REAR SHOCK MOUNTS

REAR SHOCK MOUNTS

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  • On 1st February 2016

The rear shock mounts pressed into the swing arm look so much like an integral part of it that the immediate impression is that they are permanent and could not, or should not, be replaced.  This impression seems to be reinforced by the HONDA CB500 CB550 WORKSHOP REPAIR MANUAL which makes no mention of them.  Yet, they are wearable components, which should be replaced when they are worn or damaged, or when new shocks are installed or when the rear shock mounts need to be removed so the frame can be powder coated.  The parts are, amazingly, still available.  They are inexpensive and can be purchased from any HONDA dealer or many websites.  Service Honda carries them and they are $4.74 a piece.

Removing the original shock mounts could be sometimes challenging.  Some 40 years after they were originally installed, the shock mounts could be a little rusty as can be seen in the image below:

Old shock mount prior to removal

One way to remove them is to press them out using tools readily available in your workshop.  Here is a photo of how it can be done:

Shock mount removal tool and setup

In the image above, a 3/8″ bolt 3.5″ long is inserted through the shock mount.  On the left is, a 15 mm socket 3/8″ drive with the drive end facing the shock mount.  On the right is a  22 mm socket 3/8″ drive with the open end facing the shock mount.  The idea is to screw in the nut, which will force the size 15 socket to move towards the nut and push the shock mount out into the opening of the 22 mm socket.  The 22 mm socket itself cannot move since it butts against the swing arm.

NOTE: Using a larger diameter bolt is impossible as it will not fit through the hole in the shock mount and any bolt smaller in diameter will have too much play and will likely bend or the force needed to push the shock mount out is going to be so great that the threads will likely get stripped.  The socket size given above is just what I used.  They key is to use a socket whose O.D. (outside diameter) is just a hair under 22 mm in diameter and another socket that is a minimum 22 mm I.D. (inside diameter).  You may end up using a 16 mm socket and/or a 23 mm socket.  It is very important to use a socket that is almost the same diameter as the shock mount itself.  Anything smaller will just push the rubber and the inner tube out and will leave the outer shell in the swing arm. Some people report that the shock mounts must be pressed out only in the direction towards the wheel.  In my experience, this wasn’t necessary.  I pressed out the left shock mount towards the wheel and the right one away from the wheel.

The image below shows the shock mount almost halfway out.  Note the rust.  It is a good idea to spray WD-40 or something similar prior to removing the shock mount.

Old shock mount half-way out

The key to success is to have everything is perfect alignment.  If the shock mount would not budge after sufficient force has been applied, spray with WD-40 and leave overnight.  Or tighten the nut to the point where you think it will give and then hit the bolt head with a hammer.  This might  just help brake it loose.  Mine came out relatively easily.  Other people report having to take their swingarm to a local shop.

Once the shock mounts are out, clean everything thoroughly and sand with a 600 grid sandpaper.  Wipe clean, apply a small amount of grease to all surfaces and pres the new shock mounts in using the same principle.  Here is a photo of it showing the new shock mount pressed already halfway in:

Installing the new shock mount

Both sockets are positioned so the drive side faces the swingarm and the open ends face away from it.  The bolt used for installing the new shock mounts is a 4″ long bolt.  The 3.5″ bolt used for pressing the shock mounts out is a little too short for the job.

QUESTIONS?