Guest 50Plymouth Posted April 29, 2007 Report Posted April 29, 2007 Have a soft\low pedal that hits floor with my disc conv. New lines, calipers, hoses, MC, ..will replace old booster. Calipers and MC are 80's chevy style, firewall mount. I Pressure bled system after doing vaccum method. Per the images below manuals indicate the chevy combination (used with donor brackets & booster) wants a mechanism depressed durring bleeding. Is this important, could it lead to my problem. The spring loaded metering valve to front calipers is "stuck out". See picture I underlined text describing holding the spring while bleeding. :confused: Ryan Quote
Plymouthy Adams Posted April 30, 2007 Report Posted April 30, 2007 Your underlined sentence explains a procedure and reference image U12 and you included the image U21..is this a typo in the procedure in the book? What is image U12? Quote
Guest 50Plymouth Posted April 30, 2007 Report Posted April 30, 2007 Yep, I believe so. That is my braking valve and I do have single piston caliperse. Quote
Norm's Coupe Posted April 30, 2007 Report Posted April 30, 2007 Have a soft\low pedal that hits floor with my disc conv. New lines, calipers, hoses, MC, ..will replace old booster. Calipers and MC are 80's chevy style, firewall mount. I Pressure bled system after doing vaccum method.Per the images below manuals indicate the chevy combination (used with donor brackets & booster) wants a mechanism depressed durring bleeding. Is this important, could it lead to my problem. The spring loaded metering valve to front calipers is "stuck out". See picture I underlined text describing holding the spring while bleeding. :confused: Ryan Don't know what booster you are using. However, at least some GM boosters work off vacuum from the engine. Had an 80 and 81 Cutlass Supreme company car with those systems. If the engine quit you had no brakes to speak of. I also read someplace about having to hold that spring in. Think that had something to do with power brakes. So, yes that is important to do that. Since I don't work on power brakes I don't remember exactly what the book said. Quote
Plymouthy Adams Posted April 30, 2007 Report Posted April 30, 2007 Not being there..here is a stab...first follow the directions as I am thinking that this will hold the porportioning valve center. It will slip to block if you should have a failure (open line, have seen this while bleeding). Sometimes these vlaves get off center and I am sure you don't have the alrm light hooked up indication this condition, test to ground with ohm meter) Another method of centering as was directed by ford years ago when I worked for them..(Mopar never broke so you starved to death) first stomp the brake very severely, it may seat the valve center...their method was to bleed with the power on..watch the light..bleed a rear..if light did not flash, bleed the front till you cross over with a flash or go out and stays out..if did not extinguish and did flash..then very carefully go back to other side and open with light pressure till you observe the light go off..lock her down..this will require the light hooked up and another warm body. Quote
Guest 50Plymouth Posted April 30, 2007 Report Posted April 30, 2007 Yes, GM booster off vacuum. But even\especially with no booster effect pedal should be firm. (always bleed with no booster aid anyway, never car running) The concerned spring on the combination valve pertains to front lines. I blocked one port and ran to a stock-type "T" before going to each caliper. Read that is fine to do. Since I got steady fluid via pressure bleeding I assumed those front ports aren't being restricted. Perhaps my rear shoes be adjusted wrongly? That concerned spring mechanism can't be pressed in by hand now, but perhaps if I open a bleeder it can be depressed? I put my multimeter on the electrical connection for dummy light, and looked floating-ish only .5v so I don't think the alarm wasn't going. Maybe I should post a new picture of my setup. Would a softer pedal effect happen if only half the system had a problem? I know the front is well bled with all new components. of course rear is all new too. Ryan Quote
Guest 50Plymouth Posted April 30, 2007 Report Posted April 30, 2007 Update - my brake light would be on now! (I am electrically ignorant, my wife has an electrical engineering background and had mercy on me and confirmed 6v and ground. perhaps the valve and its setting are indeed my problem. Ryan Quote
Guest 50Plymouth Posted April 30, 2007 Report Posted April 30, 2007 Excellent image, and another link to a great article on brake valves like the above and how they work. What I need to do with the above problem is somehow reset my stuck out metering spring valve on combination valve. I can't press it back in even after opening a caliper to bleed off a little pressure. I may have to completely remove the combination valve to fiddle with it. http://www.classicperform.com/ShopTalk/index.htm http://www.classicperform.com/ShopTalk/BrakeValveBasics/PV2assm.jpg Quote
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