• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Motor Mount Replacement - Step by Step

kd5dwy

NAXJA Forum User
Location
Central Arkansas
This is how I did it on my '87 with a 4.0L I6:

What you will need:
new motor mounts - I highly recommend aftermarket types (I used Brown Dog and am VERY impressed!)
new engine oil filter
new engine oil
new engine oil plug seal
new air filter?
high temperature grease
16mm socket
18mm socket
18mm box-end wrench
1/2 in. socket
3/4 in. socket (or whatever your engine oil drain plug requires)
socket wrenches and extensions
floor jack
jack stands or ramps
block of wood

Raise the front end of the vehicle using either ramps or floor jack and jack stands.

Passenger side:
1. Drain the oil and remove the oil filter
2. Loosen the bolt (16mm socket) that holds the oil filter bracket into the engine (you don't have to remove it). You want to loosen this enough to allow you to rotate the oil filter mount toward the firewall.
3. Remove the nut from the through-bolt (18mm socket and box-end wrench) on the engine mount.
4. Raise the engine using the floor jack. Place a piece of wood between the floor jack and the oil pan to help disperse the load more evenly across the oil pan and help prevent damage.
5. Remove the nut from the stud holding the outer side of the mount to the frame.
6. Crawl under the front of the vehicle and remove the nut from the stud that is attached to the engine-side of the mount.
7. Remove the through-bolt.
8. Remove the old motor mount
9. If you're installing aftermarket motor mounts, lube the faces of the bushings with high temperature grease.
10. Lube the through-bolt with high temperature grease
11. Slide the new motor mount into place making sure to orient the mount in the correct direction.
12. Slide the through-bolt through the mount
13. Install the nut on the through-bolt
14. Lower the engine while keeping an eye on the alignment of the mount to the frame stud
15. Install the bolt on the frame stud
16. Crawl back under the vehicle and install the nut on the new motor mount bolt
17. Tighten bolts according to torque spec/manufacturer instructions
18. Rotate the engine oil filter mount back away from the firewall to its original (vertical looking from front-to-back) position and tighten the bolt
19. Install the new oil filter
20. re-install the oil plug (make sure to use a new seal or this WILL leak)
21. Add the recommended amount of oil into the engine (may be more than the normal oil change since you drained almost ALL of the oil from the engine when you removed the oil filter bracket)

Driver Side:
1. Remove the air intake box lid by popping off the 6 metal retaining clips and removing all vacuum and air fittings.
2. Remove the air filter
3. Remove the air intake box by removing the two bolts (1/2 in. socket) in the front and one nut (also 1/2 in.) in the rear of the box.
4. Remove the nut from the through-bolt on the mount
5. Use the floor jack to raise the engine
6. Remove the bolt on the outer side of the motor mount
7. Crawl under the vehicle and remove the nut from the motor mount stud
8. Remove the through-bolt
9. Remove the motor mount
10. Lube contact points of new motor mount with high temperature grease
11. Install the new motor mount (if you have an aftermarket mount, you may have to do some grinding on the bushing to get it to connect with the engine. Feel the inner lip of the engine portion and you'll see what I'm talking about. I ground about 1/8 in. off of a portion of each bushing and tapered it to make installation easier.)
12. Lube the through-bolt with high temperature grease
13. Slide the through-bolt into the mount
14. Install the nut on the through-bolt
15. Lower the engine making sure to keep the mount lined up on the holes in the frame for the motor mount stud and mounting bolt
16. Install the bolt on the outer side of the motor mount
17. Crawl under the front of the vehicle and install the nut on the motor mount stud
18. Tighten all bolts/nuts according to torque spec/manufacturer instructions
19. Re-install the air intake box
20. Re-install the air filter (do you need a new one? Now is the time...)
21. Re-install the air intake box lid and all vacuum/air hoses

Lower the vehicle off the ramps or jack stands

Go for a ride and enjoy the feeling of taking a corner with no grinding. Pull through a drive-through and enjoy not having to listen to your exhaust rattle against the transmission crossmember. Shut off you engine and enjoy not having to listen to your engine rattle around in the old, loose mounts.

