Brown dog engine brackets necessary? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Cherokee & Comanche Forums > XJ Cherokee Technical Forum > Brown dog engine brackets necessary?

Dana 30 Truss for your TJ, LJ, ZJ, and XJFS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitFS: Wranger BRIGHT License Plate LED! Just $3! Great value

Reply
Unread 03-25-2013, 09:14 PM   #1
jackdup
Registered User
1998 XJ Cherokee 
 
Join Date: Jul 2008
Location: Reading PA
Posts: 762
Brown dog engine brackets necessary?

I'm planning on getting a set of brown dog rubber motor mounts but am trying to decide if the beefy engine brackets are worth the extra money or not. My understanding is the stock engine brackets are cast and can break causing a lot of damage when the engine drops. How commonly does this really happen? I'm not always the easiest on my xj. I play in the rocks a lot and I like the skinny pedal. What are your thought? Thanks!

jackdup is offline   Reply With Quote
Unread 03-26-2013, 03:15 AM   #2
Timo_90xj
Web Wheeler
 
Timo_90xj's Avatar
1998 ZJ 
 
Join Date: Mar 2006
Location: Helsinki, Finland - on the European side of the Atlantic
Posts: 5,417
If you've got a heavy foot and play on the rocks, I'd highly recommend sturdier engine mounts than the stock ones. It's not the engine mounts that break, but the mounts get sheared off the block causing damage (that is, engine block suffers the damage). Brown dog mounts use a lot more mounting holes and spread the load over larger area preventing carnage.

IMO the mounts are overpriced, it'd be fairly easy to fab 'em if you have a welder. However, it's a fairly small price to pay compared to a worst- case scenario.
__________________
1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...

http://www.jeepforum.com/forum/f13/d...s-etc-1222317/


1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
Timo_90xj is offline   Reply With Quote
Unread 03-26-2013, 07:26 AM   #3
biffgnar
Web Wheeler
 
biffgnar's Avatar
2006 TJ Wrangler 
 
Join Date: May 2008
Location: Westchester, NY
Posts: 13,289
Another option for good motor mount brackets is Stinky Fab Racing. I bought a set from them when at KOH last year. IIRC same price ballpark as Brown Dog so maybe not a helpful suggestion.
__________________
Thank you Dave Cole, Dynomax, Falken and all the Spec Class sponsors!!
biffgnar is offline   Reply With Quote
Unread 03-26-2013, 03:32 PM   #4
foggybottombob
Registered User
1984 CJ7 
 
Join Date: May 2008
Location: Monument Colorado
Posts: 5,821
The rubber tears out of the stock mounts. Brown Dog rubber mounts make your rig vibrate at idle. I have them.
foggybottombob is offline   Reply With Quote
Unread 03-26-2013, 04:08 PM   #5
biffgnar
Web Wheeler
 
biffgnar's Avatar
2006 TJ Wrangler 
 
Join Date: May 2008
Location: Westchester, NY
Posts: 13,289
Quote:
Originally Posted by foggybottombob View Post
The rubber tears out of the stock mounts. Brown Dog rubber mounts make your rig vibrate at idle. I have them.
He's talking about the brackets not the rubber mounts.
__________________
Thank you Dave Cole, Dynomax, Falken and all the Spec Class sponsors!!
biffgnar is offline   Reply With Quote
Unread 05-15-2013, 03:43 PM   #6
BerTJ
Registered User
 
Join Date: Apr 2013
Location: Auburn, CA
Posts: 4
My stock 3 bolts ripped right out of the Engine Block. If I were on the trail it could have been a PITA! Its not a bad idea to upgrade while your in there!
BerTJ is offline   Reply With Quote
Unread 05-16-2013, 07:45 AM   #7
Paradise XJ
Registered User
1990 XJ Cherokee 
 
Join Date: Jan 2007
Location: Paradise, CA, Northern California
Posts: 2,117
Quote:
Originally Posted by BerTJ View Post
My stock 3 bolts ripped right out of the Engine Block. If I were on the trail it could have been a PITA! Its not a bad idea to upgrade while your in there!
Sorry, I don't understand how this could occur, just driving along. Maybe if the integrity of the bracket was compromised due to rust etc. Had the Jeep had some traumatic event? Were they loose? Rusty? Had the bracket been removed, engine swapped?

