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Installing brake residual valve?

Discussion in 'The Hokey Ass Message Board' started by TP, Jan 25, 2008.

  1. TP
    Joined: Dec 13, 2001
    Posts: 2,024

    TP
    Member
    from conroe tx

    I put after market power master cylinder and brake pedal on the firewall of my 59 buick. The car stops but the pedal is at the bottom. I have gone through all the steps I think to install the unit correctly. Bled lines[many times},bench bled m/c,new steel and rubber lines,new brake wheel kits,new brakes and turned hubs. It has 16# vaccum. The car originally had a tredle vac power unit on it. My question is ,I am going to install a 10# residual valve in the line of the back brakes.I have also correctly adjusted the shoes. drove awhile and re-adjusted. What am I missing. The pedal stops too low. I even replaced the new 7" vaccum booster thinking it was bad. The m/c is for a drum /drum car supposedly.? Do I put the res.valve up high by the m/c or lower on the frame near the rear? I have been jacking with this for months. Help. Thanks TP
     
  2. The Wizard!
    Joined: Nov 18, 2007
    Posts: 140

    The Wizard!
    Member

    If your master has no residual valves in it you need to put them in lines for any and all drum brakes, it really doesn't matter to much where they are located as long as you have them. Without them you have low to no pedal and they often pull one way or another. You won't believe the diff. they will make.
     
  3. swade41
    Joined: Apr 6, 2004
    Posts: 6,653

    swade41
    Member
    from buffalo,ny

    With the pedal/master combo on the firewall it shouldn't need rpv's. Maybe your drums are turned to much and the shoes are having trouble expanding to them.
     
  4. thirty7slammed
    Joined: Sep 1, 2007
    Posts: 888

    thirty7slammed
    BANNED
    from earth

    TP, is you mc mounted on firewall, if so I don't think a residual valve will help, They are mostly used when your master cyl. is mounted on frame under car lower than the wheel cyls. they are just a check valve to keep fluid from bleeding back to mc. You might check bore size of new mc, that could make a difference. Call ECI and ask for Ralph, he can definately help.
     
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  5. TP
    Joined: Dec 13, 2001
    Posts: 2,024

    TP
    Member
    from conroe tx

    nope, thats not it. Calibrated them and they're good. I went by the recommendation in the book. Tighten drums until they lock up brakes and back-off I think it said 6 clicks. I am thinking residual valve will do the trick. I'll know by tomorrow night for sure. The master cylinder was supposed to have had them in it. Maybe it's bad. Anyone else have a guess of something I haven't tried?
     
  6. TP
    Joined: Dec 13, 2001
    Posts: 2,024

    TP
    Member
    from conroe tx

    Yes it is on the firewall. I know in theory it shouldn't need it but it was cheap. I can't remember bore size but it was ordered for the buick. What bore size should it be? Got a number on this ECI? Bore shouldn't affect pedal height I wouldn't think. I'm willing to try anything. I have tryed everything I can think of. If I change the m/c thats on it for one that came on a 69 chevy full size drum/drum with power that should be close wouldn't you think?
     
  7. thirty7slammed
    Joined: Sep 1, 2007
    Posts: 888

    thirty7slammed
    BANNED
    from earth

    TP here you go.

    <?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /><v:shapetype id=_x0000_t75 stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" o:preferrelative="t" o:spt="75" coordsize="21600,21600"><v:stroke joinstyle="miter"></v:stroke><v:formulas><v:f eqn="if lineDrawn pixelLineWidth 0"></v:f><v:f eqn="sum @0 1 0"></v:f><v:f eqn="sum 0 0 @1"></v:f><v:f eqn="prod @2 1 2"></v:f><v:f eqn="prod @3 21600 pixelWidth"></v:f><v:f eqn="prod @3 21600 pixelHeight"></v:f><v:f eqn="sum @0 0 1"></v:f><v:f eqn="prod @6 1 2"></v:f><v:f eqn="prod @7 21600 pixelWidth"></v:f><v:f eqn="sum @8 21600 0"></v:f><v:f eqn="prod @7 21600 pixelHeight"></v:f><v:f eqn="sum @10 21600 0"></v:f></v:formulas><v:path o:connecttype="rect" gradientshapeok="t" o:extrusionok="f"></v:path><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:lock aspectratio="t" v:ext="edit"></o:lock></v:shapetype><v:shape id=_x0000_i1025 style="WIDTH: 399.75pt; HEIGHT: 105pt" alt="" type="#_x0000_t75"><v:imagedata o:href="http://www.ecihotrodbrakes.com/images/pic04_brakefacts.gif" src="file:///C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\msohtml1\01\clip_image001.gif"></v:imagedata></v:shape>
    http://www.ecihotrodbrakes.com/index.html
     
