Not enough information provided for us to make a meaningful answer. But, these games can be fun. I will take a wild guess and you tell me if I am in the ballpark.

Maybe this is a between bearings pump that was originally built with packing but later converted to mechanical seals. Maybe the shaft stiffness is inadequate without the extra support of the original packing. Maybe the operating conditions have changed and you are operating the pump too close to rotor critical speed. Maybe the impeller was very poorly balanced at the last repair. Maybe the shaft is bent. Maybe . . .

Tell us more about the pump and service and maybe we won't have to guess.

Johnny

Johnny Pellin

Agree with JJPellin more information is necessary. Is it a split case or end suction or vertical in-line centrifugal. About 14 years ago I worked at Crane Pumps which manufacturers the Weinman pump brand.

Post some photos of the pump and I along with the other people with access to this site could give you some idea for troubleshooting.

Best of luck.

Crystal ball available for hire, please contact for more detail.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

I see several possible pump styles/arrangements.
https://www.cranepumps.com/products/brand/weinman

I'll check back after 10 or 20 insightful, probing questions have been proposed by the crew, and answered by OP.

There should probably be a few questions about the seal type, and significant detail about the nature of the seal leakage and the condition of the actual leaking seal components

---GO GET 'EM JOHNNY PELLIN !!! --- A STAR FOR YOU ----

Guessing games can be excused by newbies,

But, in recent years, I have detected a distinct Mid-Eastern attitude of leaving out important information .... on purpose !!

My Turn ???!!! ....... Why Thank You !!! ..... I can give you a few Pellin Maybes !!!

Maybe the pump fell off the truck as it was being delivered and bent the shaft and casing

Maybe you should call in a pump specialist who will perform both a shaft runout measurement and a vibration survey at different pump speeds

Maybe you could tell us how old the pump is, the age and type of mechanical seal and the amount of permitted leakage.

Maybe you could perform an evaluation.... does the maximum leakage occur at the maximum vibration speed ?

Maybe ... maybe ..... maybe....

MJCronin
Sr. Process Engineer