

Remember these are Mercedes, the door lock knob on the '61 Ponton and an '85 300D are the same part!!!!!

t walgamuth · #6 10-27-2006, 02:59 PM

those door locks were used on avantis and ferraris too!

they were great!

tom w

riethoven · #7 10-27-2006, 03:41 PM

Quote:

Originally Posted by pdxwaker

I'm suspecting bad brushes on my 220d generator... looking for help/tips on brush replacement for this model. It isn't obvious to me how to replace the brushes looking at the generator. Note that this model has the voltage regulator separate from the generator and is not like the w123/w126 alternator where brush replacement is part of the voltage regulator.

Please reply with any tips/suggestions if you've done this before...

I've had several 60's Alfas and a 1955 220a MB that had Bosch generators on them. IIRC, you just have to take off a metal band that exposes the brushes and they are held in by copper springs. I think the leads were attached with screws, not soldered. Take the old brushes or the entire generator to the local auto electric shop that works on Bosch and hopefully they can match something up for you.

One of the Alfas I had, had a bad starter and they had to order the part (solenoid) from Germany. Well, months later after always parking on a hill so I could roll start, they figured out they had the part the whole time and that Bosch had changed their numbering system a couple of times between when the starter was made, and when I was fixing it.

pdxwaker · #8 10-31-2006, 01:10 PM

I've attached some photos of the generator... I still can't find the band that holds the brushes. I tried removing the black plastic cover to expose any brushes underneath but found nothing that looked like brush retainers...

Any help?

Lycoming-8 · #9 10-31-2006, 09:20 PM

Actually I believe that is an alternator. It is short along the axis of the shaft, with a large diameter. Should still have brushes, but they will be positioned against one of the end faces instead of the outer diameter of a commutator. Unit needs to come apart before you can get to the brushes and the diodes may also be inside. Been too long, but do still have one laying around that could be taken apart. Just don't have digital camera for pic posting.

deerefanatic · #10 10-31-2006, 09:59 PM

Ya, looks like you have one of the Bosch ALTERNATORS that have the EXTERNAL voltage regulator..........

I think I heard that they can be upgraded to an internal somehow...maybe not......

Good luck......

You could always put a 115 amp AL129x on it!

I have a thread on that!

t walgamuth · #11 10-31-2006, 10:42 PM

if you want good advice you have to give us accurate info!

that is most definately an alternator.

much much simpler to change the brushes. the place where the wire plugs in is the brush/ regulator. it is a $33 dollar part for generic, more for bosch. just unplug the wire and remove the screw (i think only one,perhaps there are two) and lift out the brush/ reg combo. put the new unit in and plug the wire back in. once you get where you can reach all the parts it is literally a five minute or ten job.

good luck.

tom w

pdxwaker · #12 11-01-2006, 10:34 AM

Quote:

Originally Posted by t walgamuth

the place where the wire plugs in is the brush/ regulator.

Nope, the regulator is on the passenger firewall. Wiring diagram is here: http://mb.braingears.com/114_115_Disk1/program/ETM/54_5_4.pdf. Everything on the car seems to match this diagram from what I can tell.

I guess I assumed this was a generator, not an alternator from the wiring diagram. Funny thing is I have 2 x 220d's with the same alternator and have a 3rd from a junked car... I guess I need to do a bit more research to understand the diff... previously I had assumed that the external regulator _was_ the difference.

The alternator is a Bosch AL64x. The brushes are not easily accessible from what I can tell.

deerefantic - the Al129x will not fit into a W115 220d without major mods to the alternator mounting (different from the W123). Let me know if you think otherwise as I have a spare and would love to do the upgrade.