MP 1,1-5,1 Replacement heatsink screws for Mac Pro 4,1 (dual CPU)

[nanonano]

I'm upgrading a Mac Pro 4,1 (2009) with dual CPUs from the stock E5520, to dual X5650 which have been delidded.

While re-installing the heatsink on CPU A I noticed the threads on the top of the screws had been worn away, someone had obviously been poking around with it before, so much so that I can only secure 3 of the screws, the 4th one won't catch, too worn down.

It does run okay with just the 3, but don’t really want to use it for a long period or under load until the heat sink is properly re-installed.

The reason I think it fitted okay previously was because the stock CPUs were slightly thinner than the new ones, so the good part of the thread on the screw was visible so it would catch.

So my question, where can I source these screws which are mounted on the PCB? See photo.

I do have a spare “faulty” 4.1 tray (single CPU), but the design is different, it’s upside down, the CPU has a socket and the heatsink contains the screws, if I dismantle the heatsink can this screw be used? Or do I need to source one from a dual CPU tray?

Any pointers would be most appreciated.

 

[flat4]

It may work but its not ideal as it needs to have contact spread evenly.

I have run systems (not mac pros) with only 3 good screws and they have worked but its chance you are taking.

 

[Nguyen Duc Hieu]

I'm upgrading a Mac Pro 4,1 (2009) with dual CPUs from the stock E5520, to dual X5650 which have been delidded.

While re-installing the heatsink on CPU A I noticed the threads on the top of the screws had been worn away, someone had obviously been poking around with it before, so much so that I can only secure 3 of the screws, the 4th one won't catch, too worn down.

It does run okay with just the 3, but don’t really want to use it for a long period or under load until the heat sink is properly re-installed.

The reason I think it fitted okay previously was because the stock CPUs were slightly thinner than the new ones, so the good part of the thread on the screw was visible so it would catch.

So my question, where can I source these screws which are mounted on the PCB? See photo.

I do have a spare “faulty” 4.1 tray (single CPU), but the design is different, it’s upside down, the CPU has a socket and the heatsink contains the screws, if I dismantle the heatsink can this screw be used? Or do I need to source one from a dual CPU tray?

Any pointers would be most appreciated.

As you already have 2 machines, then it would be faster to take out both CPU trays, take out the screw and compare them side by side.
Another option is:
If you can't buy it, then make it.
Take the worn-out screws, measure it carefully, then take it to a friend who has a lathe machine.

 

[nanonano]

As you already have 2 machines, then it would be faster to take out both CPU trays, take out the screw and compare them side by side.

It's quite a bit to dismantle them both, so hoping someone can confirm before I take the plunge, but will do and report back if no one knows.

 

[majus]

If it is the top of the screw that has worn threads, you could take it to a computer dealer who does repairs. They should be able to repair the screw by adding back worn/missing material and use a die to rethread it. Or you can try it yourself if you have the tools.

 

[nanonano]

Just to give you an update in case anyone else has the same problem.

I dismantled the screw from the heatsink on a single CPU tray (1st photo) and compared it to the screws on the dual CPU tray. It's completely different, looks like this part is bespoke for the Mac Pro 4,1 Dual CPU tray (see photos 2&3).

I've decided I'm going to chance running it with only the 3 screws and see what happens, in the meantime I'll look out for a faulty dual tray to get a replacement screw, if the price is right!