The problems caused by the inferior design of the Ford/Motorcraft Mark VIII rear shock mount have been addressed many times here before but very few people know of a solid, reliable solution to the problem other than replacing the mounts once a year or more. The soft inner rubber of the mount and lack of shock absorber support both contribute to the premature failure of the Ford parts, and cars with stiffer after market rear shocks are even more susceptible to this problem. The idea of replacing the Mark VIII bushings with after market solutions is not new, but an illustrated guide has not (until now)
been provided to guide members through the process of upgrading their rear shock mounts easily.
Eric (95BLKLSC) and myself performed this modification with great success. Since there is little to no difference between the Gen. 1 and 2 rear shock mounts, this process is universal in its application to FN-10 chassis cars. Consequently, due to the widespread sharing of chassis design principles in both the MN-12 (1989-1997) Ford Thunderbirds/Mercury Cougars and FN-10 (1993-1998) Lincoln Mark VIIIs, many of the aftermarket (and some OEM) parts available for each car are fully interchangeable.
That being said, www.supercoupeperformance.com (hereafter referred to as SCP) sells a polyurethane shock mount kit for the MN-12 chassis cars which can be adapted for use on the Mark VIII.
Here is a link to the kit; go to page 3 once the page has loaded.
http://supercoupeperformance.com/partBrowser.aspx?category=31
The kit consists of new upper shock mount bushings (two for each shock) and a new bushing for the bottom of the shock You can use the metal frame of your Ford-style shock mounts as a retainer for the SCP poly mounts. Both cars that we did the modification on had Bilstein (Cobra OEM) shocks installed, but the process is more than likely identical for any shock absorber. The only exception I know of is that the new lower shock bushings cannot be used on the Cobra shocks unless the original bushing is pushed out with a press.
As with any other vehicle modification, it is imperative that you exercise safe practices and procedures when handling tools and parts. Be sure to use a jackstand to support the vehicle while it is suspended in the air, and wear protective clothing including goggles and fireproof gloves when wielding a torch. It is your responsibility to protect yourself when working on your car, and neither I nor www.mark8.org can or will be held responsible for injuries sustained while performing this or any procedure.
Don't forget to turn off your air ride before jacking up the car!
You should begin by removing the two nuts that hold on the shock mount and the single larger nut that secures the shock absorber in the mount. These can be accessed either by pulling aside the carpet in the very rear of your trunk or by removing your back seat. Continue by placing wheel chocks in front of and behind the front wheels and jacking up the rear of the car until the shock absorber stud protrudes below the hole in the chassis. This is illustrated in the following picture:
You may notice that the bushings contained within the Ford-style mount are cracked, torn, and even perhaps missing! I believe that the main reason behind premature failure lies in the too-soft rubber and large diameter opening in the metal frame. These two factors allow the rubber to flex quite a bit when the shock absorber is compressed/expanded during normal driving. If the rubber were harder and the opening smaller, these mounts would very likely last quite a bit longer. Here is what mine looked like before they got burnt:
Next, you will need to fire up your propane or MAPP gas torch and find a safe outdoor place to burn the rubber out of the metal frames. Be sure you have a fire extinguisher nearby BEFORE you begin to burn the rubber. After you initially light the rubber on fire, you will need to refresh the flames a few times to maintain the temperature of the fire and keep the rubber burning. Below are two pictures; the first is the rubber being lit initially, and the second shows the burnt rubber right before it is ready to fall out of the metal frame.
Light 'em up...
...then burnt 'em out.
If you have some water handy, you can cool the metal much more quickly by giving it a quick dunk:
Once the metal frames have cooled completely, use a wire brush and clean off the soot and any remaining rubber from the metal frame. You can also paint the frames if you wish, which will prevent them from rusting. Assemble the bushings in the frames using a liberal amount of the supplied lubricant. We assembled ours with the collared bushing on the bottom of the mount and the flat bushing on the top. Our reasoning was that the lower shock bushings handle more of the forces applied to the mounts and that the collared bushing could provide better support than the flat bushing during compression. The flat bushing is similarly better suited to the top of the mount because it does not see the same amount of compressive force as the lower bushing. Since the original bushings also acted to seal the opening in the chassis, you will need to improvise with your own solution. Once the bushings have been assembled in the mount, apply a thick bead of blue or black RTV around the circular opening in the metal mounts. The images below illustrate the proper installation of the bushings in the metal mounts and application of RTV. The top image shows how the entire assembly will fit in the car once everything is re-assembled, while the bottom image shows the portion of the mount that you should place on the shock absorber before lowering the car back to normal height.
