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-   -   Back edge of top hits legs on underside of cover on open (http://forum.e46fanatics.com/showthread.php?t=884247)

wes2952 11-05-2011 09:55 AM

Back edge of top hits legs on underside of cover on open
1 Attachment(s)
I have an intermittant problem when I open the top. Occasionally the back edge of the top snags on what I guess are support legs on the underside of the storage compartment lid. It seems like the hydrallic system looses a little pressure causing the lid to shift slightly forward right as the back edge reaches the support legs. The were foot extensions on the bottom of the legs that I removed to get additional clearance but still can get a snag. I now only open the top up with the key so that I can manually hold the lid back in case in sags downward. Any thoughts on what maybe be causing this. One Indy BMW repair shop thought that I would have to replace the hydrallic pump.

Pic Attached. The camera angle in this shot makes it look like the edge will hit the leg. But this time the lid did not droop and there was adequate clearance.

adamwu 11-05-2011 01:27 PM

I too experience the same problem occasionally but not as bad... It'll hit the rubber stoppers and then the deck lid will adjust and it'll close...

I'm unsure on the cause of the problem as it only happens occasionally...

R1200RT 11-05-2011 01:44 PM

Did the BMW indy check to make sure you had the proper amount of hydraulic fluid in the unit?

wes2952 11-05-2011 02:48 PM

It was a while back so I don't remember that it was specifically checked. But checking the fluid level is a good recommendation. I just downloaded info on how to do that today and will take a look at it tomorrow.


wes2952 11-05-2011 04:27 PM

I decided to check the fluid level today. Looks OK. At $1,000 for a new hydraulic pump, I can continue to stand outside, use the key and make sure the lid stays high enough for the edge to clear. Funny though that the top has never hung up when I am closing it.

R1200RT 11-06-2011 07:29 AM

You might want to lube all the pivot points on the roof and cover to see if that helps the operation.

I would be standing outside and assisting as well for $1000.

gbakerkingston 11-08-2011 04:45 PM

If indeed it is your pump, check ebay for used parts. Here is a link....


I purchased from this vendor. All went well... Make him a cash offer.... Lots of self help for install on the net. Make sure your vert functions as you expect it should....

If you can manually open lid completely, and it clears the roof, it sounds like your hydraulic cylinders that power the lid are getting weak and not fully opening the lid. Given your vehicle is 10 years old, the seals on the hydraulic cylinders could be wearing out. If this is the case, they need to be replaced or remanufactured. See http://www.tophydraulicsinc.com/index.html I've just sent two of mine to Klaus for repair under recommendation from another Forum contributor. Always replace in pairs....

Here's another resource for diagnostics.


Hope this helps.....

jimboe46 11-12-2011 09:43 AM

I got a used pump from Bavarian Auto Recycling on the web at www.bmrparts.com The total with shipping was $400. If your pump continues to weaken, you will eventually be using your own hands to do most of the work required to put the top up-or-down. My mechanic charged $45 to replace the pump.

S54B32YYC 01-14-2012 10:18 PM

Hey Op,

did you ever get a resolution to this problem? I have the same issue with my top and would like to see if it was low hydraulic fluid level or if it was the pump?


gbakerkingston 12-13-2012 05:55 PM


Anybody have insight into this issue? The roof of my vert has recently started to touch the lid as noted. Any solutions out there?

taylor192 12-13-2012 05:58 PM

It is really easy to check you pump fluid level. Start there.

wes2952 12-14-2012 08:39 AM

On my car the fluid level checked out OK. The fluid level needs to checked with the top down and fully stowed. Resivor is located in the trunk, driver's side. Need to open up the lining to get at it. What I ended up doing is removing the feet on the top supports to give more clearance. When I open the top I use the key in the driver's side and manually prop up the lid with my right hand to insure that the lid stays up and does not snag the top edge as it lowers into the boot. A patch I know, but never did find out the source of the underlying problem.

gbakerkingston 12-14-2012 08:38 PM

Your post is over a year old, with no forum readers affirmation of cause. Sure would be nice to have validation of cause, and a proven solution. One more time around the block...... Anybody out there offering an experienced satisfactory repair?

socks210 12-18-2012 05:43 PM

convertible storage compartment lid adjustment.
Hi Guys.. You can adjust how "far" or "high" the storage compartment lid opens by the following... Open the trunk and pull the left side rear lining back - in the area where the antenna comes thru the body. Look in that area and you will see a bracket holding a hydraulic cylinder. That bracket is adjustable... moves front to rear. Loosen the 3 (2?) bolts and slide the bracket I believe to the rear a 1/4" or so.. tighten and try the top. It's been a few months since I adjusted mine so it might be move to the front... anyway by adjusting that bracket front to rear adjusts how far up or back the storage compartment lid opens.

gbakerkingston 12-18-2012 06:32 PM

^^^^. Thanks! You're the best! I'll give it a go.

socks210 12-19-2012 03:06 PM

alright, let me know how it works out for you. I came across this adjustment by accident a while back...I completely dropped that bracket to have room to remove and replace the antenna base ( I replaced the antenna base and installed a short sport antenna) After it was all back together the top would hang up the those 2 lid foot pad things. I went back and realize that bracket wasn't in the same place ( front to rear). I think there is a hall sensor attached to that bracket that moves with the bracket that senses the hydraulic cylinder shaft position or something.

jjrichar 07-22-2013 10:53 PM

I have the same problem that is described above. My problem only occurs once in about every 20 times I lower the roof, but itís a problem that I want to address so it doesnít break anything. The PDF that has the link above is a great reference for the roof, and I used this extensively for my research, as well as much playing with the roof.

