Installing the Ford 302 / 351W shorty water pump
Water Pumps and Cooling
The shorty pump uses a removable backing plate with a gasket between the plate and the pump body. That joint has its own assembly procedure, and it is worth following exactly.
Overview
Short Answer
Do not use silicone on this pump. The backing plate gasket is bonded with contact cement (or Permatex #3 in a pinch), assembled carefully, and left to cure at least four hours before the system is filled.
The procedure
Do not use silicone for sealant.
Carefully remove the backing plate. Watch not to tear the gasket between the pump and the plate. Two bolts hold the plate, gasket and plate loosely together, and the gasket can stick to those bolts and tear as the plate comes off.
Use contact glue, the kind used for counter tops. It is very sticky and seals very well. In a pinch, #3 liquid Permatex will work. Let it set up for a few minutes.
Dry fit everything first, then bring the pieces together. Once the glued surfaces touch they stick permanently, so mark your orientation and line it all up before they make contact.
Tighten into place and let it set for at least four hours before filling with water.
Why silicone is not used here
This joint is a thin gasket clamped between two machined faces by only a couple of fasteners. Silicone stays flexible and squeezes out under clamp load, which can leave a path for coolant. A contact adhesive bonds the gasket to both faces and stays put.
If it leaks at the base after assembly
A leak at the base of the pump, rather than at the weep hole, points back to this joint. The usual causes are silicone used in place of contact cement, a gasket that tore during disassembly, or the system being filled before the adhesive had cured.
The fix is to take the backing plate off and redo the joint following the steps above, with a fresh gasket if the original tore. If you need a replacement gasket, email us your order number and we will get one out to you.
Give it the full cure time
Four hours is a minimum, not a target. Filling the system early is the most common reason a correctly assembled joint still leaks.
Still need help? Our tech support team can get you pointed in the right direction.
Contact Support