Overhauling the rear suspension of the APB

Servicing the rear suspension on an APB is pretty much identical to that on an AM and very similar to that of the 60s Moultons. After extensive use the rear suspension pivot pin or bushes may wear or may seize if the original lube has been washed out. On very early APBs the phosphor bronze bushes were not as well lubricated as those made since 1992.

Spare parts are available through your local APB dealer. It is advisable to get a new pivot bolt, sleeve and pair of phosphor bronze bushes before starting a full overhaul. It is a good idea to service the rear suspension on a yearly basis if the APB is in regular use. In this case do not remove the phosphor bronze bushes. In addition to the normal tools you will need a vice with soft jaws if the phosphor bronze bushes are removed. If the pivot bolt is seriously seized in the sleeve we recommend that you take it to your nearest APB dealer. If there is some wear present but the bolt is not seized its replacement can be tackled at home.

j1. With cantilever brakes, undo the rear brake cable from the cantilever arms and unhook the straddle wire from the other side. With V brakes, undo the inner cable clamp and pull the cable away from the arms. On derailleur models undo the pinch bolt holding the rear derailleur inner wire in place and release the hub gear wire if you have a 3 x 7 model. Similarly release the front derailleur inner cable on those fitted with a front derailleur. Pull all the inner cables through the outers so that no cabling remains attached to the rear triangle.

On 3 and 5-speed hub gear models disconnect the gear cable. With the 7-speed Sturmey-Archer hub gear, unscrew the wire behind the support arm, undo the cable adjuster completely, unscrew the connector at the frame join and the slide the outer cable away from the eye on the rear triangle so that the complete inner and outer are no longer attached to the rear triangle.

2. On some models it is necessary to remove the right hand crank. In almost all cases it makes access easier. Undo the right hand crank fixing bolt and using a crank extractor remove the right hand crank. Remove the rear wheel. With a 13mm spanner, hold the right hand pivot bolt head still and with another spanner unscrew and remove the nyloc nut on the left hand side. With a soft-faced hammer knock the pivot bolt through the sleeve; if it is very tight you may need to use a piece of steel rod to act as a drift.

3. Undo the four cross headed screws that hold the suspension rubber cone unit to the back of the seat tube. The rear triangle can then be removed from the frame. Support the rear triangle carefully and drift the sleeve out of the phosphor bronze bushes.

4. If the pivot is simply being serviced, leave the bushes in place. If replacement is required, each bush will then have to be carefully removed from the pivot in the rear triangle This is accomplished by using a drift on the inside edge of the bush. Smear the inner and outer surfaces of your new bushes with anti-seize compound, which is supplied with new bushes and pin set. Using the soft jaws of a vice, push each bush into the housing one at a time.

5. Using a soft-faced hammer, knock the pivot sleeve into place. It can be a tight fit. The pivot sleeve should protrude a small amount either side of the bushes when pushed into place. This may not be visible to the naked eye. Test for pivot bush protrusion by placing two straight edges against the bush. If a little movement sideways of the bush is possible before the straight edges touch the phosphor bronze bushes, there is sufficient protrusion. If not, remove the phosphor bronze bushes as described in 4 above, clean some paint from the edges of the pivot housing and reinsert the bushes as described above. Recheck for sufficient protrusion.

6. Place the rear triangle back in the frame. Replace the crossheaded screws that hold the rubber suspension cone in place and tighten. Push and then tap the pivot bolt through the pivot. Screw on the nyloc nut and tighten fully. Replace the right crank if removed. Replace the rear wheel. Reconnect the gear and brake cables and adjust as per their maker’s manuals. Check that the gears and brakes work fully before riding.


Modification, repair and renovation work should only be carried out by qualified people. If you do not have the experience and/or expertise to judge whether any procedures described in Masterclasses are correct, DO NOT ATTEMPT TO DO THE JOB. The information given in Masterclass articles is intended to act as a reminder to capable people who are carrying out repair work. The authors, the Moulton Bicycle Club and its Officers accept no responsibility for work carried out by owners or their agents, whether that work is done in accordance with any information contained in these articles or not.