Procedure to cure a 355 Spider roof that does not close properly due to old fluid

Flushing out the old, sticky hydraulic oil and bleeding the system.

My 355 Spider roof now works like a charm. Roof closes all the way (I thought it was designed to stop 10 inches from closed. It’s not. The roof closes all the way if your secondary cylinders are working properly.) The roof mechanism clears the seat belt mounts by several inches.

The culprit was old hydraulic fluid that had become gummy. I flushed it out using the procedure below, and now the roof works better than ever. I’m delighted that I don’t have an expensive problem with the cylinders.

Flushing and Bleeding Procedure.

Notes

Having recently replaced the hydraulic fluid reservoir I noticed on the test cycles that the secondary cylinders were not functioning at all. All the work of raising and lowering the convertible top was being done by the primary cylinders. I had never noticed this before, and just assumed that the roof was working fine, although I had to pull the roof down for the final 10 inches. Forum posts suggested that the central support bar across the roof may be bent. Mine was not. I decided to try bleeding the system.

This task is covered on Page H80 of volume three of the workshop manual, although I spent hours translating the Italian and French columns to try to ascertain what the English was meant to say. There is a Ferrarichat post, dated 2/24/07, by Dcup who did a better job of describing the procedure than the workshop manual, but I think that more detail may be helpful to members who are not experts.

This task took me two days, mainly because several of the screws and bolts were almost inaccessible to a large person. If you have svelte feminine hands, or know what you are doing, you can probably do this in a couple of hours.

Tools:

13mm socket and ratchet
17mm closed-end ratcheting spanner
13mm closed end spanner
7mm open ended spanner
Bleed kit.
#4 Allen key
#6 Allen key

Parts:

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.

Procedure:

Before you can get close to step one in the workshop manual, several trim pieces need to be removed. The roof should be closed when you begin.

1. Remove Phillips head screw from LH lowermost mechanism shroud, then pull down to unclip from trim piece above.

2. Remove center trim above the parcel shelf by unscrewing the two Phillips head screws under the black screw covers, which lever up.

3. Remove LH upper trim by removing single Phillips head screw to the right of the cylinder, and then pushing the trim and leather cylinder cover back and up off the cylinder.

4. Remove RH upper trim. There are two Phillips head screws behind the cylinder and one to the right of the cylinder.

5. Remove the leather pump cover from between the seats by unscrewing the four Phillips head screws, two each side. You may need to remove the ECU cover immediately behind the RH seat in order to get at the RH screws. (This has two Phillips head screws and the bottom and then slides upwards to disengage a clip.) Pop out the emergency roof switch from the LH side and slide the pump cover forward to rest on the console.

6. Remove the two bolts going into the LH cylinder at the base of the cylinder body using a 17mm spanner.

7. Remove the allen headed bolt with a #4 key from the front of the fork on the LH cylinder.

8. Remove the bolt holding the base of the LH secondary cylinder to the roof frame with a 13mm socket.

9. Repeat for the RH side.

10. Disconnect both primary cylinders from the roof mechanism by pulling the fork from its mount and letting the cylinders rest freely.

11. Check the fluid level in the reservoir. Refill to the Max line if required. Do so by removing the two allen bolts from the brass compensation valve in front of the pump with a #6 allen key. Push the compensation valve body to one side to reveal the 13mm brass filler plug in the pump body. Undo the #1 bleed screw in the pump body. Undo the 13mm plug and fill the reservoir to the Max line with hydraulic fluid through a tube. Replace the plug. Close the #1 bleed screw.

12. Turn on the ignition and use the emergency roof switch to run through five cycles of opening and closing. The primary cylinders must be disconnected from the roof mechanism, as described above, before doing this. End the cycle with the pistons of both cylinders fully retracted, that is to say at their innermost position of travel.

13. Move the LH cylinder such that the fork is tucked up against the bulkhead; fork down, cylinder vertical, and the bleed nipple uppermost. Attach the bleed tube to the nipple. I found it convenient to tuck the bleed cup between the carpet and the bulkhead, in a rag, so that it couldn’t move.

