| Author | Message | ||
     gordon le feuvre Frequent User Username: triumph Post Number: 84 Registered: 7-2012 |
Have '86 Corniche DHC with only 9000 miles on. When closing hood, after it passes vertical it "slams" onto header rail really hard with no damping action. The motor/pump was made by company called Smiths Industries in UK. This has now passed to their former agent Fluidlink, who are struggling to find diagnostic info. The w/shop manual does not say much either, Anyone got any experience of this please? | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1628 Registered: 6-2009 |
Gordon, This isn't Corniche specific, but is based on my experience with the convertibles I've owned. Does the top system have cables and pulleys? I seem to recall on my cars that after the top "reached peak" and was on it's way downward under its own weight that it was this feature that prevented "slam down" and the hydraulics began pushing against this seemingly spring-loaded system to do the final lowering and stretching of the top. If the Corniche has similar and something has caused that system (or whatever system performs the same function) to fail to provide resistance you'd almost certainly have a complete lack of damping on the final phase of the lowering process. Brian | ||
| David Gore Moderator Username: david_gore Post Number: 1730 Registered: 4-2003 |
The hood on DRH14434 would close quickly once it passed over its centre of gravity during the closing process but the rate was not one that caused the hood to "slam down". I never had a reason to play with the hood mechanism however my assumption would be the hood mass provides back pressure to the pump once it is "over centre" to counter the pump pressure pushing the hood closed. This would cushion the hood as it came down under its own weight rather than being assisted by the pump. | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 462 Registered: 5-2015 |
The rams are double acting. This meams that when gravity takes over the mass of the hood will try to speed up the flow of oil from the ram. You fault suggests that there may be air or low fluid level. Like all reservoirs they develop sludge. I suggest a clean out and new fluid. I have never worked on this system so can you post photos of the bits. | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 108 Registered: 9-2013 |
Gordon, Mine does the same. I got into the habit of holding out my left hand (mine is an LHD), and catch the hood that way. As we are talking about the hood, the 2 hooks that hold it closed are VW hardware, some 60EUR and not 600 as some dealers post on their website. Cheers, JP | ||
| gordon le feuvre Frequent User Username: triumph Post Number: 86 Registered: 7-2012 |
Thanks for pointers and thank you Brian. The mechanism does not have any springs/bowden cables. have found hood info on Shadow manual and whilst the pump/motor/valves look different ( as if Mk2 model) am hoping principals are the same. Will investigate and report findings. | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 116 Registered: 9-2013 |
Thinking of it, did the Corniches really leave the factory with ''slamming'' hoods? Me think not. And why do all Corniches I've came across for now exhibit this brutal behaviour? Gordon, please share your findings! | ||
| Lluís Gimeno-Fabra Grand Master Username: lluís Post Number: 400 Registered: 8-2007 |
Silly question but can it be air in the system? I am just thinking that it is expansible as well as compressible, hence the possible cause when changing from push to pull? | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 117 Registered: 9-2013 |
Good thinking Lluis! The workshop manual says nothing, zero, zilch, nada about the pump and its operation. I assume the system is self-bleeding as the fluid reservoir cap has air vent louvers. |
