Buick packing nut removal

[Darren Smith]

I have a 1927 Buick Master 6 and it has started leaking water from the packing nut on the water pump.  Does anybody know if I can loosen the packing nut and pack with graphite infused string without removing the whole pump? 

[Spinneyhill]

If you use graphite infused string or rope, make sure it has plenty of lubrication and keep the lubrication up over time. Graphite is at the bottom of the galvanic series and the shaft will rust once the graphite dries out. Leakage of coolant will follow. I used square braided PTFE rope for my 1930 Dodge 8 water pump packing.

 

Regarding your problem, I would just try it! Inspect the shaft carefully. If it is rough, it won't seal for long before chewing out the new packing. And if it is rough, it is possible that is the result of dry graphite impregnated packing.

[DonMicheletti]

Overtightening the packing nut will score the shaft too.

[Darren Smith]

Thanks.  Ill give it a go

 

[Rusty_OToole]

Yes, you can unscrew the nut and wrap more packing string around the shaft then tighten the nut. Give it a gentle turn occasionally. When it bottoms out unscrew and wrap more packing.

 

Have heard you should not use teflon packing because it wears the shaft. I don't know what is best to use, maybe the experts will chime in.

[JFranklin]

Have you tried tightening the nut a partial turn yet?

Edited May 11, 2018 by JFranklin (see edit history)

[Spinneyhill]

2 hours ago, Rusty_OToole said:

Have heard you should not use teflon packing because it wears the shaft

I put some grease on mine.

 

SKF say this about PTFE seals. They withstand dry running. But do they wear the shaft - well yes they will, as the shaft will wear the seal.

http://www.skf.com/us/products/seals/industrial-seals/power-transmission-seals/radial-shaft-seals/seals-for-general-industrial-applications/ptfe-radial-shaft-seals/index.html

"Radial shaft seals with one or more PTFE sealing lip(s) are designed to withstand aggressive environments, high temperatures, high pressures and dry running that traditional radial shaft seals made of elastomeric sealing lip materials cannot withstand. Many of the PTFE compounds are FDA approved. Main advantages of PTFE seals include:

    High chemical resistance
    Withstand speeds up to 30 m/s (5 900 ft/min)
    Wide operating temperature range, –70 to +250 °C (–95 to +480 °F)
    Withstand pressures up to 3,5 MPa (500 psi)
    Withstand dry running"

 

But then graphite packing will wear the shaft too when it dries out, as well as promote galvanic corrosion.

 

If the shaft rotates at about 2x engine speed, say up to 6000 RPM in my 1930 Dodge Brothers and is 16 mm diameter, the shaft surface speed is  ca 300 m/min or ca 1000 ft/min. This seems to be within the capability of PTFE.

Edited May 11, 2018 by Spinneyhill (see edit history)

[JV Puleo]

If the pump shaft is original there is a good chance it has already suffered from galvanic corrosion and no amount of tightening or adding new packing material will solve the problem.

[Bloo]

Packing pumps should leak a tiny bit, it doesn't take much. Run the packing completely dry and there will be a lot of shaft wear.

[Rusty_OToole]

The packing is supposed to wear and you are supposed to gently tighten the nut from time to time to keep a tight seal. Just enough that it doesn't leak. When the nut bottoms out, unscrew it and wrap more packing string around the shaft. There are millions of water pumps in heating systems etc that use this system to this day. It is simple, cheap and works well and requires only a little care.

 

It might be a good idea to put a few drops of synthetic oil on the string so it doesn't dry out, per Spinneyhill's warning.

Edited May 11, 2018 by Rusty_OToole (see edit history)

[Restorer32]

If properly tightened the pump will leak a drop now and then when running but will be dry with the engine not running.

[Mark Shaw]

Automotive water pump packing is not a severe service that would require the chemical resistance of Teflon.  Just about any graphite impregnated braded packing will work nicely.  As stated earlier, shaft corrosion will cause old and new packing to quickly fail. Pitting corrosion of the shaft is usually caused long periods of non-use as often is the case with old cars.  I suggest you pull the old packing and re-pack with a light coat of water resistant grease.  If there is a grease fitting on the pump packing gland, make sure you align the lantern ring with the grease fitting.

 

[JFranklin]

If you can make it fit, I like to use the packing sold for Model A Fords, It doesn't have string or cord that can score the shaft.

[Restorer32]

McMaster-Carr sells a variety of different sizes, shapes, and types of graphite packing.

[Darren Smith]

Thanks everybody for your comments.  I have managed to loosen the packing nut and replace the old packing with graphite infused packing string.  No leaks and runs well