| Author | Message | ||
     KC Saayman Frequent User Username: kc_saayman Post Number: 59 Registered: 10-2004 |
Hi all I am busy with a routine service on my car, and want to adjust the height control on the rear hydraulics. To achieve this I taped a string with a little weight onto the wheel arch so that it hangs down the centre of the wheel. I then made a mark on the string in line with the chrome sill trim. The idea is to adjust the height control until the mark is at the centre of the wheel. Well, when I disconnect the little adjustment arm at the ball joint and move the arm, I see no movement. The height control does not seem to work. During the last 12 months or so our local dealer has overhauled both height control valves, as well as one of the rams. Several pipes were also replaced. There are no leaks. Assuming the above-mentioned components are fine, is there anything else I can look at or test before I return the car to the dealer? I did also sit in the boot/trunk and still cannot see the car lift. The car was in neutral which should activate the fast lift function. I’d appreciate your comments. Kind regards KC 1974 Shadow SRH19461 | ||
| bob uk Unregistered guest Posted From: client-86-29-85-190.brig.adsl.tesco.net |
The fast levelling is not fast and movement is barely noticable. The normal mode is even slower. Most think that the fast mode is a gimmick. Measure the ride height load 100 kgs of weight -- a full tank of petrol will do, then drive say one mile and recheck the ride height should be the same as when the tank was empty. Which was one of the reasons RR fitted ride height. Citroen. If the layout of the rear suspension is examined it will be noticed that as the car rises and falls there is no track alteration. The Shadow as it rises and falls the track alters this means that when the car is stationary the tyres are not rolling and are being pulled side ways. Once the tyres roll they move over to the new track dimension. This resists the height correction. The front suspension on Citreon does has track alterations which is why the rear comes up be fore the front. Sometimes the front will stay up longer than the rear and if the car is rolled with engine off ( no hydraulic pressure) the front drops quickly. Citroen are often damaged due to this. The fast mode of the Shadows works like this. When the fast solenoid ( middle of the rear front cross member ) gets 12 volts and an earth it allows fluid to move a spool valve over in the ride height valve which allows fluid to pass through the valve quicker thus lifting the car quicker. What goes wrong The valve in the ride height valve can jam. The solenoid can fail. The signal to the solenoid can not be there ( the 12 volts ) Rolls-Royce have changed the logic behind when the solenoid should operate a few times. Some cars require the car in P or N and the drivers door open ( while he/she opens the door for the passengers ) Some like yours are P or N , same as mine To check connect test light to solenoid and turn ignition on. No pressure required. Mine SRH 17768 1974 is the same as yours I checked mine about 10 years ago and it was not working I had 12 volts so I un-plug it I do nothing since. If you can get it to work with out to much money and trouble then go for it otherwise it really is a gimmick. I find that within half a mile the car has corrected it self anyway. My rear springs are shot so my ride heigth is working all the time . This I think is good for the system because it keeps it working daily rather than once a month when I have a load on. I have an LPG tank as well but LPG is less dense than petrol therefore swings and roundabouts. It is thought that if the ride height is wrong that the drive shafts will vibrate. They will but not for that reason. The proper reason is that the drive shafts are running out of oil ( and they all leak ) EP80/90 gear oil. The level gets low and the angle of the shaft becomes important once the drive shafts are topped then the vibs go. The ride height needs to be say within 1/2 inch of factory specs, so lining up the sill trim is good enough. If the car looks level then it is ok While you are in that area check the rear cross member mounts to inner sill and where the springs sit in the the trailing arms ( inclined was the word I was looking for earlier). and the rebound strap to body mounting (2) ( the tops of which is under the rear seat These are rust spots. If in good condition wax oil the lot. Do not use engine oil because it drips on to the highway and gets washed down drains into streams and kills little animals. If every car owner did that the rivers would die. (Message approved by david_gore) | ||
| KC Saayman Frequent User Username: kc_saayman Post Number: 60 Registered: 10-2004 |
Thanks Bob, I am going to try your empty/full fuel tank test this weekend. I tested the system from cold start-up with the car stationary, so perhaps it needs more time to correct the ride height. Like you I also don’t really care much for the fast-lift function. I think it is an unnecessary over complication of the system. My number 2 brake lights do come on occasionally when I am stationary in traffic, but go out again as soon as the engine revs pick up. Is that an indication that the accumulator needs attention? Would that affect the ride height? I will also do the pedal pump test this weekend. Regards KC | ||
| Paul Yorke Frequent User Username: paul_yorke Post Number: 62 Registered: 6-2006 |
KC, For it to move quickly on fast leveling you will need very good accumulators or/and the car on fast idle. You will need to run the car for 5 mins or so to get all the pressures up to full running pressures. If you start it from cold you can leave the choke fast idle 1/2 on. If from hot, press the fast idle lever down briefly to bring on the fast idle. ( you may need to press the accelerator linkage as well on a Shadow I , stepped fast idle cam. It does not need to be on the FULL cold start idle.) I would check the accumulators first. As well as the pedal test - if you can bleed the accumulators try that - you should get about 1/3 to 1/2 pint of brake fluid without air in it in a fast 'whoosh'. If it has air in it - leave the engine to run for another few minuites and do it again until air free. If the fluid is fairly new and clean you can let it settle and reuse it. If in doubt use new fluid. The level will fall quickly in the reservoir, so keep a good watch on it! For fast leveling to work you need this 1/2 pint reserve to 'instantly' fill the rams. Otherwise it will just raise at the speed the hydraulic pumps can supply the fluid. Have the flex hoses from the HCV's to the body been replaced. These suffer 'hardening of the arteries' like the brake hoses and restrict the fluid going into the rams. Regards, Paul. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1281 Registered: 4-2003 |