  8. budd
    Joined: Oct 31, 2006
    Posts: 3,471

    budd
    Member

    to adjust your shoes you need to jack up the wheel, give it a spin, you should hear the shoes draging on the drums just a little, a healthy one handed spin should see the wheel make one full turn then stop, if not then adjust it up a little, get in and step on the peddle to center the shoes in the drums, get out and give it another spin, keep doing this on all 4 wheels.
     
  9. mikes51
    Joined: Oct 4, 2001
    Posts: 2,195

    mikes51
    Member

    First, I assume you car stopped okay before, and you haven't changed the brake cylinders (size) at the wheels.

    Then the bore of your new power master cylinder should be the same or very close to the bore of your original master cylinder. Can you measure the old one and compare? I'm thinking your new m/c bore is smaller. so to push as much as fluid as your old bigger bore you have to move more fluid, to do that, you have to move the pedal further.

    I just re read your post and noticed the tred vac, I don't know how that would effect my above statements. Did those tread vacs have a like their own "master cylinder bore"?
     
  10. TP
    Joined: Dec 13, 2001
    Posts: 2,024

    TP
    Member
    from conroe tx

    Mike, they were basically a power brake system with a master cylinder with a single reservoir[spelling]. They are very expensive to rebuild. It was under the floor and had about the same size bore. I ordered this for the buick expecting it to be the right size. How do you know what size is right? I have a new[rebuilt] m/c for a 69 full size chevy drum/drum that I will try. They are about the same size and weight. The cae does stop but the "oh shit" factor kicks in. This car is for my son and I'm afraid he will panic. Keep the suggestions coming. I will try them all. The car did not run when I got it. So I just assume it stopped. All brake parts are new. If someone figures this out the beers on me at the roundup. Dirty 32 called and suggested I lengthen my rod between the pedal and booster. Right now it has about 1/4 " play in it. I'm going to mark it and then make it longer and try.
     
  11. thirty7slammed
    Joined: Sep 1, 2007
    Posts: 888

    thirty7slammed
    BANNED
    from earth

    TP,been trying to post this image for about an hour now, Im not to computer savy. Anyway, this is what all the jibberish is in my last post about residual valves.

    [​IMG]
    Good luck and call Ralph.
     
  12. mikes51
    Joined: Oct 4, 2001
    Posts: 2,195

    mikes51
    Member

    That longer rod is a good idea. If the car does stop okay, then the problem is indeed psychological like you say. Psychological meaning we like to have have an inch or two between the pedal and the floor. That longer rod would move the pedal up away from the floor.
     
  13. TP
    Joined: Dec 13, 2001
    Posts: 2,024

    TP
    Member
    from conroe tx

    37 I went to their site. None of the information is about drum/drum. I'll give ralph a call if all that has been mentioned doesn't work. Mike, I agree, maybe what Danny is saying is right. I hope it fixes it because he doesn't drink beer! Thanks TP
     
  14. groove
    Joined: Jan 13, 2008
    Posts: 74

    groove
    Member
    from kelowna BC

    You will need to install the residual valves in both lines, as your new MC does not likely have them installed. The valves hold line pressure that would otherwise be forced back into the MC because of the wheel spring hardware pulling the shoes back against the wheel cylinder. I have just gone through the same thing with my Merc after upgrading the MC from a single res to a dual. Let us know how it works out.
     
  15. Wyle E Coyote
    Joined: May 24, 2006
    Posts: 442

    Wyle E Coyote
    Member

    Your pedal ratio could be wrong also. If you have too much it will take a lot of travel and feel very soft. Most power brakes only need around 5:1 while manual is more like 7:1. Measure the full length of the pedal then measure the length from the top to the rod mount and divide the divide the pedal by the rod measurement. As an example, if you have a 10" pedal and your rod is 2" from the top then you have 5:1.

