Well here's something new

[mikekaz1]

So it just relocates the engine support to other existing holes? Right? That's pretty nifty!

[Minuit]

Yep. If the original holes are usable still it uses those too.

[mikekaz1]

Yep. If the original holes are usable still it uses those too.

ah so it could be used as an upgrade too not just an issue fix.   would be good for an upgraded high power 4.0

[1stDeuce]

If the bolts broke off flush, and they can't be removed by grinding a small slot and turning them out, just put a nut over them and weld in the middle.   That usually also heats them up enough that they come right out.  Used that method many times on broken exhaust manifold bolts...     Of course, it requires a MIG welder, or really good stick skills... 

 

Not sure how well even the aftermarket mounts do if you don't use any of the original holes, but if that's what you did, I guess we'll find out!  :)

[cruiser54]

While driving my 99 xj today I started to feel a vibration like the exhaust was hitting the crossmember . When I came home I got up underneath to look and noticed the engine was tilted quite a bit , so I figured I needed a new mount . Well I thought wrong ...

 

 

The three bolts that thread in the boss' circled in the pic all sheared clean off in the block . Anyone have this happen ? I've owned this since it had 36k miles on it and never messed with these bolts at all . I'm wondering if I can even get a drill up there to drill out the old bolts and tap threads for new ones . Any help is always appreciated .

From Jon Kelley aka 5-90 @ www.kelleyswip.com

 

 

 

This is a known issue.

 

1) Unless you're going to get silly with the skinny pedal, 2xSAE8 screws on one side won't be a huge problem. You'd be better off with three, but if you don't get silly you'll be okeh. 

 

2) The Brown Dog engine mounts use two or three additional holes on each side, and spread the mount/clamping force over more of the block. This is invariably a good idea, and I'll probably be doing it as I refit my 88.

 

3) The primary reason that the screws snap is because, sometimes, the screw holes in the block aren't drilled & tapped deeply enough. This causes the screw to bottom out in the hole, so you end up torquing against the bottom of the hole instead of stretching the screw (as you're supposed to do. Not your fault - you aren't doing anything wrong.) The screw is not stretched properly, and the head is not butted up against the bracket, so there's some room to move there. Vibration then causes wear cycles on the screw, which generally leads to rupture.

 

The easy/cheap fix? When you replace the screws (3/8"-16x1.25", as I recall,) put two flat washers under the head before you screw it into the hole.

 

The check? Take a feeler gage (.003" to .005") and try to slide it under the head of the screw. You'll be able to get under the corners (look at the hex head, and you'll see that the surfaces curve toward each other slightly) if it's a standard hex head - if it's a flanged hex head, you should not be able to get under the head anywhere. If you can slip the gage under the head, you have a problem. If you can touch the shank of the screw, you have a big problem!

 

In no case should you reuse the screws after you take them out - they'll be stressed under the head, and you'll have a significant reduction in strength. Replace them outright, putting washers under the head as I mentioned before. The washers will make up for the slight lack of depth in the hole (two of them will be about 0.125" or so,) and allow the screw to be preloaded properly.