90 XJS Convertible Pump Leak

[Michael J.]

I developed a slow leak in the convertible top pump. After adding fluid to the reservior a couple of times, I finally found fluid leaking out of the grommet for the two wires on the back of the electric pump motor.

I took it apart and found that the motor shaft seal is allowing fluid to slowly seep by and into the motor itself. This seal seems to be the only thing wrong with the motor. New pumps are available for about $220 from two companies that specialize in power top parts for american cars. I have not inquired about whether the pumps fit the XJS or not yet. I wanted to try finding a seal first.

Anybody run into this before?

 

[Michael J.]

Upon disassembly of the motor/pump assembly, I found that between the motor and the pump is a porous bronze bushing that supports the motor shaft and a two part rubber seal called a "Power Pack". The Powerpack is two part. One part is an o-ring that snaps into the rubber seal. The Powerpack is held in place with a washer and a snap ring. the size needed is 3/8" X 5/8" X 1/8" and cost $2.13 at a local hydraulic supply shop that specializes in farm equipment hydraulics.

I tried the convertible top hydraulics vendors in Hemmings Motor News, but they weren't to helpful. I did not try Jaguar, the motor is listed as a complete assembly and not broken down into parts in the parts book.

What I learned (the hard way) was that it is not necessary to remove the fluid reservoir or to disassemble the gear type fluid pump in order to repair the leak. The powerpack seal had crumbled with age. There are two 4" bolts that hold the motor onto the pump housing that go though the motor. Remove the bolts and pull the motor away from the pump. The whole pump is mounted to the car by four rubber mounts that just snap in place.

Coat the seal after installation with hydraulic fluid so that it does not bind when the motor armature shaft is inserted through it. The shaft has a flat that engages the pump gear.

Try not to pull the Brushes plate from the armature. It was hard to get back on. The magnets in the motor also make it hard to reinsert the bolts again. It took several tries.

The hardest part was removing the lockable cubby to gain access to everything. Remove the molded insullation that is there to absorb sound.

Make sure that you mark each of the four plastic fluid lines and the nipple each connects to to make sure that it is connected right when reinstalled..