Motor Mount Replacement - TR4
Aged motor mounts compress, harden, crack and allow excessive vibration and motor movement. A worn torque reaction arm buffer will also allow motor movement and clatter against the chassis. Sooner or later you’ll need to replace those worn parts. The procedure is outlined below.
This job requires standard tools; a floor jack, jack stands, new motor mounts, a new torque reaction arm buffer, string and scotch tape. It’s advisable to replace the transmission mount as well to complete the process. Before you begin, soak the threaded fasteners with rust dissolving penetrating oil well in advance to ease disassembly, (Kroil is the best I've found).
Safety First. Chock the rear wheels, remove the battery, jack-up the front end and safely secure it with jack stands. Remove the front wheels to access the working areas. Drain the radiator and remove the lower radiator hose-pipe assembly to gain access to left motor mount. Loosen the hose clips on the upper radiator hose and free but don’t remove the hose connection. Be sure this hose can rotate in place, but DO NOT remove it, (the loosened hose allows movement of the motor while raising it to remove the mounts).
Remove the screws on both accelerator rod bushing flanges and the two screws securing the bracket to the firewall. The bracket secures the accelerator rod adjacent to the throttle lever arm, (the return spring and linkage attaches to it). Once free, the rod can safely be moved out of the way. Removal of the battery provides the adequate clearance to remove the accelerator shaft allowing the motor to be raised with no interference. More on this later…
Caution 1) If the above is not performed, a bent accelerator rod when raising the motor will result.
Caution 2) When jacking up the motor after freeing the motor mounts, be sure to check that the fuel line does not disconnect from the fuel pump. It can stretch a little but excessive movement may cause it to disconnect spilling flammable gas. Safest bet is to drain the gas tank and remove the hose.
Prepare the lower steering column coupler for disconnection by removing the nyloc-nut and bolt closest to the steering rack. Remove the steering column clamp and plate at the upper end where the steering column passes through the firewall permitting it to slide axially to separate the lower steering coupler from the rack.
Caution 3) To assure correct steering wheel alignment at reassembly, before separating the steering column from the rack, mark the alignment of the rack to the splined shaft and coupler to indicate the relative position of the components. If the steering wheel alignment was not correct to begin with, now’s the time to correct it, (at reassembly).
Separate the steering coupler and column from the rack; the upper steering coupler remains attached to the steering shaft and will not be removed. Use a piece of tough string to tie the steering column up and away from the working area to prevent interference and scratched paint.
Remove the two bolts securing the torque reaction arm below the right front motor mount; access is easiest from underneath. Leaving the motor weight on the mounts, remove the top nuts and lock washers from each motor mount, then loosen the bottom nuts. The bottom nuts are in very tight areas allowing only about one-sixth of a wrench rotation at a time. Remember to keep the weight of the motor on the mounts to prevent the mounts from rotating allowing the nuts to be easily loosened, (not removed).
After removing both top motor mount nuts and only loosening but not removing the bottom nuts, see time saver below. Now with loosened nuts not yet removed, carefully jack-up the motor to lift the weight off the mounts.
Caution 4) Lift the motor by placing a 2x4 wooden block between the oil pan and jack to distribute the load and prevent denting the oil pan.
Time saver) After only loosening the bottom nuts, and at this point with no motor weight on the mounts, they are free to spin. While holding the lower nut with a wrench, you can then easily remove the nut by simply spinning the mount with your other hand. This is a much faster technique to remove the bottom nuts rather than using those short one- sixth turns of the wrench to remove them with the motor weight on the mounts to prevent them from turning.
When all nuts have been removed, carefully raise the motor just high enough to remove the compressed mounts. Refer to Caution 5.
Caution 5) There is a height limit. Going beyond this limit will raise the car off the jack stands! While the motor is jacked up, you can rock it side to side just enough to provide the necessary clearance to remove the old compressed mounts.
