This water pump is deja vu all over again! (sorry, Yogi)...
This isn't the first, or last (probably) time we've seen problems with these
water pumps. I had similar problems with a pump/pulley combination I bought
from Moss several years ago.
Let me state up front that this isn't totally Moss problem, it has to do with
QH and the pulley supplier. Sometime in the late TR4/TR4A run a change was
made to the water pump which slightly changed the relationship between the
pulley and pump housing. The change wasn't much (0.16"), but it's enough that
if you are using a late water pump (such as the new QH's) and the repro pulley
(a faithful reproduction of the early pulley) that the pully hits the pump
housing.
One can either shim the pulley out a bit, as Darrell did originally, or
machine the new pulley so it doesn't rub. On the water pump/pulley
combination I bought (Spring 1991) I had to machine both the sides and the
front face of the water pump housing. If you shim it out the pulley is now
"out of plane" with the other pulleys and has an additional side load applied
to it. If the shim is not flat, the pulley shaft hole not true, or the nut
is not tight, the either the pulley will wear on the shaft (which sounds
like what happened to Darrell), or the uneven loading will cause a fatigue
break of the pump shaft just behind the nyloc nut.
So, what the hell do you do? Darrell, if I were you...
******************* DISCLAIMER ***********************
This is what Bruce would do, not what you should do.
Kids, don't try this at home!
******************************************************
1. Try to find a good late TR4A pulley to mate with a new pump.
2. Failing that, carefully machine a repro pulley and new pump and try again.
One can be successful with this method since the water pump I put together is
still working with 25,000 miles on it. A good idea is to go to a slightly
narrower belt (Gates makes a belt 17mm wide by 965mm in circumference that
worked well on our 3B) to reduce side loads on the pulley.
3. Rebuild the old pump. One can now get the required parts, all one has
to do is find the time!
Good Luck & I hope this helped!
Bruce Clough
|