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John Rowney
Experienced User
Username: johnrowney

Post Number: 149
Registered: 02-2015
Posted on Tuesday, 20 June, 2023 - 14:33:   Edit PostDelete PostView Post/Check IP

In March when on the trip to Hahndorf for the RROC national rally, I had a significant hydraulic fluid leak from the height control solenoid on my 1978 Corniche DRH32489. To cut a long story short, and 8 litres of RR363 later, I made it back to the Gold Coast. With great difficulty I removed the solenoid and installed a new kit. One of the O-rings was damaged, so this must have been the cause of the leak.
For some reason, DRH32489 has individual bleeders for the height adjusters like earlier Shadow models, rather that the combined bleeder shown in the manual.
I bled the offside system - all good. However, when I bled the nearside system, no fluid would come out.
I then removed both solenoid restrictors and cleaned them, since I thought that a blockage in the very small restrictors could be a problem. There was a little bit of gunk in the restrictors, so I thought I had the solution.

When I put everything back together, I still had the same problem - no fluid coming out of the nearside bleeder.

Before I start pulling everything else to bits, are there any ideas which may save me some time and effort? Working in this system is the most unpleasant experience I have ever had working on a car, and I want to minimise my time getting drenched with RR363.
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John Rowney
Experienced User
Username: johnrowney

Post Number: 154
Registered: 02-2015
Posted on Sunday, 23 July, 2023 - 08:46:   Edit PostDelete PostView Post/Check IP

I spoke to Steve Sparks of NBS Services in Brisbane recently. He told me that I need about 380kg of weight to get the bleeders on both sides working. I had only put 130kg in the boot. I had actually got a little bit of fluid out of the nearside bleeder the first time around, so I reckon that there was never any air in the system and the height control system works well. I am going to call it quits and assume everything is OK
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 835
Registered: 11-2017
Posted on Sunday, 23 July, 2023 - 19:31:   Edit PostDelete PostView Post/Check IP

Restrictors: After cleaning and re-assembly...did you rattle them? If they do not rattle the small discs are not free.
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 842
Registered: 05-2016
Posted on Monday, 24 July, 2023 - 09:10:   Edit PostDelete PostView Post/Check IP

The hydraulic fluid passes through the high-pressure restrictor valve to both height control valves via the solenoid valve. Return fluid from the height control system passes through the low-pressure restrictor valve on its way back to the reservoir. If there was a blockage in the high pressure restrictor valve it would equally hinder bleeding of both rams. A blockage at the low-pressure restrictor valve wouldn't hinder bleeding of either ram. In any event it's no harm that you serviced both restrictors as it's recommended when routine flushing and bleeding is undertaken. I suspect that your bleeding problem might stem from a clogged flexi hose on the HCV that is slow to bleed or an internal leak in that HCV which allows fluid to return to the reservoir before the ram has fully raised. A hydraulic pressure test gauge reading from both HCVs for comparison purposes would verify if there is a difference in fluid output pressure from each HCV to each ram. Without a pressure test gauge it's only guesswork. Another possibility is that the control levers on the HCVs have been fixed at different settings and as a result one activates before the other.
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John Rowney
Experienced User
Username: johnrowney

Post Number: 155
Registered: 02-2015
Posted on Monday, 24 July, 2023 - 14:13:   Edit PostDelete PostView Post/Check IP

Robert: Many thanks. I didn't try to rattle the restrictors. What an oversight! I just thought everything was cleaned nicely. Maybe one of these days I will do it again - not something I would look forward to, however.

Larry: Many thanks for your comments. I have printed off the responses from you and Robert and I have inserted the comments in my manual. When I get the inclination to cover myself in hydraulic fluid again, I will have your valuable suggestions to work with.

To be perfectly frank, I am hoping that the next time I can get a real mechanic to look at the Corniche, I will try and get him to go through the whole system with these notes as a prompt. Getting someone to work on the cars at the moment is rather difficult in South-East Queensland - all the guys have so much work on, it is a mission to get them to find time.
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 843
Registered: 05-2016
Posted on Tuesday, 25 July, 2023 - 10:01:   Edit PostDelete PostView Post/Check IP

I have a selection 3/8 UNF × 24 TPI male and female blanking plugs to minimise the risk of spillage when working on the hydraulics. They're readily available on eBay. I don't like brake fluid on my skin or clothing either.

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