How to service your rear suspension

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Why bother?

The linkage is a vital part of your bike’s suspension system, but as it’s sat close to the road it’s exposed to the elements. If you ride during the winter, salt and grit will be doing their best to undermine the way the suspension works by coating it in rust. The bearing or bushes which share the suspension forces are tested at MoT time – any obvious signs of wear means a fail.

What you’ll be dealing with

The main component is the rocker arm. This transmits forces from the swingarm to the shock and pivots on needle roller bearings or bushes, with spacers or collars. If ignored the grease dries or gets washed out and wear sets in.

Don’t even think about if…

…You don’t like getting your hands dirty or, more importantly, have nowhere to do it. You’ll need to lift the rear end of the bike in the air, so having a vacant roof timber to sling a rope over is a bonus.

Stuff you’ll need

A paddock stand for getting the rear wheel out, tie-down straps for suspending the bike and a mate to help when the bike is being slung from above. A workshop manual will give details of torque settings. You’ll also need combination spanners, 3/8 drive socket set, a tub of grease, degreaser and an old baking tray to clean parts in.

What can go wrong?

Badly corroded nuts can be buggers to shift – what should take two minutes to undo can take an hour! Make sure the bike is safely positioned when the shock is unbolted, either suspended from above or from a jack below.

What skills do I need?

Common sense and a sound knowledge of how suspension works.

1. With the bike on a paddock stand remove the rear wheel and bellypan. If the spindle gives too much resistance a tap from a rubber or wooden mallet helps the job along. Now the wheel is out of the way,  have a look at the bolts which go through the linkage. Check to see if anything is going to obstruct their removal.

2. In this case the exhaust pipe was in the way. Removing the bolt which secures the silencer to the subframe allowed it to be swung to one side, giving the bolts enough clearance to be removed. On other bikes removal of the silencer and intermediate pipe would have to be carried out.

3. Before hoisting the bike in the air, bind the front brake using a rubber band on the lever. Also clamp the front wheel to the bench using a tie down. This prevents the bike moving backwards or forwards. Using a front paddock stand would be a suitable alternative, so long as the bike cannot roll forward.

4. Removing the rear cowling gives good access to the rear of the subframe. Loop a ratchet tie-down over a supporting beam in the garage, then carefully tighten it up until the bike is just raised off the paddock stand. For extra safety and support, secure a tie-down on each side of the footrest to the bench.

5. Loosen and remove the nuts which secure the linkage and shock assembly. If needed, better access can be made by undoing the footrest hanger bolts and swinging them out of the way. Rust can make them difficult to remove. A breaker bar will give extra leverage if needed.

6. Tapping the shock’s lower bolt half way out, and then taking the weight of the swingarm, the bolt can be removed. Moving it in an up and down motion will give you a feel for when the bolt is loose. The shock doesn’t have to be removed, but it’s a good opportunity to give it a proper clean, or send it off for a service.

7. The bolts which go through the linkage can now be removed, including the bolt which holds the tie bars to the swingarm. Making a note of where each bolt goes is a good idea – they are sometimes similar, but not compatible in length. Carefully remove the linkage and tie bars. Moving the swingarm can help here.

8. Clean off any loose dirt with a degreaser, paying particular attention to the seals. Remove the bushes and clean using a contact cleaner. The seals can also be prised out and cleaned. Dry with a paper towel or cloth. Any excess grease should be wiped off the bearings – a contact cleaner will blast any loose dirt away.

9. With all of the parts clean and dry, inspect the bushes (above) for any signs of wear or corrosion. Be sure to check the seals are in good condition as perished or split seals will let water in. Make sure the bearings are free from signs of wear – loose rollers or rust will indicate that they have seen better days.

10. Replacing seals on their own is OK, but if the bushes are worn it’s likely the bearings will be knackered. Best thing to do is replace bearings, bushes and seals (above) as a set. Removing and replacing bearings can involve specialist tools – a trip to your dealer to do this part will ensure the correct methods are employed.

11. Work the grease in so the needle rolling bearings are liberally coated. Put the seals in and then slide the bushes in, making sure they have a light coating of grease. Any excess grease which is squeezed out should be wiped off. Some grease on the bolts will help with assembly and prevent problems with any future servicing.

12. Reassemble the linkage and shock in reverse sequence to dismantling them and tighten nuts to the torque specified by the manufacturer. Carefully lower the bike back on to the paddock stand. Install the rear wheel, ensuring the nut is tight and fitted with a split pin. Check the suspension by pushing the back end down.

MCN Technical Staff

By MCN Technical Staff