Londonmod

Hi there. I'm hoping someone has some ideas on what's going on and how I can fix it. Let's see!

I got my Bontrager floor pump out the other day to use it after a few years of it being in storage (dry, warm storage), and I immediately had problems. The plunger was stuck in the down position for some reason. I finally got it free, but there was no pressure being created or air coming out when plunging. I opened it up and dumped a small pile of fine reddish material out which I think is rust. I guess the inside rusted and flaked off or something; it doesn't seem like that has happened from looking inside the tube, but I can't think of anything else it might be from. I looked at the inside of the tube, and the inside and the bottom looks fine, as far as I can see. The O ring looks to be in fine shape, but I can't figure out why there doesn't seem to be a seal being formed in between the O ring and the inner wall of the tube to build up any pressure. There's also no grease anywhere - shouldn't the inside be greased?

Anyone have any ideas? I'm planning on cleaning out the inside with acetone on a rag, and greasing the bottom of the plunger, but I'm not sure that will work. I also can't for the life of me find a central website for Bontrager to ask them about this directly. If needed, I'd rather get a replacement part to fix the existing pump than chuck the whole thing away.

I'd post photos, but I'm new here so I guess I'm not allowed just yet.

Iride01 

I'd suspect there is a check valve stuck open. Maybe from the dust or rust that was in it. Take it apart again and look to see what lets the air into the cylinder when you pull up on the handle. Sometimes it is a valve or just a flap on the piston or sometimes in the base of the cylinder.

Should it be lubed or greased? I'd think so, but the last floor pump I had to take apart used a leather cup to seal the piston. Don't know what is inside my < $10 Zefal I've had since before 2008.

Once you get it working, you should use it more often.

KerryIrons

Squirt everything with a silicone lube (won't attack rubber or leather) and maybe a thin layer of grease on the inside of the plunger tube. Just keep working things and the pump will likely free up.

pdlamb

If the rust ate through the check valve spring, you're likely out of luck.

brewerkz 

do you know where the check valve spring is on this model? Have a backflow issue while pumping on mine.

follow up: disassembled it, the o'ring the check valve seats on actually blew past the check valve and was between the piston and the check valve.