    The rod length may be a problem but be sure you aren't presssing in on the booster when the pedal is at rest. Also check the length of the rod coming out of the booster to the master. It should just barely contact the piston in the MC. If it presses in the master even the slightest bit you won't get a good bleed on the system.

    To check the bore on the MC just measure the piston from the back of the MC. Post that info if you can find it out and that may help too.

    Residual valves aren't needed for the type of install you have, the info above about that is correct about needing them if the MC is lower then the caliper or drum.
     
  16. billwillard
    Joined: Dec 21, 2005
    Posts: 23

    billwillard
    Member

    VALVE WILL NOT HELP Is the peddle hard when only pushed once or dose it kreep to the floor if you hold it down?
     
  17. DICK SPADARO
    Joined: Jun 6, 2005
    Posts: 1,887

    DICK SPADARO
    Member

    Without explaining just what parts you purchased new that resulted in a different pedal experience makes trouble shooting difficult. Since you do have brakes but extensive pedal travel its more likely the problem one of these areas. If you have 1/4" free play in your pedal to master cylinder push rod you have way to much free travel. If your new pedal assembly pushes from the pedal to actuate the master cylinder via a clevis or heim adjuster you should re adjust the pushrod length.To get the free play necessary to prevent constant pedal pressure you should remove the bolt holding on the connecting clevis, pull the pedal to the up position desired. With the push rod inserted into the master cylinder and just touching the piston, adjust the push rod clevis so that the bolt hole opening in the clevis exposes 1/2 opening of the mounting bolt hole in the pedal arm on the master cylinder side.. Replace the clevis bolt and check the pedal to master cylinder free play, should be just a little 1/8" or so. Now just static brake check the distance the new pedal adjustment travels to the floor. If this is the same as before you have have not purchased a master cylinder with the same displacement as the old one as posted Mike 51 suggests. It is important to match the old displacement bore with the same displacement bore on the new master cylinder.
     
  18. 67Imp.Wagon
    Joined: Jun 16, 2001
    Posts: 1,191

    67Imp.Wagon
    Member

    TP, check with Flt Blk on those issues. I believe he went through somthing similar with his and I think it ended up being that they gave him the wrong unit but ca;nt remember all the specifics. But you should shoot him a message and talk to him.
     
  19. TP
    Joined: Dec 13, 2001
    Posts: 2,024

    TP
    Member
    from conroe tx

    Phil, was it on the truck or baker? the truck was mounted under the frame I believe. I'll contact him. I just got in from work and I am going to take Dicks sparados advice and start there. it's basically what Dirty 32 told me to try. We'll see in a few minutes. TP
     
  20. TP
    Joined: Dec 13, 2001
    Posts: 2,024

    TP
    Member
    from conroe tx

    Ok, I spent the evening working on my brakes. Better but I'm still not satisfied. I lengthed the rod about a half inch and it's better. I tried several other things that didn't work. found that a manal brake bore size for 59 buick is 1" but i can't find the bore size for the power. it is uasually bigger. I drive a f-350 deisel truck everyday. I guess I am judging the 59 against the truck. It just doesn't feel right. I haven't driven a car in years. I may be expecting too much. I think next I'll change master cylinders. What would someone suggest? Bore size? application?Thanks for the help. TP
     
  21. 67Imp.Wagon
    Joined: Jun 16, 2001
    Posts: 1,191

    67Imp.Wagon
    Member

    TP, now that I think about it, he was having issues with the back locking up before the fronts. It was on the Camino. There were wrong parts sent to him though and he ended up getting his stuff from another supplyer.
     
  22. gbones32coupe
    Joined: Jan 1, 2007
    Posts: 510

    gbones32coupe
    Member

    Here I will try to help see if these guys agree? if I am wrong pm me.

