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 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.
DO NOT TRY TO REMOVE THE PULLEY BY GRIPPING THE EDGE OF THE BELT GROOVE BECAUSE THE CASTING WILL BREAK.
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.
ALWAYS SUPPORT THE IMPELLER ON THE SEAL FACE DURING REMOVAL.
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.
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.
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?
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.
- 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
YOU ARE FINISHED
BTW I have rebuild kits and rebuilt BJ8 water pumps..