72 240 slave cylinder bolt screw up, good day / bad day

[lking240]

yesterday was a good day and a very bad day. Took the z to get my restored enkei's put on (pic attached) and the clutch slave cylinder failed in parking lot when I arrived. after putting a new one in haste I didn't tighten down one of the carriage bolts (other pic, pre screw up) that comes out of the transmission housing and it ended up being sucked up into the flywheel when I turned it over and luckily I was able to get it out with the help of a scope and flex magnet but now the 1 bolt doesn't hold the cylinder properly so I need to get new bolts and have them installed. Other option I suppose is tap a bolt where the original one was. Would welcome thoughts on the matter and if anyone knows where to procure these bolts of if someone has some good condition used ones I could purchase. thanks for your consideration.

 

LKing240

[zeeboost]

I've replaced slave cylinders on many different Zs, and the orientation has always been the bolt head facing towards you, and the bolt threads into a threaded bell housing. I'm not sure why yours is different, if it was modified or just a different setup that I haven't seen yet, but is there any way you could just fish the bolts out with your flexible magnet, run a tap through the bosses in the bell housing, and then just install new bolts the other direction? Then you also wouldn't run the risk of another bolt falling into the bell housing.

 

If you wish to keep the same setup, I don't know what's stopping you from just removing the damaged bolt and taking it to a local hardware store to match it up. I'm not sure what you have available in your area, but home depot should have that bolt, it'll just be a generic grade 5 or grade 8, not an automotive style. If you have a fastenal or some place that specializes in nuts and bolts only, you could get a more accurate match taking it to one of them. The generic grade 8 bolt will serve you fine, but will be cosmetically different.

 

I'm going to guess the bolt is m10x1.25, which is a pretty common thread to find locally, but you'd be better off taking both bolts, so that way the good one can be used as a point of reference for an accurate thread pitch measurement.

[lking240]

Thank you. I am puzzled by the bolt orientation as you note I don’t know why they are not screwing into the housing, it’s a standard 4 speed transmission as far as I know. Will pursue the tap approach I think.

[Patcon]

If you try to die them it will have to be to a smaller size. If it were mine I would try to remove the stud and then get new studs from an automotive supply house or someplace like Fastenal. The studs are nice and make the work easier. But you have to be careful you don't snap them off, because they will have to be drilled out if you do. If you want to try to get them out put two nuts on one of them and tighten them against each other. Then put a wrench on one of the nuts and try to turn the stud out.  It appears you are missing the rubber cover that goes around the clutch arm to prevent things from dropping in at the clutch.

[Zed Head]

4 hours ago, lking240 said:

Other option I suppose is tap a bolt where the original one was. 

Are you sure the holes aren't threaded already?  Maybe some PO just lost the bolts and rigged up something to get by.

[zeeboost]

21 minutes ago, Zed Head said:

Are you sure the holes aren't threaded already?  Maybe some PO just lost the bolts and rigged up something to get by.

That's what I'm thinking. From what I can tell in the picture, it looks like smaller bolts were just stuck in from behind the bell housing to hold the slave cylinder in place. I figured if it was a stud that threaded into the bell housing, then it shouldn't have fallen into it and catch the flywheel. It's possible the PO damaged the threads in the bell housing and just rigged something up in the meantime. If the damage is minor, the bell housing is aluminum and shouldn't put up much of a fight to rethread it with a tap, assuming there's enough material left in the boss to retain a functional thread. If all else fails, it'd be pretty easy to helicoil. 

[lking240]

Thanks for the replies! I am looking further at it later today and will see if the threads are there. I hope so! 

[lking240]

You are correct, There are threads! Thanks guys. Ordered bolt and new slave, hopefully it’ll work!

[zKars]

The bolt thread is 10x1.5, not 1.25. ALL M!0 bolts that thread into the engine block and transmissions are 1.50 thread. 

[lking240]

Got the new bolt, the threads are a bit stripped at the opening such that with the lock washer I can’t get it to grip enough. Going to see if I can get a slightly longer bolt. Thanks again for the input.

[Zed Head]

Use Loctite and no washer.

[lking240]

Will try that, thanks a lot.