That was my first thought when I saw pictures of the original HB. To thin material and to slender design.
Key Failure - Harmonic Balancer Failure
- Thread starter OCBrad
- Start date
Hmmmm, My Sprinter threw a rod out the block at 126K miles. While removing the front cross member above the radiator, etc I noticed tool marks all over, like the engine had been removed once...possibly to replace the crank that was damaged by HB failure??? and the #1 cylinder rod was not reinstalled correctly? I'll be checking the oil pan bolts and gasket for signs of removal. Food for thought...
PeteInLongBeach
New member
I am less concerned with HB failure, and more concerned with keyway failure and crankshaft damage. I suppose it could not hurt to re-torque the securing bolt at regular intervals...
Was it ever determined whether this was only occurring on vans with extra A/C ?
Was it ever determined whether this was only occurring on vans with extra A/C ?
sikwan
06 Tin Can
It is occurring mostly with ones that DO NOT have the rear A/C or the double pulley.
abittenbinder
Doktor A (864-623-9110)
Breakage of the harmonic balancers is less common then key failure and even these are not, what I would consider, common.
"Re-torqueing" of the bolt is not practical because of difficulty of achieving (and especially measuring) the specified torque and the locking of the engine against rotation. A new bolt would have to be used each time.
Data suggests key failure is most likely to strike pulleys replaced (or in the case of A/C, retrofitted) by inexperienced techs not using new bolts and not using correct torque.
A conversation with a 54 Sprinter (average mileage 450K) fleet owner a few weeks ago revealed 2 or 3 key failures and these were on heavily loaded 3500 models not his 2500's. Doktor A
PeteInLongBeach
New member
Thanks, I'm less worried now...
Altered Sprinter
Happy Little Vegemite
Page 1 on the two pdf schematics
Richard
Richard
abittenbinder
Doktor A (864-623-9110)
If you are referring to the new vs. original key design split, don't bother with the VIN.
Just read the embossed number on the head of the pulley bolt. The early design has "10.9" and the later design bolt/crank has the distinctive "1150".
Both designs use the identical pulley and chain sprocket part #'s.
I have a late key way (single key way design) late '06 crankshaft on the workbench, which has been damaged by a pulley which obviously separated prematurely from this crankshaft. Sorry no details regarding this particular failure from the dealer who shipped this to me but it does somewhat lessen my enthusiasm for the updated design. Doktor A
SewerRatz
Illinois Licensed Plumber
I am with you on that is the people out there with out the rear AC unit need to be worried about having this checked? Also f it is a problem is this going to be a recall item or something we have to pay out of our own pocket?
sikwan
06 Tin Can
To add to this, the magic build date is March 2006. If your Sprinter is manufactured before this, more than likely you will see a 10.9. After, it'll be the 1150.
My Sprinter was delivered March 2006. I have the 10.9 bolt.
sikwan
06 Tin Can
None.
You need the correct bolt for the correct pulley type (Harmonic Balancer), with the correct key.
If you read Richard's post here...
https://sprinter-source.com/forums/showpost.php?p=41606&postcount=17
...you can find the PDF file that will tell you everything that you need to know.
Some very good pictures of the old key design (using the 10.9 bolt) from Doktor A in this post...
https://sprinter-source.com/forums/showpost.php?p=41931&postcount=37
There's also a picture of the crankshaft for the newer key in that post.
sikwan
06 Tin Can
I think Bulbasor is the only one immune to this, so if I was Bulbasor, I wouldn't worry about it.
BULBASOR
Active member
Ha ha, very funny . . 
Okay, no shortcuts for me today - I'll go back and read all the stuff that Richard wrote in the links but I gotta say your making this very hard! 
because I don't speak Austrailian very well and sometimes it's hard to follow Richard but I will get out my Aussie translation guide and dictionary and see if I can sort through his droppings, I mean postings. :
Okay, no shortcuts for me today - I'll go back and read all the stuff that Richard wrote in the links but I gotta say your making this very hard! because I don't speak Austrailian very well and sometimes it's hard to follow Richard but I will get out my Aussie translation guide and dictionary and see if I can sort through his droppings, I mean postings. :Aircraft Wrench
New member
because I don't speak Austrailian very well and sometimes it's hard to follow Richard but I will get out my Aussie translation guide and dictionary and see if I can sort through his droppings, I mean postings.
Gotta love him like brother!
sikwan
06 Tin Can
Oh, yeah, the PDF file that I was referring to is not written in Australian, or would that be Tasmanian (probably why no one can read it). 