[Sean's Jaguar XJS Tech Pages]
The Water Pump: Parts

Last modified 2005 APR 07 04:40:12 GMT

I ordered the water pump rebuild kit through a local independant Jaguar mechanic/dealer/parts shop, and in turn, they actually ordered it from XK's Unlimited (yea, I should have ordered it direct, but at the time, I was just looking for someone local who might have it). Cost was about $60 delivered and taxed. The pump rebuild kit included all the parts - the seal, bearing (on new shaft), gaskets, impeller, and setscrew.

Of course, the week prior, I had picked up the Viton seal at Grainger as per a discussion on the Jag-Lovers V-12 engine list, only to discover when I went to reassemble the pump that the Viton seal wasn't the right size for the application. This was using EXACTLY the part as discussed on the list.

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Measurement of the Buna seal which was included with the pump rebuild kit (pictured on the left), and the Viton seal from Graingers (pictured on the right) revealed that the two were NOT for the same application - the Viton one is fully 1/20 inch smaller -- so much so, that it easily just falls into the bore on the pump housing. I doublechecked the specs on the Viton one, and it isn't incorrectly packaged - the published specs for it list the seal bore (the part being measured here) as 1.437" (that'd be the pressed size).

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Shaft seal from the rebuild kit - note the rough appearance (it wasn't ROUGH to the touch, but it obviously isn't polished). This is the seal which comes in the pump rebuild kit.

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This is the premium viton seal purchased for about US$21 from Grainger, an industrial supply house. Note the ultra-smooth appearance of the seal surface, and compare to the Buna one above. Nice appearance, and obviously intended for smooth operation. The bummer is that the measurements of this seal don't match those of the water pump!

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Here we have the gasket for the water pump inlet assembly.

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The various bits that come in the rebuild kit - a pair of replacement setscrews. I've no idea why they provide ones of differing lengths (possibly for different model year pumps?), but they did. Mine were in fine shape, so I reused the original setscrew and nut. My kit happened to be packaged with TWO seals (the big thing with the spring). I don't know if that was a fluke or what, since they were both identical.

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This is the pump-to-block gasket.

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This is the gasket that fits between the pump halves. Two holes are oversize, and go over the sleeved alignment shafts on the water pump.

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This is the water pump bearing which comes mounted on the shaft. Note the divot cut out of the bearing housing -- this MUST line up with the setscrew on the topside of the water pump. The original (as far as I can tell) was obviously pressed into place, then drilled for the setscrew. The front (pulley side) is the short, thicker shaft to the right in this picture, while the long narrow shaft is what the seal and impeller mounts to.

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The original one (at least in my case) was better, as it had threaded shafts specifically for extraction. While I had my pump diassembled, I centre punched marks for drilling out and threading the one which came in the rebuild kit. My original impeller had just a little corrosion on it, but not much of anything, and a quick visit to the bead blasting booth brought it back to like-new condition. The impeller blades were somewhat different between the two impellers, with this one having longer blades, but a slightly different angle. I decided the other had served well, and was suitable to keep serving just fine.

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This is what you get when you call Kragen (US parts chain) and special order a WATER PUMP GASKET. In reality, this is a THERMOSTAT GASKET. I decided to keep the purchase anyway, since I'll be needing a pair of these sometime not too long from now when I check/replace my thermos. I had originally ordered this because originally, I was considering just removing the pump, check everything, and probably just replace the seal and reinstalling the pump (requiring a new gasket). Both of the necessary gaskets were included with the rebuild kit (see above).


Sean B. Straw
Post Box 751224
Petaluma, CA 94975-1224 USA

EMail to: Sean.Straw+Jaguar@mail.professional.org

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