Austin Healey BJ8 Water Pump Rebuild

Because the only available reproduction pumps are such c**p I have been selling a bunch of Austin Healey 3000 MkIII water pump rebuild kits and many people have asked me how difficult is it to rebuild one of these pumps?

The kits cost $US68.65 which includes domestic or international shipping.

The following is a step by step procedure for this job. It really isn’t that difficult.


The Later Style BJ8 Pump

The identifying feature for the BJ8 style pump is the lack of a hex nut in the center of the pulley because they use a “press on” pulley. A puller is  required to remove these pulleys.


I Have Used This “Home Made” Puller For Years

The puller uses a 7/16 UNF forcing screw and the mounting bolts are on a 1.375″  pitch circle diameter. It is installed to the pulley using four 5/16″  x 1 ” UNF bolts.

Once the pulley has been removed the bearing locking wire needs to be located and removed.

Using a suitable tool remove the locking wire. The wire is usually made of brass or copper.

A Spike Tool Can Be Used To Remove The Wire

If the wire cannot be located and removed this step may be skipped although the force required to press the bearing out will be much higher and  there is a significant risk that the pump body will be damaged.

Once the wire is out the bearing and impeller can be pressed out of the body.

Be Careful to Provide Clearance For The Impeller

While pressing out the bearing and impeller assembly be careful to provide clearance for the impeller and DON’T let it drop to the floor!!

The Bearing, Seal and Impeller are Removed as an Assembly

Once this assembly has been pressed from the body the impeller must be pressed off to replace the bearing and seal. The impeller casting is easily broken so care must be taken when pressing it off the bearing shaft.


Use a Small Bearing Spreader Installed Below the Seal Face

Carefully press the bearing shaft out of the impeller.

The Impeller Must Be Supported On the Seal Face

Once the impeller has been removed the bearing and seal can be discarded.

Dis-assembly Completed

Careful examination of the seal from this recently rebuilt pump reveals that is is badly cracked.

I Suspect That This Seal Was Cracked During Pump Assembly



After cleaning and inspecting all the parts reassembly begins by inserting the seal back into the pump BY HAND!!

Be Sure to Clean The Seal Seating Position

I always spread a very small amount of silicone sealant on the area of the seal that seats in the pump body.

I use a large socket to press the seal BY HAND securely into its seat in the pump body.

The Seal Must Be Well Seated and Straight

Next the bearing is pressed into the pump body from the outer end of the body. The shorter end of the bearing shaft accommodates the pulley.

NEW NOTE: When talking with a company that rebuilds lots of heavy equipment water pumps they recommended using a a few drops of Loctite (or similar) bearing retainer at this stage just to ensure that the bearing stays put in the housing. They have found that age and normal manufacturing tolerances can result in the fit being a little loose.

Bearing orientation Press the bearing in using a tool which prevents load being applied to the bearing shaft.

Avoid Pressing on The Bearing Shaft

Press the bearing in until the groove in the bearing is aligned with the internal  groove inthe pump body. Don’t go too far.

Stop Pressing When The Grooves Are Aligned

Now install the wire retaining clip into the grooves. This can be a pain to achieve as some of the bearing grooves are smaller or larger than the originals. For replacement wire try 12, 14 or 16 gauge household copper wire.

Use Pliers to Push The Retaining Wire Into The Grooves

Check the sealing face of the impeller for excessive grooves.

Deep Grooves in The Impeller Seal Face Should be Removed

If the grooves are not too deep you can face the impeller off by rubbing it on sand paper on a flat surface.

Glass Makes a Great Flat Surface

If the grooves are really deep you can can face the impeller off in your lathe…you do have a lathe don’t you? Use fine sandpaper to produce a smooth surface.

There is Nothing Like a Lathe For This Job

Once the seal face is prepared the impeller can be pressed into position. Note that the shaft is on the base of the press which prevents the bearing from taking the pressing load.

NEW NOTE: I have occasionally encountered problems with leakage between the bearing shaft and the impeller. Using Loctite (or similar) here prevents this from becoming an issue.

Pressing impeller 2

Sockets Make The Best of Press Tools

When the end of the shaft is level with the face of the impeller STOP..  The impeller to body gap should be something like this.

Stop When The Impeller Gap is About This Big

If you rotate the pump at this stage your should hear the distinct “hissing” sound of the carbon seal.

Now press the pump down into the pulley.

Press The Pump Down Into The Pulley

Again STOP when the end of the shaft is level with the end of the hole in the pulley.

This Pulley is Pressed on to The Correct Position



BTW I have rebuild kits for all 6 cylinder Austin Healeys

$US68.65ea which includes intentional shipping.


By Michael

Who is this guy? Born in New Zealand some time back. Went to Maori Hill Primary School then Kaikorai Valley High before joining the RNZAF and an Airman Cadet in 1968. Graduated 1972 with an NZCE in Aeronautical Engineering. Then embarked on the typical Kiwis "Big Trip Overseas". Got to see quite a few places, and spent a while in the U.K. "home" as it was refered to by many New Zealanders in those days, before travelling on to New York and then to Canada by bus!! This trip is presently on hold (has been for the last 34 years). Met my dear wife Judy not long after arriving in Ontario and we have been happily married since 1976. After travelling around New Zealand and the pacific in 1979 I started Precision Sportscar andfor the next 23 years grew the business and helped raise 2 boys Drew and Robin.


  1. hi Michael,

    thanks for your advice.
    I need to purchase x2 BJ8 water pump repair kits and I’m in Australia – how do I go about this?

    kind regards

    1. No sorry Jeremy,
      They are really difficult to find. There were some on eBay a little while back but the asking price was too rich for me.
      Michael S

    1. Hi Peter,
      Sorry can’t help with a Somerset water pump kit. I would guess that it is the same as an Austin Healey 100 pump which I have been unable to find parts for.

  2. Re older 3000 pumps: I installed the kit and with the pix above it was probably easier than the BJ8 pump. I don’t have a lathe so used a drill press and file to dress the bearing surface on the front of the impeller.

  3. Hi, Michael.
    Thanks for your informative instructions. In the process of merely replacing the seal of my BJ8’s water pump and needed some reference. I pulled the impeller with a gear puller and will attempt to put it back without a press since I don’t have one. If it doesn’t work out, I may be in the market for a rebuilt water pump!

    1. Hey Bob, you were lucky to get the impellor off with a gear puller, usually they break irreparably. If you press it on by applying the force in near the shaft you should be okay bu go slowly and be very careful to ensure that it is going on straight.

      1. After everything, decided not to force the issue. I took the pump after starting the impeller to Napa where for $25 they pressed it home. Still have a problem, however. Lost about two quarts of antifreeze after toping up the radiator last evening. Hate to see green puddles on the garage floor in the morning. Took the radiator out again, and the pump. Need another gasket (or two, they’re cheap). Seems like I didn’t get the pump mounted tightly enough. Seal seems to have held well. Hard to get enough torque on the nuts because of the limited clearance near the pump flange. Can only use a 1/2″ crescent wrench because of the pulley being in the way. I used a gasket sealant on both sides of the gasket and thought that should do the trick. No dice. Any suggestions.

  4. An adjustable “Crescent ” wrench is not really good enough for the job. I would look for an offset ring spanner.
    It is also imperative that you completely clean both surfaces down to bare metal before trying to install the pump. Any remnants of the old gasket will cause problems.

  5. Thanks, Michael. I try to never use “nut rounding” adjustable crescents. I do have some offset box wrenches which I believe is what you call ring spanners. I’ll try them when the new gasket arrives. Thanks you for your advise. Read with great interest your blog of the restoration of Healey #174. Very nice.

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