Triumph Repair: TR7 Water Pump Spindle Bushing, dremal tool, engine swaps

Question
QUESTION: Hi Howard;

I am replacing a leaky water pump on my '79 TR7.  I have removed the complete pump and spindle bushing without difficulty.  Would you have any advice on installing a new spindle bushing?  I have tried (using a bushing driver) and the bushing becomes deformed.  Any suggestions would be helpful.  Thanks!  Matt

ANSWER: Hi Matt,

It is difficult to install a new bushing in the block partly because of the sharp edge of the hole in the block and the bushing is rather thin. Even with a good fitting bushing driver it is difficult to keep the bushing square and straight in the hole. I usually clean the upper part of the hole with a Dremal tool with a sanding drum to round the sharp upper edge. It also helps to put the bushing driver and bushing in the freezer for a while. With the upper part of the hole smooth and the edge rounded and polished I put a little STP on the bushing as STP molecules are much smaller then any oil or lube you can put on the bushing.

Even doing all that I have had to clean up some bushings with a sanding drum in a Dremal tool. It is usually the upper part of the bushing that gets deformed from the bushing driver. Careful cleaning after is important when the engine is not being overhauled. I did a lot of water pumps but not many bushings. I had considered making a guide for a fixed reamer to clean up a new bushing but never did.

You may know to be careful on matching up the water pump to the correct jack shaft as the angle of the teeth are different between the early and later TR-7s. I learned to check this because of engine swaps and even parts swapping before I would get it. There are also different angle impellers on the early and late water pumps and the angle of the impeller must match the top cover and use modeling clay to get the top cover clearance correct with number of gaskets. Some aftermarket suppliers got this all wrong.

I was factory trained on the TR-7 and use to buy them disabled after I left the dealerships. It was usually the head that tripped up most mechanics. And even machine shops. It was usually cooling system problems and the owner would over heat the engine and that would almost always warp the head. Auto machine shops couldn't put a strain on the head to hold it flat while they resurfaced the head so they just surfaced it as is and that would leave the cam bore bowed and usually break a cam. Most cam boring machines will not go down that small. And the few that could do it soon found that now the valves were too long on the center two cylinders and they couldn't find adjustment pads to adjust the valve clearance. However, you can get thinner pads for a Saab 99 and use them. In some cases I had to turn the inside of the lifters and cut a little off of the valve stem and then use Saab pads to get them correct.

Howard

 

---------- FOLLOW-UP ----------

QUESTION: Hi Howard;

Thanks for the reply and advice.  I have followed your advice to the letter and I was able to successfully install the water pump spindle bushing.  I cleaned up the hole a little with the Dremel tool, and then installed the pre-chilled bushing.  I used STP oil treatment as a lubricant.  I installed the bushing slowly using a bushing driver and a light hammer.  The total install maybe took me 45 minutes. I was careful to not hammer the bushing driver too hard. Right now it looks good with very little distortion of the bushing. I will continue with the water pump install.

Which leads me to a follow up question.  The TR7 workshop manual is a little vague about installing the new pump.  The Haynes manual says to install the new pump complete (which includes the brass cage assembly).  I know to install it being careful to engage the jackshaft gears and not hammering on the pump assembly.  However, I am wondering if this approach will seat the brass cage assembly properly.  I notice there are 2 holes in the impeller.  Are these 2 holes meant for proper seating of this brass cage assembly?  I think you could insert a drift through those holes and tap down on the cage assembly to insure proper seating.

Any advice on this install would be appreciated.  Thanks for the advice and answers.  It is much appreciated.  

Regards,
Matt

Answer
I always liked to assemble the pump in the block One piece at a time, rather then put the whole pump in assembled. One main reason is I could never be sure the outer brass case was fully seated and I didn't like the idea of beating on the edge with a punch. another reason was that the pump shaft and bearing may not be seated all the way in the brass sleeve. I would clean the block bore and install the brass sleeve with it's new "O" rings first, then the shaft with the slinger, bearing and snap ring next with a piece of pipe that cleared the inside of the brass sleeve and rested on the outer bearing race. Continuously checking to see that I had free play in the drive gear. This way I could be sure that the brass sleeve was seated all the way and the bearing was seated all the way in the brass sleeve with out putting any strain on the snap ring. Then I installed the oil seal and then the water seal and last the impeller with it's left handed bolt.

The end result must be that the impeller and pump shaft must have a slight free play to confirm after installation that it is not in a bind. Then check with modeling clay for the clearance between the left threaded bolt and the cover and between the impeller blades and the cover. If the clearance is not correct you must adjust the clearance by adding or removing gaskets from the cover. What ever you do never beat on the end of the pump shaft nor bolt.

Half of the water pump work I received in the dealership was from other shops and owners who tried to install a new pump as a whole unit. Some used a punch on the brass sleeve and deformed it and others just beat on the head of the shaft bolt and even displaced the snap ring doing it.

Some even tried to drive it in with a hammer when the gear teeth ware mismatched due to having the wrong jack shaft and pump match, because of a parts company giving them the wrong pump or a previous owner putting in a different block or jack shaft.

Howard