F355 Top Question

Is it possible that the right hand secondary ram plunger is bent and not extending/retracting properly? I have heard of cases of bent ram plungers. The secondary rams are the smaller ones.

Hydraulic control of the both secondary rams is through a single valve (located behind the left hand seat), so the secondary rams should be operating at the same time (in sequence).

For info, in the left hand secondary ram, there is a microswitch which stops the pump motor running when the ram is fully extended (although on my car, it hits the window frame with a thud before this happens). The microswitch, however, is not used during emergency operation, so the electrics sound ok.

Here is a graphic of the hydraulic setup:

https://www.dropbox.com/t/19MBxySFYc1iS6E9

And a nice coloured graphic of the hydraulics provided by a fellow FChatter:

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Secondary rams are #1 and #2

Of course, if the ram is bent, we have to figure out why it bent.

How are the fluid levels?

 

I see from the coloured graphic above that there are separate pressure and return ports for the the right hand secondary ram on the so-called "F1" solenoid valve hydraulic block (in the LH buttress behind the driver's* head) . See the inset on the graphic (and the purple and light blue lines)

My first impression was that you had a mechanical problem, but I'm not sure of the internal(hydraulic) setup of the F1 block. Just wondering if the hydraulic ports or lines going to the RH secondary ram are compromised/blocked.

*LHD car.

 

Would you be able to measure the extension you have on your secondary rams are in the closed or as close as you can get to closed position

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Mine is 5cm (closed and locked). I don't know if this is typical.

 

How's the fluid level? Should be checked and topped off every two or three years.

 

The windows are controlled by the microswitch on the top of the windshield frame (left hand side) and the microswitch at the bottom of the slider on the left hand primary ram. Changing the state of either of these should restore window function. If the roof is not latched in the window top frame, to get the windows to move again, you'll have to disconnect the plug on the microswitch on the left hand slider primary ram slider (guide). You may need a small flat screwdriver to remove the plug on the microswitch.

 

Yeah, definitely something fishy going on here. Contrary to what I thought earlier, it looks like the left hand ram has extended too far. Unless that's just an optical illusion from a wide angle lens?

Is this with the roof as far as it will go (up)?

Can you take a measurement?

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For info: This is the "S5" microswitch in the left hand ram which stops the pump motor running at the roof fully forward position

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Just had another look at my roof and the clean section on rod on the right hand ram is about 21mm (or near enough to 2cm)

I've used your photo of the left hand ram to show this measurement

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I think it was just an optical illusion previously. After looking at the relatively lengths of the clean section on your car and mine, the left hand ram does look normal. The right hand ram is probably the faulty one.

Is there enough movement in the ram to detatch it from the roof mechanism (at the forward point), just to see if will extend without having to push against the roof? That way it will tell you if the roof mechanism is jamming or if the actuator is faulty.

 

Sorry.. word soup... I mean to say disconnect the plug on the bottom of the left hand primary ram (actuator) slider.


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it simple. You put the top down and leave it there. It's a convertible!

 

"Neither snow nor rain nor heat nor gloom of night stays these F355 driver's from the swift completion of..."

I heard BC had a temperature of 47.9C (118F) last year...

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Yes that was in the interior. Lasted about a week. Was insane hot. Especially for us Wet Coaster. We are not use to that kind of weather. About 600 people died from it. Mostly older folks that were already having medical issues. I'm in the air conditioning business too!

 

Sorry, mislabelled that window reactivation switch in my photo. Should be "Sx".

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See wiring diagram here:

https://www.dropbox.com/t/wZtgXvV6Do9ABZpt

 

Is this to the centre of the pivot point as shown?

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In this case, there may be a chance that both rams may be under-extending. Did you check the fluid levels?

 

You could also replace the ram if it is defective. Both rams were replaced (at the dealer) on my F355 spider by the prior owner just before I purchased it...I suspect because the reservoir was allowed to run dry. But I owned the car for ten years and the only thing I ever had serviced on the top was to replace the elastic straps just before I sold it. I checked the fluid and topped it up every two or three years, that was it.

 

Thanks for the confirmation. I haven't pulled one of these rams apart before. I can't think what would cause the problem other than a bent ram (or fluid simply not getting to the ram).

I would certainly try moving the ram with it disconnected from the roof before making a decision. The roof itself may be binding, so switching to a manual roof may not help.

Considering the crazy prices of new RH rams (P/N 64967200), I understand why you would want to go for a manual conversion.

 

I just sent an email to tophydraulics.com to see if a Solenoid Valve Block can cause a problem with one ram not extending fully.

I'm just wondering if it's possible to interchange the pipes going from the Solenoid Valve Block to the secondary actuators to see if the problem switches to the other side.

 

I was surprised to get a response from tophydraulics on a weekend, but Klaus there kindly confirmed there is simply a T inside the valve block which splits the output of the valve into two and feeds the hoses for the left and right secondary actuators. Klaus said that hose blockages were rare and thought that air might be trapped in the system (from a previous leak).

Does the recoil also move the left side back. I'm guessing your elastics aren't strong enough to pull the roof back to the beep trigger point. Note that the secondary rams have fluid on both sides of the piston. I'm wondering if leaky seals on the pistons might put pressure on the wrong side of the rams causing the recoil?

Anyway, I'd try to bleed the system and also see if the right secondary ram is moving freely when detached from the roof.

 

I may be wrong about this. The primary actuators have fluid on both sides of the rams, but it's not clear what is on the other side of the secondary rams. Certainly a leaky seal on either secondary ram would prevent full extension, but I'm not sure about the recoil aspect.

A secondary cylinder rebuild is around U$280. Where are you located?