How do you change the sanding pad - Tools & Hardware - Others

Did it make the noise and THEN you changed the pads? Or did you change the pads and then it started making the noise?

If it started after changing the pads, try sanding the pad surfaces lightly with sandpaper. If they are too smooth, it will cause a squeak.

Here is a link to the manual to your Royobi p400. You can download it. Tried to copy & paste the illustrations but they did not show up. Go to page 14 of the manual. Looks pretty easy, just peel down from top. Good luck. & happy Sanding.

CHANGING SANDING SHEETS AND PADS
HOOK-AND-LOOP
See Figure 8.
PAD
The sander is packed with sanding sheets and scrubbing
pads designed for a variety of uses. To change sheets and
SANDING
pads, simply pull the used sheet off the base and attach the
SHEET
desired sheet by pressing the sheet or pad onto the base
of the sander.
ROTATING THE SANDING SHEETS
See Figure 9.
The majority of wear in a precision sanding application occurs
at the tip of the sanding sheet. The unique Tri-Flex design of
the sanding sheets allows you to detach and rotate the top
two thirds of each and extend the life of the sheet.
To rotate the top of the sheet, simply remove the top two
thirds along the perforation. Rotate the sheet so that a clean
corner is located at the tip of the base. Press the sheet firmly
onto the pad.
NOTE: Scrubbing and polishing pads are not perforated
and cannot be rotated.

Use a heat gun. You can easily remove the pad from the sander.
More details https://discsanders.wixsite.com/best-disc-sanders

Slim 17mm spanner between dust skirt and backing pad ( might need to jiggle pad about to get spanner to lock shaft ) then simply unscrew pad

It simply unscrews. The pad is held on by a small bolt length attached to the pad. Unscrew it.

If pad is hook and loop style use compressed air or clean nylon brush to clean debris from hooks.If using adhesive backed dics try wiping a little alcohol across the pad surface to clean it.

Most of the time when this happens, it's because the owner is using that S-100 spray on their black painted calipers. Any type of wax like that gets on your rotor or pads, they will squeal. You may be able to stop it by removing your brake pads and lightly sanding them. Put a sheet of sand paper on a flat surface, place the pad on it face down, and lightly sand the face of the pads. Next, get yourself a can of "BrakeKleen" and clean your rotor thoroughly. Make sure all your hardware for you brake pads is in good shape, the little metal clips that go in the caliper to hold the pads and such.

You use a 1/2 inch socket wrench to remove the nut at the top of the spindle shaft, slide the old sanding sleeve off and the new one on.  Replace the nut.  You may also have to insert a different size table insert if you are changing the sleeve size.
Instruction manual is available free at: http://www.dewaltservicenet.com/documents/English/Instruction%20Manual/Delta/a20932,sa350k.pdf

I'm not familiar with that particular model, but they are virtually all replaced the same way. There are a few screws through the pad into the base. Simply remove them and screw the new pad on. You'll see that it's quite simple once you get the new pad in your hands.
Just be careful not to strip the head of the screw: use the right size screwdriver tip.

I hope this information allows you to resolve this issue. If you need further assistance, please post back with a comment to this thread. If I've managed to answer your question or solve a problem, please take a moment to kindly rate this post....thanks!

You did not specify how the sanding discs are meant to be attached to your sander's backing pad.  My experience with this type of problem is material from the sanding process builds up on the backing pad and does not allow the sanding discs to adhere properly.  If you have a velcro type system, clean the hooks on the sander's backing bad by soaking the pad's face in a plate of paint thinner for 20 to 30 minutes then use a wire brush to remove the rest of the paint physically.    For adhesive pads clean the sander's backing pad surface with denatured alcohol.  Do not use isopropryl or rubbing alcohol as this may not be 100% alcohol and could contain a lubricant like glycerin.  When the sander's backing pad is completely dry and clean it will hold adhesive backed pads fine.    Flaky paint is best scraped off before sanding, use a wide putty knife or a paint scaper to remove large flakes before sanding.  This will minimize airborne dust and cleanup.    For best results with adhesives, always keep your surfaces  clean!    Good luck and happy sanding!  Michael Mittelsdorf