Disk Brake Conversion

[Greg W 41 Dodge WC]

I converted my front drums to disk today. I used the Scarebird conversion kit sold through DCM. All went as expected until it came time to install the calipers. It was then that I discovered that I need to grind back about 1/8” where the new backing plate attaches to the spindle plate (tip of screwdriver in photo) in order for the caliper to sit properly. Once I did that everything lined up and went together well. I bleed the brakes and got proper pedal resistance. I did notice before I shut down for the evening that my rotors no longer turned freely within the caliper (they did prior to bleeding) so I’ll need to sort that before I take a test drive. This could be because I’m using my original Master cylinder without proportioning valve (drums in rear). Advice appreciated as always. 

[lostviking]

I did the same conversion on my 3/4. I didn't have to grind anything though. Should have been the exact same kit I believe. I did a thread you can refer to if you'd like. There should be a minor amount of drag if you bleed the brakes and haven't driven it. The slight wobble of the assembly pushed the pads back, otherwise they lightly make contact with the rotor.

Tight, or just a bit of dragging sound?

[Greg W 41 Dodge WC]

Thanks. The caliper is completely locked. The front end is still on jackstands and after bleeding I cannot turn the rotors by hand.  I have a couple of in-line 2 lb. residual valves arriving tomorrow (got to love Amazon) and will see if that relieves the back pressure on the caliper. 

[kencombs]

Your original master cylinder has an internal residual valve.  Guessing, but it is probably 10 psi or so and is holding the caliper pistons against the  rotor.   It will need to be removed.  I would use a 2psi for the front and a 10 or so for the rears, if they will be remaining drums.

[lostviking]

Edited: I used a PV2 proportioning valve and I also swapped in a Toyota dual circuit master cylinder. There is a thread from another member that gives the part number. I didn't know this for sure, so I just looked it up...it is a combination valve. It is designed specifically for disk/drum combos.

I'd think about doing the master cylinder upgrade, and yes, for safety it is an upgrade. Then use a proportioning valve so the rears don't lock up at the worst possible moment.

 

Edited February 13, 2022 by lostviking

[Greg W 41 Dodge WC]

Thanks for the support guys. I agree that installing a dual master cylinder is the right play and will get to that as soon as possible. In the short term I just received two 2 lb proportioning valves. I'll install those in-line to the front disks tomorrow and add a set of 5's to the rear drums later in the week. 

[kencombs]

16 minutes ago, Greg W 41 Dodge WC said:

Thanks for the support guys. I agree that installing a dual master cylinder is the right play and will get to that as soon as possible. In the short term I just received two 2 lb proportioning valves. I'll install those in-line to the front disks tomorrow and add a set of 5's to the rear drums later in the week. 

Have you removed the one from the master?

[Greg W 41 Dodge WC]

No. I’ll need to leave the master as is until I get the 5 psi regulators for the rear drums. In three weeks I’m putting in a Jeep 8.25” / 3.55 (replaced with 3.83) along with a S-10/T5 NWC. I’ll probably just not drive the truck until that time and include the dual MC and front back regulation as part of that big project.