Crankshaft rear flange?

[Einbbx]

So my flywheel recently exploded.... the center part where the six bolt holes are located... just turned into little Itty bitty metal bits, I've got my new flywheel and I'm about ready to slap her on but I can't seem to find the TORQUE SPECIFICATION in my Haynes manual.

 

Can anyone please help me with the SPEC?

-I would really appreciate the help

-I am going to put some locktite on the bolts incase you were going to suggest it

_hope someone can help

[Einbbx]

Ooh! I believe I have it.

Haynes manual chapter 2A-3

Flywheel/driveplate-to-crankshaft bolts= 101 to 116 ftlbs.

 

Is this correct!?

[Lockleaf]

That looks about right

[datzenmike]

Better to call it a flex plate.

 

 

Flywheel/driveplate-to-crankshaft bolts= 101 to 116 ftlbs.

Is this correct!?

 

Correct and the same as the '84 FSM, I checked.

[Einbbx]

New problem has arisen, one bolt sheared off inside the plate where the six bolts go... how do I go about removing that plate... the one on the back of the crankshaft... this is just getting worse and worse.

[Einbbx]

I believe it's called crankshaft rear flange... if I'm correct

[Einbbx]

Was replacing a damaged Flexplate/flywheel/driveplate

One of the six bolts that attaches it to the back of the crankshaft got stuck and broke off inside, idk if it's the easiest thing but I've decided to remove it and replace the whole thing.. is it called crankshaft rear flange?

What is the easiest method to go about extracting this thing?

Went from a simple Flexplate replacement to this whole mess.... ayy ayy ayy.

-any help/advice would be greatly appreciated

[Einbbx]

Good lord.... it's part of the crankshaft isn't it...

[wayno]

Yes

[Einbbx]

This means... I need to replace the whole crankshaft... doesn't it?

[wayno]

You need to drill a hole in the center of the broken bolt and use an easy out to get it out of there, you may also have to use some heat, and if you use heat you may have to replace the rear seal, for it to break you had to be cranking on it hard, it should have went in easy until it bottomed out and then it needed to be torqued.

I turn them in with my fingers until I know it's not cross threaded.

I have never heard of anyone breaking a crank bolt before, them things are tough.

[Einbbx]

Ok, so my friend here is trying to convince me that the flange is removable.. I keep saying it's part of the crank and a solid single thing. Can you clarify and reassure me that it IS a solid piece?

 

I assumed I'd have to drill and tap it, or weld another bolt. The I didn't break it on putting it on it broke while I was trying to remove it, impact failed, breaker bar failed, wd40 didn't do.. ended up using a ratchet extended it with a cheat bar and it snapped..

 

I'm considering my options, I DON'T want to do a crank swap and seing as it broke trying to extract I assume drilling it won't work, as it won't come out.. maybe weld another bolt on it and give it a shot.. but I am entertaining the idea of just slapping the other 5 bolts on, putting on the FLEXPLATE and putting the broken head on with some locktite and calling it.. would this be Ill advised? I just want my baby back already.

[Rick-rat]

 

Inconceivable, how much bolt if any is sticking out from the crankshaft, any pics of it?

[datzenmike]

The flex plate is sandwiched between tow smaller plates. The engine side clips over the end of the crankshaft. Just pry it off.

 

 

 

 

[wayno]

This is what I have done in the past when I had no other choice, I drilled a small hole in the exact center of the bolt that was broken off flush, then I used larger and larger drill bits till I was at the start of the threads, then I used a tap to clean out the threads.

I have never had a bolt break off in a crank, so I don't know what I would do about it.

I have never looked at an automatic flex-plate, but we are talking about a Z series engine, correct?

Don't be putting broken pieces of metal in there that can come flying off, if I had no other choice I might just use 5 bolts to hold it on, but that would only be a last choice I made after I had tried everything else.

[datzenmike]

WHO SAID A BOLT WAS BROKEN?????

[wayno]

WHO SAID A BOLT WAS BROKEN?????

Read first post

[datzenmike]

No wonder I'm confused this is the 3rd post on the samr damn flexplate. This one we are on is two that I merged together plus this one... http://community.ratsun.net/topic/70854-at-flywheel-bolts/?do=findComment&comment=1435904

[Einbbx]

Unfortunately I am unable to post pics, possibly due to the fact that I'm a newer member to this place? Or perhaps I just don't know how to find the option. But the answer is the bolt broke flush.

 

I was not aware that the engine/crank side had a plate on it aswell, I will remove it and see what I can do.