Notes:
1. Overtightening the through-bolt on aftermarket mounts can cause more vibration to be transfered to the vehicle. Make sure to follow the directions that came with your mounts.
2. You may still feel vibration even if everything goes right on your motor mounts. This is most likely coming from a bad transmission mount. If you're replacing the motor mounts, plan on replacing the transmission mount at the same time or soon thereafter.

Good luck!
 
Good write-up, Will there be an issue with the exhaust manifold or exhaust pipe when jacking the eng up? I didn't see any mention of it.
 
parkeruph said:
Good write-up, Will there be an issue with the exhaust manifold or exhaust pipe when jacking the eng up? I didn't see any mention of it.

There should be enough flex in the system to allow jacking up the motor a bit. If any severe binding occurs, I would undo the pipe at the header.
 
I didn't have any problems with the exhaust. As far as clunking when putting it into gear, that is still happening. I'm going to get one of the Daystar tranny mounts and swap it in. That should fix the tranny clunking. My engine was leaking oil for a LONG time (the previous owner never replaced the drain plug seal when changing the oil, so it was CONSTANTLY losing oil and the tranny mount is right behind the oil pan. Since I've heard that oil breaks down the rubber, I'm sure the tranny mount is toast. I'll try to write it up as well when I get it done.
 
kd5dwy said:
I'm going to get one of the Daystar tranny mounts and swap it in. That should fix the tranny clunking.

After you install the daystar tranny mount, check your mechanical fan for radiator clearance before you start the jeep (don't just look at it - actually spin it through a full rotation to be sure). Had to pull mine out right after I installed it on my '96 because of this, and I'm not the only one to run into this problem. I'm hoping that installing some new motor mounts beforehand will keep the engine tight enough that the tranny mount doesn't push it so far forward ... though of course that would beg the question of how you get it all bolted back up, if you aren't displacing the engine, and obviously aren't compressing a very solid piece of polyurethane. Saving the answer to that one for a warmer day :D
 
It's got to be better that the OEM style rubber... Besides, I'm sure the XJ will just stretch a little to make room (in a very Rodney King style gesture).
 
"New motor mounts - I highly recommend aftermarket types (I used Brown Dog and am VERY impressed!)"

I saw those also and was wondering about added vibration transfer or noise. How do you like them?

I'll be doing the manual trans mount also because I'm tired of searching for the shifter when driving off road.
 
Well, there is a bit more vibration. I get quite a bit of vibration at idle in drive, but that's probably from a bad transmission mount as opposed to the motor mounts.

I bought aftermarket because I know this is not going to be a DD, but a weekend warrior machine. I can go with rough ride and some vibration to ensure that my motor isn't going to fly out at an inopportune time.
 
kd5dwy said:
I didn't have any problems with the exhaust. As far as clunking when putting it into gear, that is still happening. I'm going to get one of the Daystar tranny mounts and swap it in. That should fix the tranny clunking. My engine was leaking oil for a LONG time (the previous owner never replaced the drain plug seal when changing the oil, so it was CONSTANTLY losing oil and the tranny mount is right behind the oil pan. Since I've heard that oil breaks down the rubber, I'm sure the tranny mount is toast. I'll try to write it up as well when I get it done.

I dont see how leaking oil at a drian plug could get on the tranny mount, isnt the tranny mount over the crossber all the way at the back of the trans? or are there two? or do you have a manual tranny and the mount is up closer to the motor? correct me if im wrong
 
maine96xj said:
I dont see how leaking oil at a drian plug could get on the tranny mount, isnt the tranny mount over the crossber all the way at the back of the trans? or are there two? or do you have a manual tranny and the mount is up closer to the motor? correct me if im wrong

It could easly blow back while driving, spraying/covering most the underside with it. Over time, it could ruin the mount. The manual tranny mount isn't that much closer to the engine.
 
Exactly what CanMan said. It also blows onto the exhaust and causes a burning oil smell (which is really nice while cruising down the road).
 
replaced my broken motor mount, here is the drivers side one.

S5000670.jpg


S5000673.jpg
 
Good write up, the only thing I would add would be that when you rotate the oil filter housing, why not take it off all the way and replace the "O" rings. Might as well "kill two birds with one stone",save ya doing it later.
 
Back
Top