Author Topic: 280SL Suddenly won't start  (Read 156 times)

johnshenry

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280SL Suddenly won't start
« on: August 07, 2025, 15:45:14 »
Our '69 280SL has been running flawlessly for a few years after a new engine rebuild.  Yesterday went to take it to the golf course and it wouldn't start.  A loud click and a whining sound (fuel pump I presume) when I turn the key to the start position.

Put a charger on it over night, went to try it today, same thing.  Put a meter on the battery is was 12.47 volts, and around 12.1 when I turned the key to start so I presume the battery isn't the issue.

Oddly, the taillights and reverse lights come on when I turn the key to the start position, and, I found that I can push/roll the car when it is in D, R or P (?).

Been a gearhead for 40+ years, and have several other antique rides, but confess I don't wrench on this one much (I write checks).  Ideas/tips on what to check next?

Vander

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Re: 280SL Suddenly won't start
« Reply #1 on: August 07, 2025, 16:08:59 »
If you can roll the car in any gear it sounds like your shifter linkage bushings broke underneath the car.

They are on the side of the transmission, and can be seen easily if you have a way to jack it up and get underneath.

Car won't start because the transmission is not in park, even though the shifter inside appears it is. Neutral safety switch is doing its job.
1969 280SL

johnshenry

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Re: 280SL Suddenly won't start
« Reply #2 on: August 07, 2025, 16:41:56 »
If you can roll the car in any gear it sounds like your shifter linkage bushings broke underneath the car.

They are on the side of the transmission, and can be seen easily if you have a way to jack it up and get underneath.

Car won't start because the transmission is not in park, even though the shifter inside appears it is. Neutral safety switch is doing its job.

That makes sense given the symptoms.  I'll get under there and have a look.  Thanks......

rwmastel

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Re: 280SL Suddenly won't start
« Reply #3 on: August 07, 2025, 20:53:33 »
These bushings are a common problem.  Use our Search feature on this forum and learn all you need to know.
Rodd

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2017 C43 AMG
2006 Wrangler Rubicon
1966 230SL auto "Italian"

Mike Hughes

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Re: 280SL Suddenly won't start
« Reply #4 on: August 07, 2025, 21:50:27 »
These bushings are a common problem.  Use our Search feature on this forum and learn all you need to know.

Type "shift lever bushings" in the Search box and select "Entire forum" in the adjacent drop box then click the blue "Search" button in the top right-hand corner underneath the Pagoda SL Group logo.
- Mike Hughes  -ô¿ô-
  1966 230SL Auto P/S
  Havana Brown (408)
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johnshenry

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Re: 280SL Suddenly won't start
« Reply #5 on: Today at 01:08:21 »
Thanks for all the tips.  I didn't mention that our 280SL is an Automatic.  Does the "check shift lever bushings" still apply??  Hope to get the car up tomorrow and have a look.  But the theory that it "thinks" it is not in park and won't start makes sense.

Vander

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Re: 280SL Suddenly won't start
« Reply #6 on: Today at 01:19:25 »
Thanks for all the tips.  I didn't mention that our 280SL is an Automatic.  Does the "check shift lever bushings" still apply??  Hope to get the car up tomorrow and have a look.  But the theory that it "thinks" it is not in park and won't start makes sense.

You may not have said the word automatic, but you still told us when you mentioned 'D' and 'P', manuals don't have those.  😁
1969 280SL

Kevkeller

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Re: 280SL Suddenly won't start
« Reply #7 on: Today at 01:26:14 »
I am wondering if the spinning sound you hear is the starter turning but not extending and engaging on the flywheel? The voltage dropping to 12.1 volts sounds like it might be the starter motor turning without a load.

Just a guess.

Kevin
1970 280 SL

Mike Hughes

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Re: 280SL Suddenly won't start
« Reply #8 on: Today at 03:38:53 »
Thanks for all the tips.  I didn't mention that our 280SL is an Automatic.  Does the "check shift lever bushings" still apply??  Hope to get the car up tomorrow and have a look.  But the theory that it "thinks" it is not in park and won't start makes sense.

Here is the issue:  There are two very inexpensive nylon shift lever bushings at each end of a rod that is connected through the bushing to the base of the shift lever itself at one end and the selector on the side of the transmission at the other.  The nylon bushings were not envisioned to last in service for 50-60 years. One of the nylon bushings invariably lets go while the driver is shifting into or out of 2,3,4, R or P.  So you might think you are putting the car in Park because that's where you placed the lever, but when a bushing actually lets go the transmission might have been in Reverse, Neutral, or any one of the forward gears.  The neutral safety switch in not governed by the position of the shift lever, it is governed by the position of the selector on the side of the transmission.  It will only allow the starter circuit to engage if the selector is in N or P.  Since you can't start the car, it isn't in Neutral, and since you can roll the car, it isn't in Park.  When you get under the car you will find that the selector on the side of the transmission is in R, 4,3,or 2.

The nylon bushings are available through your local M-B dealer or from many parts suppliers.  I got mine from Authentic Classics.  They also sell a tool that makes removing and installing the bushings much easier. 
- Mike Hughes  -ô¿ô-
  1966 230SL Auto P/S
  Havana Brown (408)
  Light Beige (181)
  Cream M-B Tex (121)

rwmastel

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Re: 280SL Suddenly won't start
« Reply #9 on: Today at 04:36:46 »
They also sell a tool that makes removing and installing the bushings much easier.
Is that tool expensive enough to make it worthwhile loaning/shipping it to other members?  I ask because a tool loaning program was brought up in another thread.
Rodd

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2017 C43 AMG
2006 Wrangler Rubicon
1966 230SL auto "Italian"

 

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