Removing/retorqueing crank pulley bolt on an auto

[aww999]

Hi guys,

I need to do the cambelt on my Lexus LS400. The torque spec on the crank pulley bolt is 220lb ft or 300Nm. I have no impact wrench. What is the best way to stop the engine rotating while I undo the bolt, and then retighten it?

On a manual car I've always put it in gear, handbrake on, wheelchocks etc to stop the engine turning when retightening. Of course, this car is an auto, so the only resistance will come from the torque convertor, which will be a lot less than 220lb ft!

I thought about jamming something in the ring gear of the flex plate, but that seems like an awful lot of torque to put through one little tooth . . . what is the best way of doing it?

[WhoseGeneration]

aww999 said:

Hi guys,

I need to do the cambelt on my Lexus LS400. The torque spec on the crank pulley bolt is 220lb ft or 300Nm. I have no impact wrench. What is the best way to stop the engine rotating while I undo the bolt, and then retighten it?

On a manual car I've always put it in gear, handbrake on, wheelchocks etc to stop the engine turning when retightening. Of course, this car is an auto, so the only resistance will come from the torque convertor, which will be a lot less than 220lb ft!

I thought about jamming something in the ring gear of the flex plate, but that seems like an awful lot of torque to put through one little tooth . . . what is the best way of doing it?

Often there are holes in the pulley for the official workshop tool to locate in.
If there are on your's it's not hard to fabricate a locking tool.
Bit of mild steel strip of adequate width and thickness a pivoting smaller piece, then bolts as locating pins. Make the handle long enough so it locks to the floor or so you or another can hold it whilst cracking the pulley bolt.

[Starfighter]

And use a new bolt, the old one will have stretched.

[EDLT]

aww999 said:

I thought about jamming something in the ring gear of the flex plate, but that seems like an awful lot of torque to put through one little tooth . . . what is the best way of doing it?

You have to do that on a BMW X3, there is even a special tool for the job.

[aww999]

WhoseGeneration said:

aww999 said:

Hi guys,

I need to do the cambelt on my Lexus LS400. The torque spec on the crank pulley bolt is 220lb ft or 300Nm. I have no impact wrench. What is the best way to stop the engine rotating while I undo the bolt, and then retighten it?

On a manual car I've always put it in gear, handbrake on, wheelchocks etc to stop the engine turning when retightening. Of course, this car is an auto, so the only resistance will come from the torque convertor, which will be a lot less than 220lb ft!

I thought about jamming something in the ring gear of the flex plate, but that seems like an awful lot of torque to put through one little tooth . . . what is the best way of doing it?

Often there are holes in the pulley for the official workshop tool to locate in.
If there are on your's it's not hard to fabricate a locking tool.
Bit of mild steel strip of adequate width and thickness a pivoting smaller piece, then bolts as locating pins. Make the handle long enough so it locks to the floor or so you or another can hold it whilst cracking the pulley bolt.

I found the right page in the (HUGE!) workshop manual and this is exactly the method they recommend. I will make my own tool though, rather than buying the Lexus-approved one

Starfighter said:

And use a new bolt, the old one will have stretched.

Thanks, I will get one when I order all the other parts.

Edited by aww999 on Saturday 16th October 20:27