alternator question 66 230 sl

[merrill]

drove my 66 230 sl today and the alt light dimly came on and stayed on AND the voltage meter I have pluged into the lighter read over 16 volts at 3000 rpm and about 15 volts at idle.

should I suspect the regulator or alternator?  I have a new regulator and the last time I plugged it in the alt light came on bright.  put back in the old one and the alt light went out.

next, can the alt be tested if I take it in to the auto parts store?
and if mine is bad the only alt I see for the sl is bosh AL64X.  (I know this is the 35 amp unit)

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[merrill]

called a local alt rebuild shop, they said it probably was not the alt.  suggested I check all connections.

so, cleaned all contacts at regulator, ground, then went to the alt.
turns out the line that bolts to the rear of the alt was loose. (not the 3 prong plug)
cleaned and tightened all connections at alt then turned on car.

well, the light came on still and did not go out.
turned off the car, plugged in the new volt regulator and light went off.

not sure what happened but the light if off now and I will keep an eye on the voltage.

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[merrill]

asked an mb tech about the problem and he said it was a diode going bad.
installed new alt and problem solved

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[rwmastel]

quote:Originally posted by merrill

asked an mb tech about the problem and he said it was a diode going bad.  Installed new alt and problem solved.

Matt,

Is that something an alternator rebuild kit would include.  I believe I've read that these Bosch alternators can be rebuilt.  Anyone?   :?:

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[hauser]

I just put in a new alternator from Bosch.  The 35 amp is hard to come by so I went with a 55 amp unit.  It takes the factory plugs just like the original so no mods were needed.  The alt was $153.00 with the dealer markup.  The core exchange was $45 but I decided to keep it.

1969 280sl 5 spd
Gainesville, Fl.

[jacovdw]

Rodd,

The short answer is yes. The Bosch units can be rebuild. I still have the original 35A alternator in my 230sl with the separate posts at the rear for the different connections. I intend to keep the alternator and have done a lot of research when I experienced similar problems like Merrill.

To cut a long story short, most reputable auto-electricians would be able to do a complete rebuild including worn out slip rings. Sometimes, it is just easier to replace...

Jaco van der Walt
1964 w113 230sl
1975 w114 230.6

[merrill]

regarding the rebuild.  the alt shop I contacted in austin said they could get the parts to rebuild my alt,  but did not have any.

I walked into car quest, told them I could get one off the net from az autohauz for $77 but did not want to deal with the shipping and I got a rebuilt one for $100.  (core charge was separate)

I find that letting these supply houses that I can get the parts cheap off the net causes them to match the price.

the car quest list for my alt was $230, but I got it for $100.


matt

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230

[waqas]

Hey Matt,
How did your replacement work out?

When I started the car this morning, the alt light came on and stayed on  until I'd driven for about a block. It hasn't come on again yet (went for a longer drive over lunch). I wonder if my voltage regulator is starting to go bad...

WAQAS in Austin, Texas

[merrill]

waqas,
new alternator is in, but if I use the new voltage regulator the light stays on.  Put on the old voltage regulator and the light goes out.

I will see if the voltage regulator can be tested off the car.



Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230