VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 water pump packing- 36 master deluxe

I'd like to know how to correctly replace and adjust the packing in the water pump on my 36 master deluxe. This is a 206.5 inch engine. Mine pump is leaking enough that it's leaving quite a puddle when parked and there is evidence of antifreeze being blown around in the engine bay. I've watched under the hood when running and parked and the pump packing is the only thing dripping. It has been getting worse for a while. Used to be a lot less leaking. I tried tightening on the packing nut but that seemed to make it worse. I just got the car this summer so I don't know how old the packing is. I removed the pump from the car. It doesn't seem to be enough room between the backing nut and body to get at the old packing or install new packing. How does the water pump come apart? Once I do get the packing replaced, what is the correct adjustment? Should it drip a little or be dry when parked and running? Any help will be appreciated.

Your pump should run completely dry. New packing will only solve your problem for a short time.

If you removed and disassembled the water pump you would find the shaft rusty and scarred at the point where the seal meets the shaft. This damaged spot eats the packing very quickly. To solve your problem the pump should be rebuilt with a new shaft and packing.

On most pumps of this vintage the pulley needs to be pulled off and then the impeller and shaft are removed as a unit. You can then inspect the shaft for wear and also the bushings. Repair kits usually have new shaft,impeller,bushings and seals along with a mounting gasket.

New pumps, both Genuine Chevy and aftermarket are frequently for sale on eBay.
A NOS GM pump is currently on for $130.00. That's a bit high for my taste, but your call, not mine.
NORS (aftermarket) pumps sometimes appear for $50-$60. If you buy a kit and pay a shop to remove and reinstall your pulley, it could be a better deal to just get a new pump. I installed a NORS pump on my '36 truck and it seems to work fine after a couple of packing nut adjustments.

ike

How do you remove the pulley? Is it pressed off and if so how? What should the end play be (clearance) when I press it back on? Are there places I can send the pump to have it rebuilt?

The pulley is pressed off and on and there should be no end play.

You can send your water pump to the Filling Station www.fillingstation to be rebuilt.

If you have to locate, buy, and ship a kit then send your pump off to have it rebuilt (shipping two ways). The $130.00 NOS GM pump is looking cheaper all the time. My advice is GO TO EBAY and get the pump ASAP.

I have several '35 pumps available, but only 2 '36 pumps. I hate to get rid of them as long as I am still driving my truck.

Mike

Look up your local machine shop. They should be able to "press" off and on "new" parts to the pump. You can order new parts from various vendors over the net. Or even a whole new pump.

It is recommended that you back the packing nut off as far as it will go. Then place new packing. You will not be able to place much in there; however, place as much as you can (perhaps one turn or one and a half turns) It is recommended to then tighten the nut until the leaking stops. The old packing will be compressed toward the back of the unit. That is the way I (Dad, Grandpa) do it. If it still leaks...remove packing nut and see if more new packing can be added as the old packing should compress further to the rear. Only if this repeated process fails does it go to the machine shop for disassembly and entire new packing placement and/or parts. During the 1930's every penny counted and only after every possible repair was tried first was replacement looked at.

On two of the 29 water pumps I have worked on I used my steering wheel puller. The pulley is not pressed on all that tight. That way you can look at the shaft and see if it is badly pitted. Now the impellor IS rather tight on the shaft and a press will probably be needed to press it off.

Rust,

My experience with the 1936 Chevy water pump comes from my ’36 pickup that I’ve owned since 1965 and restored in the early 1970s. In all those decades of being regularly driven it has had the same water pump and leakage has never been a problem. A few times a year I put a drop of oil in the oil cup and give the grease cup an occasional refill and clockwise turn. When, on rare occasion, slight seepage shows at the packing nut I give the packing nut a slight turn to tighten it. Twice in all these decades I have added packing thread. It is not necessary to remove the pump, let alone do any disassembly, to add packing thread. I don't know why others think that is necessary.

This packing material I have is labelled on the box “Raybestos Twisted and Graphited ASBESTOS PACKING”. The box is a full ¼ pound that I’ve had for all the decades I’ve had this ’36 PU and is definitely “The right stuff” because it works perfectly. If you’d like to try some of this stuff let me know.

I also have a NOS '36 water pump rebuild kit that it appears won't be needed in my lifetime. You could probably install it at home without any expensive outside services. It would require only removal and reinstallation of the pulley, that could probably be accomplished with a simple puller to remove and a big C-clamp to reinstall.

Ray W