M119 Engine Starter Replacement - procedure

[DW SD]

Hi Gang,
For the last several months my starter would work on first crank sporadically. It'd always spin, but sometimes the drive wouldn't engage, so I'd hear a ZING... This never happened more than once in a row, but it did happen about 50% of my first cranks. Fear of being stranded and annoyance that it wasn't working perfectly motivated me to resolve.

I initially thought I should just buy a new Bendix and install it. After exploring the cost of those parts and taking a look at the removal process, I decided I wanted to be a bit more conservative (it is a pain in the ass, a bit, to remove it.)
I bought Bosch's highest grade starter (but not Mercedes branded version) through Pelican Parts Part #: 004-151-78-01-88-M14.

Shipped it cost:
$283.25 + tax of $21.24 = $304.49
minus $65 core
plus $8.80 to return the core.

Here's the process:
1. disconnect the battery - I always disconnect ground.
2. remove the under engine plastic pan
3. remove the passenger's side of the steering drag link (you'll need some sort of puller, popper, pickle fork, etc.)
4. remove the various heat shields surrounding the starter, the steering idler and drop them out of the way. (Take a picture here of the heat shields if you question how they'll go back together. It isn't obvious and re-assembly is a bit of a puzzle).
5. Disconnect the two connections to the starter - 13mm nut and phillips screw for solenoid.
6. use 10mm allen drive to remove two bolts retaining the starter. I started with the top, since it was harder to get to. I used a 24" 3/8" drive extension and a u-joint socket along with 10mm socket to remove the top. The bottom I just used a 1/2" long 3/8" extension with my 3/8" ratchet driver. ***note, when you are removing the second bolt (lower), use your other hand to support the starter. It wants to start to fall out and that torque makes the bolt hard to remove.
7. keep track of the two spacer plates which are trapped by the starter. One has an indexing pin which must be paid attention to when restating the starter.
8. drop the starter out of the hole created by swinging the drag link out of the way.
9. match up your two starters to make sure they are the same.
10. line up the spacers, keeping a tip of one of the bolts though the spacers, they remain aligned. (I started with lower bolt since it was easier to get to.
11. tighten the starter in place making sure the spacers and index pin are properly aligned.
12. torque to spec (can't remember. guessing 50 ft lbs. They are large diameter bolts.)
13. install connections.
14. install heat shields.
15. reconnect battery ground
16. Test the starter function (before completely buttoning up)
17. all good and re-install drag link. I needed a small allen head wrench to keep the drag link bolt from spinning within the steering arm until there was sufficient friction from the cone-shaped bolt being tight within the steering arm.
18. plastic engine pad shield.

 

[Glen]

Thanks Doug. My high miler was doing that fairly consistently from the time I got. Then, after I got it back from the repaint it stopped and hasn't happened even once since. Weird. I still plan to replace my starter at some point so it's nice to see these instructions. Any pictures?

 

[DW SD]

Maybe I should have had mine re-sprayed? Seems that *could* have fixed it too... How funny!

Sorry, no pictures. It is straightforward though if you follow the steps. As usual, the lift made it easier. But the job is very do-able with ramps or jack stands.

I will add the comment that it cranks over obviously *much* faster now and engine catches quicker, too. I'm now glad I had replaced the whole thing instead of just the failed parts. A local auto electronics shop doesn't even rebuild any more. they would sell the Bosch bendix for $40 and the solenoid for $50. I figured at that point, another $100 - ish for a brand new, high quality part was the way to go.

Doug

 

[gsxr]

Increased cranking speed means the old starter was probably weak and on the way out. Good thing you changed it.

On a side note, if you need to replace the lower wiring harness, it's MUCH easier with the starter removed... do both jobs at the same time.

 

[DW SD]

Increased cranking speed means the old starter was probably weak and on the way out. Good thing you changed it.

On a side note, if you need to replace the lower wiring harness, it's MUCH easier with the starter removed... do both jobs at the same time.

I suspect the brushes in the motor had seen better days. Thankfully, my harness was good. Agree with your suggestion, though.

 

[samiam44]

Interesting,

I did mine and got a noticeably higher cranking RPM. I opted for the MB remanufactured Bosch which is done in Germany. I think with our discounted connections it is inline with the price mentioned. Mine was purchased last year so it whom knows.

I'd highly suggest 1/2 drive as mine were very tight. The stiffness of 1/2 drive is huge compaired to 3/8. FYI there is a special flex hex drive especially for MB's.

Don't loose the indexing pin.

Michael