Replacing Engine Mounts

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Diagnosis

Clunking on acceleration or deceleration. May sound like it is coming from the rear. Wayne Toy once had a squeak on left turns, with no squeak but a mild vibration on harder turns, which turned out to be the right engine mount isolator. In his case, it had collapsed, leaving the engine sitting half an inch lower on the right side. He paid $38 for a new isolator at the dealer (part 4505411, list price $58) and it took half an hour to replace.

Transmission mount replacement (Paul Berkebile)

On a 3.0L A-604, the tranny mount is easy. Maybe a half hour to do.

First, I bought a new one from the dealer ($45), then cut Delrin blocks to fit in the openings, and then filled all openings with Urethane. I cooked it in the oven to make sure the Urethane hardened (it takes days to harden in small windshield applications - imagine inch think blocks of it).

It came out real nice looking too. The black Urethane covered the Delrin and rubber front and back.

Now to replace it:

Jack up the car and the trans/engine separately.
Remove the driver side tire.
There is a bolt head covered by a plug, remove that. (this will make the transmission fall if not supported.)
Now to remove the mount from the trans by removing I believe (3) bolts near the same location.
Lower the trans/engine slowly to get the old mount out
Put the new one in a reverse.

It is a little tricky lining it back up to put the new mount in, but I did it with just two jacks and a socket set in about 45 minutes.

John Auto Tech wrote: The easiest way to align the mounts is to perform an engine centering procedure. With the vehicle stationary and on the ground, remove both axle nuts and push the outer spline into the hub . If the splines push in the same amount on both sides then the mounts are centered.

Ed Hennessy's replacement instructions

If you take the thing out, not that much, depending on how squashed the old one is.

After you bend open the tabs and hammer-and-screwdriver the old one out of the bracket, you'll notice that the new one is not by ANY stretch going in without a fight! It's sort of an open C, whereas the old one will have been bent/compressed into a square O by installation and wear. The trick is to compress the new one somehow so that it will slide into the bracket. That's the hard part. A vice, a hammer, whatever works will be okay. Then you need to bend the tabs out and/or down to secure it. That can be fine.

Basically, screwdriver/chisel/small pry tool and ball peen/standard hammer should do it. It may take a while, but it will go it. Not hard, but perhaps tedious.

Gus uses wood!

Mopar Performance sells stiffer, stronger mounts out of their catalog. I took the cheap way out. I cut 3" long pieces of wood, and shaped them with a grinder to fit the triangular holes in my mounts, and banged them in place with a hammer. This increases vibration transmitted through the mounts, I had a V6 which is smooth, anyway. Even my 4-banger isn't bad... I ran 12's all season, and the mounts are still perfect. No sag. That was after trying hot melt glue, and silicone. The wood works the best.

Roger Crawford uses Mopar Performance

The Mopar performance mounts should work with no problems on your (2.5 TBI) car. If you use the full set, you will notice more vibration, as the mounts are much more solid than stock. Best price I've found on the mounts so far has been Forward Motion. Of course there's also your local Mopar dealer ($).

Mounts are for right and left side, and front, for a 2.2. You might want to double check with FM on applications..

P4286765 Right side-All
P4286766 Front-All
P4286765 Left Side 81-83 only

All are $33.75 list. I paid $28 at Forward Motion (FM).

The one to the rear of the car is simply a shock absorber. The dogbone is the one that attaches to the front reinforcement bar below the radiator. Usually the weakest mount is the right side one, as the torque twists the motor hard onto the mount, and that mount has a strong tendency to collapse.. Next to go, is the front dogbone. That's also the one than can literally tear loose from hard acceleration. That prob is more specific to the turbo cars. The rear shock is designed as a damper to slow the front/back twisting action, removing a small amount of stress from the dogbone.

Dan Stern brought up a "root cause"

I want to say for anyone who's got an EEK with the "shock absorber" type rear torque strut (serving as the rear engine mount) that you should dump the stock item. Currently, your torque strut is in the form of a shock absorber. This allows way too much engine movement back and forth. This is why R/Ts go through engine mounts so fast and why the whole drivetrain goes "judderjudder" when you're on and off the throttle at any speed. It's also why these cars wear out exhaust "doughnut" gaskets so fast, causing them to go "squeaksqueak!" whenever you engage or disengage the clutch.

