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Omar M. Shams
Frequent User
Username: omar

Post Number: 90
Registered: 4-2009
Posted on Tuesday, 01 December, 2009 - 06:43 am:   Edit PostDelete PostView Post/Check IP

I have had a few hydraulic system interventions on my Wraith II that have been done for me by mechanics as i hate getting underneath the car. I am getting a bit too old for that now, and I would sooner pay someone to get muck and crap on his face than endure it myself. It was ok many years ago, but not now.
The problem I have is "feeling the brakes come on partially when the rear suspension travels slightly". It does not happen all the time, but often enough to make driving the car an awful experience. I wonder if this is caused by:

1- components being incorrectly fitted (pipes connected incorrcetly on items like the height control valves, rams, accumulator bodies, master cylinders etc). Is it possible for the pipes to be fitted in the wrong holes on the bodies of the castings?

2- Air in the system that needs to be bled out. I am sure this must be a contributing factor although it could be compounded by another problem too.

3- incorrectly overhauled height control valve(s)

4- incorrcetly overhauled accumulator bodies

5- Problem with the G valve (this has never been taken off the car in the time I have had it).

The brakes work perfectly and the car stops better than any Shadow/Wraith I have ever driven. Admittedly I have only driven around 8 different cars, but that must surely be enough to convey the sharpness of the brakes. The accumulators are good. I can switch the engine off and come to a perfect stop with bags of braking power still left.
What should I look at first?
Expertise and experience is certainly welcome here.
Thanks
Omar
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Ross Rackham
Unregistered guest
Posted From: 121.127.211.14
Posted on Saturday, 02 January, 2010 - 10:00 pm:   Edit PostDelete PostView Post/Check IP

Omar,

I have kept my mouth shut as I am not welcome on this forum but since this is a safety issue that could cost you your life and it's been a month with no assistance to you, here is one possible explanation.

This is quoted from the Hydraulic section at the site http://www.rrsilvershadow.com

The site has proved priceless to me for work on the hydraulic system.

The below sounds like your problem

Quote: When the restrictor in the return pipes is choked by dirt or old fluid the height control valves will stick in the fast mode. This can cause such a high pressure of the fluid in the height control valves that during spring deflection the pressure in the return pipes becomes too high. Because the height control valves are fitted in the same circuit as the front brake pistons, the car will brake spontaneously. This is one of the reasons the fluid must be changed regularly."

Have a look at the site, it's very helpful.

Cheers
Ross

(Message approved by david_gore)
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David Gore
Moderator
Username: david_gore

Post Number: 928
Registered: 4-2003
Posted on Sunday, 03 January, 2010 - 08:45 am:   Edit PostDelete PostView Post/Check IP

"I have kept my mouth shut as I am not welcome on this forum but since this is a safety issue that could cost you your life and it's been a month with no assistance to you, here is one possible explanation."

Ross - this is not true; some BUT NOT ALL may disagree with some of your opinions and this is a sign of a healthy forum where differences of opinion are encouraged rather than censored.

The secret is to consider opposite points of view and if they have merit, be prepared to modify your opinion accordingly and be open about it. The best outcome is in a "win-win" compromise rather than a "win-lose" battle.

Hey - if you are not welcome then why did I approve your post? Please continue to contribute whenever you wish.
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Omar M. Shams
Prolific User
Username: omar

Post Number: 105
Registered: 4-2009
Posted on Sunday, 03 January, 2010 - 07:11 pm:   Edit PostDelete PostView Post/Check IP

Ross,
I am grateful for the help, and many thanks for the advice. I was rather sad that no one knew what to do given the seriuousness of the matter. I soldiered on and solved the problem only in the last two weeks. As soon as the problem was solved, I went away on holiday to France and the Uk and did not get enough time to write up the follow-up to the problem. I am now in the UK where they have normal key-boards on their computers and I am able to post this reply. The French keyboards have all the letters in different places and it takes 3 times as long to type anything. Good God it is cold here!!! I am not too sure how my hydraulics would work if I had to live here in this cold weather - my YAK363 would certainly not be as good as it is in Dubai!!!

The two rams were removed, overhauled and put back together with new seals. Hey presto, problem solved!!!
Your suggestion of looking for dirt in the system is offcourse very applicable, but in this case, the hydraulics are squeaky clean. The idea of asking a question is to get as many angles on possible scenarios - all of which are always greatly welcomed. Your response is spot on. As would have been to overhaul the height control rams.
Once again, thanks for the response, it means a lot to me.

Best Regards
Omar
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Ross Rackham
Unregistered guest
Posted From: 121.127.211.14
Posted on Monday, 04 January, 2010 - 09:44 pm:   Edit PostDelete PostView Post/Check IP

Hey Dave and Omar,

First Dave, thanks for the kind and level headed words. When I'm not trying to protect the country from bad people (often in conflict with current government policy) I often relieve my stress by getting drunk and obnoxious. This is no excuse but hopefully explains some things.
It's probably best in the short term if my contributions are screened by more sensible heads that mine (i.e. yours or other moderators).

Omar, great to hear your problems are solved. As stubborn and pig headed as I can be I'd rather eat humble pie than see some one get hurt.

Cheers and safe motoring
Ross

(Message approved by david_gore)
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Omar M. Shams
Prolific User
Username: omar

Post Number: 106
Registered: 4-2009
Posted on Tuesday, 05 January, 2010 - 12:20 pm:   Edit PostDelete PostView Post/Check IP

Sounds like you have all the ingredients for an upstanding benevolant citizen. Thanks again for your contribution.
All the best
Omar

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