Water pump replacement - do bolts break?

[aprotogerellis]

Hi there,

I'm replacing the belts and front engine seals on my 944 turbo and, given the age of the car, I think it makes sense to also replace the water pump...

I've heard that its likely that the old bolts will break while removing the old one and if they do it probably means a month in the garage machining them out...

Does anyone have any thoughts or experience on this? How likely is it and how nasty will it be if it happens?

Many thanks!
Alex

 

[morris944s2john]

are you worried about mild steel bolts shearing due to corrosion in an ali thread making the very tight? Read Clark's garage section on "waking up the bolts" http://www.clarks-garage.com/shop-manual/bolt-01.htm

 

[peanut]

yes is the answer , very regularly.
The garage broke 3/4 of mine on my 928 and they are no differant on the 44.

If I were you I would recommend doing the job yourself if you ar happy to drill, tap and insert helicoils otherwise leave it to the garage and they can have the aggro. Its not an easy job,
In removing the bolts you need to turn very slowly 1/4 turns at a time . Alternate each bolt as you go . If they squeak or squeal be especially careful and take it really slowly so the bolts don't get hot from the friction and shear off.

If bolts do shear off you usually only get one chance to turn the sheared bolt out before it gets too mangled and you have to drill it out.
I recommend you only use a 9" or max 12" Stilsons nothing else. A stilson grips tighter the harder you turn it .You don't need to grop or apply any force to keep the jaws closed.
The more force you apply the more stilons grip. Be careful it doesn't fly off obviously.
They can succesfully grip a stud half the width of their jaws if you are careful.
Don't reuse the bolts get new and personally I would recommend helicoiling all the threads regardless if you intend keeping the car so you have an easy job next time and nothing shears when you torque it all up.