Sheared RH motor mount bolts.

thecarreaperMember

well my newly delivered 71 has this famous issues.

my question is why? is it a matter of torque that shears the heads off the bolts?
i guess that means the car may have some power!( have not driven my Pantera yet, or anyone elses for that matter)!

the purpose of this thread is to see if there are any tricks or better fixes for this.

do any of the vendors sell stronger bolts, or better mounts?

should i also replace the left side bolts due to age and stress?

thanks for any help!

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7/22/075:07 AM

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thecarreaperMember

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7/22/075:08 AM

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panterrorMy 74 GTS

IMO, it's likely they were/are siezed and were broken when removal was attempted.

Drill, heat with torch, apply big breaker bar and easy out, and keep moocho profanity in reserve.

Kelly

7/22/076:41 AM

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panteradougMember

Nice PB!

Don't fret about the engine mounts. They really aren't prone to failure.

Panterror's vision of the cause is likely highly accurate.

Support the engine and pull out then entire assembly. Put the mount on the bench and clean everything out.

Just be sure to use grade 8 or stronger bolts when you put it back together.

It won't ever happen again.

The caution on the early cars is the rear mount on the transaxle. They are prone to failing.

7/22/078:06 AM

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marlinjackThe Machinist #5723 AMARGOSA MACHINE 'Running on Empty- Middle of Nowhere'

...When You Torque those Grade 8 Bolts back in; I believe 55 Ft/Lbs, Put some 'Anti-Seize' Paste on them, and You'll never see broken bolts again!...

7/22/079:29 AM

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thecarreaperMember

thanks for the replies, i am going to get my tools together this week and replace them.

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7/22/072:18 PM

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crazydaveEFI Expert

I used to have this problem. I did two things to solve it.

First, I quit doing burnouts. Well not as many anyway.

Second, I took off the motor mounts and milled the surface that mates to the block. It seems that they had gotten a little rounded on top and were rocking putting stress on the bolts. Once I did this, I have not breaken a bolt since.

7/22/079:34 PM

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johnnywoodsMember

Thecarreaper,

Another thing to consider, when you remove the mounts, inspect the rubbers, if they have compressed on the inside this puts strain on the mount and can cause bolt failure. Replace the rubbers, or at least rotate them 180 degrees.

Johnny

7/23/0712:39 AM

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thecarreaperMember

thanks, i have been busy with work and will work on this asap this week. this is the only thing keeping me from driving the car!

7/24/073:09 AM

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thecarreaperMember

i got the bolts out, off i go to find some grade 8 stuff for both sides. the castings are super cool, i must have played with them for half an hour like a fool. i think they are magnesium as they are so lite for their size. seems aluminum would be heavier.