When attempting to tighten up the torque convertors flywheel to torque plate bolts, should you be able to turn the flywheel manually to gain access to all of the bolts in turn?. I got the inspection cover off, and found the first bolt about ready to fall out.. tightened it up no probs, and then tried to turn the flywheel.. it wont budge!.. not by hand or even with a crow bar!. I cant get it to rotate at all, and consequently I cant get to those other bolts. Even tried driving the jeep, and jacking it back up, but the flywheel always seems to stop in the same position with the same bolt showing.. Im putting it in neutral, with the parking brake applied, which is what I think im supposed to do?.. its a great jeep (xj 1993 limited 4.0), except for that damn knocking noise!. Got to get to those bolts.. any and all advice appreciated - thanx guys.

 

1) LocTite #242 (or equivalent) on all those screws is very nearly required.

2) Sounds like you have a screw loose enough that the head is hanging up on something in the casting. Two possible solutions here:
-- You can try cranking with the starter motor, but this will probably wreck the screw that's binding up. Have replacement screws handy (don't bother checking the local hardware/DIY store for them. First, M10-1.5x15m/m isn't a common size. Second, it's a "place bolt," and not a standard hex head capscrew. You can try a "Farm & Fleet" place, or just go to a local Fastenal and get/order them there. Be sure to specify a "place bolt" - the guy should know what you're talking about. You cannot use a hex head capscrew in this location!)
-- Pull the transmission back a few inches so you have room to "bow" the flexplate. This should get you the slight clearance you need to turn the crank without damaging anything. Good luck!

 

This is the kind of answer a guy wants to read - informed and complete. Well done.

But it brought a question to my mind - what is a "place bolt"??

 

Thanks 5-90, much appreciated!. When I finish work tonight I'll jack the jeep back up and get to work with your suggestions. I had no idea that the bolts were so specific ("place" bolts).. good to know - thanx man.

 

Thanks for this post..
I lost 2 convertor bolts and now I have to find them..
This size listed sure helps, I got 2 wrong threaded ones today from a Bolt and Bearing shop -- go figure
I could have damaged the TQ if I continued to tighten them up.

 

tell me about it - I finally managed to rotate the flywheel (had to crank it using the starter as 5-90 suggested.. thanx 5-90 for that tip), and found that 3 of the bolts have apparently vanished?.. Im pretty sure that inspection cover has never been off, so theyve got to be in there somewhere.. anyways, I had to order the place bolts, but they arrived in a couple of days, and I got them locTited in nice and solid.. did the trick, no more knocking on starting or revving.. just a bit of a worry that Ive got three bolts rattling around loose.. somewhere

 

There are a number of different head styles for capscrews - "place bolt" is essentially one of them.

"Hex Head Capscrew" (HHCS) - this is the common "bolt" you're thinking of, with the hexagonal head.

"Flange Head Capscrew" (FHCS) - the head is typically reduced (about shank diameter,) and there is a circular flange. This gives more consistent bearing area.

"Socket Head Capscrew" (SCHS) - Internally-wrenching screw, typically meant for use in a counterbore (but also gaining ground for use with automated assembly, particularly when using Torx(tm) wrenching.) NB: A SHCS will typically be H&T to Grade 8 (SAE) or Property Class 10.9 (ISO) strength.

Skipping down more than a few...

If you look at the typical capscrew, you'll note the slight fillet under the head - caused by the cold-forming of the head proper (screws start their life as simple wire of whatever diameter: they are cut to length, rolled to size, have the threads rolled on, then the heads are cold-stamped into place. Inspect, package, and distribute. Threads are rolled because it is more convenient for them to do so - but it works to our advantage, because a rolled thread is essentially cold-forged into the metal and therefore stronger.) Capscrews are typically meant to be loaded in tension (pulling) through fairly significant sections of material.

A "place bolt" has a special head (it has a slight undercut near the screw shank) to allow for a more consistent clamping load on a thin metal section (like a flexplate,) and that also allows it to take a shear load rather better - since it isn't taking the shear load directly on the shank. A place bolt may not be replaced by a typical capscrew - in some applications, it just flat won't fit (you'll know this by reaching torque, and then being able to slide a .001-.003" leaf gage under the head all the way into the shank. That screw will fail under load!

Place bolts are moderately exotic items. You won't find them at the local hardware/DIY store, you might find them at a "Farm & Fleet" type store, and you can probably order them from Fastenal - I haven't checked. Place bolts also don't tend to follow conventional standards on sizing (you won't find 1/2"-20x1/2" screws at the hardware store of any particular variety. You won't find M10-1.5x15m/m or M10-1.5x20m/m, either. Period. Don't happen,) which makes them a bit more "exotic" than merely the head style. But, it's vital that you have the proper screw size and style in these applications - when Engineering wins an argument with Accounting, there is a very good reason they did so! Even if you don't know what is was, follow the precedent and you'll be fine...

I have got to sit down and write that fastener guide I've been kicking around. BillAVista did a good job with his at Pirate - but I think the field could be explained better to the hobbyist - there is much more out there that needs to be known! I'm after a signifciant expansion of his work, not a duplication...