As shown in the bottom picture, place the whole assembly EXCEPT the flat bushing and large flat washer on the shock stud and carefully lower the car back to normal height. You should lower the car down in two steps; first, lower it only an inch or two so you can guide the shock stud and mount into their respective holes in the chassis, then lower the car to its original ride height while watching the mount to make sure nothing binds or catches.
You can now install the flat bushing on top of the portion of the mount inside the car and place the large flat washer on top of it. Tighten the whole assembly using your original shock nut until the bushing begins to compress but not so much that it bulges on the side. For those of you with Bilstein/Cobra shocks, the bushing will be adequately tightened with 3-6 threads visible above the nut. Below is a view of the fully installed assembly as seen inside the trunk.
If you get a chance to push down on the rear end of the car before and after the installation, do this while keeping an eye on the movement of the Ford bushings and the complete lack of movement of the polyurethane bushings. I jumped in the back seat (well, the empty space where his back seat was) of 95BLKLSC's car while he drove up and down his dirt and gravel driveway after we installed the bushings. While he was moving at about 5-10mph, I did not observe more than perhaps 1/16th of an inch of movement present in the new poly bushings. This is compared to 1/2 inch or more of movement present in the stock bushings just by pressing down on the rear bumper! The noises I had coming from my rear end before the mod, which consisted of a light, dampened thump over bumps has disappeared completely. The cracked and torn bushings shown above are mine, so if your vehicle exhibits this and other behaviors you should definitely check into this mod.
Please address any questions to either 95BLKLSC or myself in this thread so we can build more knowledge into the forums. I give 95BLKLSC full credit for getting the parts together and finding the information necessary for this mod. He also assisted me in writing this article which I hope helps all of you. I took the pictures, and I ask that they not be reproduced in any manner other than a quote in this or another thread on markv8.org. Please let one of the moderators know if you see this article reproduced elsewhere on the 'net.
I must add that this article does not constitute endorsement of www.supercoupeperformance.com or the linked Web sites, information, products, or services contained therein. Please address the www.mark8.org rules of conduct and other policies for any other legal ramifications of using the information contained within this post to work on your car.
-Domenic (98BLKLSC) & Eric (95BLKLSC)
been provided to guide members through the process of upgrading their rear shock mounts easily.
Eric (95BLKLSC) and myself performed this modification with great success. Since there is little to no difference between the Gen. 1 and 2 rear shock mounts, this process is universal in its application to FN-10 chassis cars. Consequently, due to the widespread sharing of chassis design principles in both the MN-12 (1989-1997) Ford Thunderbirds/Mercury Cougars and FN-10 (1993-1998) Lincoln Mark VIIIs, many of the aftermarket (and some OEM) parts available for each car are fully interchangeable.
That being said, www.supercoupeperformance.com (hereafter referred to as SCP) sells a polyurethane shock mount kit for the MN-12 chassis cars which can be adapted for use on the Mark VIII.
Here is a link to the kit; go to page 3 once the page has loaded.
http://supercoupeperformance.com/partBrowser.aspx?category=31
The kit consists of new upper shock mount bushings (two for each shock) and a new bushing for the bottom of the shock You can use the metal frame of your Ford-style shock mounts as a retainer for the SCP poly mounts. Both cars that we did the modification on had Bilstein (Cobra OEM) shocks installed, but the process is more than likely identical for any shock absorber. The only exception I know of is that the new lower shock bushings cannot be used on the Cobra shocks unless the original bushing is pushed out with a press.
As with any other vehicle modification, it is imperative that you exercise safe practices and procedures when handling tools and parts. Be sure to use a jackstand to support the vehicle while it is suspended in the air, and wear protective clothing including goggles and fireproof gloves when wielding a torch. It is your responsibility to protect yourself when working on your car, and neither I nor www.mark8.org can or will be held responsible for injuries sustained while performing this or any procedure.
Don't forget to turn off your air ride before jacking up the car!
