Snapped two bolts. Am I doing this wrong?

loki_racer

loki_racer

Well-Known Member
Joined
Sep 7, 2005
Location
Pittsburgh, PA
I got a Riddler Dana 30 diff cover for my XJ. Painted it up the other day and installed it today.

Online it says to torque the bolts to 30-35. I have a torque wrench but have never been school in it's use. I set it to 5 and tightened a bolt to see what happened. The handle gave a small click when I think it reached the 5 ft lbs. I turned it up to 20 and snapped the head off a bolt.

Off to the store to get another bolt and liquor gasket.

30 minutes later after cleaning off the new (ruined gasket) and removing the snapped bolt I start to put it back together. Second bolt in and I snap another bolt.

I'm no mechanic or superman, but I must be doing something wrong here. Any ideas?

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You're using the wrench correctly from what I see. Could be that they just guessed at a torque spec., the wrench is cheap and inaccurate, or the bolts are used and have been stressed previously effectively weakening them.
 
Couple of things.
1. What is "liquor gasket"? Sounds fun.
2. Torque wrench looks like a Harbor Freight. My 1/2" one feels good compared to my Craftsman, but the 3/8" HF one always seems to overtorque stuff.
3. Are the bolts bottoming out before they pull down the cover? When I need to thrown on a cover real quick, I've hit em with the impact and never had a problem with them breaking or stripping the threads, and that'd be way more than 30ft-lbs.

I would guess there are inaccuracy issues with the torque wrench. I've got one at the house if you want to call me tomorrow or sunday and run by and get it, or I'll bring it over. Give me a call.
 
A few possibilitys
Bolt too long or hole has something in it.
Low grade bolt?
Wrench inaccurate
Directions should have read inch pounds not foot pounds?
 
1. liquid gasket. liquor gaskets come after the install.
2. I checked to make sure the bolts were not bottoming out before installing. All the bolts were brand new and came with the diff from Riddler.
3. using an AmPro T39913 from local auto parts store
4. I checked the directions and online and both state 35 ft lbs. I snapped both bolts with the wrench set around 20. I barely felt like I was wrenching on them.

What are the chances of two "bad" bolts. I have to admin, vs. the stock ones, the Riddler ones look like Mattel pieces. Maybe it was how shiny they were.

jeepinmatt, I'm headed to Callalantee around 1pm, but will be around all day before that. I would swing by if you have a second so we could check your wrench vs. mine.
 
Possible it was 35 inch pounds?

With a liquid gasket you really only have to tighten the bolts enough to make the liquid gasket begin to ooze out a bit. If you over tighten them you are just squeezing the liquid gasket out.

I know this is much less than 35 foot pounds but with all 10 bolts @ 35 inch pounds, I doubt you cover is going anywhere.

To b 100% honest 35 inch pounds sounds way to low....
 
Dana site says 30 - 40 ft-lbs. My guess would be an uncalibrated torque wrench. Is it new or one that is a rental type?
 
Here is a handy chart I found on the net. Its a military torque chart. I use this when a spec isn't provided or a given spec seems too high or low..

I forget if the D30 has 5/16" bolts or 3/8" But even w/ 3/8" your in the Grade 8 range at 35lb/#

All that said, its just a cover use a regular ratchet, or box wrench. Its good to know what a particular torque setting feels like by hand. If you have to do trail repairs you may not have a torque wrench handy...

mil-torque-spec.jpg
 
jeepinmatt said:
Are the bolts bottoming out before they pull down the cover? When I need to thrown on a cover real quick, I've hit em with the impact and never had a problem with them breaking or stripping the threads, and that'd be way more than 30ft-lbs.
Click to expand...


x2 Ive always just used my cordless impact and a good gasket maker. Never had one leak on me yet. Id say your bolts may be too long. try one 1/8th inch shorter
 
i see tons of china crap hardware these days.
 
Its funny that this comes up, we were just discussing at work that the habit of leaving a torque wrench set at a certain torque tends to send it out of calibration more quickly. We have to torque the cable clamps for our zipline weekly and its important that our wrenches are fairly on, too loose is obviously bad and overly tight will slowly cause us to deform the cables over time.

+1 more for with RTV just get it tight enough that you see it oozing out and the bolts feel snug. Burying the bolts all the way will squish out your gasket.
 
I always use the "half a turn before breaking point" method.:D
 
ya may wanna ck to make sure there is no silicone buildup in the holes. I have seen where that would cause a bolt to bottom out.
 
Benfield said:
I have one of those covers for my Dana 44. That is inch pounds on the torque specs.
Click to expand...

30 inch pounds is cant be right, thats not even finger tight :lol:

30 inch pounds=2.5 ft lbs

upnover said:
http://www.jkowners.com/forum/showthread.php?t=13395
Click to expand...

I was going to say I've seen guys break them before also. I've also seen the bolts break for the solid covers too. I upgraded mine to grade 8 hardware and just use a ratchet to tighten them. Heck if you get lube locker gaskets they dont even have to all be tight to not leak :lol:
 
Thanks for all the suggestions. I ran all the bolts in to their holes with the diff cover removed before trying to tight them down with the diff cover on. This was to make sure none would bottom out.

I have a feeling the bolts were just cheap, which is unfortunate since they came with the Riddler cover and I expected them to be high quality.
 
Another possibility is that there was some crapo in teh threads, e.g. old gasket material, gunky oil, etc. That iwill throw off the torque reading.
 
I'm no expert but with RTV on the diffs I just do barely past finger tight for 15 mins set to let the rtv start to ruberize and then a little past snug tight after that. I've not had them leak yet. 30 isn't really that tough so yeah I'd go with the el crapo bolts unless you were holding the wrench wrong.

I also just used grade 8 bolts I picked up at the lowes since my cover didn't come with any. Cheap enough.
 
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