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Thread: Bleeding Hydraulics !!!

  1. #1
    Senior Member essexdave's Avatar
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    Bleeding Hydraulics !!!

    Hi People.
    Is there any specific method or way to bleed the hydraulic system for the roof ??
    My car is fitted with the (Laurens fave) smiths minipac unit , but when in the closed position dosent hold down very well for long before you can see and here the canopy "Bounce" , theres no sign of anything leaking around the pump or rams . I know it used to hold position well and i must have bled the system before but it was a long time ago and you must make allowances for age....... mine, not the car .
    I have scanned through the hydraulics section as i thought id seen something about it before but cant find it now, so sorry if its here and ive missed it but any pointers would be most welcome.
    Cheers.

  2. #2
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    Re: Bleeding Hydraulics !!!

    Hi essexdave

    My first thaught was the ram seals? apossable but what ram do you have? Dose you roof stay open or dose fall back down It mite be a pump problem? I know I am not helping

    I rember very well driving in the snow In my first Nova. I did not need to put the wind screen wipers on. The snow found a way around the car and not hitting the screen.

    bushboy found a good way round by putting a flat flour in his reek.

    But every Nova needs a front spilitter to stop air going under the car as it a wing on wheels.

    What is take off speed on aircraft?


    Ben

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    Re: Bleeding Hydraulics !!!

    Hi sorry essexdave

    I misted your point to realase air crack the pipes at the rams air is thiner than oil and will escape before oil crack top and bottom to all the air out. I never found it a problem because the smith pump is self bleeding.


    Ben

  4. #4

    Re: Bleeding Hydraulics !!!

    Ben is right, the smiths minipack is self bleeding so this won't be your problem. One possible cause is that the pressure relief value nipples have started to corrode and are not seating correctly in their cups allowing the fluid (and pressure) to pass by them.

  5. #5
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Bleeding Hydraulics !!!

    Yes, the internal ram seals would be my first thought, but as Ben says that would also cause the canopy to slowly sink down when open, as the fluid works its way past the seals between the "up" and "down" chambers. I was also wondering if your ram seals project below the input ports at the bottom of the ram body when fully retracted, but on reflection this would also affect the lift function (as fluid would be entering both the "up" and "down" chamber at the same time) from the fully retracted position.

    I have read that in certain cases ram pressure seals can last only 2 years, and that some of the rams sourced by the Elams and later Graham Slayford were poor quality with only a single O ring seal.

    Any residual air trapped in the system should bleed out after a few cycles. If the canopy is raising evenly on each side then I doubt that an air lock is the problem. Are you sure that both solenoid valves in the pump are closed? If the "down" solenoid valve remains energised that would bleed all the negative holding pressure. Other than that, its down to Dave's suggestion of a faulty relief valve (if you can keep the pump running after the canopy is closed, you can hear the pump working to compress the seals until the relief valve opens). On Green Machine there is a noticable drop in the note of the pump motor when operating into this load. If your pump runs with little or no apparent change in note, the relief valve may be suspect.

    Good luck!

    Lauren
    only Pythagoras can save me now!

  6. #6

    Re: Bleeding Hydraulics !!!

    i took my smiths pump system apart recently ( to fit a simple plug in system) what i found was i had to run the canopy up and down about 20 times, then what happenes is you get little tiny air bubbles in the system leave these to disperse usually couple of hours and repeat, after about 5 times of doing this my air bubble and air lock had disapeared!. its possible that your airlock is near your ram which could be causing the problem so try moving the rams full up and fully down this worked for me. also the way i have my system set up i can hold one ram in the down/up position (not connected to the cannopy hold this up with a stay or brush ) while activating the system which makes the other ram move quicker untill it gets to the fully up/down position then it starts to push the other ram(the one you are holding) so be carefull because if you get your hand trapped between the ram and something else it will have no problem snapping it off! . this also help in gettin rid of the bubbles. the one where you hold the ram do this as a last resort and make sure you are clear of all objects because this can be dangerous if done incorrectly (my canopy was not attached when i did this so i had no objects in the way).

    give these a try first, and is it one side that has air in or both sides?
    please let me know if this helped?

  7. #7

    Re: Bleeding Hydraulics !!!

    Quote Originally Posted by Ben
    Hi essexdave

    My first thaught was the ram seals? apossable but what ram do you have? Dose you roof stay open or dose fall back down It mite be a pump problem? I know I am not helping

    I rember very well driving in the snow In my first Nova. I did not need to put the wind screen wipers on. The snow found a way around the car and not hitting the screen.

    bushboy found a good way round by putting a flat flour in his reek.

    But every Nova needs a front spilitter to stop air going under the car as it a wing on wheels.

    What is take off speed on aircraft?


    Ben
    Isn't it the other way round? you want air going under the car, as fast as possible, like with a flat floor, smooth air under the car, dirtier air over the car and it'll stick to the road better?
    Follow my Avante Build - Target = Stoneleigh 2012 Definitely!!

  8. #8
    Senior Member essexdave's Avatar
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    Re: Bleeding Hydraulics !!!

    A huge thanks for the info people, i'll be taking a closer look at it this weekend.... weather permitting.... the canopy stays up no problem at all but does seem to run on longer than i remember to get the canopy to seat down firmly so that might be a clue, its currently at the mot station waiting to be tested in the morning so fingers crossed it'll be on the road tomorrow, but it wont be going anywhere until ive sorted this cos i just know that if i say " im just taking it for a spin round the block " i'm bound to find the biggest pot hole this side of the known universe ... the canopy will bounce and i'll end up making frantic phone calls to pilkington...... just not worth it,
    There will probably be more questions once i delve into it further but i'll keep you up to date.
    Thanks again guys...... and of course Lauren.
    Dave.

  9. #9
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Bleeding Hydraulics !!!

    Good luck Dave!

    Lauren
    only Pythagoras can save me now!

  10. #10
    Senior Member essexdave's Avatar
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    Re: Bleeding Hydraulics !!!

    Hi All
    Tried various tips on the pump mentioned here to see if it cures the "Bounce" problem but its still there so it seems more and more likely to be a pump/valve/seal problem ans mentioned by several of you, Anyway after a number of phone calls ive finally found a local-ish hydraulic company that knew the pump type and he said more or less the same, upshot is if its not raining tomorrow i'll be taking off the pump and rams, and whizzing them up to their premesis , he said he would pressure test everything first to find out where any possible fault lays and will keep you posted.

    However all this sitting in the car tinkering has brought another thing to the fore that was "niggling" me and playing games with my sanity..... i'll post that one in the Interior section
    Dave.

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