Is it standard to replace head bolts?

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Hey all. So I rebuilt my '73 1F a couple years ago. I just blew my second head gasket since. (1st was due to water pump belt, resulting in overheating) To be honest I'm not 100% sure what happened this time. Water pump spins but it blew all my coolant out and now my oil is milky. I'm hoping just the thermostat failed.

Some people are telling me I need to replace my head bolts as I've reused them a couple times. Is this true? I know it's a low compression engine and my manual didn't call for it. But I don't want to put it all back together if the bolts stretched over time and have this happen again.

Thank you for insight.
 

Pighead

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I've re-used mine once or twice without a problem. Don't know if there's a use by date.
If you can find new OEM, great. Otherwise re-use.
Don't forget the retorque.
 

cruisermatt

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Cylinder head thickness, gasket brand, would be my two questions before the fastener integrity would be questioned, I have reused these head bolts tons of times without issue.

Where did the gasket blow? Same place both times? Pics of failure? Your post lacking lots of critical info.

Have read posts from JimC about head and block both being decked and head bolts bottoming in threads.
 

brian

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these head bolts are not the torque to yield type, and can be reused over and over again as they do not stretch....but i think you have other issues if you have over heated this a few times.
 
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Not saying this is your problem but was mine. Rebuilt the 22R in my 82 pickup and blew head gasket. Friend said new head bolts needed. I did not think so but want this job done and done right. Was thinking the night I got it back together and decided to check my digi-torque wrench. Yes it was off. I had used it on the entire motor so pulled the oil pan to check the mains and connecting rods. The higher the torque value the more it was off. My 2cents -no on new bolts but check your torque wrench. Mike
 

Blastservices

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Did my F155 and was surgical about all of it. Decked the head, proper calibrated torque wrench and not my first time and reused my old bolts after zinc plating and the gasket blew after about 100 miles. Buy head bolts. It’s cheap insurance. Small corrosion pits on a bolt actually do affect its ability to hold torque.
 

brian

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Did my F155 and was surgical about all of it. Decked the head, proper calibrated torque wrench and not my first time and reused my old bolts after zinc plating and the gasket blew after about 100 miles. Buy head bolts. It’s cheap insurance. Small corrosion pits on a bolt actually do affect its ability to hold torque.
Why would you zinc plate them?...sounds like that might have been an issue.
 

Blastservices

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Why would you zinc plate them?...sounds like that might have been an issue.
Because I can… and wanted the exposed bolts to not look like old rusty bolts. Zincing a bolt plays zero part in its ability to be strong.
If you are a tech in todays world you never reuse headbolts. If you are guy that has worked on cars in the 70’s -80’s you would never replace headbolts. So being that these engine are made then I tried to think like a person and carry out the same procedure but it failed. Why ? I don’t know… but after redoing the entire procedure and spending a good amount of money, time , and effort doing it over it held up just fine. Also, why do you suppose they sell head bolts ? You aren’t loosing them…
 

pb4ugo

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Did my F155 and was surgical about all of it. Decked the head, proper calibrated torque wrench and not my first time and reused my old bolts after zinc plating and the gasket blew after about 100 miles. Buy head bolts. It’s cheap insurance. Small corrosion pits on a bolt actually do affect its ability to hold torque.
Did your head bolts break? If so where did the bolt break? Were the bolts professionally plated?
 

Trollhole

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Because I can… and wanted the exposed bolts to not look like old rusty bolts. Zincing a bolt plays zero part in its ability to be strong.
If you are a tech in todays world you never reuse headbolts. If you are guy that has worked on cars in the 70’s -80’s you would never replace headbolts. So being that these engine are made then I tried to think like a person and carry out the same procedure but it failed. Why ? I don’t know… but after redoing the entire procedure and spending a good amount of money, time , and effort doing it over it held up just fine. Also, why do you suppose they sell head bolts ? You aren’t loosing them…
Usually in the plating process the bolts are run through an acid bath which can cause hydrogen embrittlement unless you had the bolts baked after to return them back to original hardness. Also the coating of zinc might have been enough to throw torque specs off. I don't plate the headbolts on any restoration.
 

cruisermatt

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Why is everyone refusing to show/tell where their head gaskets failed
 

pb4ugo

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Usually in the plating process the bolts are run through an acid bath which can cause hydrogen embrittlement unless you had the bolts baked after to return them back to original hardness. Also the coating of zinc might have been enough to throw torque specs off. I don't plate the headbolts on any restoration.
Ding, ding, ding.This is why i was asking questions earlier. I wish I could offer multiple "likes" instead of writing this.
 

