Replacing the convertible top hydraulic reservoir in a 355 Spider

I had asked in another post for help in replacing the plastic reservoir bottle in the Spider hydraulic pump system. No-one seemed to have done that job, so I post the procedure I followed here in case it helps others.

Tools list:

Phillips head screwdriver

8mm socket and ratchet with at least a 3” extension.

10mm open-ended spanner.

No. 5 allen key.

13mm closed ended spanner.

T 25 long handled Torx driver (I picked up a set for $5 at the local motorists discount store). A Torx head in a ratchet will not work; at least one bolt is inaccessible without interfering with the hydraulic pipes.

A double-ended hook to suspend the pump valve block out of the way. A six inch piece of metal coat hanger bent into an S shape would do.

A clean squeezy bottle and tubing to insert hydraulic fluid in the filler hole of the pump.

A shallow bucket (a plastic washing up bowl works well) for catching the hydraulic fluid, and plenty of rags and shop towels.

Parts List:

Ferrari Hydraulic Cup Kit, Part 000168881. Table 166, Part 21 on the diagram below.

Mercedes ZH-M hydraulic fluid. Some have said use regular jack oil. Maybe that’s fine, but the Mercedes fluid is what the Ferrari dealer uses and costs $14 a liter, which is not bad. You will only need a single one liter bottle for this job.

Notes:

Several of the steps here are for draining the reservoir before removal. Mine was cracked at the top in two places, where stress fractures from over-tightened bolts had radiated down from the top. I had also just filled the reservoir with new fluid before realizing that there were hairline cracks. If your reservoir is empty you may not need all these steps.

Procedure:

Turn off battery at the cut off.

Remove the cover from the bulkhead behind the RH seat by removing the two Phillips head screws at the bottom and then lifting up to unclip.

Remove the four Phillips head screws, two each side of the pump shroud.

Move the shroud forward between seats.

Remove the black electronic control station box: From the RH side, remove the two nuts holding the bracket to the system body using an 8mm socket. Lay the black box on the carpet on the RH side.

Remove each relay and fuse block, en masse, by removing the bolt holding the bracket to the system body.

The system body should now be clear of any electronics.

Undo the two Allen bolts from the front of the hydraulic pump compensation valve, which is the rectangular brass block sitting in front of the pump body.

Move the compensation valve to one side, revealing a brass plug bolt in the main pump body.

Using a pre-fashioned double-ended hook, suspend the pump valve upside down from the glove box on the rear shelf, protecting the leather box with a cloth. The pump valve should swing freely to this position with no strain on the hydraulic hoses.

Prepare to remove pump body from the rear bulkhead by undoing the two shouldered 10mm nuts, one at the top on the LH side, the other at the bottom on the RH side. Allow the pump body to rest in situ for the moment.

Remove the brass plug bolt in the front of the pump body using a 13mm closed-end spanner. This reveals the filler hole in the pump body. Undo the #1 bleed screw in the side of the pump body by turning three turns counter-clockwise.

Carefully slide the pump body off the threads and away from the bulkhead. Support on rags and ensure hydraulic pipes are not trapped underneath.

Place rags and a container under the pump body to catch hydraulic fluid.

Lift up the pump body and tilt it to drain the hydraulic fluid from the plastic reservoir through the filler hole.

Support the pump body on its side, such that the four torx head bolts that hold the reservoir to the pump body are facing the LH side of the vehicle.

Remove the four bolts, evenly, using a long T 25 torx-headed driver.
With the torx bolts removed, ease the plastic cup away, very carefully and evenly, one corner at a time, so as not to harm the seal. My seal was in good condition and was left in situ.

The old reservoir had two cracks in it, caused by over stressing the bolts at two of the corners.

To fit the new plastic reservoir, first lubricate the seal with clean hydraulic fluid. Gently slide the reservoir over until snug. Insert the four torx bolts and tighten evenly. Do not over-tighten.

Place body back on the bulkhead threads. Fill with hydraulic fluid to the Max line. Close the #1 bleed screw.

Reassemble everything, leaving the pump cover off for the moment.

Turn the battery cutoff back on.

Pop the emergency roof switch from the leather pump cover and use it to run the system through 5 cycles. One side of the switch has an O, the other a C. It is recommended that you run the engine when running through the cycles to preserve the battery. Keep hold of the button for a few seconds at the end of each cycle. This helps to flush air from the fluid. If the system has variable pitch or is not working smoothly the system may need a proper bleeding. See my separate post on how to do that.
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Here is the roof hydraulics diagram that didn't upload properly with the post.
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