Replacing Seals in Caravan & Motorhome Opening Windows

This guide explains how to replace your caravan or motorhome opening window rubber. Replacing this seal is required once your existing seal starts to deteriorate or is no longer providing a sufficient seal. By fitting a new window rubber you can ensure that your caravan or motorhome is water tight and warm.

We sell a range of opening window seals suitable for most caravans and motorhomes. We also sell a range of accessories, such as cover strip fitting tools and silicone spray to help with the installation process.

You will need to measure the panel (wall) thickness of your caravan or motorhome and diameter of the sealing bulb on your existing seal to determine the correct replacement seal.

To measure the panel thickness, remove the existing seal and measure the thickness of the wall. This measurement should be between 25mm and 40mm. If you are not able to remove the existing seal, you can calculate the wall thickness using two pieces of wood. Place one piece of wood under the seal on the outside of the van and the other piece of wood under the seal on the inside of the van. Take a measurement from the outside of one piece of wood to the outside of the other piece of wood. You can calculate the wall thickness of the van by subtracting the thickness of the two pieces of wood from the overall measurement.

For example, if the overall measurement (A) is 77mm and wood B and wood C both measure 25mm, the wall thickness will be A (77mm) - B (25mm) - C (25mm) = 27mm.

You will also need to measure the diameter of the sealing bulb (D) on your existing seal. This measurement should be between 10mm and 14mm.

There are two different styles of sealing bulbs on opening caravan window rubbers. The first type has a fin and the second type has a double bubble. We recommend looking at your existing seal to determine the shape of sealing bulb required.

CS1679

CS784

CS1680

CS785

CS1681

CS786

CS4090

CS3002

CS4091

CS4556

Open your caravan or motorhome window and carefully note how the small hinge for the window stay is fitted. Take a screwdriver and undo the fixings for the two window props on the caravan so that they hang loose. The window can either be removed or propped up out of the way. Noting the way the fittings go, remove them and keep them safe with their screws.

Locate the end of the white, grey or black plastic cover strip and pull it out. Next remove all of the staples holding the rubber to the wall of the caravan. You should now be able to find the end of the rubber and carefully pull it away from the caravan.

Go around the window opening with a chisel or a flat bladed screwdriver and scrape away any sealant that was left from the window rubber. After removing as much as you can by hand use white spirit to remove the remainder. Once you have used white spirit you will then need to use Meths or Acetone to clean off the oil film left by the white spirit.

The new rubber comes complete with a layer of butyl mastic applied to the inside of the outside leg. Carefully push the rubber onto the wall of your caravan or motorhome.

Cut the window rubber to the correct length ensuring that the ends are fitted tightly together.

Staple the seal in place to ensure that it is held firmly onto the wall of your caravan or motorhome. These staples will be hidden by the cover strip once fitted.

Next, fit the grey, white or black cover strip into the top of the window rubber. The easiest way to do this is with the use of a cover strip fitting tool and lubricating silicone spray. Our cover strip fittings tools (CST4335 and CST5015) and silicone spray (SS4363) are available from our website.

To use the tool, lubricate the inside of the window rubber cover strip channel with the silicone spray. Insert the tool into the channel ensuring that the two legs at the back of the tool are securely inside the channel lips.

Insert the grey, white or black cover strip through the center of the tool and push the end back into the rubber under the lips. Gently move the tool forward to lay the cover strip into the window rubber. Once you have been all the way around the window end by overlapping the end of the cover strip over where you started.

The final step is to refit all of the window fittings and stays.