The Ed Peters Torque Strut is a solid bar link of adjustable length with a factory Chrysler oblong bushing at the lower end. It stops this ridiculous back-and-forthing, neatly solving the above problems. It also makes the clutch and shifter action much more positive, since the cables for those mechanisms are no longer being pulled around by the engine/trans movement. And here's the best part. The instructions for the strut say that "some increase in vibration may be noticed", but I'm here to tell you that my '91 R/T is smoother and quieter from idle to 90 mph (haven't had it above that speed) with the strut than with the absorber. I would never go back. Even my mother raves about the improved clutch feel and lack of shakiness, and she's clutch-o-phobic. Get one. Best $35 you'll ever spend on the car. Important note: for personal reasons, Ed Peters has left the business...so these parts are very hard to find. You might however be able to have one fabricated.

[As for the rubber isolators,] Slick trick: Go to an auto windshields place and purchase a caulk gun cartridge of structural urethane windshield setting compound. This stuff is much stiffer than RTV silicone when set and should be perfect for this application. ... Hot melt glue is a low-melt plastic. It will not bond to rubber. The windshield setting urethane is a material expressly designed to adhere well to all sorts of rubber. It will actually become a part of the rubber of the engine mount. I would probably want to give mounts so treated a nice long time in a nice warm place to ensure the urethane had set completely. I might even be extra-cautious and fill the gaps in several stages, since this urethane bonds so well to itself. It costs about $6 for a cartridge and if you get it on your hands you'll be sorry--it is hard to remove! I'm away from my cars' mounts for the foreseeable future, though, Gus...you may wanna try this yourself.

Ed Treijs

If you unbolt it at the yoke (where the bracket bolts to the bracket from the engine), unbolt the cross bolt first, and the big nut that's on the bottom second, or you won't be able to get the cross bolt out! You will also need some pretty big sockets, like 22 mm (if I recall) for the bottom yoke nut. A 22mm deep would be best, but a normal one will more-or-less work. Also 19 mm, and 15/15deep. If the mount bolts have been tightened by Godzilla, you'll need 1/2" drive and a breaker bar.

The first thing to do, however, is to take off the nuts attaching the mount to the fender reinforcement, and jack up the engine to clear. I used the supplied tire jack and a piece of plywood under the oil pan; worked fine.

It's really not a big job; I took my time and fiddled with a ground strap, and it probably took me a 90 minutes. A mechanic working on flat time would be through in 30 minutes or less.

(Regarding the front mount):

This whole part was a PITA. There isn't much room to slip the mount assembly out or back in (I did not unbolt the front part of the mount from the crossmember....maybe I should have). I suppose if you cut the lower rad hose.... I put the bolt back through the mount after struggling to get both sides of the mount's insert into the receiver bracket. That was not fun. As far as lining it up, the first bolt I got started was the lower left-pointing bolt, the long one you get at from below, that goes through the bellhousing. Then the other bolt which points left into the bellhousing. Then the two bolts which go back into the motor -- Both ends have four bolts holding 'em. Anyway, do NOT try to line up bolts from the top--none of the three upper bolts to the block will line up, you have to start from below. Trust me on this.

It is also a good idea to put the trans into neutral. When in Park (and I suppose even more so if a manual in gear) the engine doesn't rock nearly as easily!!

I didn't use a jack. Doubt it makes much difference unless you can rotate the engine using the jack. Mind you, I was also working with the front end of the car sitting on the wheels, on the ground. Not much room to work underneath.

(Measuring the driveshaft lengths:)

I grabbed a pair of the gazillions of cheap dry-cleaners' coat hangers I still have stuck in the closet, and bent them up to be measuring gauges. Rough ASCII diagram: __ |________________| (not to scale!)

The extended leg on the left side was created to indicate the "tolerated variation" in the lengths.

So, all you have to do is crawl under the car (still not jacked up!!), and place the short little bit (by feel) at the inner CV joint edge. You can see the outer CV joint....observe where the tolerance leg is sitting. Easy! Don't need to fiddle with a measuring tape, can do it one-handed, and it gives you a go/no-go indication.

Now, here's the interesting thing: the driver's side (LH) was in tolerance, but the RH was compressed about 1 cm more than it should be. I tried shoving the engine around, but I think the front mount has to be disconnected at the crossmember (i.e. front part) to shove the engine from side to side, as I didn't seem to accomplish much. I will try later....the front mount-to-crossmember bolts look quite rusty so I'm not looking forward to this.

