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Faulty residual presssure valve!

Discussion in 'The Hokey Ass Message Board' started by 38jon, Jul 10, 2009.

  1. 38jon
    Joined: Oct 28, 2007
    Posts: 82

    38jon
    Member
    from York,PA

    So I,m coming home from GG Rhinebeck, go to stop at a traffic light, and right away I knew I didn't have rear brakes, got it stopped in time but holy shit, scared the hell out of me. I get home and try troubleshooting the problem, couldn't really bleed the rear brakes. No fluid, no air, no nothing coming out, thought the master cylinder was bad, got a new one no luck still couldnt bleed the brakes. Only thing left was the residual pressure valve, (drum brakes 10lb), took it off looked inside and the plastic spring retainer turned to goo, and the rubber check valve was deformed, and all the plastic goo blocked the lines and bleeder. Got a new one flushed everything out works now. But I was wandering what caused the brake fluid to eat away at the plastic and rubber.
    Brake fluid is regular Dot 3 fluid.
     
  2. ibcalaveras
    Joined: May 30, 2006
    Posts: 599

    ibcalaveras
    Member

    Very interesting! What brand of valve do you have. My brakes are not working as good as they used too. I think I will check mine out...
     
  3. 38jon
    Joined: Oct 28, 2007
    Posts: 82

    38jon
    Member
    from York,PA

    It was a Speedway, now I put a Wilwood, hope it last's longer, although inside it looked the same.
     
  4. chopolds
    Joined: Oct 22, 2001
    Posts: 5,995

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    It's not too close to the exhaust sytem is it?
     

  5. 38jon
    Joined: Oct 28, 2007
    Posts: 82

    38jon
    Member
    from York,PA

    Yeah I thought that too, but its on the inside of the x member and exhaust is on outside, and after running for a while it's not even warm. The plastic looks like paint when you use paint remover on it.
     
  6. Tman
    Joined: Mar 2, 2001
    Posts: 35,180

    Tman
    ALLIANCE MEMBER


    Both suck, we have discussed this before. Use only the Brass ones like ECI sells.
     
  7. Old thread but I figured its worth adding to it for those that search (I did and couldn't find much more info).

    I rebuilt a rat rod upon purchase, and reused some of the brake components, which were disassembled for 1-2 years.

    It had speedway rpv 's. I can't say for sure whether the missing rpv plastic clip referred to above was already missing upon reassembly, but its odd to me that both fell out somehow. Additionally I had good residual pressure in the rear system initially. But almost immediately I was fighting weird behavior: mysterious new air bubbles always showing up on front brakes, rear never building pressure as quick as front or as they had initially, and strangely intermittent low peddle. While changing a rear line that had a high loop in it that I thought might be causing a bleeding problem, I just happen to notice there was nothing holding the inside of rpv in place (I.e. little plastic clip). Found same in front valve. WTF?

    The rubber in the front valve was even wide open.

    To be clear, there was never a sealing problem where the 1/8 npt adapter threaded in.

    RE eci valves, i understand the bodies are brass but to my knowledge the insides are same as wilwood, speedway, etc.

    To conclude, its hard for me to believe that both of my retainers mysteriously fell out, which makes me think the OP is onto something. I too had DOT 3. Attached are some pics of valves. The first two are the guts of the valve (sans plastic clip). The last is my front valve, intact; you can see the rubber mouth on the valve was wide open.

    Lastly if u are shopping, I will say that the fact that speedway valves are round with only wrench face machined in them makes them a pain in the Dick to get a wrench on and tighten in tight spaces, like against a frame rail. That alone makes another brand worth a couple extra bucks.

    I still have to rebleed and test, but I suspect my problems will be gone.

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    Last edited: Oct 29, 2013
  8. Follow up. Holy cow. Those rpv's were definitely the problem. I was really getting bummed and starting to question everything in brake system, etc. I finally bled the brakes tonight after replacing with new valves (wilwood, hopefully these last longer), and what a difference in pedal height and feel.

    Incidentally, I found the reason the front one was wide open was because little spring somehow worked its way into the opening of the little rubber valve.

    As an aside, I couldnt get my usual brake bleeding helper (only way I've ever done it). So I was getting impatient. I purchased no name speed bleeders from HELP SECTION at AutoZone. Aside from cost, my front and rears are different, plus no size the had fit my 57 Chevy rear. I saw one post on the Hamb where a guy machined an adapter to a speed bleeder so he didnt have to replace them on all his cars..... They don't hold a lot of pressure so I took it a step further and machine the threads and tip off a single speed bleeder to accept short length of hose between it and stock bleed screw. So I could use it anywhere and drape a long piece of hose vertically over the tire to a reservoir to see fluid/air coming out

    Wow was I impressed. Way better and faster than 2 man method in my opinion. Doesn't actually actuate brakes, moves a ton of fluid freely and easily. Done. I think u still need two sets of eyes to pump and watch hose. but the hotrod was small enough, that with open wheels and no pedal pressure to fight, I could always find a way to reach the brake pedal and pump and still see the wheel/hose.



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