Re-use flywheel torque to yield "stretch bolts" - Page 2 - Toyota Yaris Forums

bronsin · 11-02-2016, 02:25 PM

I'm thinking if ANY of the bolts aren't reusable They didn't use the right grade of metal in them in the first place.

That would also suggest the first use of the bolts might result in failure.

bronsin · 11-02-2016, 02:28 PM

Quote:

Originally Posted by Jason@SportsCar

The Yaris head bolts get replaced after use.

That I've heard of.

I can't explain it but that would only MAKE ME REUSE THEM!

sorka · 11-02-2016, 03:45 PM

Quote:

Originally Posted by CrankyOldMan

I took a look at the OEM Yaris repair manual and it seems that truth is stranger than fiction! The A/T flex plate CAN reuse the bolts, but the M/T flywheel CAN'T. Even stranger than that, is that the xD repair manual (not pictured) only shows the M/T bolts as "precoated", and not "non-reusable", but also has a post-torque turn requirement.

It seems that the difference, then, is in how the joint is engineered. The flywheel experiences significantly higher shear loads and is safety critical, so it needs a tighter joint, and it was engineered with Torque Turn to Tighten (TTT) joints. The flexplate has a lot of "slush" factor from the torque converter, so it can rely on standard torque to friction joints. (I read an article on it, for reference: http://www.enginebuildermag.com/2001...rque-to-angle/)

In this case, I would specifically follow the OEM procedure and replace them for a M/T vehicle, instead of following "shop lore" about if you can or can't, based on other vehicles' requirements.

I'm following the TIS 6.6A for the 2007 yaris. Step be of installing the flywheel is:

"(b) Clean the 6 bolts and their holes."

So it appears you really can re-use them which is why the dealers don't stock them.

That said, I did end up getting 6 new ones this morning and used those. They came with thread lock on them already. If the shop manual didn't intend for you to re-use them they woudn't tell you to clean them and apply red thread lock which it does.

That said, there length difference was 29.29 (new) vs 29.80 (old) which is a pretty big difference.

crumbs · 09-18-2021, 05:24 PM

Hello are the flywheel bolts spline or 12 point bolts? Thank you

shane21 · 02-21-2023, 12:39 PM

Sorry to revive a multi-year old thread but I just completed an engine swap on an '07 Yaris Sedan A/T and am finding all kinds of conflicting info on these flywheel torque specs. Below is the supposed Toyota FSRM and it states the "6 torque converter set bolts" should be torqued to 20ft/lbf (page 176 of the "U340E Automatic Transaxle" chapter). It mentions nothing about torque, wait XX minutes and retorque. Nothing about using Loctite. Nothing about torque then additional XX degrees of rotation. Nothing about replacing the 6 bolts. Can anyone shed any additional light on this?

https://jdmfsm.info/Auto/Japan/Toyot...air%20Manuals/

mirageman · 03-06-2023, 08:56 PM

I'd use fixodent....and forget it!

LOL... I'd use loctite and overtorque a bit and never worry about it again. My oldschool mechanic always said torque specs are bs ... I don't think they are all the time, but for torque converter I'd go tighter. You don't want them to loosen like they did on Dodge caravans over 20 years ago and rattle grind against the bell housing.

11-02-2016, 02:25 PM	#19
bronsin Drives: 2009 Base Hatch 2 Dr Auto Join Date: Dec 2008 Location: nj Posts: 4,712	I'm thinking if ANY of the bolts aren't reusable They didn't use the right grade of metal in them in the first place. That would also suggest the first use of the bolts might result in failure. __________________ Synthetic Oil: Its All In Your Head

02-21-2023, 12:39 PM	#23
shane21 I've made a post! Drives: 2007 Toyota Yaris Sedan Join Date: Feb 2023 Location: Ohio Posts: 1	Sorry to revive a multi-year old thread but I just completed an engine swap on an '07 Yaris Sedan A/T and am finding all kinds of conflicting info on these flywheel torque specs. Below is the supposed Toyota FSRM and it states the "6 torque converter set bolts" should be torqued to 20ft/lbf (page 176 of the "U340E Automatic Transaxle" chapter). It mentions nothing about torque, wait XX minutes and retorque. Nothing about using Loctite. Nothing about torque then additional XX degrees of rotation. Nothing about replacing the 6 bolts. Can anyone shed any additional light on this? https://jdmfsm.info/Auto/Japan/Toyot...air%20Manuals/ Last edited by shane21; 02-21-2023 at 01:09 PM.

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mirageman Drives: 2009 yaris Join Date: Feb 2016 Location: poughkeepsie ny Posts: 28	I'd use fixodent....and forget it! LOL... I'd use loctite and overtorque a bit and never worry about it again. My oldschool mechanic always said torque specs are bs ... I don't think they are all the time, but for torque converter I'd go tighter. You don't want them to loosen like they did on Dodge caravans over 20 years ago and rattle grind against the bell housing.