Where to buy bolts for turine housing

[Dirtleg]

The bolts that attach the turbine to center section on the turbo I have are a 5/16"-20 thread. I have never seen these for sale anywhere and to confirm my fears McMaster-Carr doesn't carry anything in that size. Usually they will have just about any bolt I need. The rebuild kit came with new bolts but they are 5/16"-18 thread pitch and so wont fit. Yes I verified the thread count with a gauge. And no it's not a metric 1.25 pitch thread as I checked that too and although close it was not correct either.(I was thinking M8 x 1.25)

Any suggestions as even if I wanted to reuse the old ones (I don't) I ruined one in the removal process.

Also I was able to get the broken off bolt out of the turbine housing. Here is how I did it;

I took a scrap of 3/8" plate and drilled a 15/64" hole through it. I then drilled a 13/32" hole down into that until it was about 1/16" from going through the plate. I slipped the 3/8" plate (1" wide x 8" long) over the broken off bolt which was protruding about 3/32" above the turbine housing. I made certain it was square with the face of the turbine housing and then plug welded the hole in the plate until I had completely filled the hole. At this point I heated and bent the plate so that as I turned it, it would clear the flange for the turbine inlet. I then had to make sure it was still square with the turbine housing face.

Once it cooled I took a mini sledge and started tapping the bolt out. It pretty much had resistance all the way out but it came out without breaking or stripping any threads.

So that is what worked for me after having the bolt head strip and then cutting it off. Just in case you were curious.

 

[Dirtleg]

O.K. so far McMaster, MSC, fastenal, ARP, Summit. Nothing listed at all in 5/16"-20. The only lead I have so far is that Mopar Oil Pan bolts were 5/16"-20. This is crazy IMO. Do I have a one-off or something? I am so tired of having to find unique parts it's driving me crazy. I have to do these things in my job as well. They are huge time wasters.

 

[suv7734]

I think what you have is an M8-1.25. Inch to metric conversion of the thread pitch shows 20.32 threads per inch. Here is a pic of an M8-1.25 x 25mm capscrew that you might be able to use for comparison.

 

[Dirtleg]

O.K. you're right. They are M8x 1.25. Thanks for talking me off the ledge SUV 7734. Apparently my metric thread gauge doesn't have a 1.25 arm. When I was checking I saw the 1.5 arm and went to the next one down. It's 1.0, so in my apparent haste I overlooked the fact that I wasn't actually checking for a 1.25 pitch. Oops. I need to slow down a little I guess. Been too stressed this past week.

Also as I was cleaning the threads on the housing I noticed that right under where it says ".82 A/R" there is an "M8" embossed into the housing. I guess that should have been my clue.

 

[suv7734]

Glad to help. You've had a rough few weeks to say the least.