My mud cups are about 4-5 mos old and have begun to squeal randomly. The water box if full and oilers are oiling. They usually only squeal when pumping but not every job. Oh yeah this is on a putz.

my pump does this when im bringing my washout balls back. I think it squeals when you are pumping slowly, try turning your volume up when this happens.

Put a bit of dishwashing soap in the water box.  Always works for me.

Dish soap worked for me too.

I YOU HAVE THE TIME TRY TURNING THE HEADS HALF A TURN IT MAY WORK `BUT WHEN THEY START MAKING A NOISE IT COULD BE THAT THEY NEED REPLACING 

mine are brand new and squealed whenever the cylinders and water box are "squeaky clean".  I always give the water box a splash of hyd oil when I refill it.  Would dishsoap be better or hyd oil....?  Dish soap has a grease cutting ability (not good), where hyd oil is what the "oilers" inject.  your thoughts....

MIGHT WANT TO LOOK AT YOUR CYLINDERS FOR MARKS OR GOUGES,ONCE I HAD A PIECE OF STEEL THAT GOT EMBEDDED IN A CUP,SCARRED UP CYLINDER PRETTY GOOD.

how often do you change the water? do wait for the cups to cool off b4 you add water? you might have something in there like pudg said. I use a little slickpac in my box.

just had a similar problem by the sounds of it, give me a call and ill see if I can help. 701-740-3382 Rodney

I have used the dish soap before but for a different reason. A pump mechanic told me once that dawn dish soap will swell the cups, he used that on semi worn out cups to prolong their life a little bit. I personally like the citrus smells good when bubble are coming out of your water box. I can try the dish soap again. I drain my water box everyday and fill it up each morning and check each job. I know this sounds odd, but I have noticed that they only squeal when I get a certain companies concrete. Does not do it on any others. Just a coincidence......mmmmmm......who knows.

This same thing happened to me just after I replaced my cups so I rinsed out my waterbox used 1 cup of "Cutsol" (water soluble oil) and the problem stopped

This may also be from types of material you are pumping . I have noticed this with pumping Micro silica . This stuff is like powdered sand and can pass just between the cup if there are little tiny scratches in your cylinders. this is why it is very important to use clean water every morning and at the end of the day rinse your water box out .