Sheared motor mounts
Ok guys I have a 97 zj 4.0 a few days ago the motor mount bolts on the drivers side sheared off. Well I took it to the local mechanic and they were only able to retrieve just one they put a new on in and the engine sirs fine ( for now ). I'm wondering if there is any mods that I could do without replacing the engine ( which was replaced 20k miles ago ). Any imput would greatly be appreciated.
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 740
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Welcome to CF!
Those bolts were probably not grade 8 or were loose when the engine was installed. They can be drilled out and extracted, but because or space restrictions, the engine may have to come out to do it. I wouldn't trash the engine over a couple of broken bolts.
One of the coolest things I've seen done is to weld a smaller bolt to the broken one and remove it that way. That works well if the bolt isn't seized. If it was too long and bottomed in the thread, it'll have to be drilled out.
Those bolts were probably not grade 8 or were loose when the engine was installed. They can be drilled out and extracted, but because or space restrictions, the engine may have to come out to do it. I wouldn't trash the engine over a couple of broken bolts.
One of the coolest things I've seen done is to weld a smaller bolt to the broken one and remove it that way. That works well if the bolt isn't seized. If it was too long and bottomed in the thread, it'll have to be drilled out.
Yeah from what the mechanic said they are extremely seized or cross threaded like no other.. I've been looking into these bomb proof motor mounts.. I do have a 97 zj but the engine I replaced it with was a 4.0 out of a 00-01 wrangler I believe and from what I see its a type II 4.0. So should I look into getting the bomb proof ones for the zj or the wrangler. I know that the holes for the frame may not line up. Is that true?
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 740
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Oh, wow! The mount bosses are in different places on the two motors. No wonder you had problems. Are you using aftermarket mounts? The later engine has the oil filter screwed into the side of the block, right?
Yes it does.. so do they make after market ones that will accommodate for them or should I get the wrangler ones and have the figure out new wholes for the frame? Wish the *** clown who put the engine in would have mentioned this!!!
CF Veteran
Joined: Jul 2013
Posts: 7,554
Likes: 17
From: Monett, MO.
Year: 1999
Model: Cherokee
Engine: 4.0
Try Brown Dog motor mounts (they use 6 bolt holes on the block each side not just 3) I had to order a set for this 4.0 engine I bought for my 99 XJ (another 99 4.0 with 103,000 mi.). Here is what happened to it when they drove with a broken mount and hit a big pot hole. No repair for this hole lol.
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Seasoned Member
Joined: Feb 2016
Posts: 261
Likes: 10
From: Columbus Ohio
Year: 1998
Model: Grand Cherokee
Engine: 5.9L 360 ci
Try JB weld if you havent already scrapped it.
I have used it to do some INCREDIBLE things. give it plenty of time to dry. read the instructions. Make sure you insert the bolt while its still soft.
TIP: lubricate the bolt a little before you put it in the JB weld, so its easier to remove after it cures.
CF Veteran
Joined: Jul 2013
Posts: 7,554
Likes: 17
From: Monett, MO.
Year: 1999
Model: Cherokee
Engine: 4.0
Try JB weld if you havent already scrapped it.
I have used it to do some INCREDIBLE things. give it plenty of time to dry. read the instructions. Make sure you insert the bolt while its still soft.
TIP: lubricate the bolt a little before you put it in the JB weld, so its easier to remove after it cures.
I have used it to do some INCREDIBLE things. give it plenty of time to dry. read the instructions. Make sure you insert the bolt while its still soft.
TIP: lubricate the bolt a little before you put it in the JB weld, so its easier to remove after it cures.
I'm going to use the Brown Dog mounts on that engine when it goes in.
Moderator CF K9-unit
Joined: Apr 2012
Posts: 5,842
Likes: 12
From: Alaska
Year: 2000 sport
Model: Cherokee (XJ)
Engine: New 4.0l from s&j engines
Try JB weld if you havent already scrapped it.
I have used it to do some INCREDIBLE things. give it plenty of time to dry. read the instructions. Make sure you insert the bolt while its still soft.
TIP: lubricate the bolt a little before you put it in the JB weld, so its easier to remove after it cures.
I have used it to do some INCREDIBLE things. give it plenty of time to dry. read the instructions. Make sure you insert the bolt while its still soft.
TIP: lubricate the bolt a little before you put it in the JB weld, so its easier to remove after it cures.
CF ADMIN

Joined: Sep 2010
Posts: 34,087
Likes: 256
From: Lantana, Fl
Year: 1996
Model: Cherokee (XJ)
Engine: 4.Slow
Try JB weld if you havent already scrapped it.
I have used it to do some INCREDIBLE things. give it plenty of time to dry. read the instructions. Make sure you insert the bolt while its still soft.
TIP: lubricate the bolt a little before you put it in the JB weld, so its easier to remove after it cures.
I have used it to do some INCREDIBLE things. give it plenty of time to dry. read the instructions. Make sure you insert the bolt while its still soft.
TIP: lubricate the bolt a little before you put it in the JB weld, so its easier to remove after it cures.
CF Veteran
Joined: Oct 2013
Posts: 5,924
Likes: 203
From: Greenville, SC
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 740
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Out of curiosity, I just went to Brown Dog Offroad and found they make super-strong motor mounts for Wranglers and Cherokees but NOT Grands. The 6-bolt mounts will fit the engine but NOT the body of the ZJ. I'm sure, however, you can drill holes to make them fit. The only reason they were changed was to balance the 4.7 in the WJ. It was a simple thing for the engineers, but started a nightmare for parts swappers.
Last edited by dave1123; Apr 11, 2016 at 05:29 PM.



