Pictorial: W123 300D Turbo Starter Motor Replacement - Page 2 - PeachParts Mercedes-Benz Forum

Stretch · #16 01-09-2011, 04:11 AM

Well done dieseldan44 - you've made your mark!

funola · #17 02-14-2011, 03:27 PM

Has anyone drilled a hole through the tranny tunnel or would it be the firewall to access the top bolt from inside the car? Is it clear with not much in the way such as the heater core?

funola · #18 03-10-2011, 01:57 PM

I put in a good used starter last week and since I do not have 2 ft long 1/2" extensions I did it differently. My upper bolt was missing so I did not have to take it out and only had to put one in. I threaded both the top and bottom bolts in by hand from up top. To do this, I had to remove the battery tray, air cleaner, heat shield and transmission didpstick bolt. To tighten the upper bolt, I used a short 10 mm box wrench on a 3/4" long 10 mm allen L wrench cut-off with an 18" long 3/4" o.d pipe on the wrench and a hammer to impact it tight. I think this would also work in removing the upper bolt by jacking the box wrench from below

pic of wrench on upper bolt and pipe w/o the hammer

To remove and install the bottom bolt I used a 3/8" ratchet and the 18" pipe extension for leverage on a 3/8 drive 10 mm allen bit. A ratchet is absolutely necessary since the exhause pipe does not give enough swing room for a breaker bar.

ratchet on bottom bolt from below.

zeke · #19 03-10-2011, 07:15 PM

I am doing this this weekend -

funola - so what did you do from the bottom (if anything)

Did you take out the turbo?

funola · #20 03-10-2011, 08:15 PM

Quote:

Originally Posted by zeke

I am doing this this weekend -

funola - so what did you do from the bottom (if anything)

Did you take out the turbo?

I broke as well as torqued the bottom bolt from the bottom. Did not take out turbo. Unless you have a lift and work from the bottom, work from the top and use a mirror to see what hardware secures the small wire (mine was a slotted screw but have another starter with hex bolt). From the top (before jacking up the car), work blind by feel to remove wire hardwares as well as the bracket 4 x 10mm bolts (I used a ratchet with extension).

Turn the steering full right for more room to get starter out/in. Leave bracket off to allow starter to go up and in the tight opening easier, then put bracket on starter. Leave the 10 mm bolts loose and do final tightening after the engine bracket bolts are threaded in..

62bhp · #21 05-08-2011, 01:41 AM

Dan what an excellent write up. Just finished putting a Bosch rebuilt starter in my NA 617-glad I don't have a turbo. Would like to double check that the torque specification is 50nm. Is this listed in any of the Mercedes Technical Manuals (I haven't been able to find this number anywhere) or have most concurred that this is close enough?

-Mike

Stretch · #22 05-08-2011, 03:53 AM

Quote:

Originally Posted by 62bhp

Dan what an excellent write up. Just finished putting a Bosch rebuilt starter in my NA 617-glad I don't have a turbo. Would like to double check that the torque specification is 50nm. Is this listed in any of the Mercedes Technical Manuals (I haven't been able to find this number anywhere) or have most concurred that this is close enough?

-Mike

Haynes specifies this torque to be 25Nm - sometimes it is reliable.

62bhp · #23 05-08-2011, 02:39 PM

Army,

Thank you very much. I have a Haynes manual but didn't see 25nm listed, maybe I'm blind.

-Mike

Stretch · #24 05-08-2011, 03:19 PM

Quote:

Originally Posted by 62bhp

Army,

Thank you very much. I have a Haynes manual but didn't see 25nm listed, maybe I'm blind.

-Mike

It is at the front of the chapter - an irritating trait of a Haynes manual in my opinion - why not put it in with the instructions?

Anyway I've been trying to find it in the FSM but no luck so far - which is strange - it must be there somewhere. I'm trying to check for you because sometimes Haynes is just wrong when it comes to torque limits.

So if anyone out there knows which chapter in the FSM specifies this limit... please post it!

62bhp · #25 05-09-2011, 02:36 AM

Army,

Its funny, before you posted I was just about to ask whether or not the number you provided from Haynes could be found in the FSM. I would very much appreciate it if you could find and verify it as I do not own the FSM (yet). Like you said, the specification in Haynes must have come from somewhere.

Although I realize most will just put in the new one, tighten it down and call that good, I'd like to be a bit more precise than that as I'm still getting comfortable with the procedure.

Thanks again,

-Mike

Stretch · #26 05-09-2011, 03:57 AM

Quote:

Originally Posted by 62bhp

Army,

...
Although I realize most will just put in the new one, tighten it down and call that good, I'd like to be a bit more precise than that as I'm still getting comfortable with the procedure.

Thanks again,

-Mike

I agree Mike, it is always good to know what you are meant to do before you decide to give it one, two, three, or four white knuckles!

I'm stumped - I can't find it anywhere in the FSM...

