Reuse Headbolts??? (94 corolla 1.8L)

[94_Rolla_Guy]

soon all will be revealed, but a another bump in the road, the Toyota service manual dosn't say you can't reuse the headbolts or doesn't have the diamond for "not reuseable" but most parts people say they need to be replaced soo???


I donno if i should use the old ones or not, BTW it is my car 94 corolla 1.8L .....

Also how does one know what bolts are reuseable or are of the TTY (torque to yeild / non reuseable) variety???

[darcsyde]

the had bolts are TTY bolts, they should be replaced but i've known people to reuse them ONCE and then replace them

[Flashmn]

If they are TTY bolts, you cant reuse them. NEVER.
If people reuse them, well they're gonna have problems. The reason is that when you torque them, you stretch them to hold the head, well when they're stretched, they wont stretch another time.

[03mooncorolla]

Originally Posted by Flashmn

If they are TTY bolts, you cant reuse them. NEVER.
If people reuse them, well they're gonna have problems. The reason is that when you torque them, you stretch them to hold the head, well when they're stretched, they wont stretch another time.

Flashmn Pretty much said it all, manual says replace them ( I would ).

Is it really worth taking the chance. Could lead to doing it again or worse

[94_Rolla_Guy]

yeah i sorted out my little problem parts store shorted me one bolt in the set, i figured it would take a day or two to correct... but it only took a couple hours to fix so problem solved

[toyotaspeed90]

ok... here's the deal.... IF they are torque to yield (TTY) then there will be a torque tightening sequence where you have to go to each bolt, then 45 then 45 (or just then 90... depending on application)..... if the manual just says "torque to XX" and shows one sequence... then they are not TTY bolts....

in the case that they are not TTY bolts, you can reuse them... they aren't stretch bolts

[Flashmn]

Yeah, like i said in my previous post if they are TTY bolts then dont use them.

[tashirosgt]

It would be interesting to have a definite answer to 94_Rolla_Guy's question. For the '90-92 Corolla, the Toyota service manual says to tighten the head bolts, in a certain sequence, in several passes, to a definite torque. I don't have the book in front of me now, but it isn't an extremely large torque, something like 44 ft libs. As Rolla_Guy says, while many parts are marked as "not reusable", the head bolts are not marked this way. But as I recall, Chiltons gives directions along the lines of tightening to some smaller torque and then turning the bolts so many degrees. I trust the Toyota manual more than Chiltons, since much of the stuff in Chilton's is just general boilerplate that they repeat in all their books.

[Flashmn]

Torque to yield bolts are always tightened to a specific degree, it theres a torque reading as in 62NM/FT-LB/whatever, then they 99% likely are not stretching bolts.

Also looking at bolts would give you some clue as to wether they are stretching, if they have a narrow portion on the bolt, then they might be stretching bolts.

4A-F/FE on the AE92 are not stretch bolts and are not supposed to be tightened with a degree gauge. If you do that, chances are a)you have too much torque b)you fucked the threads of the block/bolt.

I'm probably using my headbolts for the 5th time by now (I lost count), next time I might go with studs.

[darcsyde]

guess i was wrong always thought they were TTY bolts