Disc conversion issues...
dauntless89
Jeeper
- Posts
- 130
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- Location
- Spokane, WA
- Vehicle(s)
- 1969 CJ5. 225 V6, T86, D18, D44 R & D27 F, 4.88:1
Alright, so after a grueling adventure to put discs on my '69, I've hit an obstacle that requires some reaching out.
I went to hook the lines up. I hear everybody saying there's a residual check valve that you need to remove. It holds 10psi or something in the lines when the pedal is up to keep the drum hardware from collapsing. When you swap to discs, you take it out or the brakes drag.
I pulled the brake line out of the MC port and removed the little brass fitting seat, and there was nothing behind it.
I do have an old-school counterpart of a proportioning valve which the FSM calls a "line tee." It's in front of the MC, mounted to the frame rail, and it has 4 lines going in and out of it in a sideways H orientation. The two rear lines are from the MC, and the front two go to the front and rear of the rig. It occurred to me that the valves might be in there, otherwise, why would you even have it? However, removing it will require cutting and re-making 3 pieces of hard line, and I don't want to have to do that until I'm double damn sure I need to.
The FSM and every online resource I could find say that the part I need to remove is inside the MC itself, in the port, and that it was quite a bit later that they started putting the residual valves in the proportioning assembly. I thought, hmm, maybe mine doesn't have one at all? So I hooked all the lines back up and did a quick and dirty vacuum bleed, then pumped up the brake pedal to see if any pressure would hold in the line. They definitely seemed to be dragging, so I cracked a bleed valve. There were a few bubbles but no significant amount of fluid. The drag pressure reduced some, but only by roughly 30%.
I'm inclined to think there is a check valve SOMEWHERE that I need to make go away.
Rig is a '69 with a V6, and there is no power assist on the brake system. I replaced most of the hard line when I did my lift because I couldn't put the extended soft lines on since the original hard line fittings were totally rusted and rounded off.
halp!
I went to hook the lines up. I hear everybody saying there's a residual check valve that you need to remove. It holds 10psi or something in the lines when the pedal is up to keep the drum hardware from collapsing. When you swap to discs, you take it out or the brakes drag.
I pulled the brake line out of the MC port and removed the little brass fitting seat, and there was nothing behind it.
I do have an old-school counterpart of a proportioning valve which the FSM calls a "line tee." It's in front of the MC, mounted to the frame rail, and it has 4 lines going in and out of it in a sideways H orientation. The two rear lines are from the MC, and the front two go to the front and rear of the rig. It occurred to me that the valves might be in there, otherwise, why would you even have it? However, removing it will require cutting and re-making 3 pieces of hard line, and I don't want to have to do that until I'm double damn sure I need to.
The FSM and every online resource I could find say that the part I need to remove is inside the MC itself, in the port, and that it was quite a bit later that they started putting the residual valves in the proportioning assembly. I thought, hmm, maybe mine doesn't have one at all? So I hooked all the lines back up and did a quick and dirty vacuum bleed, then pumped up the brake pedal to see if any pressure would hold in the line. They definitely seemed to be dragging, so I cracked a bleed valve. There were a few bubbles but no significant amount of fluid. The drag pressure reduced some, but only by roughly 30%.
I'm inclined to think there is a check valve SOMEWHERE that I need to make go away.
Rig is a '69 with a V6, and there is no power assist on the brake system. I replaced most of the hard line when I did my lift because I couldn't put the extended soft lines on since the original hard line fittings were totally rusted and rounded off.
halp!