All I can suggest is that at the front of the Haynes manual they have a useful(ish) bit about the size of the thread / head of a bolt and the typical torque range for it. Have you seen that bit?

Failing that:-

Calling toomany_MBZ - where are you? Are you on holiday?

ngarover · #27 08-12-2011, 07:51 PM

Thanks for this great writeup. I followed your instructions and it was easy as pie... A kind of tough pie... But pie none the less. I cut off a 10mm Allen end using my ryobe, kind of a large version of a dremel, that tip was great and really made the breaking of the bolts easy. I actually had to use the floor jack to break both bolts, even after heating them etc.

Assault · #28 12-07-2014, 10:48 PM

Thank you very much for this tutorial, it was exceptionally helpful.

There were a few things I did which made this project much easier for me.
*The week before I tackled this project I soaked the two bolts with WD-40; the day prior to removal I soaked them again, and when I began the project I soaked them again. This allowed me to loosen the bolts by hand once they were 'broken' using the extension unit without the breaker bar in the way.

*Removing the steering dampener is highly recommended as this will create significantly more room(a. to snake the starter though, and b. to remove and reattach the wires fro the starter) this will require a 17mm wrench and 17mm socket put the wrench on top and allow it to naturally brace itself.

*I also removed the clip from on top of the engine and moved the metal rod (don't know what it's called exactly) towards the engine to allow a slight bit more room to remove the top bolt.

*Since I had no available help; prior to removing the two starter bolts, I took 12 gauge wire and fed it between the solenoid and the starter motor and tied it over the exhaust pipe directly above. This held the starter in place and allowed me to gently lower it down.

*Lastly, I used the following to remove the bolt
1/2 breaker bar
1/2 to 3/8 reducer (connected to breaker bar)
maybe 24" worth of 3/8 extensions (longest and newest ones I had)
T-55 (if I recall correctly) bit socket 3/8
3/8 ratchet to reinstall bolts
I snaked the extension chain though the transmission tunnel and put the socket into the bolt then attached the breaker bar to the extension chain. I was able to position the breaker bar just behind the transmission mount plate, and was able to use the exhaust tunnel as a leverage point (where the extension chain ends, that is the levarge point on the right.) Sit up facing the car with your legs under the car and give a nice pull and 'pop', the bolt will be lose. This was very simple method, which also helped keep the extension chain as straight as possible. The more it curves in the extension chain the higher the chance of failure. When I used 5' worth of extensions I managed to break a 10" one and twist it. Fortunately it was a craftsman, so it was replaced.

Post #116 (w116)

mach4 · #29 12-08-2014, 01:43 AM

I found it interesting that this thread was near the top of the current listing of topics as I was reviewing this very thread in preparation for doing my starter this weekend. It wasn't as bad as I thought and was able to do almost the entire job from above.

Keep in mind that my 617 is an '85 Cali version with a test pipe and is mounted in a R107 chassis. I'm highlighting what I did that was different on the off chance that the techniques may be applicable. The repower conversion was virtually a bolt in job so the engine bays and transmission tunnel are very similar.

I elected to pull the down pipe to provide access from the top. I don't know if this is feasible on the 123. I also removed the transmission dipstick. The bottom bolt I did as outlined in the thread. The top bolt however, I was able to do from the top with a make-shift tool. I cut off about an inch of 10mm Allen wench and then used two 10mm combination wrenches taped together (to gain enough strength to pop the bolt loose) with the angle pointing toward the front of the car. (See below) Since a 10mm wrench is so short I couldn't break it loose manually so I just cut a piece of wood to length and placed a floor jack in a position to jack the wrench handle up till it popped loose. I'm assuming the 123 firewall is approximately in the same relative position and if so, this technique should eliminate working from the bottom with the long extensions, u-joint and awkward angles for the top bolt. With the down pipe out of the way and no dipstick in the way the starter slid right out the top.

I replaced the Cali starter (the one with the solenoid on the bottom) with the Federal starter from my spare engine ( the normal one that has the solenoid on the top). I can report that the starter fits physically. Unfortunately the solenoid is only 1/4 inch away from the test pipe which means the solenoid will very likely get cooked...maybe not during the winter but almost certainly during the summer. I fabricated a heat shield which will hopefully help but the plan is to find a place that can rebuild my Cali starter and install that this spring. The reverse, i.e. using a Cali starter on a Federal car is no problem.

Thanks for the tutorial. It definitely helped to get prepared mentally for the process.

BillGrissom · #30 12-08-2014, 04:09 PM

Thanks. A tough job no matter how you approach it. We all wish Mercedes had chosen to install the 2 bolts from the starter side (as in most cars). I got the top bolt from behind, with the long extensions shown, and an allen socket (Harbor Freight 3/8" drive set). A helper would be nice, one to insert the allen and one to support & turn the wrench way back there. It is grubby above the transmission. Many have used a cut-off allen w/ wrench from the engine bay (post 29). A ratcheting box wrench would work well there, once you get it loosened.