The brackets on my MJ are original, as are the stock mounts. When I replace the mounts last weekend, they were toast, but the brackets were rock solid.

Like said above, if you push the Jeep hard and climb around in the rocks, you're better off with beefed up brackets AND mounts
__________________
1990 XJ Laredo - White & Chrome
1988 MJ Pioneer - Metallic Green and Black
Paradise XJ is offline   Reply With Quote
Unread 05-16-2013, 07:47 AM   #8
cj7allday
Registered User
2008 TJ Wrangler 
 
Join Date: May 2013
Location: abilene, texas
Posts: 6
go with ALOT sturdier ones
cj7allday is offline   Reply With Quote
Unread 05-17-2013, 09:54 AM   #9
BerTJ
Registered User
 
Join Date: Apr 2013
Location: Auburn, CA
Posts: 4
The Stock Brackets were fine but only use 3 bolts to the block. These Brown Dog brackets utilize 7 bolts on the driver and 8 on the passenger. Sometimes just a speed bump and the block will give way and your bolts rip right out.
BerTJ is offline   Reply With Quote
Unread 05-17-2013, 09:20 PM   #10
NHJeep4x4
Registered User
1999 XJ Cherokee 
 
Join Date: Feb 2009
Location: New Hampshire
Posts: 342
I recommend replacing the stock ones; I've broken the passenger side bracket twice (replaced the first one with a junkyard unit). The motor rolled to the side and took out the distributor. I was just driving down a dirt road, not even wheeling. The second time, it broke just getting into the trail. I threw a log over the engine bay and held up the motor with a ratchet strap and it got me the 3 miles home. Neither of them sheared the bolts, but just broke in half.

Now I have Brown Dog brackets on both sides. If not Brown Dog, at least get something better than stock.
I guess they added a lot more bolt holes since I bought mine.

__________________
4.0L Auto D60/14B, 4.10, spools, 3 link and leaves, 38s, homemade bumpers, Warn X8000i
Build Thread
NHJeep4x4 is offline   Reply With Quote
Unread 05-18-2013, 06:55 AM   #11
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 9,950
Quote:
Originally Posted by Paradise XJ View Post
Sorry, I don't understand how this could occur, just driving along. Maybe if the integrity of the bracket was compromised due to rust etc. Had the Jeep had some traumatic event? Were they loose? Rusty? Had the bracket been removed, engine swapped?

The brackets on my MJ are original, as are the stock mounts. When I replace the mounts last weekend, they were toast, but the brackets were rock solid.

Like said above, if you push the Jeep hard and climb around in the rocks, you're better off with beefed up brackets AND mounts
Here's what usually happens. Seemed to be most prevalent in the early HOs.

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.
__________________
Quote:
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
Refresh*Connections*Before*Replacing*Components
cruiser54 is offline   Reply With Quote
Unread 05-21-2013, 07:07 AM   #12
bpvideo
Registered User
1995 XJ Cherokee 
 
Join Date: Feb 2013
Location: Lexington, KY
Posts: 26
I have a 95 2dr stock 4.0, about to have to replace the exhaust manifold that is cracked. I have a "rough" idle or at least a vibration at idle and engine does shake a bit, how can I tell if my engine mounts are bad? They visibly seem ok, but not a lot you can see on these. I am not doing any off roading at this is just a 2wd. But I have heard the horror stories and do not want to have to replace the header I am about to put on.... any help on diagnosing or testing the motor mounts?
bpvideo is offline   Reply With Quote
Unread 06-06-2013, 05:33 AM   #13
NHJeep4x4
Registered User
1999 XJ Cherokee 
 
Join Date: Feb 2009
Location: New Hampshire
Posts: 342
Quote:
Originally Posted by bpvideo View Post
I have a 95 2dr stock 4.0, about to have to replace the exhaust manifold that is cracked. I have a "rough" idle or at least a vibration at idle and engine does shake a bit, how can I tell if my engine mounts are bad? They visibly seem ok, but not a lot you can see on these. I am not doing any off roading at this is just a 2wd. But I have heard the horror stories and do not want to have to replace the header I am about to put on.... any help on diagnosing or testing the motor mounts?
I've noticed that the stock motor mounts wear out when the rubber disintegrates. This will not cause the motor to flop over, as it's still supported, just not by the rubber anymore. The horror stories are from when the engine bracket fails (either the bolts break or the bracket itself). I would think the only ways to check the engine brackets are to check the bolts or for any cracks in the bracket.