Something is missing here. At least on our '72, you need the door open to activate the fast levelling, and that is with the ignition key in any position. When you open the drivers' door, you hear a click from the solenoid valve as the interior lamps come on (hint: does the door lamp work ?). The levelling then responds instantly if you fiddle the height levers (which should never need adjusting by the way), at a rate, which would embarrass a high-rise elevator. Ours never needs the levelling as the steel springs are in good shape, so I disconnect the levers at major services and give the rams some exercise. It goes up and down like a yo-yo on fast levelling but is as slow as the QE2 docking at Circular Quay in slow mode. Do check that the fast mode is activated before panicking. | ||
| KC Saayman Frequent User Username: kc_saayman Post Number: 62 Registered: 10-2004 |
Report back: When I tested the height control the fuel tank was about a quarter full, and I had the gearbox in Park with the driver’s door closed. Also, I tested from a cold start. I should have driven the car for a few miles first (Thanks Paul) I followed Bob’s advice and drove the car to fill the tank. With a full tank of fuel and a few miles driving the car still sat too low. I adjusted the linkages, left the gearbox in neutral, left the driver’s door open, and revved it a bit. Within a minute or so the car was sitting with its rear end up in the sky! So, what did the trick? My car is a 1974 model, so the fast leveling should work by selecting either Park or Neutral, but perhaps it is still wired up like earlier Shadows and works off the driver’s door? (Thanks Richard) The extra weight from the full fuel tank probably helped because the car was now noticeably sitting low, so any adjustment would be noticed (Thanks Bob) I now have it leveling out about 1cm higher than it should. The chrome sill trim is just off wheel centre, a little higher. Is this OK, or is it bad? Regards KC | ||
| Paul Yorke Frequent User Username: paul_yorke Post Number: 64 Registered: 6-2006 |
Hello KC Did you check the reserve pressure in the accumulators? Having it slightly higher will not cause any problems as long as the rams are not over extending. This shouldn't happen unless your springs are really really soft or you start jumping over ramps Evil Kenevil fashion!  Listen our for any strange noises. | ||
| KC Saayman Frequent User Username: kc_saayman Post Number: 63 Registered: 10-2004 |
Hi Paul I have not yet checked the reserve pressure in the accumulators, but it’s on my list. I will continue with the service next weekend. I do this for fun, so I pace myself  Regards KC | ||
| bob UK Unregistered guest Posted From: client-86-29-84-111.brig.adsl.tesco.net |
The little bit too high should not cause problems. This could settle to bit when you drive a bit more. As I said exercising the ride heigh on a every run basis is good for the system. If springs are weak then rubber towing assistors can be fitted -- works better than one would think--- and cheap at £10 a pair To check the reserve pressure start engine light out switch off and pump any less than 30 and you need to recharge soon. less than 20 recharge NOW. because that system (No2) drives the ride height which uses up more quantity of DOT oil than many applications of the brake meaning that the should the engine stall the reserve could be used up quick time. Shadows do not have priority valves. My car 90 pumps on No 2 and 100 plus on No1 which is about right, for a good system. I prefer to fit Fully recon spheres. A lad at a garage called the french car co once tried to charge a Citreon sphere while fitted to the car. The diaphragm was split and also the pressure relief valve was damaged. The car was in for many hydraulic faults which after the event turned out to be the valve. The event was that the LHM was blown out of the tank by nitrogen. It went every where it was dripping off the roof. Lucky it was not DOT. Shadows have piant stripper for fluid.!! (Message approved by david_gore) | ||
| Bill Coburn Moderator Username: bill_coburn Post Number: 919 Registered: 4-2003 |
For what it is worth Bob, I recharge accumulators on Shadow I's in situ. First remove the charging cap and gouge out the plastic sealing ball. If there is brake fluid there the diaphragm has punctured and you return to where you started without collecting $200! If there is no fluid, exhaust the accumulators either via the bleed nipple or pumping then screw on the charging hose and gently give the things they crave most - dry nitrogen. Do it gently lest you blow the charging valve retaining circlip out of its groove. I take the pressure to a bit over the 1000 psi since there is always a bit of a leak and it gives you time to drop the cap the sealing ball, swear etc. Before you start put the danger signs and wave washers over the valve and have the sealing ball with a bit of vaseline and the little 'O' ring if you are using it, handy! The diaphragms I have found are about as predictable as the weather. Some last 2 years but the record I have had was 11 years. When they first started making the diaphragms they had trouble with aeration - probably too much yeast in the brew!!!! | ||
| bob uk Unregistered guest Posted From: client-81-108-181-227.brig.adsl.tesco.net |
My spheres were changed in 1993 so They have held well. (Message approved by david_gore) | ||
| Gus Brogden Experienced User Username: gus Post Number: 50 Registered: 2-2008 |
I use dry nitrogen in my refrigeration business. I found a regulator in the pile that's capable of delivering 5000 psi and silver brazed a fitting so it will screw onto my nitrogen tank. A quick trip to my local hydraulics expert, and he built a hose for me that connects my regulator to the accumulators. I had SRX2838 charged to 1000 in minutes. One side took very little, the other was at 300 psi and took a bit more. I now have 100+ pumps before they light up. It's probably the best decision I ever made in a tool. I'm just not looking forward to charging the SS II, it looks like a daunting task. | ||
| Dr. Omar M. Shams Experienced User Username: omar Post Number: 17 Registered: 4-2009 |
I have never been too happy with the Rolls-Royce design one-way-valve arrangement for introducing nitrogen into the spheres. I have modified my spheres to take 5000psi check valves from a Williams High pressure injection pump. My accumulators do not leak since this modification. |
