HI Folks! Is the big 30mm nut that bolts the drive-belt pulley to the crankshaft reverse threaded? I am in the process of changing the timing belt on my '98 Volvo V70 AWD and I was trying to loosen the nut by rotating it counter-clockwise when a friend told me to make sure if the nut is reverse-threaded in which case I have to rotate it clockwise to loosen it. Also it seems plausible that the nut should be reverse threaded 'coz the clockwise rotation of the running crankshaft keeps the nut tighter. Can someone confirm it? Thanx!

 

It is normal thread. Not reverse.

 

You shouldn’t have to loosen the crank shaft pulley? You loosen the tensioner pulley and the belt should come off. If you do remove the crank shaft pulley make sure you torque it properly. I had one come loose on a Mazda I had many years ago (87 B2000 at 120,000 miles). The pulley ripped through everything. I had to replace all the plastic and the Radiator.

 

Actually it's the drive belt pulley on the crank shaft. I have to remove it to replace the timing belt. But before that I am stuck with a problem. Apparently one of the four small 10mm bolts on the pulley has been tightened very hard; I tried to loosen it and the socket slipped. The bolt head is half way thru losing its hexagonal shape and rounding off. Little force applied and the socket slips over it now. I don't want to round it off completely. Is there any thing I can try to remove it? Would an impact wrench help? Would appreciate any tips. Otherwise I am thinking of simply abandoning the timing belt change task, just install the new drive belt and wind up the job. Thanx!

 

You do not really have to remove the pulley.
If you remove the metal sheild behind the pulley you can sneak the belt out through there.
If you really want to get that bolt out then Yes an Impact will help. Or even an Impact driver.
I would try to tap a 3/8 socket on there and use the impact or impact driver.