2005 Odyssey Belt Tensioner Bolt Keeps Breaking Off

[frogbite]

This is such an odd thing. I did my timing belt a few weeks ago in my wife's 07. I did not replace the tensioner so I used the old bolt and did not have this issue. Wondering if the replacement bolts may be the issue as there seems to be a rash of these. Did anyone have this issue using the original bolt or with the tensioner assembly purchased as a Honda OEM part?

[jentet]

What is the solution when it is the Honda Certified Service departments (note plural) that are replacing the tensioner bolt that keeps breaking? Here is the gist. I agreed to the recommended belt replacement at 80K miles. One month later when driving for approximately one hour and a half, we hear a PING and the belt and clamp (we learned later) go flying from under the car. The same service department replaced the tensioner, belt, and P-S pump. Then 2 1/2 months later while approximately 5 hours into a road trip, same thing happens again. This time a Honda Service department in Alabama does the repair work. Now it is 8 months later and after 2 hours on the road, it happens again. There were no problems before the routine belt change so what is going on? Does anyone have any ideas?

[cnn]

Someone needs to let Honda HQ in Torrance know, this is a potentially safety issue: loss of PS at high speed is very dangerous!!!

File a complaint with National Highway Traffic Safety Administration (NHTSA):
https://www-odi.nhtsa.dot.gov/ivoq/

My best guess is either:

a. Honda used cheap bolts from Chinese supplier, sorry but I have to guess it this way.

b. Is this only in J35A7 engine? If so, maybe the jolt from the VCM puts undue pressure on the belt system (3 cylinders cutting off) ---> jolt on the hydraulic tensioner.

c. Use of bolts smaller than appropriate.
Note that J35A6 engine uses M10 bolts. So glad I bought LX instead of EX.
Note J35A7 engine uses M8 bolts, no wonder it breaks due to:
- poor quality
- torsional stress during install
- jolt from VCM

So, my suggestion for folks with J35A7 engine:
- during install, reduce the torque a bit to limit torsional stress on the bolt (use a bit of Loctite).
- Or buy a bolt from a BMW E39 series bolt (PN 07119904252 is M 8 x 35, use a washer or grind the tip down to 32mm). It is $1.00 at BMW dealer, just make sure the thread pitch is the same.

[scmorgan]

Correction alert!

Be carefull cnn: Your assumption is incorrect as the bolt you have circled in the J35A7 diagram is not the bolt that is breaking. The actual bolt is the one that can be seen installed on the tensioner, but it is not labeled seperately (it comes with the tensioner). The Touring bolt is actually an M12, larger than the M10 on the non-Touring models.

I had hoped of trying the non-Touring adjuster to see if it solved this issue, but cannot due to the bolt size difference. It would appear that Honda was aware that the Touring hydraulic adjuster needed a stouter bolt and used the M12. Apparently not stout enough!

I also am on my 2nd broken bolt following a timing belt change (self-performed) and assumed I must have done something wrong. I reinstalled the original tensioner and bolt only to have it break a few days later. I then procured a high grade bolt and just replaced it only to have it fail after a couple weeks. My next option was to replace the tensioner, but from the looks of it, this is not as final solution either.

What else could it be? Did everyone replace the serpentine belt also? Could the replacement be too short causing undue strain on the tensioner?

Come on guys, someone out there must have a solution! Jester747?

[cnn]

scmorgan,

Thanks for pointing it out. I have posted the correct photo (taken from 1st page of the thread).

Now I wonder if:

a- Honda changed supplier since the factory time.
Just a theory: this auto-tensioner was made in a different factory and somehow the bad bolt was made?
Note that many wheel lugs are M12 bolt and routine torqued to 100-110 ft-lb w/o any breakage.
This tensioner bolt torque is only 54 ft-lb and yet it breaks, so it must be defective to start with.

b- I notice the 2nd Gen Ody also uses M12 bolts and virtually we never hear about 2nd Gen Ody tensioner break at all.
Perhaps, one can find out if the 2nd Gen Ody bolt fits here, maybe a good mod???
PN for 2nd Gen Ody, such as 2003 Ody EXL model is 95801-12080-08, M12 x 80 bolt.
I am just listing this as a thought.





