Frequently Asked Question

If you can’t find a answer to your question, please contact


Jefa has a large selection of bearings for old production boats, see our ftp server. If you boat is not on the ftp, please contact us at, so we can help you replacing the old bearing.
The typical solution is to clean the bearings. The bearings doesn't need any maintenance except for a good hose down when the ship is taken out of the water. The main reason for this hose down is to remove the salt water out of the bearing housing so it can't crystallize. In some case you will need to drop the rudder, take the bearings out, and clean them well. Please see JEFA RUDDER service tip.
No, you need to take the boat up of the water. Then you can give the bearing a good hose down.
The outside surface of the bearing and the conical hole in the hull will have to be cleaned thoroughly. The outside of the bearing will get a film of sealant (Sikaflex 291 or 221) and pushed into the conical hole. The nut will be mounted and tightened, so the bearing will be strongly fixed inside the hole.
It's a good maintenance to clean the bearings once pr year, and drop the rudder every third year for a full cleaning. When you do this, the bearings will normally work like new again. Read more about it on our Maintenace page. See a example how bad it can be here: Example
Because our 4S ball bearing is composed of several types of materials that react differently in the different temperatures they encounter, small openings may occur between the parts. We recomend sealing the bearing if the problem occur. Please follow this guide: Sealing manual for 4S000 bearings.
Please see this video showing how to do it: Video link.
Make the shaft a bit rough with a angle grinder, where the sleeve shall be mounted. Before you put glue on the shaft, first dry run the sleeve over the shaft, making sure it fits. As the room between the shaft and the sleeve is only a couple of tenths of a millimeter one should use a thin epoxy resin (for example Araldit, available in every marine shop). Clean the shaft and inside of the sleeve. Put the epoxy resin around the shaft and inside of the sleeve and slide the sleeve over the shaft while rotating. Remove all obsolete resin with a cloth and a dissolvent. Seal the top and bottom with Sikaflex 221 so no water can run between the shaft and sleeve.


Yes! Jefa has over 25 rudder blade molds, so we should be able to find a match for your boat. Please see our ftp server if there already is designed a rudder for your boat. Please see our rudder blades here.
Jefa can match the angle on your blade by using 3D printed inserts in the rudder blade mold. Please note, the rudder blade gets shorter when using inserts.
Jefa need a sketch of your rudder so we can make a production drawing. Ones there is made a drawing, you will make the approval. It would be good if you also sent some pictures of your rudder (both stock and blade).
If the sealant is bad, then remove it, and give it a new sealant. Use Sikaflex 221 or 291. Please follow this guide. The sealant should be checked when possible.
Yes, that's something you should be worried about. You must check if there is power from autopilots or anything else. You can read more about it on our electrolysis page.

Sealing system

When you have bought our PUR lip seals, please follow this guide for installation.