Additional Concerns with Rear Subframe Bushings

Discussion in 'Pedders Suspension' started by dms, May 25, 2010.

  1. May 25, 2010 at 12:35 PM #1
    dms

    dms LX Suspension Specialist

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    Additional Concerns with Rear Subframe Bushings​


    Pedders has been discussing the concerns and excess movement of the rear LX subframe bushings for a long time. To review, a brand new subframe bushing will allow 13mm or a 1/2 of side to side movement of the entire rear subframe that is separate from the body. Even though this is a handling hinderance and one of the major causes of the new Challenger wheel hop issues, it is not normally a safety concern, but just a handling concern.

    HERE IS A PICTURE OF THE SUBFRAME MOVEMENT AND CONTACT TO THE BODY WITH UNDER 700 MILES​


    [​IMG]​

    The black marks are the rubber bumper scuffings of the rear OE subframe sliding back and forth. This picture was taken from a new Challenger SRT8


    What is fairly normal with a 50,000 miles subframe bushing movement with a LX that is driven moderately hard? ​


    [​IMG]​

    The above picture shows approximately 1 inch of side to side movement. This is very common to see.


    But then we started getting inquires about very odd handling complaints, that seem to be more concentrated in the snow belt areas where salt and corrosion are common. Here is a picture of a 90,000 mile police Charger that advised us the dealer could not find a problem and had the corrosion present as you can see from the picture:


    PICTURE OF SUBFRAME BUSHING WITH 90K, AND IN THE SNOW BELT
    [​IMG]
    ​

    Now the the problem these bushings were causing, was when you go into a corner, it felt like you had a flat tire. The entire subframe was moving 2 plus inches separate from the body. Kind of scary. The picture only shows a lot of corrosion on the center ferrule. So we lowered the cradle to inspect the bushings more closely and this is what we found:

    BAD SUBFRAME BUSHING CAUSING 2 INCHES OF SIDE TO SIDE MOVEMENT
    [​IMG]
    ​
    This picture shows the OE rubber bumpers were moving almost 2 inches! Again, the black marks are the scuffing of the upper OE bumpers on the bushings themselves. This is what we found:
    CENTER FERRULE 95% DELAMINATED FROM THE RUBBER​

    [​IMG]​

    This picture shows the center ferrule 95% delaminated from the rubber and less than a 1/4 of an inch of rubber was actually galvinized to the ferrule

    Not all of these bushings are failing on high performance or hard driven LX products. Last weekend we inspected a AWD LX, which uses the same basic rear assembly as a 2WD. This LX had around 70,000 miles, and lots of tire wear concerns. and felt loose. Here is a picture of his subframe bushings:

    [​IMG]
    ​

    Again, lots of corrosion, but not obvious tearing until you look at it very closely:
    [​IMG]    ​


    This picture shows you can push a pocket screwdriver thru the ferrule to rubber bonding!
    There is a serious amount of corrosion that came out. We really do not know exactly how bad these bushings are, but the are 100% wasted and needed immediate replacement

    Having your back end "step out 3/4 to 1 inch on a hard turn can create a very huge instability concern that you must get addressed. The challenge you will have, however, the lack of knowledge on these problems is significant, including the new car dealers!


    What is the best way to fix this concern? With Pedders EP1172 bushing kit pictured below:
    [​IMG]    ​


    Why Pedders and not a factory replacement? With a new OE bushing, you will still have a 1/2 inch movement side to side. With Pedders, you are virtually eliminating all movement partially by our 640% increase in bushing to body contact, and the strength of our poly material.

    Need more visuals? Check out these 2 videos ​




    If you have any questions, just ask

    thanks
    mike
    dms
     
  2. May 26, 2010 at 9:07 AM #2
    dms

    dms LX Suspension Specialist

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    We have had a number of inquiries and questions about these bushings. Here are some answers to questions:

    1. when we say pricing for each, that is each package of 4 sets. So 1 package does the all the subframe bushings.

    2. The cradle does not have to come out of the car but does have to be lowered one side at a time.

    3. Not having the custom Pedders bushing remover, the alternative method that works well is to use a reciprical saw with metal blade, and cut out the rubber (2-3 minutes). Cut a 1 inch section of the outer steel jacket out, being careful not to cut into the eyelet of the subframe (3-5 minutes). Make another cut 180 degrees (2 minutes) Using a punch, the remaining outer jackets will nearly fall out, depending on how much corrosion you have.
    Clean the subframe eyelet very well and remove any rough edges if your made contact with the eyelet. Cleaning and removing all burs on the top of the eyelets is important as well.So once the subframe is lowered, this should take no more than 15 minutes, maybe 20 minutes a bushing.


    Thanks
    mike
    dms