Blastservices

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So you are saying the black zinc the head bolts are plated in when you purchase new is making them risky? Also when you run to lowes or Home Depot or buy from fastenal or Mc Master Carr the fasteners you purchase are all suffering from hydrogen embrittlement. C’mon.. think logically.
 

Blastservices

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Did your head bolts break? If so where did the bolt break? Were the bolts professionally plated?
No they didn’t break. I assumed they were not able to hold torque being that the head gasket leaked between each cylinder mainly between 3,4,5 and right into water jackets.
And yes they were zinc’d by a shop that does millions of parts a year. So I guess that’s proffesional.
 

Trollhole

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So you are saying the black zinc the head bolts are plated in when you purchase new is making them risky? Also when you run to lowes or Home Depot or buy from fastenal or Mc Master Carr the fasteners you purchase are all suffering from hydrogen embrittlement. C’mon.. think logically.
No that is not what I'm saying. Most industrial plating businesses are not plating old hardware nor are they usually having to remove grease or rust of hardware that comes to them. But I can assure you that every quality head bolt that is new isn't just getting plated and shipped. They get baked. If the bolt is acid dipped before plating it will suffer hydrogen embrittlement unless baked. It might not make a difference on some hardware but on head bolts it does.


As far as the original question. Yes you can reuse f and 2f head bolts as long as they spec out. Chase the threads in the block, check your block and head for warpage. And use some 30weight oil on the head bolt threads and the area where the head of the bolt and block meet.

Usually we see head gaskets blow between 5-6 or 4-5 occasionally number 1. Might also want to get the head pressure checked, decked and magnafluxed to check for any cracks.
 

pb4ugo

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Once a hardened fastener has gone thru certain types of plating there is a process the fastener has to go thru to prevent Hydrogen Embrittlement. Hydrogen bubbles can form internally usually where the shank and head meet. As Trollhole mentioned, the hardened fastener then needs to be baked at a certain degree for a certain amount of time to get rid of the hydrogen bubbles. This is why you should never use a tow ball or chromed recovery points on your vehicle. This includes any hardened or drop forged item that has been welded on. Usually Torque specs are listed using a clean plain steel bolt properly oiled. Zinc plating might effect torque values.
 

brian

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So you are saying the black zinc the head bolts are plated in when you purchase new is making them risky? Also when you run to lowes or Home Depot or buy from fastenal or Mc Master Carr the fasteners you purchase are all suffering from hydrogen embrittlement. C’mon.. think logically.
its not black zinc, its black oxide.

no those fasteners that were coated by the manufacturer went through all the steps to relieve the chemical hardness.
 
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Because I can… and wanted the exposed bolts to not look like old rusty bolts. Zincing a bolt plays zero part in its ability to be strong.
If you are a tech in todays world you never reuse headbolts. If you are guy that has worked on cars in the 70’s -80’s you would never replace headbolts. So being that these engine are made then I tried to think like a person and carry out the same procedure but it failed. Why ? I don’t know… but after redoing the entire procedure and spending a good amount of money, time , and effort doing it over it held up just fine. Also, why do you suppose they sell head bolts ? You aren’t loosing them…
Today's techs replace them because today's head bolts are torque to yield. One time use only.

And they sell head bolts because some of us do loose them :beer::beer: :p

As some other's have pointed out, the ones you buy from Home Depot that are already plated have gone through some treatments that we can't achieve in our garages.

@mrjordann As @ToyotaMatt pointed out, you really need to determine the cause of the failure. Where did the coolant go? Just into the oil?

I'd figure that out before moving forward, but to answer your original question, you can reuse the bolts. These are not torque to yield and unless you really over torqued them the last time you did this job, they will not have stretched.
 

ToyotaMatt

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Today's techs replace them because today's head bolts are torque to yield. One time use only.

And they sell head bolts because some of us do loose them :beer::beer: :p

As some other's have pointed out, the ones you buy from Home Depot that are already plated have gone through some treatments that we can't achieve in our garages.

@mrjordann As @ToyotaMatt pointed out, you really need to determine the cause of the failure. Where did the coolant go? Just into the oil?

I'd figure that out before moving forward, but to answer your original question, you can reuse the bolts. These are not torque to yield and unless you really over torqued them the last time you did this job, they will not have stretched.


@cruisermatt pointed that out not me :D


one good reason to replace a head bolt with a toyota genuine parts one is if there corroded badly or at all pitting on the smooth upper part above the threads / below the hex head portion ..

- that leaves and begs the question ?

- do u replace as a entire set for good measure and sound mind bod and soul u can sleep at night value added ?


- me .......

- hell yes ill replace as a whole set if only one requires it , but that's just me .....

- otherwise , the head bolts are indeed re-useable per the F and 2F and 3F and 3FE FSM's


 

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