New crank bolt when changing timing belt?

I changed my timing belt yesterday and about 10 minutes after I was done I noticed that the factory service manual indicates that the big bolt holding the crank pulley is non-reusable. Does anyone know why this bolt must be replaced, and has anyone reused it successfully?

I've got the 3.4L v6.

 

I've never replaced one & I've R&R many of them. I tighten the hell out of them.

 

I'm not sure that's right. It has a torque spec, but I honestly don't know exactly what torque to yeild means or if it's mutually exclusive with a torque spec.

I do know that when I went to the dealership parts department to get a new one the counter guy wanted to know why. When I told him he said that he's never had a tech in the dealership ask for one and they the re-use them.

 

I've never worked with a crank bolt on the Tacoma but any other engine I've torn down the crank bolt is not reusable since it's a stretch bolt. Similar to head bolt.

 

That's what I would expect from a dealer. They charge full pop according to the jobber book but they don't put in the time to do the job right.

 

Out of the thousands we've done at my shop, have never replaced the bolt nor seen any repercussions of reusing the original one. Just make sure to torque it down to specs and you'll be fine.

 

As cheap as they are I put new ones in .

I never really checked the FSM to see if they should be replaced .

I will ask the Service manger at my dealer I am late dropping off Her Christmas Present.

 

The theory, as mentioned, is that it's already stretched and will not re-torque properly.

On heads, I get that, you're holding compression together. On a crankbolt, not so much. However, it's cheap enough replacement would be standard in my personal garage, because we're only talking every 15 years or so.

On some other marquees I've messed with, it's quite common to reuse the bolt (given it's clean and in good shape) with Locktite blue (NEVER red) and over torque about 30 lbs to 'restretch'. I've seen lots of these just fine, hitting their 7200 redline multiple times a week.

Dealers, while not my fav reference point for quality, don't want returns with a bunch of damage from a bolt like this backing out. So if they are reusing them regularly, they must not be seeing problems with it.

 

^I agree. You should be fine torqued to specification. If you look in most service manuals, even the most mundane repair requires new bolts. If you want a warm, fuzzy feeling, get a new one.

 

if you use the engine to break the crank bolt loose then I wouldn't try to reuse it, period.

as others have mentioned, I don't think you will find high failure rates from people reusing them, so yes you "could" do it, but its cheap to replace so I see no reason not to replace it.

after all, you can also get away with reusing the head bolts as well but why would you in either case?

 

I've never heard of someone replacing the bolt unless there was a specific issue with it. It also can't be compared to a head bolt as they serve two completely different purposes. Head bolt physically holding down the head during the combustion cycle, under an immense amount of stress. Crank pulley bolt just keeps it in place, no load is placed on the bolt itself. Pulley rides on the crankshaft with a woodruff key to keep it indexed.

Anyways, decided to pull up TIS, and low and behold, it's not listed as a replacement part.

 

I agree with 1MK.

I replaced one once and didn't on a dozen other t-belt jobs (5vz). It's one big ass bolt. Toyota fooled around with and revised that bolt and the torque somewhere around 99

Here's a "low and behold" from the 2000 FSM. "non-reusable part" same thing in the 99 FSM.