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Author Topic: Single To Dual Master Cylinder Swap  (Read 1678 times)

mike

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Single To Dual Master Cylinder Swap
« on: May 29, 2012, 04:18:24 AM »



I swaped over my single mc on my 56 belvedere to a 68 dart duel mc its all on and bolted and i got all the right adapters im using my old dist block and just pluged off the rear port. Does anyone know if i have to put any loops in the brake line coming from the mc? i know from what i can see the dart had a single loop for front and rear brake but my car had a line stright to mc.
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Steve

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Single To Dual Master Cylinder Swap
« Reply #1 on: May 29, 2012, 06:59:31 AM »



Proportioning valve from a 67, 68, 69 drum brake system would be better.  Without one, the rear brakes will wear like the fronts.
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mike

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Single To Dual Master Cylinder Swap
« Reply #2 on: May 29, 2012, 08:18:09 AM »



ok ill do some bends then.  And damn i know im going to mess up my front lines going to the old Proportioning valve  as i cant get them loose.  Ill have to car junk yard too to see i he has any and how much he'll charge
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Steve

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« Reply #3 on: May 29, 2012, 12:08:01 PM »



Should come right off
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mike

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Single To Dual Master Cylinder Swap
« Reply #4 on: May 29, 2012, 01:25:26 PM »



yea ill have to get a tank and  a wrench cause i got one but its loose feeling and i can feel it  getting ready to slip
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Brian

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« Reply #5 on: May 30, 2012, 12:27:23 PM »

Do you have drums on the front, or disc? The rear just come straight off the MC and put a manual proportioning valve in line to the rear brakes...done. 

The fronts if they are still drum you need to know if the front brake cylinders have springs in them or not.  If not then you will need a small residual valve..10lbs? To keep the fluid under pressure and the cups in the wheel cylinders charged.


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Brian

02 Chrysler Concorde Lxi
84 Dodge Crewcab, Cummins/5speed
68 Chrysler Station Wagon 440/auto
48 Desoto 2dr Sedan flat 6/3spd manual

mike

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Single To Dual Master Cylinder Swap
« Reply #6 on: May 30, 2012, 02:10:06 PM »



 
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Brian

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Single To Dual Master Cylinder Swap
« Reply #7 on: May 30, 2012, 04:24:56 PM »

Same set-up I have on my 48 Desoto.  They do have a spring in them so you could probably get away with running the front brakes directly off the MC..no proportioning valve or anything.  I know on my 48 Desoto the whole brake system is just run straight off the MC..no junction blocks or valves.





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Brian

02 Chrysler Concorde Lxi
84 Dodge Crewcab, Cummins/5speed
68 Chrysler Station Wagon 440/auto
48 Desoto 2dr Sedan flat 6/3spd manual

mike

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Single To Dual Master Cylinder Swap
« Reply #8 on: May 30, 2012, 04:47:17 PM »



y couldnt i leave my original  junction box and plug rear port then run the rear directly from the rear mc?
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Single To Dual Master Cylinder Swap
« Reply #9 on: May 30, 2012, 07:25:27 PM »

The proportioning valve is to ensure the fluid pressure is balanced a little more than directly from the master cylinder. Here is something to take into consideration that I learned from the brakes on my 39 Nash. The rear wheel cylinders are something like 13/16ths diameter plungers. The front is something like 1 and 3/16ths. I have to be very careful not to lock up the rear brakes. Reason being the rear cylinders require less fluid to expand compared to the front cylinders, thus I need an adjustable proportioning valve to alleviate this issue (I learned how to drive around it for now). So, if you are not going to use a proportioning valve, which is basically set up as a 60/40 split pressure-wise, not really a good idea, balance is out of kilter, front to rear, but also side to side in the front (two lines from MC to proportioning valve, two out to the front, one out to the rear, there's a reason for that), but also make sure the front wheel cylinders have a smaller diameter than the rear. It's not like it is that difficult to get one from a salvage yard, or even aftermarket new.
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Brian

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« Reply #10 on: May 30, 2012, 07:34:45 PM »

I was having nothing but problems with the proportioning valve in my wagon.  All the troubles went away when I finally ditched that darn thing and went straight off the MC to the front brakes, and an adjustable valve to the rear.  Car has never had better braking.

The factory proportioning valve is a compromise in braking...and a slight advantage in emergency stop situations with it helping with wheel lock up.  I would never use one again.. I'd run dual adjustable valves for the best in fine tuning if I felt the front locked up too easily.





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Brian

02 Chrysler Concorde Lxi
84 Dodge Crewcab, Cummins/5speed
68 Chrysler Station Wagon 440/auto
48 Desoto 2dr Sedan flat 6/3spd manual

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Single To Dual Master Cylinder Swap
« Reply #11 on: May 31, 2012, 05:32:35 AM »

Dual adjustable valves, now that's taking a proportioning valve to a whole new level!
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