[Ian21401]

My 940 has single piston sliding front callipers. During general service after purchase I found that the piston dust seal on the front offside was split. It was not practical to deal with it at that time so I sprayed silicone spray through the slit as a first aid stop gap measure. On previous cars I’ve had the dust seals located in a lip on the caliper and a groove on the piston so it was easily possible to replace the seal without disturbing the piston so no bleeding required and caliper overhaul kits were easily obtained. On the 940 the dust seal locates within the bore of the caliper so it is necessary to pop the piston. I didn’t relish this job. The dealer could not supply any kit or dust seals but I eventually obtained some Scan Tech ones via Braden Motor Co. (part no. 18.4134). Popping the piston was the easy part. I found that the old seal was well stuck in the groove on the inside bore of the caliper. Having eventually removed it it was necessary to clean the crud from that groove. This was accomplished by using a small rotary brush on a rotary Dremel type drill and the end of a piece of bent coat hanger wire. Fitting the new seal was extremely fiddly but eventually it was in. Feeding the piston back through the seal and into the caliper bore was equally fiddly but patience prevailed. After bleeding everything was ok and it'’s still ok. This had no effect on the hoses, so if they are ok then they shouldn’t need replacing.