Roof not working - roof motor changed. Stops halfway

[ph001]

It doesn't stack up to an RCH related issue though - the pump is still clearly running when the roof is halfway up and continues running with no further roof movement. Ultimately that can only be no hydraulic pressure in the rams for some obscure reason. Got me stumped.

Maybe some kind of airlock somewhere??? Kinked hose?? I appreciate that the system is supposed to self bleed when you open and close it a few times but maybe it's not for some reason.

 

[Smartbear]

I’m thinking slave cylinders (rams) on the roof mechanism could be letting by?
Rob

 

[Strayker270]

Just to confirm; when you changed the motor, you wrote 'new ZHM oil'.
Really stupid question no doubt, but did you put the right amount in?

Yes. I've topped up several times (3-4 times) until the hydraulic fluid was stopped being taken from the reservoir.

Maybe some kind of airlock somewhere??? Kinked hose?? I appreciate that the system is supposed to self bleed when you open and close it a few times but maybe it's not for some reason.

Checked and didn't noticed any kinked hoses.
Pump should have enough power to force the hydraulic fluid thru the hoses into the hinges but the airlock seems likely. Any idea how to check it? Maybe try to unhook hoses on the hinges? Tought job to do tbh

I’m thinking slave cylinders (rams) on the roof mechanism could be letting by?
Rob

You talking about those inside hinges?
Does this mean i have to remove the whole roof completely??

 

[Smartbear]

Just to confirm; when you changed the motor, you wrote 'new ZHM oil'.
Really stupid question no doubt, but did you put the right amount in?

Yes. I've topped up several times (3-4 times) until the hydraulic fluid was stopped being taken from the reservoir.

Maybe some kind of airlock somewhere??? Kinked hose?? I appreciate that the system is supposed to self bleed when you open and close it a few times but maybe it's not for some reason.

Checked and didn't noticed any kinked hoses.
Pump should have enough power to force the hydraulic fluid thru the hoses into the hinges but the airlock seems likely. Any idea how to check it? Maybe try to unhook hoses on the hinges? Tought job to do tbh

I’m thinking slave cylinders (rams) on the roof mechanism could be letting by?
Rob

You talking about those inside hinges?
Does this mean i have to remove the whole roof completely??

If they’re the root cause, yes. There’s people on here who know more about the roof mechanism then me, so I’d wait for more ideas before you dive in on my suggestion
Rob

 

[ph001]

Have a look at this video around 5:10. The guy talks about replacing the seals on the hydraulic rams.... I wonder if this could be your problem?

https://youtu.be/y3dTm8iL5OQ

 

[Strayker270]

Have a look at this video around 5:10. The guy talks about replacing the seals on the hydraulic rams.... I wonder if this could be your problem?

https://youtu.be/y3dTm8iL5OQ

He's just saying that there is a company that can change the seals on both rams for $400.00


So....
Today I took the roof completely off the Z. Alone. It turns out that you can remove soft top just by yourself. Most difficult part of the whole process was to put it back.
Checked the hinges, no leaks. Took the hoses off and all 4 had hydraulic fluid inside.
Roof still behave same. It's going up and suddenly just like someone released the pressure and roof going down with gravity.
I think I'm going to leave it as it is becaouse I don't have any more ideas what to do . Some pictures from today.

 

[ph001]

I think it could be the seals inside those black hydraulic rams in your pic.

 

[Davz]

I think it could be the seals inside those black hydraulic rams in your pic.

If the seals had gone there would be hydraulic fluid leaking but they look dry. If it wasn't for lockdown you could have taken them for testing.

 

[enuff_zed]

I think it could be the seals inside those black hydraulic rams in your pic.

If the seals had gone there would be hydraulic fluid leaking but they look dry. If it wasn't for lockdown you could have taken them for testing.

No I think you're missing the point. The internal seal that separates the two sides of the piston may have failed. So the correct amount of fluid is still present, but when the going gets tough it sneaks round to the other side of the piston without moving it.

 

[ph001]

^^^^^this

 

[Davz]

The internal seal that separates the two sides of the piston may have failed.

I had thought of that but considered that the very little use the cyclinders get and that PU is 8 times harder wearing than steel they wouldn't have worn out...... If it is that (I reckon your spot on), then it must be age related or I wonder if some seals have had a poor additive mix, not many seem to have failed? I assumed that smartbear thought the rod had been contaminated with dirt/corrosion and allowing oil to seep when under pressure. I don't think the system is all that good, it does suffer from drift.
Me thinks this is going to be expensive for the OP, is it possible to unscrew the cap from the cylinder tube and replace all the seals, assuming a kit is available?

OP, I have a guide that I downloaded when I was doing my softtop (can't remember where from) It explains how to replace the cylinders step by step with images, looks straight forward, thankfully I didn't need it! Its a PDF document, which won't attach, not sure if it will attach to a PM I haven't tried. PM me if you want the guide.

 

[Strayker270]

Davz yeah mate you can send it.
Changing whole rams it’s not that complicated tbh. Haven’t seen repair kit for cylinders and I’m assuming that you can’t fix them by just unscrewing top of it, take all internal pats out replace and score it back.

I’ll try again on weekend to take the roof out and check the cylinders and all wires/cables.

 

[Jas- USA]

I think it could be the seals inside those black hydraulic rams in your pic.

If the seals had gone there would be hydraulic fluid leaking but they look dry. If it wasn't for lockdown you could have taken them for testing.

No I think you're missing the point. The internal seal that separates the two sides of the piston may have failed. So the correct amount of fluid is still present, but when the going gets tough it sneaks round to the other side of the piston without moving it.

The above advise is 100% correct. The original poster posted a youtube video where his top failed to drop correctly with new motor/pump. The OP did not install the emergency by-pass. Without the emergency by-pass engaged the top should have been very, very difficult to push down. Instead it simply fell down as if empty of fluid. The reason is because the rubber seals are shot in at least one or both hinge lifters. There's simply no back-pressure which hinge lifters with good seals will cause.

I know there are two outfits here in the States that rebuild lifters (are they open …..or will they survive financially after this is over is anyone's guess). Anyway, I hope there a outfit in the UK which rebuilds Hinge lifters.

 

[Strayker270]

Just an update:
My roof works again!
Changed the ram on the driver side and it’s alive again.
So happy now!
Thank you guys for all the ideas

 

[ph001]

Bingo!

 

[enuff_zed]

Excellent news.
I think there was another similar question by someone earlier this week so let's hope this info helps them too.

 

[05_3.0i_zoom]

Just an update:
My roof works again!
Changed the ram on the driver side and it’s alive again.
So happy now!
Thank you guys for all the ideas

Hi, I would like to know where did you purchase the Ram from? Tia