HINT 1) Before re-fitting new motor mounts, be sure the nuts thread down the entire length of the studs. Check the threads on the new mounts to be sure they are not marred. If the nuts do not thread down effortlessly, recondition them to allow the nuts to spin freely. Fitting new, uncompressed mounts in place is more difficult than removing compressed mounts so you only want to install new ones once. Marred threads will force you to remove the mount(s) to recondition the threads, then install them a second time, (this ticked me off so I write from experience, …yes it happened to me!).
HINT 2) Install the right mount FIRST (facing the motor from the front). With the motor at the highest jacked-up position, work from the center of the motor compartment. Insert the lower ount stud into its hole first (but don’t attach the nut), then raise the mount to insert the upper stud through its mounting hole. Now, fit the washer and catch the upper nut to its stud and turn it down only a couple of turns and NOT more. Leave the mount loose for movement with enough thread extension to catch that lower stud. To catch the lower nut, lower the motor just enough to allow the stud to enter into its mounting hole.
Caution 6) Carefully and slowly lower the motor during this operation. Lowering it uncontrollably may risk wedging the mount and damaging the threaded stud.
To catch the lower nut, use scotch tape to join the lock washer and nut together. Next tape the joined lock washer and nut it to your finger. Use a finger that will allow reaching the desired location. Now with the motor lifted to permit spinning of the motor mount, insert the nut-&-washer-taped-finger into the tight assembly area. Using the other hand, reach in and turn the mount to catch the nut. Catch ONLY a couple of threads. It is easiest to get both hands and fingers in place through the wheel wells. Remember, only catch a couple of threads. Do not tighten the first mount yet. Now take a break as more fun is about to commence.
With the right mount in place and both nuts caught by a couple threads ONLY, raise the motor to the max. This will slightly stretch the right mount, (this is OK, but don’t over-do it). Stretch the mount as little as possible, which is why only a couple of threads on each stud should be engaged, (the more thread engagement, the more stretch, so minimize stretch with little thread engagement).
You will notice that a bit more lift is necessary on the left side to install the mount. Insert the mount stud into its upper hole. You will notice the bottom just won’t go, as it needs just another eighth of an inch to fit. Remember, the old mounts were compressed making them easy to remove. To proceed, engage the top nut and washer by a few threads ONLY, then carefully lower the motor just slightly until you’re able to rock the motor. Now, rock the motor enough to gain clearance to pass the lower stud into its mounting hole. Use the tape & finger method described above to catch this last nut.
At this point, all 4 nuts are ready for tightening. Remember to keep the motor weight off the mounts while tightening the lower nuts allowing the mounts to spin while holding the nuts with a wrench. Slowly lower the motor completely. The weight of the motor on the mounts will prevent them from turning. Now spin the upper nuts all the way down snug. All nuts are completely threaded down and can now be properly torqued.
Fit the new torque reaction buffer to its bracket arm and then install the assembly in place. Screw adjust the buffer firm but not too tight against the chassis then lock it in place with the jamb nut.
Complete the job by refitting all disconnected components as they were. It is advisable and highly recommended to clean the steering shaft splines and coat them with electrically conductive grease before re-fitment to assure a good electrical ground as a poor rusted ground through the steering shaft and couplers is the leading reason for intermittent or loss of horn function.
It may also be wise at this time to take care of other PM (preventive maintenance) activities like new hoses, perhaps new steering column couplers, etc. It is recommended to grease the front end, flush the radiator and add fresh coolant at this point of disassembly. Check steering wheel alignment because if it is not properly aligned, the turn signal indicator lever may not work properly). Replace the transmission mount, ( a simple 15 minute task) to complete this motor mount reconditioning procedure.
Remember, plan the job, have all necessary items at the ready, take your time and cut no corners and think safety first!.
I hope this is helpful to you if you are doing the job. Let me know if clarity or more information is needed. Have fun and enjoy the ride! de