14. On the RH side of the car turn the RH primary cylinder upside down, such that the fork is in the air and the cylinder is resting on the parcel shelf.

15. By hand, push each small secondary cylinder in and out. Do they move freely? Does the pivot mechanism the fork end is attached to move freely? Lubricate the pivot (part of the roof frame) with WD40. If your secondary cylinders are seized, you may be looking at having to replace them, which I do not cover here. Mine moved freely. Leave them unattached until the end of the procedure.

16. Undo the #1 bleed screw on the side of the pump body. Three turns counter-clockwise is enough.

17. On the LH primary cylinder, open the bleed nipple with a 7mm open ended spanner.

18. Pull up on the fork of the RH primary cylinder. This should draw oil from the bleed nipple on the LH cylinder into the cup.

19. When the RH fork is fully extended, close the bleed nipple on the LH cylinder.

20. Check the fluid level in the reservoir. Given that you have drawn out fluid, it should now be below Max.

21. Refill to the Max line, using the procedure in 11.

22. Close the #1 bleed screw in the side of the pump body.

23. Undo #7 bleed screw on the bottom side of the compensation valve. There should be enough play in the tubes and wires that the compensation valve can be tilted towards you to access the bleed screw.

24. Unwedge the LH primary cylinder so it is free to move.

25. Turn the ignition on and use the emergency roof switch to extend the LH fork as far as it will go. Both the RH fork (which you pulled out) and the LH fork should now be at their outermost position of travel.

26. Close #7 bleed screw.

27. Run through 3 or 4 cycles using the emergency switch, keeping the button pressed for 2 seconds when the innermost or outermost points of travel are reached. This helps get air out of the system. Both forks should come in and out in unison. Finish with them fully retracted. Turn off ignition.

Now you have a decision to make. Undo the bleed pipe from the nipple, and examine the contents of the pipe and cup you just drained from the system. Mine was gummy, viscous and yellow. In fact, within a couple of minutes of being exposed to air, it started to solidify in the tubing. Compare to the new fluid. If the old fluid is in poor condition, repeat the bleeding procedure that began at step 11, being sure to refill the reservoir each time. You should get to a point where the fluid coming out is less viscous and approaching the quality of the new fluid you put it. If you were still getting air in the bleed pipe when the RH cylinder was fully extended, you will also have run through the bleed process again. I had no air in mine.

When you’re done reassemble everything. Be careful with the 17mm bolts – the ones on the outside of the cylinders are very fiddly to get back in. Make sure bleed screw #7 is tight before putting the compensation valve back.

When everything is back together, run the engine when running through cycles of putting the roof up and down so the battery doesn’t get flat. With any luck your roof will be quicker and the secondary cylinders will now work, closing the roof all the way.
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There seem to be two questions raised in this thread:

1. The fork does not engage the pivot pin when the hood is going up.

2. Even after the bleeding procedure I detail at the beginning of the thread, the secondary rams don't work.

On #1, I'm not an expert, but in my experience the fork missing the pivot is independent of the secondary rams not working, meaning even when you get them working, the fork will still miss the pivot.

The geometry of the frame determines if the fork will miss the pivot. There are three bolts on each side holding the frame to the body. Loosen all 3 and pull the frame back, towards the rear of the vehicle. Tighten the bolts while pushing the frame back. You should be able to influence the geometry of the frame by the 1/4" or 1/2" that will make all the difference.

I had the canvas top replaced on my car recently. In adjusting the frame so the rubber seals around the window sealed better, the top shop played with the geometry, causing one of my forks to miss the pivot. The shop called a Ferrari tech around to sort it out, and the guy said in doing these for a decade, there was no science to it, just loosen the bolts, give it a good push back and tighten the bolts. Do that a few times and eventually you'll get the fork to engage.

On #2, the first thing is to check you don't have a fluid problem. Is the reservoir full, is the fluid good quality, not sticky, do you have air in the pipes. If you bleed it properly you should be able to eliminate the hydraulic fluid as a cause.