What the FSM sez on length:

"A shorter than required driveshaft length can result in objectionable noise. A longer than required driveshaft length may result in potential damage."

At least I'm avoiding damage....but maybe also this is producing the knocking knoise :-) I'm getting somewhere from the RH front, at wheel speed.

Wes Grueninger

For the passenger side engine mount:

Remove the two 13mm bolts holding the engine mount to the body.
Remove the ground strap going between the body and the engine mount bracket.
Place a floor jack underneath the engine oil pan, preferably with a block of wood between the pad on the jack and the pan.
Jack the engine up until you have a clear shot at the 15mm bolt going through the engine mount. This *will* lift the car slightly and requires quite a bit of jacking - DON'T PANIC. It is a Good Idea<tm> to spray some penetrating oil on the visible end of the bolt to aid in it's removal.
Remove the bolt.
Jack the engine up until you are able to pull little engine mount 'block' out from between the bracket.
Insert the new mount and install the 15mm bolt loosely. Remember that the mount is directional, so be sure to install it correctly!

Most new mounts have 'top' stamped on them. Make sure the new mount is in there straight and tighten ther 15mm bolt. Chances are the engine will have been pulled forward from the jacking. Don't worry, lowering the engine should make the new mount pop into place. If this is a turbo engine, be sure to reinstall the two little steel plates underneath the 'ears' of the engine mount. With the mount 'popped' back into place, finish lowering the engine. The bolt holes should have lined up with the slots in the new engine mount if everything has gone properly. Reinstall the two 13mm bolts, and reattach the ground strap. Now it's time for:

The front engine mount:

Using a wrench and a ratchet (I *believe* these are 14mm.), remove the through bolt holding the engine mount to the radiator core support. This procedure *is* easier with the engine cooling fan removed.
Unclip the lower radiator hose and coolant line from their retainers on the engine mount bracket.
Using a 18mm(?) socket, remove the two bolts holding the engine mount bracket to the engine block.
Remove the two bolts holding the engine mount bracket to the transmission. If you bought the front mount from the dealer, then it came installed in a new bracket. Installation is the reverse of removal. Be sure to swap over the plastic radaiator hose retainer clip - the screw holding it on should be 10mm.
If you bought just the engine mount rubber isolator 'cube' from a parts store like Schlep Boys or AutoStoned, then bend the tabs down which are holding the front isolator in place, and pound it out.
Compress the new isolator enough to get it installed in the bracket, pound it into place, then bend the tabs back over to lock it into place. Installation is the reverse of removal.

The transmission mount:

Hooboy. Raise the car and support it on jackstands
Remove the driver's side wheel
Remove the driver's side splash guard so that you can see the tail end of the transmission.
Remove airbox inlet hose (to the SBEC)
Remove the battery and its tray. This was necessary on my ex-'88 Shelby Z, but Your Mileage May Vary<tm>
Support the transmission with a floor jack
Remove the bolts holding the transmission mount to the top of the transmission. On said Shelby Z, this required a propane torch in order to get the bolts to come out.
With the mount unbolted from the tranny, it's time to remove the through bolt. Remove the body plug in the driver's side wheelwell which covers over the mount's through bolt. Check the style of mounting hardware used! On some vehicles, the nut that the through bolt threads into is welded to the body. On others, the through bolt threads into a snarky 2" long hex nut. If this is the case, then it may be necessary to have an assistant hold a wrench on the snarky hex nut while you remove the through bolt. If you have the nut welded to the body, then spray some penetrating oil on the visibile threads sticking through it. Remove the through bolt.
Remove the mount. In my case it was necessary to lower the transmission slightly to remove the mount from the top.
Installation is the reverse of removal.

These procedures have been my experience approximately 90% of the time on the 20-or-so EEKs that I've replaced mounts on, so I hope this helps you out some.

Wes Grueninger

Jason Baker added

Just wanted to add something to possibly help a troubled Shadow 2.5 CONVERTIBLE owner. Was reading the entries on replacing engine mounts. I finally found out the hard way that the convertibles have a different passenger-side mount. This mount, fluid filled, only seems to be available through Mopar ($165). Don't ask me why they're different for convertibles, still trying to figure that one out.