Car I purchased has 4 wheel brake conversion but rear's don't seem to be working?

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by KCSTECK, Mar 26, 2020.

  1. KCSTECK

    KCSTECK New Member

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    IMG_2697.jpeg I purchased a 73 Camaro been putting it all back together it didn't have motor but has 4 wheel brake conversion 9 inch etc ...but now that I have it driving the rear brakes don't seem to be working? There isn't a adjustable aftermarket poportioning valve ? Is that what is needed and the previous guy over looked it? or change the stock looking proportions valve that has brake sensor in it might still be the stock front disc rear drum valve
    IMG_2745.jpeg IMG_2722.png IMG_2718.jpeg
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    Rear discs require a different master cylinder than rear drums. This is common with conversions done by people who don't know what they are doing. They put together a bunch of mismatched parts and the brakes end up worse than the original factory system.
     
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  3. KCSTECK

    KCSTECK New Member

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    Thanks Gary... Do I have to go after market like wildwood or can this be done another way.Can I put A factory GM version I can put in its place?? have any ideas what Might work?
     
  4. mrfleet12

    mrfleet12 Veteran Member

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    Kinda depends on your setup, I used a master from an early 80s TA with 4wd and the prop valve, prop valve is PV72 I believe and I can get the master part number if you want it.
     
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  5. dave@ztech

    dave@ztech Veteran Member Lifetime Gold Member

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    They have , like Mrfleet12 , said, disk disk , prop valves , that look just like the disk drum, that you can swap in, however, need a little more info and pictures to really help much.
     
  6. KCSTECK

    KCSTECK New Member

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    Dave@ztech. Do you need pics of the master and the proportion valve that I currently have? is it possible I can do this with just changing the proportion valve or most likely both need to be changed? let me know what pics to take and Ill do that right away. Nothing else to do with this lockdown. Really appreciate this guys!!!
     
  7. KCSTECK

    KCSTECK New Member

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    Thanks Mr fleet .sure I would apreciate to have the part number if possible so if I have to go that route ill be ready with the part numbers
     
  8. dave@ztech

    dave@ztech Veteran Member Lifetime Gold Member

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    I am just curious if he knew enough to actually replace the prop valve , I see from the other pictures it looks like he upgraded the rear line to a SS russell ? line, so a couple of pictures of the parts under the hood, and any part numbers you can see might really help
     
  9. badazz81z28

    badazz81z28 Veteran Member

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    The master cylinder reservoir size really wouldn't be a problem other than running out of fluid (due to capacity). I ran a disc/drum resv for some time before upgrading. You need an adjustable prop valve that will allow the proper line pressure to reach the rear calipers.
     
  10. KCSTECK

    KCSTECK New Member

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    03F4A100-15F7-43C9-BAF8-9E12C7A0A0F9.png Here are pics of proportion valve and number under master cylinder 05947CB0-963A-47F1-B81E-AF3449887959.jpeg A261C4E5-F804-4DE0-A5CC-20B2DF597C71.jpeg B3369341-5748-4790-BC8F-7418575BA8F1.png
     

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