PS: scmorgan, if you still have the broken bolt fragments, could you bring it to Honda dealer and see if it matches up with 2nd Gen bolt. Maybe others can benefit from this "mod".

[scmorgan]

No dice on the 2nd gen bolt - it is too short. The M12 bolt for the Touring is 100mm long versus only 80mm for the 2nd gen.

[Dirkdaddy]

I has started this thread thinking some other klutz besides me screwed up something on reinstall and it caused the break. But sounds like issue. Hmm... And my belt change is coming up...

[cnn]

Further to this pivot bolt on the auto-tensioner breakage.....I notice that some Honda parts website says 31170-RKB-005 is replaced by 31170-R70-A01.

Interesting!


http://www.hondapartsnow.com/genuine...0-RKB-005.html

[scmorgan]

I procured a new tensioner from the local dealer yesterday (amazed that they had one in stock) and just checked the number: It is the new 31170-R70-A01 part number. I hope to get this repaired tonight and will see if I can determine what the difference may be vs. the original. I plan to be very religious regarding bolt torque, application of engine oil, air bleeding, etc. I even bought a new Honda belt in case there is anything funny there and will compare it to the gates belt that I put on last month when I did the timing belt. We'll see if it all makes a difference.

[cnn]

scmorgan,

Please keep old broken bolts and post some photos.
Also, check your old records of the part that you bought recently and post some photos.

If all you have is a broken bolt, why replace the whole assembly (with 2 pulleys and tensioner), just curious can you get a Grade 8.8 bolt somewhere like "Fastenal" or NAPA autoparts?

Personally, if this were me, I would err on the low side, if the book says 54 ft-lb, I'd probably go to 50 ft-lb.
It seems that this bolt suffers torsional stress.

You might want to speak to Honda dealer mechanics and pick their brain as to why these bolts keep breaking. By now, they should see some broken bolts...and they may know why...

[scmorgan]

I will see if I can find the origonal bolt and show it. The replacement that broke is gone as it fell out somewhere on the road. You can get a grade 8.8 at most hardware big box stores like Lowes or Home Depot. I'm replacing the tensioner this time in case there was any issue with the original tensioner (stiff hydraulic cylinder, worn bearings, etc) that could be contributing to the issue. You can't just buy the tensioner, but must purchase the whole assembly. I negotiated with the Honda parts person to get it for $153.

I also engaged the Honda master tech at this dealer, but he was no help. He stated that he had seen this issue on some Civics, but never before on an Odyssey. I'm not sure about Honda's tech structure, but there must be a higher up reegional or national person that the techs call when they are stumped. This person may be more aware of the issue.

[cnn]

2006 Honda Civic issue is TSB 09-007.
It is an M10 bolt torqued to 40 ft-lb.

Please see attached pdf, similar issue for Civic vs Ody.

http://ww2.justanswer.com/uploads/yo...1514_civic.pdf

PS: I wonder if you want to do some experiment using similar M12 x 100 bolts from Home Depot, Lowes ($1 each), clamp it to a vise and see what torque is needed to break the bolt, I suspect you need more than 200 ft-lb to break it, as the wheel lug bolt is routinely torqued to 100 ft-lb w/o any issues.

[redmondjp]

There may be another manufacturing issue that is causing this bolt to break. I had a similar problem on a 1971 LTD where my alternator bolt kept breaking off after I replaced the water pump. FINALLY, I found out that one of the bolt holes on the replacement water pump was about 1/8" off-center, and this was putting a side load on the alternator bolt due to the mis-placement of the support bracket. You could be having a similar issue.

[iamhives]

Seems like this is still an unanswered question?. I'm about to do my timing belt but this makes me a little wary of embarking upon it until there is a resolution. Incidentally I did replay my serpentine belt a few months ago (keeping same tensioner and bolts) and haven't had a problem.

[scmorgan]

Update:

OK, it has now been about 5 weeks and I haven't had another failure (Good!).

Per my previous note, the Honda part number for the tensioner was superseded to a new number: 31170-R70-A01. It looks as if everything on the tensioner assembly is exactly the same except for an upgraded bolt.

as I mentioned previously, I was meticulous regarding bolt torque, application of engine oil to the bolt, air bleeding (3X), etc. and I installed a new Honda belt (replaced a Gates).

Looks like I may have conquered this demon...knock on wood.