 

Thanks for the suggestion I will likely go through the process of drilling it out as described by Datsunaholic, and yes it is a z series. Z24, I went to junkyard and tore apart a clutch kit and Flexplate to see what I was dealing with. Major differences is that manuals have a thicker flex (cast iron) and the one on mine was far lighter material. I do own a tap and can rethread the hole. I will likely replace the spacer with a fresh one. I'm so glad you guys are here to help me out, my heart sunk when that bolt snapped... that's also why it's in three threads hahaha I panicked and was desperate for advice! Thanks so much. I'll let you guys know how it goes (since this is apparently a rare occasion of breaking a Flexplate bolt haha)

-and please keep the good advice and encouraging info coming. I'll take all I can get in this endeavor

[wayno]

You have to get that hole you drill almost dead center and straight in which is very hard to do, otherwise you will need another crank.

I don't know if you can get away with 5 bolts holding the flange/flex-plate on, I suppose in the end if I had to get it on the road I would try it if I didn't think I could drill it out, being that your going to be under the truck doing what I told you is at best a crap shoot, the only way to do it right is in a drill press.

I have done what I told you to door hinge bolts that broke off trying to get them out, they are a lot smaller, and a lot softer metal, plus I wasn't under a vehicle with a work light, but as I said, I started with a well centered small drill bit, and I worked my way up to the drill bit size used for tapping the hole.

I am one guy here, maybe someone else has a better way to fix this than drilling it, I don't have one myself, but that doesn't mean there isn't a better way.

I was reluctant to even say anything on your first post, as I believed that this just became a nightmare for you.

To post photos you need to host them somewhere and then grab the IMG link and paste it in the reply field, that is how I do it on my desk top, I don't know any other way.

 

Datsunahaulic is a title like yours is newbie, my user name is wayno. :)

[Einbbx]

It sounds like a reasonable enough plan to me, I am on PST so I will get on it bright and early and have a whole day to dedicate to slowly and safely drilling out that sum biskit that ruined my whole day. I plan to tap the bolt with a nice punch in the center and working my way on it, with patience and some due diligence Im sure it can be done... given that I have drill bits that can handle the bolt.

 

It was a bit of a nightmare... but I figure I can always do the whole works later on if need be, but for now I just want to get her on the road and enjoy her a bit.

 

I don't think I'll be posting pictured then.. maybe I'll find a way someday, I can't even upload a profile pic because the demensions are so small!

 

Well I learned a thing today about titles, thanks for being a good help and a good sport wayno.

[datzenmike]

The 5 speed standard uses a flywheel. It's heavy to store energy, and has a clutch surface.

 

Automatics don't use a 'flywheel' but a thin 'flex' or 'drive' plate to connect the crank to the torque converter. The torque converter becomes the spinning 'weight' that smooths the idle.

 

 

I sheared off all 6 bolts on my 521 back in the day from simple stupidity. It took a lot of time but I drilled them out with a Black and Decker electric hand drill. That was in the mid '80s and I think I removed the engine just to be easier to get at. I over sized the holes and tapped them for an over size set of bolts. The holes were not very straight but it worked perfectly.

 

With the engine in, and the broken bolt at the bottom, there should be lots of room to work on it if the vehicle is blocked up high enough. The good news is there is only one to do. Start with a small drill size and work up to the finished size in stages. Like I did it, might be easier to over size and tap new threads. Any fine thread grade 8 metric or SAE bolt (which ever is cheap and easily found) will do. You'll need a tap and drill for the correct hole size for tapping. In '80s money the tap, drill and 6 grade 10 bolts was about $30. I think now, that I had to borrow a 1/2" or 3/4" electric drill to finish the final hole size. 

 

This is totally do able.

[G-Duax]

I have never failed to remove broken bolts doing what wayno described.

Even if the drill wandered a little off to one side.

Just be careful to watch for when using the larger drills to when they break into the tops of the threads.

I use a really sharp center punch to start pealing the remaining bolt threads away from the crank threads.

 

But I have also removed many with just drilling the bolt to use an easy-out, a little heat & Liquid Wrench.

The trick to getting the LW to work is heat cycles.

Heat, spray LW, let cool down, repeat.

Every time you heat that area, gasses expand, and push out. Spraying the LW will start cooling the part, and as it does, the cooling pulls the LW farther into the joint.

Also, tapping the center of the bolt with a hammer & punch. The shock wave travels through the metal, causing movement between the threads of the bolt & crank.

[Doctor510]

If you start drilling with a LEFT Handed drill bit often the heat and the direction of the twist can help, Good luck

[thisismatt]

Since you mentioned welding, why don't you weld through a nut to the broken stud, then unscrew it?