Looking for brake conversion help

[boogywoogycreep]

I've upgraded my front drums to disc with this kit- https://www.jegs.com/i/JEGS/555/631916/10002/-1, and wasn't aware of the whole proportioning valve thing or master cylinder. My master cylinder is new, along with the brake booster; however, I just can't figure out if I just need the master cylinder or the whole thing. Basically, a hundred bucks versus $500. The pic is what I have in there now.

Any suggestions? What one to buy? What do I actually need to buy? Thanks!

 

[67Dart273]

the way you have worded this I do not understand. It may be that your factory master/ booster will work. depends on the bore. If it is too small you won't have much pedal. You WILL need a prop valve. Many guys buy an aftermarket adjustable one which of course allows a certain amount of tailoring.

If your master you have now was your drum master, you will have to remove or rupture the residual pressure valve in the line feeding the disks which is normally the rearmost fitting on the master. The prop valve goes in the rear line. You did not mention the year, make, and model, but---If you have or are keeping the warning light switch, you need to plumb the new prop valve to the rear of that in other words master--differential switch--prop valve--to rear brakes

as an example for master, I was using the factory drum master on my 67 Dart to feed 4x disk brakes. It is manual, but worked fine. I ruptured both front and rear residual valves, just stuck a nail through them

 

[boogywoogycreep]

the way you have worded this I do not understand. It may be that your factory master/ booster will work. depends on the bore. If it is too small you won't have much pedal. You WILL need a prop valve. Many guys buy an aftermarket adjustable one which of course allows a certain amount of tailoring.

If your master you have now was your drum master, you will have to remove or rupture the residual pressure valve in the line feeding the disks which is normally the rearmost fitting on the master. The prop valve goes in the rear line. You did not mention the year, make, and model, but---If you have or are keeping the warning light switch, you need to plumb the new prop valve to the rear of that in other words master--differential switch--prop valve--to rear brakes

as an example for master, I was using the factory drum master on my 67 Dart to feed 4x disk brakes. It is manual, but worked fine. I ruptured both front and rear residual valves, just stuck a nail through them

Yeah, I guess what kind of car would be helpful. Lol. I have a 1970 Plymouth Duster. I've been told that I need a bigger reservoir for the disc brakes, so I was thinking I could just replace the master cylinder. At this point, maybe just the proportioning valve should do the trick, unless I run into the pedal travel issues.

 

[67Dart273]

There are three things about a disk vs drum master

1...The drum master has residual valves in both outlets for a drum system. You must remove or puncture whichever feeds the disks


2...Bore size may or may not be workable when changing. Too small the pedal will be closer to the floor and you may not have enough pedal to be safe. A larger bore, too large, my create poor stopping with more pedal effort required. when switching around, be careful, as power/ vs manual masters have different hole lengths for the pushrod. You must make sure that the piston can fully return, and you can usually easily see this by observing fluid "spurt back" through the holes in the bottom of the reservoirs. Not returning enough also causes the brakes to lock AKA hydraulic fluid lock.


3...The small reservoir is a myth. the only problem there is that as the pads wear, the fluid goes down faster in the disk end of the master, than the drum end, because the piston bores are always larger. all you need to do, LOL, is check the fluid once in awhile. the larger reservoir was made for people to drive these cars for 10's of thousands of miles with no attention.

 

[boogywoogycreep]

I finally got the front brakes put in, along with new upper control arms and all the other parts necessary to make it safe to drive. Now, I have to put in a prop valve, which showed up today, and hopefully, the current brake booster/master cylinder I have will work.

 

[Deltatech]

I'm running a stock manual drum master with 4 wheel Gm metric discs so I could run the cheaper 5x5 Chebby wheels.
I just Drilled holes through the residual valves which I believe were just plastic.
No problems since I did it 4 or 5 years ago.

 

[boogywoogycreep]

There are three things about a disk vs drum master

1...The drum master has residual valves in both outlets for a drum system. You must remove or puncture whichever feeds the disks


2...Bore size may or may not be workable when changing. Too small the pedal will be closer to the floor and you may not have enough pedal to be safe. A larger bore, too large, my create poor stopping with more pedal effort required. when switching around, be careful, as power/ vs manual masters have different hole lengths for the pushrod. You must make sure that the piston can fully return, and you can usually easily see this by observing fluid "spurt back" through the holes in the bottom of the reservoirs. Not returning enough also causes the brakes to lock AKA hydraulic fluid lock.


3...The small reservoir is a myth. the only problem there is that as the pads wear, the fluid goes down faster in the disk end of the master, than the drum end, because the piston bores are always larger. all you need to do, LOL, is check the fluid once in awhile. the larger reservoir was made for people to drive these cars for 10's of thousands of miles with no attention.

Just to be clear, before I start punching holes in stuff, is this the outlet that I want to puncture? After getting all the brakes installed and bled, the brakes work; however, as mentioned before, the pedal is soft and goes all the way to the floor.

 

[WickedDart69]

I too am looking at buying the Jegs front kit as well. How well did it go together? Does it seem like its well built equipment?
Not to hijack your thread either, but if i have a 5x4 fronts now can i buy the 4.5 jegs set and it will work with my stock control arms?

 

[boogywoogycreep]

I too am looking at buying the Jegs front kit as well. How well did it go together? Does it seem like its well built equipment?
Not to hijack your thread either, but if i have a 5x4 fronts now can i buy the 4.5 jegs set and it will work with my stock control arms?

The new disc brake setup is much more beefy than the OEM stuff. I used the 5x4 kit because I didn't want to buy new rims for the car. However, to answer the other part, no, the stock upper ball joints will not fit in the new spindles. They have the holes for the larger B Body ball joints, and the original control arms have the smaller size. Assembling it was extremely easy. Once you have everything ready to go, it takes about 20-30 minutes per side. Don't forget to torque the bolts as you go. I forgot on one side and had to disassemble it just to torque two bolts. Even then, it was quick. Here are the links to the stuff I bought. I also used the Jegs promo code and got the kit for $587
https://www.jegs.com/i/JEGS/555/631916/10002/-1

Classic Performance 6374SCA-UK Classic Performance Stock-Type Control Arms | Summit Racing

Free Shipping - Classic Performance Stock-Type Control Arms with qualifying orders of $109. Shop Control Arms at Summit Racing.

www.summitracing.com

 

[WickedDart69]

I just looked at your link and it says it includes what i assume to be a spacer for the stock balljoints, did yours not invlude those or had you already planned on replacing them?

____________________________________
By installing this kit you do not have to replace the upper control arms like other kits on the market. The kit includes adapters to make the smaller upper ball joints fit the spindles included

 

[boogywoogycreep]

I just looked at your link and it says it includes what i assume to be a spacer for the stock balljoints, did yours not invlude those or had you already planned on replacing them?

____________________________________
By installing this kit you do not have to replace the upper control arms like other kits on the market. The kit includes adapters to make the smaller upper ball joints fit the spindles included

I didnt have a spacer in the kit, however, that doesn't mean it isn't supposed to come with one.