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  #1  
Old April 15th, 2012, 17:03
XGarfX XGarfX is offline
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2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Alright two questions here..

1. Does anyone know the size and length of the engine block motor mount bolts? I just ordered some brown dogs but decided to retain my OEM block bracket, I've heard the bolts get fatigued and/or are bottoming out in the engine block before they reach their correct torque? I want to replace the bolts with some new fresh grade 8s of the PROPER length when I put the brown dogs in. From what I was told from BD, is that the bolts are 3/8s w/ 16tpi. I want to know the correct length I would have to get for both bracket sides (driver and passenger bracket bolts)

second question..

2. I am replacing my dana 30 pinion seal and yoke and need to know the correct torque on that pinion nut? For reference it has 4.88 yukons and an aussie locker, bad pinion angle killed the new seal so I'm replacing it with a new timkin seal and a much better condition yoke (polished and drilled out for u bolts) as I think my seal could possible have a groove worn into it. Changed my pinion angle so want to seal up this bad boy for the final time, im hearing anything ranging from 135 ft lbs - 250 ft lbs.... any help here guys???

Thanks in advance!!
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  #2  
Old April 15th, 2012, 17:06
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Outlander560 Outlander560 is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

not sur eon the first one...but the second questions is 150 ft lbs
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Old April 15th, 2012, 17:06
DanMan2k06 DanMan2k06 is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

I'll be honest, as far as the pinion nut goes, I've always just blasted it on nice and tight with my 1/2" IR impact gun. I hold the yoke in my hand so it's not bouncing back an fourth against the ring when tightening. I'm sure this isn't the right way, but I've done about 6 so far and never, ever had an issue.
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Old April 15th, 2012, 18:06
XGarfX XGarfX is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Its a high pinion 30, does it have a crush sleeve in it? I would assume if its just shims only then it would matter a lot less then if it had a crush sleeve
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  #5  
Old April 15th, 2012, 23:18
jeepfreak1020 jeepfreak1020 is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Motor mounts are 75 foot pounds.

Pinion nut is 150 foot pounds.
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  #6  
Old April 16th, 2012, 06:02
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cruiser54 cruiser54 is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Quote:
Originally Posted by XGarfX View Post
Alright two questions here..

1. Does anyone know the size and length of the engine block motor mount bolts? I just ordered some brown dogs but decided to retain my OEM block bracket, I've heard the bolts get fatigued and/or are bottoming out in the engine block before they reach their correct torque? I want to replace the bolts with some new fresh grade 8s of the PROPER length when I put the brown dogs in. From what I was told from BD, is that the bolts are 3/8s w/ 16tpi. I want to know the correct length I would have to get for both bracket sides (driver and passenger bracket bolts)

second question..

2. I am replacing my dana 30 pinion seal and yoke and need to know the correct torque on that pinion nut? For reference it has 4.88 yukons and an aussie locker, bad pinion angle killed the new seal so I'm replacing it with a new timkin seal and a much better condition yoke (polished and drilled out for u bolts) as I think my seal could possible have a groove worn into it. Changed my pinion angle so want to seal up this bad boy for the final time, im hearing anything ranging from 135 ft lbs - 250 ft lbs.... any help here guys???

Thanks in advance!!
I've never heard that the bolts were too long at the motor mount brackets before. Interesting, as I believe the issue cropped up somewhere in the early HO production. Perhaps the machine that taps the block had it's depth set up inproperly?
Being suspicious of this, I would personally run a bolt in and see how much is sticking out and compare that to the thickness of the bracket itself.
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Old April 16th, 2012, 07:22
Talyn Talyn is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Some years the bolts going to the block would bottom out before clamping the bracket. The problems isn't the bolts are too long but the holes weren't drilled and tapped deep enough.

Both sides use the same length. Best bet is to pull one out and take it to a hardware store to match. But 3/8" sounds about right. Those bolts don't torque to 75 ft lbs. They are only 45 ft lbs.
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Old April 16th, 2012, 07:30
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MoparManiac MoparManiac is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

The motor mount bolts are definitely 3/8-16.

If it's a HP30, almost positive it doesn't have a crush sleeve. Tighten it to anything over 200 ft lbs.
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Old April 16th, 2012, 07:58
ktm racer 419 ktm racer 419 is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

i have the brown dog super motor mount brackets.

pretty sure their instructions said to torque the 3/8" bolts down to 40 ft/lbs with red loc-tite, and the 5/16" bolts to 25 ft/lbs with red loc-tite.

then again those brackets mount using many more points on the block than the stock units.
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Old April 16th, 2012, 08:04
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MoparManiac MoparManiac is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Quote:
Originally Posted by ktm racer 419 View Post
i have the brown dog super motor mount brackets.

pretty sure their instructions said to torque the 3/8" bolts down to 40 ft/lbs with red loc-tite, and the 5/16" bolts to 25 ft/lbs with red loc-tite.

then again those brackets mount using many more points on the block than the stock units.
The coil mount uses 5/16-18 bolts. Pretty sure they pick those up.

The stock motor mounts use all 3/8-16 bolts.
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  #11  
Old April 16th, 2012, 08:06
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cruiser54 cruiser54 is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Quote:
Originally Posted by Talyn View Post
Some years the bolts going to the block would bottom out before clamping the bracket. The problems isn't the bolts are too long but the holes weren't drilled and tapped deep enough.

Both sides use the same length. Best bet is to pull one out and take it to a hardware store to match. But 3/8" sounds about right. Those bolts don't torque to 75 ft lbs. They are only 45 ft lbs.
That's what I thought it might be. I have a buddy here in town that worked at that 4.0 manufacturing plant. He said they made about 5 million 4.0s and didn't stay up on maintenance of the machines.

This could also explain why guys have their bolts break, replace them and they break again.
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  #12  
Old April 17th, 2012, 06:20
XGarfX XGarfX is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Does anyone think the solution might be to run a washer or two under each bolt to just space it out a smidge farther?

I don't have an issue with mine so far but more so looking to do this as preventative while I'm putting the new motor mounts in.
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  #13  
Old April 17th, 2012, 06:28
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

I ran a tap through every hole that my motor mounts used (granted I built my own and used extra bosses like the Brown Dogs).

After that, I just bought the correct length grade 8 hex head bolts by sticking a caliper into a bolt hole and checking the depth. I just made sure I had at least 3/8" of thread engagement in all holes, and went a bit shorter than the caliper measurement so it wouldn't bottom out.





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  #14  
Old April 17th, 2012, 07:20
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cruiser54 cruiser54 is offline
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Re: 2 Questions: engine block motor mount bolts & dana 30 pinion nut torque ??'s

Quote:
Originally Posted by XGarfX View Post
Does anyone think the solution might be to run a washer or two under each bolt to just space it out a smidge farther?

I don't have an issue with mine so far but more so looking to do this as preventative while I'm putting the new motor mounts in.
I would prefer to VERIFY by measuring. Run one of the bolts in til it stops threading in and measure how far it is from the block to bottom of bolt.
I'm not sure if the issue ie that the hole wasn't drilled deep enough or that it was, and not threaded deep enough. Hence, the above suggestion.
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