Maybe to test the motor mounts, you could jack up the motor a bit to see if there is significant play in the mounts.

Also, Brown Dog has great customer service!
__________________
4.0L Auto D60/14B, 4.10, spools, 3 link and leaves, 38s, homemade bumpers, Warn X8000i
Build Thread
NHJeep4x4 is offline   Reply With Quote
Unread 06-06-2013, 05:59 AM   #14
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 9,950
Here's what happens with the bolts. Easy enough to take care of BEFORE catastrophe strikes.



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.
__________________
Quote:
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
Refresh*Connections*Before*Replacing*Components
cruiser54 is offline   Reply With Quote
Unread 06-07-2013, 05:14 AM   #15
cdn_xj
I've returned to the fold
 
cdn_xj's Avatar
1999 XJ Cherokee 
 
Join Date: Mar 2007
Location: North Vancouver, BC
Posts: 233
I have had this happen. Passenger side bolts holding the mount to the block sheared off. the engine rolled to the passenger side and was held up by the distributor resting on the mount. Fortunately the damage was limited to that. UNfortunately the issue was discovered the week before Christmas and no one had shop space or time to effect the repairs for me.

Soooo...The Friday night before Christmas about 3 years ago I stayed late after work and working only with some hand tools, a right angle drill, some stubby drill bits that I still had to cut down more, no engine hoist, and an air compressor that kept tripping the breaker I pulled an all-nighter and drilled out 3 bolt shafts that I could not see and replaced the 3 bolts. And it only took me 14-1/2 hours.

The issue: I could not raise or lower the engine enough to get clear access to the last bolt. The frame rail was in the way. Hence the use of a right angle drill and stubby bits that had to be cut down further. In retrospect, I cannot remember whether I unbolted the driver's side mount or not. either way, it took me something on the order of 5 hours to get at and drill out/easy out the first bolt. And for the record, easyouts, contrary to the name, are NOT that easy to get broken bolts out with under ideal conditions and damn near impossible under adverse conditions.

Upon inspection it appeared that 2 of the bolts had sheared off previously and I had been running on the remaining bolt for some time. until i hit a big pothole.

The ONLY thing that was positive about the whole ordeal was the fact that the broken bolts were Grade 5 and not Grade 8 otherwise it might have taken me the entire weekend.

So, in a nutshell, if you even THINK you need to ugrade to the BrownDog mounts (or similar), Do it.
__________________
'99 XJ Sport 4-dr
4.0 HO - AW4 - NP231 - D30, 4.10, Open - ChrysCo 8.25 29-Spline, 4.10, OEM Trac-Loc

INSTALLED:
5.5" home brew lift (BB + JKS ACOS/bastard packs + 1.5" Boomerang Shackles) | RE DBs + Adjustable UCAs & LCAs | JKS BPEs & Quicker Discos | Kevin's Offroad Trackbar | 33x10.50-15 BFG ATs | 15x7 Type 058 Eagle Alloys | RuffStuff Specialties HD Diff Covers | AA SYE | Modified Tom Woods driveshaft | LeBaron hood vents | Redline Hood Lift | B&M Tranny cooler | Reese Class III Receiver | 62mm bored TB | Borla Cat-Back Exhaust | C4x4 Fab Rear bumper & tire carrier | ORO Licence Plate relocation Kit | Kelley's WIP HD wiring upgrade | ZJ rear disc brakes | Stainless Brake lines | ARB front Bullbar | Orvis Edition Rear Spoiler

TO BE INSTALLED:
JKS Mini Skids | Rock Lizard Corner Guards | AEV/Nth Degree Oil Pan Skid | TnT Customs Unibody Stiffeners, HD Belly Pan & U-Bolt Eliminators

PLANNED:
ARB Roof Rack | Warn 9000lbs Winch | Warn Manual Hub Upgrade | Rock lights | 231 Wide Chain Kit, 2Lo, 4:1 | Brown Dog Motor Mounts | Snorkel | Dual Batteries | OBA
cdn_xj is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.