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Extreme Veteran
Posts: 474
 
Location: Rushford Minnesota | Finished my front disc conversion on my 59 fury, bled the system today and planned to go for a drive, one issue, seems like only one side of my brake system is working, almost like all the pressure is going to the front brakes and the rears aren't working at all, if i pump the brakes a bunch i can get them to engage but then I almost lock them up, any one done this conversion that can help. I have connected the fronts to the larger side of the brake resivoir as several people and the shop manual stated that was the front side of the ciircuit, do i need to add a proportioning valve ar a residual pressure valve? where in the system should i add them? car a little hard to drive right now as i can do burn outswithout trying to hard as the rear wants to keep spinning. Please help as I want to get this figured out. Thank you |
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Extreme Veteran
Posts: 444
Location: North of the 49th | Usually disc /drum combinations call for a proportioning valve , rear brakes believe it or not actually come on first with the application of the brake pedal...pressure climbs to a certain point before the front discs come in to do the majority of the braking. Mopar performance sells an adjustable proportioning valve that may solve your problem. |
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Board Moderator
Posts: 3186
 
Location: The not-so-great, dirty-white North ( Michigan) | Colin...
What Master Cylinder did you use?
Reason for asking is that some have residual valves built into them (as opposed to the ones that used the "combo" prop valves).
If you have an internal residual valve going to the front discs, then that can cause lockage. The front discs basically want no or only about 2 psi of residual pressure. The rotors push the pads back during rotation.
If you have a 10 psi drum residual valve in that Master Cylinder, then the discs will be applied all the time.
I would check that. Easy to do. Step on the brake fully about 3 times and then quickly go to a front caliper bleeder. If when you crack it, it sprays out with force rather than dribbling, then there is a residual (check) valve in the system somewhere that is too high a pressure. |
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Extreme Veteran
Posts: 474
Location: Rushford Minnesota | I used a master cylinder from a 74 dart with front disc so the check valve should be correct for the disc brakes, brakes were returning properly in the front, main issue at this point is getting the rears to function correctly, I will install an adjustable proportioning valve and readjust the rears, Does any body know for sure that the check valves are in the master cylinder or do i need to add them to the system? I recall a few systems in the past that had the residual pressure valve built in to the combo valve assembly. was this one of them? |
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Veteran
Posts: 228
Location: Centerville, SD | I have used a 77 Volare system on a project that I would guess is similiar to the 74 Dart. It DOES have a separate proportioning valve in the system. |
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brake troubleshooting help needed