Below are my conclusions on why the problem occurs, and a possible solution. But first some background information on how the system works.

The storage cover is opened and closed by hydraulics. If you look at the hydraulic diagrams below, you will see that whenever the pump is pumping, hydraulic fluid is ported to the lowering side of the storage cover cylinders. This occurs at all times the pump is on, and when power is not applied to the storage cover solenoid.




When power is applied to the solenoid, fluid is ported to open the storage cover. Note that fluid is still ported to the side of the piston to close the cover, but due to the difference in area on each side of the piston, the overall force is to open the cover. For this reason, there isnít loads of force to open the cover, just the difference in force due to the difference in piston area. This force remains to keep trying to open the cover until the solenoid has the power removed, and then the flow is reversed to close the cover.

Additionally, there is a Hall sensor that detects when the storage cover is open. For those who are unaware, a Hall sensor is one that detects a change in magnetic field, and they are used all over the car (engine, transmissionÖÖeverywhere). In this case, the sensor is attached to the left hydraulic cylinder, and detects when the cylinder is near full extension, and sends a signal to the convertible control module to say the storage cover is open. Itís important to understand that this doesnít turn of the hydraulic fluid that is still being ported to the opening side of the cylinder. Even when the Hall sensor detects the storage cover is open, fluid is still being ported to the cylinder to push it open as hard as it can. The Hall sensor is there just to indicate when the cover is open so that other roof components can now start to move.

Now letís look at the opening sequence. After the storage cover has opened (tension bow has already raised), and the Hall sensor has sent its signal to say the cover is open, the convertible module now activates a tension bow solenoid to lower the tension bow. At this time, the hydraulic power is still being ported to the cover cylinders to keep the cover open. Simply, the pump is trying to hold the cover up as well as lower the tension bow at the same time.

Iíve noticed when the problem occurs on my car, the cover initially opens to the correct position, but when the tension bow initially starts to move down, the cover closes a small amount, creating the confliction. My hypothesis is that due to the extra load on the system when the tension bow is lowered, the pressure is not enough to hold the cover fully open, and it sags down a bit.

Why? I donít know exactly. There could be loads of reasons, and without extensive testing, you wouldnít really know. Some reasons could be internal piston seals leaking slightly, the pump motor not turning as fast as it used to, the pump not being as efficient as it once was, low voltage going to the pump, or the pressure regulating valve in pump not keeping the correct pressure. Who knows?

So why does it sag back? If you look under the storage cover, you will see the arms that raise the cover rest on a rubber stop. This stop is a progressive stop, not a solid one. It acts like a spring that is trying to close the cover a bit when itís fully open. When the cover is open the hydraulics are constantly pushing against this stop. The more hydraulic force, the more the cover opens (albeit slightly). If there is less hydraulic pressure, the cover will not open as much.


I believe that reducing the pressure applied by this stop is key to ensuring the cover stays completely open. My solution, I removed each stop and cut out the wedge middle piece with a sharp chisel to allow the stop to compress more. If the stop is still applying too much pressure, I can gradually remove more and more of it so that it stays in the correct position.

With regard to the comments above about moving the bracket that holds the cylinders, I initially tried this a while back and it didnít make any difference. Moving the brackets will only make a difference if the maximum movement of the cylinder piston isnít enough to get the cover fully open. Unless the bracket has actually moved, or something has been bent, the maximum movement of the piston is ample to get the cover all the way open.

Cayne23 06-11-2015 07:57 PM

Well i moved the bracket towards the rear. It made the problem way worse. So i moved it towards the front as far as i could. I was only able to move the bracket back to the original position. Same problem.
So when im opening the top, i stop it right before the top hits the rubber feet. If i then start to close the top, i see the tonneau cover raise up about half an inch. Then i start to open the top and there is no contact
I have already cut the rubber feet that are above the arms for the tonneau cover. Last year that helped, but this year i have a problem. So now i have trimmed of some rubber from the rubber feet on the end of the legs. The rubber feet just pop out. I wonder if they can just be removed all together, but they probably rest on the soft top when its in the storage compartment.
So now, no contact.
Probably my pump is going out.

FFWD 03-08-2016 06:12 PM

Anyone ever figure this out after all this time?

Cayne23 03-08-2016 06:23 PM

Well like i said. If i let go of the open button for a second and then hold it down, the tonneau cover will go up just a bit more. Enought that the top clears it. I think 5his is a sign of the pump wearing out. I think it loses hydraulic pressure during the opening sequence. And letting the button go for a second and then pushing it again, it gets full pressure again and then it probably loses it again, but by that time the top is folding into the storage compartment

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