Fisherguy

I though grade 8 was the best you can get..?

hivoltage

I've never heard of a grade 10 either. As far as your problem,I'd leave it alone if it doesn't leak. I stripped one of the holes on the front diff of my '04 half ton. I left it without a bolt the whole time I owned it (year and a half) and no problems. Look at it this way,it's not leaking so it's not hurting anything. You go to messin' around with it and there is a chance of screwing it up worse. If it leaks in the future then you can take further action. If the bolt isn't one of the very bottom ones I doubt you'll ever have trouble.

SundayMoney

You're right on about the 15-20lbs being good.

The aftermarket diff cover on my truck re-uses the factory gasket. The specs for the aftermarket bolts are 15 ft-lbs.

No leaks since I put it on last Spring.

Utundra

Not that I am an expert...I think there are newer bolt extractors than there use to be, the Sears stuff comes to mind. I have a 20 year old Blue Point - Snap-On extractor. The few times I have used it it works quite well. It has drill guide that fits over the broken bolt so you drill straight. Then a splined shaft that you tap into the bolt and finally a hex drive that goes over the spline so you can use a socket to back out the broken bolt. I know...too much info...

Spooler

My suggestion is to get it out now. That way it dosen't have a chance to get good and stuck. I have done many broken stud jobs. I have a lefthand set of drill bits from Snapon. If it is loose they will back it out with the quickness. When you drill. Go slow and apply some cutting oil or you will burn up the cutting surface of the bit rendering it useless unless you have a sharpener. This is one job I always got and I hated it with a pation. Very tedious and hard to mark booktime on it. You really have to be perfect. If not, God help ya. LOL...

billie

My education for grade 5 and 8 came from hitches (and provincial regulations). Grade 8 is not legal for hitches (at least up here) as a 5 will stretch before breaking where a grade 8 will snap. The grade 8 is stronger but any abnormal strain on a hitch demands a 5. Put it in perspective or me when choosng bolt applications.

Cya

OOPS

Just to let you know those bolts are metric, not SAE. Good luck in finding a 2,5,or 8 grade metric bolt they are graded different.

I have had good luck getting bolt pieces out with a small punch and a hammer and tapping it around.

Spooler

That is funny. I have NEVER been lucky enough to do such with a punch and hammer. I would normally deal with the ones that will not come out with an extractor. The ones you have to drill out completely and helicoil. I have also had to deal with ones that someone broke an extractor off in and those suckers are hard as nails. Drill bits won't touch them. So, whatever you do, be careful not to cause more harm then good.

CANCERMAN

Thanks for all the responses. I havn't had time to look at the thread for a while. I am torn between just leaving it (has not leaked yet) and going after it before it has time to hunker down and seize up. I did put a thin coat of antiseize on the bolts. It sound like a good initial approach would be the left handed drill bit. I just hate to take the diff cover off again and waste a few quarts of mobil one!

I have thought about aftermarket diff covers. I think Genos has them on their sit. I would think they would come with a new set of bolts.

Thanks for the info on grading bolts. I learned something new. I printed that article and it goes in my garage information file for future refernece.

CRXsi

There are many threads on this issue. I too have had broken bolts after torquing to the 'spec' with a calibrated torque wrench...30lbs/ft is too high IMHO.

Definitely get that broken bolt out otherwise it will also corrode in and be a nightmare to get out later.

As for bolts there are metric, 10X1.25mm and I can't remember how long. The grading on metric bolts is different and these particular bolts need to be 10.9

Metric bolt info

Bigiron

A long time ago when I worked as a machinist, there was a place we used to go that did "electronic desintigrating." We used them to take broken off tools out of expensive parts we were manufacturing. They could remove a HS tap out of a piece of mild steel without damaging the threads. I remember that they did a lot of automotive work removing broken bolts. Could be an easy fix for this kind of problem if you can find such a place.

Jeff in TD

On my 03, I got through the 1st oil change fine at 30 ft/lbs, so I figured I got lucky and didn't get any weak bolts...

2nd change, one snapped off, and it hardly got snug when the head just kind of fell off.

Anyway, I tried a left handed drill, which wasn't quite enough. It came out easily with a bolt extractor, though. I prefer the ones with the spyral flutes, as opposed to the straight flutes.

I got it done w/o pulling the cover back off.

I suspect if you take your time, and use a quality American made extractor, you will get it out no problem.

Now I just snug them down by hand (maybe 20-15 ft lbs) and I've never had another problem.

CANCERMAN

Just a follow-up on my broken diff bolt problem. I went to Mid States Bolt and Screw in Flint MI (great place they have everything under the sun as far a bolts and screws) and they recommended a broken bolt/screw remover which consisted of a small drill bit 5/64 and a conical coarsely threaded device for a whopping $2.90. It worked like a charm. I drilled into the broken bolt (with diff cover on) and the was able to back the broken part right out. I blew the metal shavings out of the hole with my air compressor. I also bought 30 new bolts (they had the right spec on hand about $10 total) and replaced the broken one. The next time I change diffs I will put the rest of the new bolts in. The guy at Mid States said you shouldn't torque a 10.9 bolt like these any more than 26 ft/lbs and thought the spec was little high.

rallydriver

Thought I would share, this just happened to me on my rear diff today. Was doing a fluid change on both front and rear for the first time and broke two bolts while torqueing them down on the rear diff. After about two hours of non-stop drilling, I was able to extract them both with "easy outs" (tapered LH drill bits). Since I was also installing the Defiant diff guard as well, I was able to take two of the seven stock bolts from the front diff (the guard comes with longer bolts) and replaced the broken rear ones. Instead of torqueing them down to 30ftlbs, I just hand tightened them with a ratchet. I couldn't believe Class 10.9 bolts (metric "grade 8s") would snap like that.

-Chris

Bowser50

I worked at napa for a minute, never heard of grade ten's ever, sold literally millions of nuts and bolts to oil rigs and they always chose grade 8 bolts and nuts. Grade 8 is stronger than grade 5 but this doesn't mean you should always use Grade 8 they are just stronger, it just depends on what your application is, I would suggest using grade 8's where there areas of high stress like on bumpers and winches and frames, grade 5 should be fine for holding a dif cover. by the way grade 8's have six hash marks on top grade 5's have 3 in a y shape at top. hope that helps.