I've had a Bontrager Flashcharger pump for many years. It has recently developed an issue when charging in that the pump handle bounces back up at you and it gets really hard to pump at all vary quickly. I've taken it apart, and it looks like there's a wee rubber bit at the end of the pump shift that is damaged (officially an elastomer valve cup apparently. It is a numbered part, but Trek don't sell it anymore and no bike shops have it in stock.
Quite annoying that such an expensive (and useful) pump is knackered for want of a wee rubber grommet.
Grr.
Could you cut a new grommet from a sheet of rubber? If you know the thickness you need I reckon someone may be able to scavenge you an off cut?
Unfortunately not. It is quite a specific moulded part. Really annoyed about it. I've bought another pump now (Topeak equivalent) and it isn't as good at seating tyres, probably due to having a smaller air cylinder. Grr.
I'm of the opinion that tubeless booster pumps aren't worth it, buy a decent track pump and an Airshot separately, less to go wrong and with a lot of tyres you won't even need the Airshot
I had the same fault on my Flashcharger a couple of years ago.
Bontrager/Trek were useless in trying to get a replacement rubber cup thingy. They just didn't want to know and didn't care that an expensive pump was made useless for the sake of a part that would probably cost pennies.
Same here. I guess it's s problem with all pumps. I'd wager that very few people service pumps so the plungers runs dry all the time and slowly wear to the point that the air gets past. On a £30 you just replace it without a second thought. A £100 pump is another matter.
Note to self, take mine to bits and pop on some grease! To be fair, I bought mine when they first came out and it's been faultless.
Is the pump a rebrand of another make or would other pumps have similar rubber bits inside?
Could be worth looking through SJS pump spares page to see whether there is anything likely of bodgeable. Looks as though spares for Topeka may be the easiest to find, not that it helps you but might influence new pump choice.
Is the pump a rebrand of another make or would other pumps have similar rubber bits inside?
I did look at this when I was working a shop a few years back now. As you say, Topeka were good for spares but the available part was slightly too big iirc. It's probably not an insurmountable issue to over come that I ought to put some thought into before I have to fork out for a replacement.
Not quite sure what that bit does but if it’s to do with the plunger air seal in the good ole days dad was able to rejuvenate car foot pump seals by using greased chamois leather wrapped around the knackered seal.
Note to self, add diary reminder for annual pump seal regrease.
+1 for getting a separate pump and charger. If something goes wrong with one that's unfixable it means you don't lose two bits of kit.