brake question |
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JimW
Senior Member Joined: 09-December-2003 Location: USA Status: Offline Points: 602 |
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Posted: 16-December-2003 at 6:34PM |
Having brake troubles with my Torino, soft pedal, goes pretty much to the floor without appreciable stopping power compared to when I first bought the car. Replaced master cyl, front lines, rear wheel cylinders, bled the brakes several times, but still a soft pedal that's now been there for 4+ years. The car will stop, just not with a great deal of confidence.. There is an assembly that in the manual is called a distribution valve, but isn't supposed to be on my car (was there when I bought it).. This is just downstream of the M.C., and has what appears to be what the manual calls a bleeder valve on the front (there is a rubber plug with a pin sticking out of it, the pin moves slightly when you put the brakes on). The front calipers aren't leaking either. I don't have access to other intermediates to see what they have, but I need to get this taken care of, any help would be greatly appreciated.
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1976 S&H Gran Torino
460/C6/4.33 13.05@105.6 545/C6/3.56 11.52@117.8 More to come!!!! 463rwhp/495rwtq two tons of fun see it and hear it at: www.torinocobra.com www.st |
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buster
Member Joined: 29-November-2003 Location: United States Status: Offline Points: 15 |
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Jim, Don't know if this will help and I am sure if you have done all you have this will sound stupid but nonetheless it can't hurt. I took my 76 Elite to the mechanic with the same problem. Solution was very simple almost too, the back drum brakes had some rust in the components which impeded them from operating as they should, he took them apart, cleaned and then adjusted them and the soft pedal went away. I know this is so simple but thought I would tell you about it. I was expecting all kinds of problems with master cylinder and such but not the case. This car had been setting for 10 years +. Now that is what he told me he did to it to stop the soft pedal if it makes sense. Paul |
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JimW
Senior Member Joined: 09-December-2003 Location: USA Status: Offline Points: 602 |
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Thanks, I actually replaced all the rear brake parts since the problem started, and cleaned and greased everything while I was in there.. My next move is to mess with the proportioning/distribution valve.. It's frustrating as hell.. Thanks again! Jim |
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1976 S&H Gran Torino
460/C6/4.33 13.05@105.6 545/C6/3.56 11.52@117.8 More to come!!!! 463rwhp/495rwtq two tons of fun see it and hear it at: www.torinocobra.com www.st |
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MTorino74
New Member Joined: 30-July-2003 Location: Finland Status: Offline Points: 3 |
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Hi, You didn't specify, is there a break power booster in Your car ? When I got my Torino (with the booster), the breaks were really sharp, just think pressing the pedal and one almost goes through the window... When disassembling the booster, we found there was a lot of water and who knows what other stuff mixed in that water inside. After servicing it, the break power (actually the force You need to push the pedal) was much higher, but the breaks operated much more accurately. It was OK But then... This is a good example that one should not touch anything that's working... I made some parts orders and also ordered a replacement kit for head cylinder just to make sure it is serviced as well...). Result was that after 10-15 miles of driving front discs started to jam (drums in the back, but they were OK). Releasing the fluid line going to front discs from head cylinder (with releasing I mean I opened the break line nut of the main cylinder that much that the extra presssure would go out) helped that much that I could take the car back to garage. This happened several times ! EVERYTHING in installing the new parts was done as in the instructions and still... On the other hand, when working OK in the beginning and after driving some time (even without utilising brakes !) could this be be some kind of a heating problem ? Any ideas, gents ? But for now: I wish a Merry X-mas and a Happy New Year to all of You ! Br, --- MEK |
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MEK
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JimW
Senior Member Joined: 09-December-2003 Location: USA Status: Offline Points: 602 |
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My car does have the booster, and it seems to be working fine, I have exactly the opposite problem as you, when moving the car around in a parking lot, there is a bunch of pedal travel and not much braking.. Yours could be heat related, have you checked to see if the front wheels rotate freely when the car is in the air before you drive it? As well, you should run the car in Park, with the front wheels in the air and see if they tighten up once vacuum builds.. When a problem comes up after replacing a part, I suspect that part first, then everything attached to it.... Another thing to consider is replacing the rubber lines, occasionally I have heard that they can delaminate inside and prevent fluid from returning to the Master Cylinder (head cyl as you call it). The other thing could be that your have a sticky/frozen caliper that is causing you problems.. Once you do get it sorted, make sure that the rotors and pads haven't been badly damaged by the problem. Good luck and happy holidays! Jim |
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1976 S&H Gran Torino
460/C6/4.33 13.05@105.6 545/C6/3.56 11.52@117.8 More to come!!!! 463rwhp/495rwtq two tons of fun see it and hear it at: www.torinocobra.com www.st |
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ibuy72s
New Member Joined: 26-December-2003 Status: Offline Points: 2 |
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Hi: Sounds like you still have air in the system. I say this because fluid is incompressible and if you don't have a leak, a bad flex line, out of adjustment brake shoes or a master cylinder with an internal leak you have air. I know you said you bled the system, but sometimes air is very difficult to get out once introduced. If you didn't bench bleed the master cylinder before you installed it, go back and bleed it from that point. Personaly, I would go back there and do it again anyway. Air will find the highest point and bleeding downstream of it doesn't do a thing. Also, if you are using the master cylinder to bleed the system it is extremely important that it is not air bound. Another thig to do is check the location of the bleed fittings on your front calipers. Somtimes a fitting is located so that the caliper has to be bled off the rotor and held so that the fitting is at the highest point. If you have to do this, place a block of wood to prevent the piston from being forced out. If you bleed the brakes with the master cylinder don't repeatedly pump the brakes before you open a fitting as this can force the air into small bubbles and make it harder to remove. One application down has always worked for me. If you have a dual master cylinder you are going to have a pressure differential valve downstream of it. This devise is use to alert the driver that one of the two systems (front or rear) is putting out more pressure than the other. This devise places a piston between the output pressures to the front and rear brake systems. If the one system puts out a lower pressure the piston slides and activates a light in the dash. This could be the pin you're seeing move and would happen if air is in one of the two systems. The other devices you might find in the brake system is a metering valve to the front brakes which delays pressure buildup to the front brakes when discs are used up front and drums in the rear. This device is used because drum brakes require a greater amount of fluid before they start working compared to discs. Another device you might see is a proportioning valve in the rear lines which reduces pressure to them. I hope this helps and Good luck! |
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