| Author | Message | ||
     davide frada Experienced User Username: davidef Post Number: 20 Registered: 11-2008 |
Hello, Following a few months of reliable, exceedingly pleasant use, I thought it prudent to put the Shadow back on the hoist and attend to a few issues - power steering hoses, pads, belts, and a few other bits and pieces. One of the items on the list is finally sorting out the height control. In order to diagnose an ongoing issue with the rear circuit, I blocked off the height control, if only to confirm the proper operation of the accumulator valve/brakes and so forth. It would appear that the ride levelling system is bypassing, not allowing the circuit to pressurise. I referred to the wwtechnical online manuals, however, they are relevant to cars with front levelling, fitted with thee fluid lines, unlike mine, which has only two. The solenoid valve operates when the ignition is switched on, in neutral. Are the control valves known to bypass? Regards d | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 364 Registered: 6-2006 |
Hello Davide, It is possible that either a pipe has been fitted incorrectly or something has been left out of, or fitted wrongly in the HCV. Maybe the shadow II manual may help, Mine's in black and white though - so not ideal  | ||
| Nigel Johnson New User Username: nigel_johnson Post Number: 7 Registered: 12-2008 |
Davide, have you tried disconnecting the HLV arms and pushing them up. Perhaps the flexible hoses are blocked. My apologies if this is obvious to you. Regards, Nigel. | ||
| Nigel Johnson New User Username: nigel_johnson Post Number: 8 Registered: 12-2008 |
Sorry, HCV. | ||
| billy UK Unregistered guest Posted From: 86.0.218.85 |
Don't forget the lovely hydraulics animation (upload too big I'm afraid) (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 893 Registered: 4-2003 |
The simulation may be downloaded from the following website: www.samag.no/silvershadow/index.htm It is a very useful aid for anyone with a Shadow. | ||
| davide frada Experienced User Username: davidef Post Number: 21 Registered: 11-2008 |
Hello again, thanks for the replies... i've had another play and have found the following - if i block the ride level return, the system will pressurise and the dash light will extinguish. as the right valve had a leak from the oring around a fluid inlet (which i replaced), i thought perhaps there might be a further fault in that valve. i blocked off that valve's return and fast level port, but the situation didn't change. can failure of a restrictor valve cause this sort of fault? when the solenoid operates, is it designed so that one port supplies pressure to the valves (fast level port), and the other counteracts the return pressure, via the restrictor, thus aiding fast rise? if failure of a restrictor valve won't prevent the system from pressurising, i must therefore have narrowed it down to the left control valve... unfortunately this is all made quite difficult as the colour coding is long gone, and it is quite difficult to follow the lines. ! | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 369 Registered: 6-2006 |
Davide, Blocking the return hose will make that o'ring (fluid return) fail, or if you are unlucky and the the o'ring is good but the valve corroded - will push the circlip and end of the HCV off. The 3 high pressure HCV outlets are screwed in, the return is an o'ring a circlip designed for very low pressure. Did you download Nord's circuit above? - more helpful than the book diagram. To isolate the slow leveling restrictor and see if the fluid is bleeding straight off to the reservoir, you need to block the slow levelling restrictor at the solenoid valve, or restrictor.(usually the restrictors block – but somebody may have left a part out) If that doesn't stop the fluid returning, you then need to isolate each HCV and block the high pressure feed to each valve one at a time. (you can do it any any order. Listen to the feed pipes to the valves and the one from the solenoid valve with a stethoscope - you may be lucky enough to hear the fluid passing through.) | ||
| davide frada Experienced User Username: davidef Post Number: 22 Registered: 11-2008 |
hi Paul some background - i purchased the car with brake failure. it was in regular use, but was parked when the brakes failed. i don't think the previous owner took any steps to resolve the issue, so it seems a safe bet there are no mislaid pipes. i isolated the soleniod with some bleed screws - no change. running out of ideas, i once again clamped the return, watched the light extinguish, pushed up the control valve rods, and opened a bleed screw - there was a small spurt of fluid, then just a few drips. leaving the screw open and manipulating the rod makes no difference - with either valve. this seems to point to valve failure. it seems strange both should fail, and both look as if they had been the subject of rebuild not too long ago. with the return clamped, fluid does not spill from the valve's fast level port. what are your thoughts? | ||
| davide frada Experienced User Username: davidef Post Number: 23 Registered: 11-2008 |
worth noting that the leaky return oring was resolved just after purchase - first step was to fill the system to help find the source of leakage... and this was one problem area. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 370 Registered: 6-2006 |
Davide, "i isolated the solenoid with some bleed screws - no change. " PLURAL? What ports did you isolate? Did the light go out when it was isolated? I think Really you should only block the slow level line. which is, I think, the bottom one. (It's been a while since I've had to do one) If that doesn't do anything, You will then need to block the High pressure feed to each valve one at a time. Perhaps the feed pipe and return pipes have been "short circuited" at some point by two pipes being swapped. First you really must ISOLATE the valves individually though. It is possible that both valves have somehow failed or been stripped and re-assembled incorrectly at some point. Good luck on this confusing system! | ||
| Nigel Johnson Experienced User Username: nigel_johnson Post Number: 13 Registered: 12-2008 |
Hi Davide,I would strip and clean the restrictor. The holes in the tiny plates get blocked with gunge carried round in the brake fluid. Regards, Nigel. | ||
| davide frada Experienced User Username: davidef Post Number: 24 Registered: 11-2008 |
hello again, some success! having exhausted all other possibilities, i removed and stripped a valve to find that the slow and output valve assemblies had been reversed. i went ahead and stripped the other, which was also assembled incorrectly. the car now has working height control for the first time in goodness knows how many years. it would seem, then, that a problem cropped up in the height control system, the previous owner went to the trouble of having the valves rebuilt, and in the process, made the car undriveable, forcing its retirement.... it seems firmer in the rear than it was, which is somewhat unexpected. at times, the height control can be noisy in operation but i am hoping it will quieten as it all comes to life. it also seems to have introduced a clunk somewhere in the rear which will require further investigation. thanks for all the help - what a wonderful resource. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1839 Registered: 4-2003 |
<<<<<<<<<<<<<<<<<<<<<<<<<< the slow and output valve assemblies had been reversed jjjjjjjjjjjjjjjjjjjjjjjjjjjj the previous owner went to the trouble of having the valves rebuilt, and in the process, made the car undriveable, forcing its retirement <<<<<<<<<<<<<<<<<<<<<<<<<< Pass me a meataxe. Was he in Disneyland, on Viagra or what ? | ||
| davide frada Experienced User Username: davidef Post Number: 25 Registered: 11-2008 |
the effect of mindset - setting oneself up for failure - is powerful. if a mechanic thinks it is just horrible unreliable old pommy garbage, the car will probably live up to his views, no matter his talent. personally, i don't know how anyone with an eye for these things could be anything but impressed by the quality and precision of these valves. re clunks: inspection today revealed two disintegrated horizontal compliance bushes... does anyone know the original length of these bushes? |
