sker66

Hello All,

I am having an unusual Trunk Hinge issue that i cannot find an answer to at this time.

The symptom is as follows.

Trunk in "Open" position.
When i depress the red lighted button to close the trunk it proceeds to close but instead of pulling the trunk lid (@ Rear Glass) lip down and close against the seals the hydraulic drive Hinge (Passenger side) forces the trunk upward away from the closing position. ( Please see pic attached)

When this happens you can hear the hydraulic pump screaming and sounds like it will burn itself out and or break something in short order.

The only way to stop this incorrect cycle is to quickly open the trunk with the key.
This stops the electric circuit that powers the pump.

I have read the thread here whereby another member had issues with his self closing


system and replaced the powered hinge setup for a manual hinges ( with springs ) that was the manual setup for our cars.

Has anyone heard of my same issue and or solution?

Has anyone changed there auto system to manual hinges?

If not outrageously expensive to fix i would like to attempt repairing the auto close system but considering changing to manual hinges.

TwinTurboTim

Are you sure the hinge has not loosened up? I would check the bolts just inside the lid.

sker66

Yes all is Factory tight. If you look at the pic the hydraulic actuator that turns the shaft to operate the hinge appears to be turning the trunk lid upward and not downward to close the trunk lip toward the seal on the body. Its as if the direction of rotation got itself backwards.

This happens after the trunk closes to the "Latched" position.

Has anyone on this forum experience with the hydraulic actuator positioned in the passenger side rear quarter that drives the hinges to open and close the trunk?

tusabes

http://www.edmunds.com/mercedes-benz/cl-class/2005/long-term-road-test/2005-mercedes-benz-cl65-amg-misaligned-trunk-lid.html

TwinTurboTim

When mine was doing that I just tightened the hinge and it went away. You may think yours is tight but there is so much force with those hydraulics. I have also replaced my pump if you need help with that.

sker66

Thanks for the link but in my case the hydraulics never shut off. I will check into it further and let you all know what i find.

sker66

Thanks Tim for responding.

Check my post above. When your hinge was loose did your hydraulic pump keep running when the trunk closed as in the picture?

My pump starts screaming when the trunk closes and i have to quickly open it with the Key to stop the hydraulic circuit.

I will check again mor thoroughly on the loos hinge.

Do you know if their is some sort of switch placed somewhere so as when the lid seals at the back glass it shuts off the hydraulic circuit?

How much did it cost and labor hours to replace your pump? ( under the battery right?)

I have heard some people have taken out the hydraulics and installed the manual hinges with good results. Have you knowledge of this conversion?

Thanks again Tim.

awiner

Make sure to check the pump for proper oil level as well. These pumps have a habit of running dry as their oil get lost little by little out of deteriorated connections.

When that happens you will lose effectiveness and it will get very noisy.

imantr

Hi sker66,
I am now facing the same issue with you, whereby my trunk pump never shut off. Have you resolve the issue?

Thanks

2014CL600

From what I understand, one of your springs is possibly broken. This causing the unit to over extend the auto trunk closure piston. Remove your inner trunk liner and look to see if the spring is broken or missing. That is what usually causes this issue. The springs tend to fail.

sker66

There are no springs as it has the Auto Actuated Trunk mechanism.

I ended up having a local tech repair the car with a new hinge and reprogramming the latch home position which shuts off the hydraulic drive unit.

All that and a new Latch assembly made it like new and my wallet very thin. Thanks for all your input

2014CL600

There is a spring on the LH side for sure. I thought there was a spring on both sides but from what your telling me this isn't so. I apologize for giving incorrect information.

imantr

Hi Sker66,
Did you replace the hydraulic hinge with the spring? Would you explain more what the tech did with reprogramming latch to the home position?

Thanks

2014CL600

No I really cant explain more, the car was under warranty and if I remember, I walked in the back and watched them fix it. They removed these covers in the trunks liner, where there were hidden springs. One had broken causing the lid to raise up on one corner. I think if I remember the mechanic told me it was a known issue and MB was changing them out with different springs because of a recall. I think I even remember seeing a NTSB bulletin on it at one time.

tusabes

I have a 2000 cl500 without the power trunk , it had springs
My 2002 cl500 with power trunk lid does not have springs , it has gas struts on the lid and the hydraulic ram to raise /lower

2014CL600

You are probably right. I think my 00 didn't have a power deck lid, and I didn't have issues with any of the other ones, as they were power.

imantr

Finally I resolve the issue by changing the relay for opening and closing as attached picture.