If there are no leaks in the cylinders, all the hydraulic pipes are intact and not leaking, then it may be an electrical problem. Two signs of it being electrical are that both secondary rams failed at the same time, and that the problem is intermittent.

If the primary rams work, but then nothing happens to the secondary rams, it may be a solenoid problem. The solenoid valve diverts fluid pressure from the primaries to the secondaries.

Here's how to see if you have a bad connection that is stopping the solenoid from doing its job. First, turn the battery off at the cut off switch (under the RH flap in the front storage trunk of the car). If you haven't checked lately, see if the fuses next to the hydraulic pump (under the leather cover between the seats) are OK.

After taking off the trim covering the LH primary cylinder, you'll see a brass cube to the side and below the LH primary cylinder. It has two hex bolts in the top. Undo them with an allen key. Lift the solenoid valve block away from the bulkhead. See photos below.

You'll see an electrical connector on the side of the solenoid housing. Unclip it. Follow the wire down to the connector on the bulkhead. Undo it. Using an ohm meter, check for continuity on the wires (you're looking for zero readings). See if any of the wires to the microswitches have been trapped or cut by the roof mechanism. Make sure there is no corrosion where the wires earth to the bulkhead. (See photos). Check that both spades inside the solenoid connector are clean and intact, not broken off. Then spray every connection with WD40.

With all the wire connectors plugged back in, turn the battery back on and try the top using the regular button on the center console, not the override switch. Hopefully your secondary rams will work. If not, you may have more serious issues. The ECU could have an issue, the cylinders themselves could have failed, the actual solenoid could have failed.

Hope this helps those who are having problems.
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JGV - The only thing that looked like an earth I saw was the bolt that connects all those black plastic connectors to the bulkhead. I tightened it and sprayed with WD40 at the same time as I undid all the connectors and sprayed them. So I'm not sure exactly what I did to solve the problem, but since I did that it has worked like a charm.

If you have a working solenoid (you say you put 12V over it and it clicked), and plenty of clean fluid in the pipes, then it seems to me that either your ECU is not sending a signal, or there is a problem in your electrical connections that is preventing the solenoid engaging.

I was keen to check all the low cost elements first and rule them out before worrying about the expensive components. By checking no wires were cut or trapped, no connectors had a dry or corroded joint, and the earth bolt (if that's what it is) was clean, I got it working. My problem was intermittent, which in my simple mind, made me think a loose earth was a likely culprit.

Hope you track down your problem.

 

The secondary cylinders should be pushed in, as I recall, before bleeding because that way there is less oil (which may have air bubbles in it) to be drawn through the system by the bleed and into the cup.

I'm not certain if the cylinders should be able to be moved by hand after the bleed.

I believe the #1 bleed screw, on the side of the pump, is to force air from the reservoir. The #7 bleed screw, on the bottom of the compensation valve, is to bleed air from the compensation valve.

The secondaries are sealed, hence why the rams move when fluid is diverted under pressure into them, so I know of no way that air can be removed from them other than by pulling enough fluid through the LH primary bleed nipple that all the trapped air has been bled.

I hope this helps. I know these systems can be frustrating. Make sure there is plenty of fluid in the reservoir, no leaking pipes, that you draw plenty of fluid through the system as you bleed, and no air bubbles are coming out. Once everything is tightened up, listen for the solenoid diverting fluid to the secondaries when you run through a full cycle using the regular switch (not the emergency override).

 

What do you mean by "to put in phase both of the primary cylinders, probably I left a bit of air in the system?"

I'm not an expert in hydraulics, but I would imagine that if you leave air in it will rise up to the highest point and your secondary cylinders won't work.

I would not crack open the secondary cylinders if I were you. They are sealed units and subject to a lot of pressure. Assuming your system is sealed (no split tubes, no oil leaking from any cylinders) you just need to push the rams in on the secondaries and bleed the system so you've drawn so much fluid out of the LH bleed nipple, filling the reservoir up repeatedly (as you would if you were bleeding brakes after a fluid change) so that there are no air bubbles left in the system. When you run the system 4 or 5 times with all the bleed screws closed it should equal out the pressure between the left and right primaries, but no air should be getting it.