Brooklands hood

[bnwood]

The electric mechanism has failed. The light flashes by the hand brake but no sound from the pumps motor. When trying to raise it manually the top comes up ok but the rear does not come up far enough for the tonneau to clear it. The rams for this seemed stuck but on diconnecting these they were quite free. The fault seems to be that the rear section has folded too far, over centre and jammed. I have with the help of my son tried to force the rear down but no joy. I have noticed that two screw headed bolts, which the hood pivots on have come adrift on one side so the whole hood off to get at these.
   a.Has anyone had a similar problem? What was the remedy?
   b.What oil is used in the hydraulic reservoir? There is a layer of gunge in the bottom, so will clean out and refill.
   c.Is there a fuse anywhere for the hood motor?
   d.a wiring diagram would be useful. no mention of a hood in either of the fuse boxes.
   e.Did Karmann have anything to do with the design and manufacture.

[bobbylangley]

Try Neil Fisher at Redline Engineering, Woking area

[Max Allan]

I've been in Spain for past 3 weeks [8D] and only just read your post. Have you fixed the hood problems or are you still seeking help?
   
   The hood must be raised manually lifting the whole assembly via the bottom hoop. Attempting to raise by lifting the two upper hoops will cause the mechanism to jam.
   
   The pump is protected by a 30amp fuse located behind the left hand boot trim alongside the battery.
   
   The hoods were purpose made by a company in Germany.
   
   Let me know if you need more assistance as many hours spent last year perswading the hood I acquired close into a well 1 inch shallower than the norm has left me with a fair knowledge of how the mechanism work. I also have the hood wiring diagram, although in true AC tradition the actual wiring does not altogether tally with the diagram and the diagram is not colour coded. [:(!]

[bnwood]

Thanks for that Max. I've been busy but have managed to get the hood up again. Now when I use the button to lower the hood the rear rises up and sometimes the tonneau release releases. Then nothing. There is obviously a switch not letting the electrics know how far it has got and letting it proceed to the next sequence. I will try and check the various connections to the micro switches to see whether I have not forgotten to reconnect one. I hope it is that easy! I read somewhere that the switches are on the right hand side. There seems to be back pressure in the rams that lift the tonneau now. This prevents me from lifting it manually. I have not tried any force yet.

[Max Allan]

The only external micro switch is on the R/H horizontal strut leading forward to the screen rail. It prevents inadvertent operation of the hood while it's still locked to the screen rail. The switches that initiate each step opening or closing hood are located internally in the two right hand rams. It is unlikely they are faulty.
   
   There is a pressure release valve in the hydraulics that keeps the system pressurized during hood operation. It opens to release the pressure when the tonneau cover locks shut or when the ignition is turned "OFF". With the ignition "OFF" you should be able to manually raise or lower hood albeit against the resistance of oil through the rams.
   
   Have you got the loose pivot screws back in place?

[bnwood]

Hood now working perfectly,fingers crossed,two top ups to the reservoir after several up and down sequences allowed the system to complete the cycle.Having cleaned the reservoir out, ie disconnecting from the car to do it,air got into the pipes and rams which took a while to purge.
   The door locks are now playing up.I couldn't unlock with either the key or the Sigma widget.I had locked with the key but pressed the sigma widget to unlock. Ten minutes of pressing and turning the key in both locks got nowhere even though the sound effects suggested it was unlocking, when suddenly the door opened for no apparent reason.