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Carl Jensen
Yet to post message
Username: carl_jensen

Post Number: 1
Registered: 2-2005
Posted on Monday, 30 May, 2005 - 05:06 pm:   Edit PostDelete PostView Post/Check IP

I just finished rebuilding the rear height control valves and fast/slow solenoid on my 1976 Shadow LRD20648. I used the new formulation RR363 to flush the system and also cleaned the restrictors.

I had disabled the system about 5 years ago by disconnecting the height control valve arms where they bolt onto the chassis and then positioning these valve arms so they would not activate the rams. The reason I had to deactivate the system was that I had similar rebuilding done by someone else on the rear height control system, but intermittently the left rear ram (or solenoid?) would give a loud knocking noise. This is now happening again following my recent rebuild and what is especially weird is that the knocking happens some when I am driving but also continues for a few minutes after the engine has been shut off. The knocking is loud and can be heard from outside the car around the left-rear ram area and sounds like someone is hitting the car with a hammer.

Has anyone had a similar experience? This knocking can't be good for the system, and I had hoped that by using the new RR363 the knocking would end, but that hasn't happened. Any advice would be greatly appreciated. Thanks!
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David Gore
Moderator
Username: david_gore

Post Number: 466
Registered: 4-2003
Posted on Monday, 30 May, 2005 - 08:24 pm:   Edit PostDelete PostView Post/Check IP

Hi Carl,

My suspicions are that this is being caused by the ram sticking in the bore due to the extended period of inactivity possibly causing some corrosion of the components. The resulting surface damage causes the ram to "hang" in the bore until there is sufficient load on it to break it free causing the metallic knock. This tapping noise was the first clue to the problems with the reformulated RR363 3/4 years ago.

If the corrosion isn't too extensive; it is possible regular use with the current RR363 will polish out the damaged areas giving a gradual reduction in the noise. If the noise is still present after a couple of months use; you may have to remove the rams and rehone the bores/polish the pistons. The corrosion will have been caused by moisture in the stagnant fluid reacting with the highly polished metal surfaces in the ram.
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Carl Jensen
New User
Username: carl_jensen

Post Number: 2
Registered: 2-2005
Posted on Tuesday, 14 June, 2005 - 01:57 pm:   Edit PostDelete PostView Post/Check IP

This sure seems to be a strange problem. I rebuilt the two rear rams (those seal kits are expensive) and also switched the rams from left to right in case something was wrong with the ram on the driver's side. Fortunately I didn't really see any scuffing, etc. on the ram pistons.

The knocking noise is still happening in the left-rear side of the car, and this knocking occurs for a few minutes after the engine has been turned off. I'm not sure if the noise is coming from the ram itself, or perhaps it is from the slow/fast solenoid which is also towards the left-hand side of the car. However, when reinstalling the left-side rebuilt ram it took some doing to re-center the top of the spring assembly (the part that the ram screws into) so that I could reinstall the rebuilt ram. I'm not sure if that has anything to do with the knocking. The top of the right-side spring assembly stayed centered just fine for the ram removal and reinstallation. It just seems strange that even after switching the rams the noise is still coming from the same area.

I have a neat little gizmo that has six microphone-type things that I can attach to various areas of the rear suspension to find where the noise is the loudest. I'll give that a shot and report back to the forum. I'll also try disconnecting the slow/fast solenoid to see if that is causing the knocking. If anyone has additional thoughts it would be appreciated (and thanks to David Gore for already helping out with some suggestions!). Thanks!
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William H. Trovinger II
Prolific User
Username: bill_trovinger

Post Number: 222
Registered: 8-2003
Posted on Tuesday, 14 June, 2005 - 03:59 pm:   Edit PostDelete PostView Post/Check IP

Carl;

I maybe all wet here and if so I hope other will correct me. However, after rebuilding my rams and valve controls the other year I got what I think is the noise you are describing. It never happened before the rebuild only after. It also was after the car had run more than 30 minutes and there had been an increase in load (rear seat passengers or fill of the tank). The clicking (knocking) noise did sound as if it came from the rear left ram and would last a minute or two after that car was turned off. When I went in the boot while the clicking was happening and felt the ram and lines the vibration seemed to be much stronger in the feed line to the ram then the ram it’s self or the bleed line. At the time someone (I do not remember for sure but it was either Bob-UK or Albers) suggested that I should re-bleed the rams. I did this and since then the noise is almost gone, I still get it once in a blue moon but only after the car has been sitting for extended periods.

Best of luck,
Bill T.
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Bill Coburn
Grand Master
Username: bill_coburn

Post Number: 445
Registered: 4-2003
Posted on Tuesday, 14 June, 2005 - 11:05 pm:   Edit PostDelete PostView Post/Check IP

Bleeding these things is a pain. For ram bleeds I have the engine at fast idle, someone to pour fluid in the reservoir as it exhausts, disconnect the height control valve link push it up to activate the rams wait until it is fully extended and then open the bleed screw. When the ram hits the bottom I leave the accumulator to exhaust and then pump for a minute of so and then repeat the procedure about three times. Then I do the other side. Each time I let the accumulator fully charge before opening the bleeder fully open. Expect to use 12 litres of RR363 for a full bleed of both systems!!!
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whunter
Prolific User
Username: whunter

Post Number: 149
Registered: 10-2003
Posted on Wednesday, 15 June, 2005 - 01:56 pm:   Edit PostDelete PostView Post/Check IP

Expect to use 12 litres of RR363 for a full bleed of both systems!!!
This = a large pool if you do not use a bleed line into a vented container.
Safety glasses are needed to keep splash and spray from your eyes, a dust mask will help keep it out of your mouth.
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William H. Trovinger II
Prolific User
Username: bill_trovinger

Post Number: 224
Registered: 8-2003
Posted on Wednesday, 15 June, 2005 - 03:10 pm:   Edit PostDelete PostView Post/Check IP

I have found that running the tube into a 2-liter clear plastic bottle works great. I use duck tape to hold the tube in the neck and punch holes just below the base of the neck for venting.
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bob UK
Unregistered guest
Posted From: 81.168.83.66
Posted on Monday, 10 October, 2005 - 10:50 pm:   Edit PostDelete PostView Post/Check IP

I have seen this posting late.

The knocking noise describe is indeed the rams.

I suspect that what is happening is that because there is air in the system the air compresses and the ram jerks giving more volume of fluid required and the air has to be compressed again.

The rams are differcult to bleed and I am not entirely convinced that my car has no air in the hydraulics somewhere.

(Message approved by david_gore)