Crankshaft bolt coming loose (1988) 4wd

toyota
4runner

#1

We replaced the timing belt and replaced the water pump. Since this repair about 2 months ago, all of a sudden the crankshaft bolt is coming off the truck. This is second time in as many days. Any ideas, suggestions?


#2

Lock-tite and an impact wrench…


#3

Wrong! A new bolt, Loctite, and torqued to spec’s.

Tester


#4

What new bolt? What torque wrench?


#5

Well, it seems it will really need a new bolt and the “key” I know it has another part to that, but it is gone, baby, gone. In my humble opinion, new motor, but in my humble bank account, lots of hard work instead. So, anyone live in the Gainesville, Ga area who has an impact wrench I can borrow to get it on tight once the new parts are installed :slight_smile:
Thanks everyone for the responses


#6

If the key is gone you really need to examine the keyway in the crankshaft nose and the slot in the balancer before doing anything.

If the keyway in the crank nose is wallowed out then you’re in a bit of trouble. If the keyway is still good then you might consider adding a lock washer, star washer, etc, of some sort underneath the head of that bolt along with making sure the threads in the crank nose are good.
Many older Cadillacs didn’t even use a balancer bolt at all. The hub that holds the balancer is simply pressed onto the crankshaft where it remains in place with no help at all.


#7

The problem with getting proper torque on the bolt, the engine wants to turn over before any meaningful torque can be applied. The flywheel or flex-plate needs to be locked in position before any torque wrench will work. Hopefully, the crankshaft is not buggered up to bad…You can also lock the engine by feeding a length of rope into one of the spark-plug holes if you MUST use a breaker-bar to tighten the bolt.

An impact wrench will tighten that puppy down without the need to lock the crankshaft in position. You can rent or sometimes borrow one from a parts store. Do you have 120 pounds of compressed air available? If not, they make electric impact wrenches. You need one that has a capacity of around 200 foot pounds of torque…Put some Loctite “RED” on the threads and hammer that puppy down…No washers at this torque level.