When I last had the engine out 3 years ago for the mods, I had the engine on the stand and attempted to remove the flexplate for the intended purpose of replacing the rear main seal. I couldn't budge the flexplate bolts, rounded the heads off w/12-point socket, still couldn't get anything done with a 6-point socket after that, etc. One thing I didn't try was to remove the engine from the stand and persuade them with an impact wrench. I finally just left it alone and took my chances on having a leaker (it didn't).

The engine is coming out again shortly this time for a 350 shortblock transplant, but this time I need that flexplate or I'll have to get another one (another case of selling something earlier that I could have used now). I suppose I could use a cut-off wheel and cut the heads off the bolts, but that seems so barbaric.

This is a one-piece rear main, for what that's worth.

So, what lengths have you all had to go to, and what finally worked?

 

spend 35 dollars for a new one....

EDIT: oops 45... http://www.bowtieoverdrives.com/cata...BCAT&CATID=RA1

 

if you have access to a wire welder you could weld a nut on the surviving bolts and then impact gun,impact driver, or a very manly pipe wrench.

 

I have had great luck using a large hammer and a chisel. On rounded off bolts, I like to tap a little nick into the head of the bolt just to get you started. Then you can put your chisel at an angle and gradually pound harder. If this does not do it, try heating AROUND the bolt with mapp gas. If that doesnt work, you may want to try an impact 12 point socket that is one metric size too small. Then pound it on each bolt with a large hammer. I use this method with wheel locks. Good luck!!

 

This may be a completely insane idea, but I wonder if one might be able to put a few holes in the end of a cheap socket and then through the holes just put in a couple of tack welds... I have been very tempted to do that before lol.

edit: Just read 65panhed's reply. Much better idea lol.

 

I've done this trick many times on other people's screw ups. I have also used a smaller socket driven onto the head, but welding a nut on works much better for high torque bolts.

 

I have had good luck doing this myself. Also, another possibility, is to grind down two sides (opposite each other) flat on the head of the bolt. Then lock a pipe wrench (or open end wrench) And use a cheater bar. The trick is though, dont apply pressure. Right off the bat beat the hell out of it with a BFH. Sears also sells some bolt extractors that work reasonably well, but I dont know that they would be up to the task of what you are doing.

 

try a little heat. there's half a chance someoneused loctite o n te bolts, and if i did it 100% chance. even if there's no loctite the heat will still help. if you're afraid of heat try a can of r134 or "caned air" held up side down. cold is abvout as good as heat, only backwards. i have a set of extractor type sockets from snap on that grip anything, sears sells them too. try one of then along with heat and an impact .

 

The cold is a good idea. Hadn't thought of that one. Shrinking the bolt in the hole just may do the trick.

I'm fairly confident this was put on by the factory rather than having been changed/tightened by someone later, although I couldn't prove that in court, so there shouldn't be any Locktite on it. Heat would expand the bolt in this huge heat-sink of the crank rear flange, when I should be expanding the flange - don't think that's going to happen. Although if there is Locktite on it, that may loosen it.

Of course, there is always the "$45 solution".

 

I run into this problem almost every day. I found nothing beats a good old air hammer on whats left of the points. After a few pops (chisel tool) they can be taken out with pliers. I only had one bolt give me trouble before and that one required grinding an X in it to gain new points for the chisel to hit.

Another method Ive always considered was to drill a hole in the bolt and use an easy out but the crank needs to be locked to do it this way.

 

Welder and a 7 ft. breaker bar.

 

16lb sledge, crowbar, ziploc baggie, 2 oz of corn starch, and some carmex lip balm.

 

2 gallons of gas and a match!

 

Hey, at least my answer was serious!!

 

My first one was, i just couldnt help myself, it needed some comedy relief.

 

Couldn't remove them even with an impact? Were you using cheapie chrome sockets by any chance? Or quality impact sockets? I've had many fasteners that wouldn't budge with the chrome sockets, and zipped right off with the proper impact.

 

The big problem with flywheel bolts are the heads are so friggin' thin, especially production bolts. I've ground sockets down specially for this situation so they would fully engage the bolt heads.

Since your bolt heads are already fubar'd, at this point it's probably best to use an acetylene torch on the heads to heat up the bolts (to disolve any loctite, rust, gum, etc), and hammer a modified 6 point socket (as previously described) on, and use a breaker bar (no impact). I've never had to cut and/or chisel any bolts off in this situation - no need to be a neanderthal.

This always worked for me.

 

Yea but the air chisel works soo well. I especially like to use it on clutch fans, one pop in the right spot and they come off by hand.

 

Saying the bolt heads were "rounded off" was probably a bit of an overstatement. It was more of a "spirialing off", and the 6-point would grab but I couldn't hold the socket on while twisting while the engine was still on the stand. I never took it off in order to try the impact wrench.

Grinding the socket down is a good idea. There is a slight chamfer on the end of the flats, and having the flats go all the way to the end of the socket may make the difference. And, I'll try all this as soon as I split the engine/tranny, before the engine goes onto the stand.

I've taken off plenty of flexplates in the past, this is the first one that gave me trouble. It's also the first one-piece rear main I've had, not sure if that had anything to do with it.

 

i like the idea of grinding down the socket... sounds like it could work...


btw, i would put heat on them.. if it was put on by someone, theres a high chance they used locktite.... the heat would breakup the locktite, and let you break it loose.


so if it was me, id grind the socket flat so theres no chamfer on it (to grab the thin bolt head better)

then heat the bolt with a torch, smack it with a deadblow hammer, tap the socket on flush and tight, and use a hammer on a cheaterbar on the breaker bar...


should work... if it doesnt, then you're going to have to cut the bolt.

 

i have a couple of sockets i turned down the ends in a lathe for flywheels/flexplates, works great and so far not split the thinned down ends even with an impact

 

I'm 99% sure the flexplate was installed by the factory.

 

Wow, didn't realize how old this thread is. Anyway wanted to let the posters know how helpful this thread was for me just today.

I recently bought a donor '94 Roadmaster - my first GM product - and on the way to replacing the rear main seal, ran into issues removing the six flexplate bolts on the 4L60E. I first tried a hand ratchet with cheater - no luck. Went to impact and got only two out, rounded the heads of the other four. So I did a web search and came across this thread this morning.

I tried three of the four bolt removal methods posted and finally got all the bolts out!! Took only two hours from web search to final bolt removal.

1) Tried banging them loose with a chisel and BPH. No luck
2) Tried hammering a smaller sized impact socket onto the rounded heads and impacted three out, but couldn't get the last one.
3) MIG'd a 316SS nut onto the last bolt head and impacted it right out.

I'm happy. Thanks again for the posts!!

 

A heads up for you. I reacently did a 305 to 350 swap and used the stock flex plate. When I installed it to the transmission I ended up twisting the flex plate. After some research I found it needed to be shimmed. Because I had twisted it I ended up having to buy a new one. This is just to give you a heads up so you don't make the same mistake.