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  • Brakes: Hydrovac problems?

    I just installed a rebuilt Hydrovac on a friend's '56 Golden Hawk. If I drive the car for 10 or 15 minutes (local city streets), the car seems to get more and more sluggish. It definitely feels like the brakes are dragging. When I stop, if I jack it up, it is difficult to turn the wheels AND the stop lights stay on. If I open the forward bleed screw on the Hydrovac, fluid squirts out and the brakes release (and the stop lights go out). It appears to me to be a problem of the Hydrovac not releasing. By the way, the car has Ultramatic, so it isn't the hillholder). I need some advice. Thanks Howard
    Howard - Los Angeles chapter SDC
    '53 Commander Starliner (Finally running and driving, but still in process)
    '56 Golden Hawk (3 speed/overdrive, Power steering - Running, but not yet driving)
    '62 GT Hawk (4 speed, A/C, Power steering - running and DRIVING!)

  • #2
    Sounds like the rubber line coming out of the HV has constricted. I'd replace them both at same time, the one coming in and the one coming out.

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    • #3
      Thanks Joe.
      Howard - Los Angeles chapter SDC
      '53 Commander Starliner (Finally running and driving, but still in process)
      '56 Golden Hawk (3 speed/overdrive, Power steering - Running, but not yet driving)
      '62 GT Hawk (4 speed, A/C, Power steering - running and DRIVING!)

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      • #4
        Check your pedal to M/C adjustment, if too tight will create a dragging problem.
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        • #5
          I would check master cylinder to pedal problems first. pedal free travel is very important, no free travel and brakes are constantly applied a tiny bit, till you drag to a stop!Something has to activate that new HV and my money would be on pedal free travel. Just a thought. Luck Doofus

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          • #6
            Agree, check the pedal free play first. But if the HV rubber hoses are over 5 yeas old, I'd at least check them. To check, remove ad blow through them. Supposed to be 1/8" ID, so should blow through like a similar size straw. If any restriction whatsoever, I'd replace them.

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            • #7
              Before swapping out the hydrovac, bypass the hill holder. I went nuts chasing a brake lock up problem on my 63 R2 Hawk replacing everything until I realized the problem was the hill holder.

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              • #8
                Tim, I'll crawl under and look, but I don't think automatic transmission cars came with a hill holder. Thanks.
                Howard - Los Angeles chapter SDC
                '53 Commander Starliner (Finally running and driving, but still in process)
                '56 Golden Hawk (3 speed/overdrive, Power steering - Running, but not yet driving)
                '62 GT Hawk (4 speed, A/C, Power steering - running and DRIVING!)

                Comment


                • #9
                  I can only go by a modern unit that I am working on but there is a threaded adjustment between the hydro vac and the master cylinder, maybe a turn or two in may help. With the unit we are working on we are having a problem with the pedal going to the floor with the engine running and the pedal is right hard at the top when not running we are somewhat bewildered as to the cause. We have bled gallons of fluid through the system with the engine running and not running. We replaced the master cylinder and the hydro vac all the brake cylinders and still the pedal goes to the floor. We bench bled the new master cylinder as per directions. With the engine running we additionally bled the new master cylinder and that is where air bubbles continue to appear until we ran out of fluid. We have finally given in and are taking it to a brake shop to have it power bled.

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                  • #10
                    Originally posted by altair View Post
                    I can only go by a modern unit that I am working on but there is a threaded adjustment between the hydro vac and the master cylinder, maybe a turn or two in may help. With the unit we are working on we are having a problem with the pedal going to the floor with the engine running and the pedal is right hard at the top when not running we are somewhat bewildered as to the cause. We have bled gallons of fluid through the system with the engine running and not running. We replaced the master cylinder and the hydro vac all the brake cylinders and still the pedal goes to the floor. We bench bled the new master cylinder as per directions. With the engine running we additionally bled the new master cylinder and that is where air bubbles continue to appear until we ran out of fluid. We have finally given in and are taking it to a brake shop to have it power bled.
                    If it's a good brake shop, they will probably start by replacing all rubber hoses.

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                    • #11
                      I had my Hydrovac rebuilt by a company in San Jose, CA. I had the same issue and followed all the above suggestions. As it turned out it was a faulty rebuild. I sent it back and they corrected it. It has been working great so far since I got my car on the road. I only have about 1,500 miles on it so far, but it works great.

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                      • #12
                        I will clean this ball #19. A friend had rebuilt one, her silver hawk had the same problem.
                        I found this rusty ball.
                        GT Hawk 62 V8
                        Lark 62 hardtop skytop 6 cyl
                        Silver Hawk 57 Hardtop 6 cyl
                        Transtar 57 V8
                        Starliner 54 V8

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                        • #13
                          Originally posted by JoeHall View Post

                          If it's a good brake shop, they will probably start by replacing all rubber hoses.
                          Every thing is new, cylinders, hoses, drums, master, hydro vac, front rotors and calipers. The competent shop we took it to did a token bleed job and said it is ok, the pedal engages about 1 1/2" from the floor. I am not buying his diagnosis.

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                          • #14
                            Well, here is the latest. Everything is new; wheel cylinders, shoes, master cylinder, front and rear hoses. We just loosened up the pedal to master cylinder rod to get a little more free play (although I believe it was OK). Checked to make sure shoe adjustment is OK. Still almost no driving (less than a mile and the brakes are almost locked up (car barely moves with a lot of throttle). Just replaced the rubber hoses to the Hydrovac. No improvement. When it is locked up, if we open the most forward bleeder screw on the Hydrovac, it squirts fluid and the brakes release. My feeling is that the check valve in the Hydrovac is not releasing. Just removed the Hydrovac to take it back to the rebuilder so he can re-check it. Breaking news at 11 (10 for those in the Central and Mountain time zones)
                            Howard - Los Angeles chapter SDC
                            '53 Commander Starliner (Finally running and driving, but still in process)
                            '56 Golden Hawk (3 speed/overdrive, Power steering - Running, but not yet driving)
                            '62 GT Hawk (4 speed, A/C, Power steering - running and DRIVING!)

                            Comment


                            • #15
                              Originally posted by brngarage View Post
                              Tim, I'll crawl under and look, but I don't think automatic transmission cars came with a hill holder. Thanks.
                              My 53 auto trans Commander has hill holder. They just don't call it that. It is called something like "anit-creep". Really dumb, IMHO. If you don't want it to creep in drive (or reverse) hold your frigging foot on the brake.

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