You should begin by removing the two nuts that hold on the shock mount and the single larger nut that secures the shock absorber in the mount. These can be accessed either by pulling aside the carpet in the very rear of your trunk or by removing your back seat. Continue by placing wheel chocks in front of and behind the front wheels and jacking up the rear of the car until the shock absorber stud protrudes below the hole in the chassis. This is illustrated in the following picture:
You may notice that the bushings contained within the Ford-style mount are cracked, torn, and even perhaps missing! I believe that the main reason behind premature failure lies in the too-soft rubber and large diameter opening in the metal frame. These two factors allow the rubber to flex quite a bit when the shock absorber is compressed/expanded during normal driving. If the rubber were harder and the opening smaller, these mounts would very likely last quite a bit longer. Here is what mine looked like before they got burnt:
Next, you will need to fire up your propane or MAPP gas torch and find a safe outdoor place to burn the rubber out of the metal frames. Be sure you have a fire extinguisher nearby BEFORE you begin to burn the rubber. After you initially light the rubber on fire, you will need to refresh the flames a few times to maintain the temperature of the fire and keep the rubber burning. Below are two pictures; the first is the rubber being lit initially, and the second shows the burnt rubber right before it is ready to fall out of the metal frame.
Light 'em up...
...then burnt 'em out.
If you have some water handy, you can cool the metal much more quickly by giving it a quick dunk:
Once the metal frames have cooled completely, use a wire brush and clean off the soot and any remaining rubber from the metal frame. You can also paint the frames if you wish, which will prevent them from rusting. Assemble the bushings in the frames using a liberal amount of the supplied lubricant. We assembled ours with the collared bushing on the bottom of the mount and the flat bushing on the top. Our reasoning was that the lower shock bushings handle more of the forces applied to the mounts and that the collared bushing could provide better support than the flat bushing during compression. The flat bushing is similarly better suited to the top of the mount because it does not see the same amount of compressive force as the lower bushing. Since the original bushings also acted to seal the opening in the chassis, you will need to improvise with your own solution. Once the bushings have been assembled in the mount, apply a thick bead of blue or black RTV around the circular opening in the metal mounts. The images below illustrate the proper installation of the bushings in the metal mounts and application of RTV. The top image shows how the entire assembly will fit in the car once everything is re-assembled, while the bottom image shows the portion of the mount that you should place on the shock absorber before lowering the car back to normal height.
As shown in the bottom picture, place the whole assembly EXCEPT the flat bushing and large flat washer on the shock stud and carefully lower the car back to normal height. You should lower the car down in two steps; first, lower it only an inch or two so you can guide the shock stud and mount into their respective holes in the chassis, then lower the car to its original ride height while watching the mount to make sure nothing binds or catches.
You can now install the flat bushing on top of the portion of the mount inside the car and place the large flat washer on top of it. Tighten the whole assembly using your original shock nut until the bushing begins to compress but not so much that it bulges on the side. For those of you with Bilstein/Cobra shocks, the bushing will be adequately tightened with 3-6 threads visible above the nut. Below is a view of the fully installed assembly as seen inside the trunk.
If you get a chance to push down on the rear end of the car before and after the installation, do this while keeping an eye on the movement of the Ford bushings and the complete lack of movement of the polyurethane bushings. I jumped in the back seat (well, the empty space where his back seat was) of 95BLKLSC's car while he drove up and down his dirt and gravel driveway after we installed the bushings. While he was moving at about 5-10mph, I did not observe more than perhaps 1/16th of an inch of movement present in the new poly bushings. This is compared to 1/2 inch or more of movement present in the stock bushings just by pressing down on the rear bumper! The noises I had coming from my rear end before the mod, which consisted of a light, dampened thump over bumps has disappeared completely. The cracked and torn bushings shown above are mine, so if your vehicle exhibits this and other behaviors you should definitely check into this mod.
Please address any questions to either 95BLKLSC or myself in this thread so we can build more knowledge into the forums. I give 95BLKLSC full credit for getting the parts together and finding the information necessary for this mod. He also assisted me in writing this article which I hope helps all of you. I took the pictures, and I ask that they not be reproduced in any manner other than a quote in this or another thread on markv8.org. Please let one of the moderators know if you see this article reproduced elsewhere on the 'net.
I must add that this article does not constitute endorsement of www.supercoupeperformance.com or the linked Web sites, information, products, or services contained therein. Please address the www.mark8.org rules of conduct and other policies for any other legal ramifications of using the information contained within this post to work on your car.
-Domenic (98BLKLSC) & Eric (95BLKLSC)
