Inner primary case bolts won't budge

[jec3]

I am looking for advice on how to break loose the three 5mm allen head bolts that hold the inner primary case on.  I am disassembling my 2002 500es to put in a new sprag starter bearing.  Dis-assembly was going great until I got to the last step of removing these 3 allen bolts.  I tried tapping the the bolt heads, heating the bolts and engine case with a torch, and they just won't budge.  I know if I try any harder I will just strip the allen head then will next be drilling these out.  Searching around I didn't find anyone else with this problem so not sure why mine are so tight.  These wouldn't be right hand threaded bolts would they?

Thanks in advance for any suggestions...

[barenekd]

Impact gun. Or an impact driver.
Bare

[jec3]

Thanks, I have one but was afraid to use it for such a small bolt.  Seems like it would just strip the allen head...

I'll give it a try, gingerly...

[Arizoni]

  These wouldn't be right hand threaded bolts would they?

The bolt should be a right hand thread like all of the rest of the bolts.
Right hand = Righty tighty, lefty loosey.  Turn the bolt counterclockwise to remove it.

A socket head bolt that uses a 5mm hex wrench should use about 7-8 foot pounds of torque to tighten or loosen it.
For one of those typical bent, hand held wrenches this can be quite a load but for a 3/8" drive socket with a 5mm hex bit in it, it should break loose without a problem.

The 2 shoulder bolts that hold the rocker arm cover on the UCE are a 5mm hex drive.
When I removed the covers to stop a slight oil leak.
I set my Snap On torque wrench to 7 ft/lbs but it probably took 10 ft/lbs of torque to break them loose.

[jec3]

All the heat cycles must have did mine in.  I got two off with the air gun, I do have a socket with 5 mm allen head.  My guess they were on 50-100 ft lbs.  The third stripped before it would break free.  It took me well over an hour to drill the head off if it, was like drilling tool steel, took two bits with several breaks to sharpen the drills.  I got the case off but haven't tried to back out the bolt I drilled the head off yet.  Spent a half hour trying to get the snap ring off the sprag bearing, its a heaving gauge spring and I just can't seem to pry it enough to get behind it to start it out.  Got too frustrated so gave up for the day.

Now I will need to find a replacement bolt, probably replace all 3.  What I thought was going to be an hour job will most likely be 4-6 by the time I am through.  At least I will have my starter back when I want to use it.

Thanks for the replies...

[barenekd]

As far as stripping the head out of an allen head bolt goes, those things are really hard. You'll generally tear up an allen wrench before you damage the bolt.
Suggest you get a Helicoil kit if you tear up the threads in the hole, but an EZ out will probably the remains of the bolt out.
Bare

[ace.cafe]

I have had to drill out a lot more of them than you want to know about.

It happens a LOT.

[jec3]

Thanks, don't feel so bad then.  I was lucky and found the exact replacement bolts at our local Tacoma Screw Co.  I should be able to get it all back together tomorrow.  If anyone has suggestions for a trick to get the "C" retaining spring off that holds the sprag bearing in please let me in on the secret.  Once I get past that hurdle I am looking at 30 minutes max to have her back on the road with a functional starter again.

Oh and would anyone recommend anti-seize on the inner case bolts or would this not likely help if I have to pull it again sometime in the future?

[mikail gransee]

Anti-seize is good but I would still put a drop of thread-lock on the bolt head before tightening.

[baird4444]

the only danger using the anti seize is that it can actually
"Lube" the threads; making it possible to overtighten and
possibly strip out the soft alloy case material... 
a torque wrench will not give a true reading when using anti seize...
              - Mike

[Arizoni]

Usually, torque values for bolts/screws are for dry threads.
If a fluid like oil or thread locking compound is applied to the threads the specified torque value should be reduced 30 percent to achieve the same stress and clamping load.