Zhimarko

Hi All,

New member here, I'm changing the timing belt/balance belt for the first time (for me) on my 1987 951. While torqueing the guide rail nuts to what I believed to be the correct torque spec of 15 ft-lbs, I sheared the upper guide rail stud. After a bit more research seems like this was probably twice as much torque as I needed for this. I am wondering if these are studs I can remove from the Water Pump and replace? Every picture I see of the "new style" water pumps with the guide rail studs shows them installed. Otherwise, any recommendation for fixing this? The guide rail feels like something I definitely want installed, however an entire new water pump seems like overkill for this stud. Water pump has very few miles on it.

Thanks in advance!

Droops83

Yes, M6x1.0 fastener torque should be in the range of 7 ft-lbs/10 Nm. If you are ever in doubt about the torque spec of a given fastener, figure out the diameter and thread pitch of said fastener and look up the requisite torque value. There are standardized charts for this based on the grade of the fastener.

If you have a friend who is handy with a MIG or TIG welder, you could weld a M6x1.0 nut to the broken stud and then attempt to crack it loose---you have a decent chance of this because the reason for the broken stud was over-torquing versus being corroded and breaking while attempting to loosen the nut.

mj951

There's no real forces placed on the guide rail and it looks like there's a few threads left for the nut to grab.
I would have to see how it looks with the rail installed and nuts in place but would be tempted to install using some Loctite on that top nut.
Tough call because it's not something you want coming off with the engine running but if the nut catches full threads some red Loctite would keep it in place.

931guru

Not enough thread for the shouldered nut to grab onto. Remove the broken stud using the welded nut method... Works like a champ, especially on steel stud in aluminum.