    If your wheel cylenders have a one inch bore than you need a one inch bore master cylender. If the bore is smaller in the master cylender it will not push enough fluid to the wheel cylenders and will make the pedal easy to push and pedal will travel closer to floor. If the bore in the master cylender is larger than the wheel cylenders too much fluid not enough pressure and the pedal will be hard to push and the car wont stop. also check to see if the wheel cylenders are the same bore on both sides. My cylenders on my model a have two different bores and had to do some math to figure that one out when I ordered a new master. My proportioning valve helped me controle the rear wheels from locking up fully manual breaks and it stops good.

    On some cars the bore in the master can change if it is disc break or power break.

    If the breaks are ajusted prop they will have very slight drag when jacked up and spinning the wheel.

    Now this may seem real stupid but if there are no leaks and all your hoses are new and not expanding than mabe you do have air in the system up in the master. but I am shure that you have spent plenty of time on that. its prob not that but I would mabe try bleeding again cause even if you bench bleed you can get air trapped in the master. don't hate me for saying this.

    Residual valves won't correct your problem but they can help a little with having an instant break pedal. don't assume that the master you baught has a residual valve in it cause some aftermarket ms are used for hydrolic clutch. In that case the valve is removed. The residual valves do need to be placed as close to the master cylender as possable. I think it is 7lb for disc and 10lb-15lb on drum breaks.

    Did you use dot 5 break fluid cause I have hered that that silicone break fluid can create a smushy pedal.

    I know this question has been asked before but are you getting a realy good pedal when the car is not running? If you are not getting a realy good pedal then somthing is wrong right off the bat. air,fluid or adjustment in breaks or linkage

    If breaks suck while running only mabe vacume leak? prob not but. I tryied to help.
     
  23. HanibleH20
    Joined: Jan 17, 2004
    Posts: 139

    HanibleH20
    Member

    The residual pressure valve went bad on the last night of racing this year. No air found in the lines anywhere. We over bled the brakes on all four wheels. I run brake pressure gauges in the cockpit to adjust brake bias. I run a Wilwood dual master cylinder pedal with a cockpit adjustable balance bar. I also run a cockpit adjustable proportioning valve to adjust the brakes across the front instead of front to rear. I like a car set up tighter than most, so I run a lot of rear brake to help turn the car. Here is what I see in the gauges. When there is air in the lines the brakes with the air will gain pressure with each pump, as you would expect. When the RPV is bad the front gains pressure before the back, but the back finally passes the front and feels solid. (I only have an RPV on the rear) On the second pump the rear hits right away and is always way higher pressure than the front with the only limitation being leg pressure. Nothing like being on a big fast track and having to pump once so you can get the car to turn in!

    I'd say if your pedal has good pressure and not spongy at the bottom of the first pump,like it has air, and full pedal right away at the top of the second pump you need a rpv, because the first pump is moving the pad to the drum. If it goes to the bottom on every pump you have other problems. It was always my understanding in the past, that rpv's were for disk brakes because of the piston sucking back into the caliper. The adjustment in the drum brakes should already have the pads to the drum when the wheel cylinder is backed off.

    I may be way off there, so let me know. I'm here to learn! Hopefully I was a help.
     
  24. tommy
    Joined: Mar 3, 2001
    Posts: 14,735

    tommy
    Member

    After 25 years in a brake shop that's a new one on me. So exactly how much is a "click" supposed to be? When did they start calibrating star adjusters?

    You adjust the brakes as stated above for a light drag. How many clicks is that? Damn if I know! I never counted (but my gut says it's less than 6). It's a feel thing. The tire will spin by hand with a slight drag about one revolution. That is what you are looking for. How many clicks is irrelevant. It's bad enough with disc-drums but with 4 wheel drums it's critical. With 4 wheels out of adjustment the pedal has to go to the floor. All of your pedal travel is used to take up the loose adjustment. Once that is taken up then you have decent brakes but the pedal is now close to the floor. (Which is the problem as I understand it) Adjust all 4 wheels for a slight drag and I bet the pedal comes up to a more acceptable level.

    BTW 75% of the disc/drum brakes on the road today have the rear drums out of adjustment and wear out the front pads prematurely. But you say my car has selfadjusters?? 75% don't work in the real world for various reasons.

    If you use a M/cyl from a 4w drum brake application, it will have the RPVs already in place. No need to add any.
     

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