70 Duster power to manual brake conversion

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72bluNblu said:
Could be a lot of things. If the pedal is that weak though I would look at air in the lines, contaminated fluid, maybe a bad master cylinder. Leaks can suck air in and make it impossible to bleed the brakes. If the master cylinder wasn't bench bled it could do that too. Could be the wrong size master cylinder, or maybe the wrong push rod. Mismatched parts kind of thing. Does the pedal pump up at all?

Pad contamination usually means you have a good pedal, but don't stop. The hydraulic side works fine but you just don't slow down because there's no friction. Your issue sounds like a hydraulic problem.
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fluid clean power bled system with no signs of air master is 1 inch bore 6 to 1 ratio on pedal master was replaced recently but i am suspecting it may be my problem also have adjustable proportioning valve brakes feel best when valve is set for least rear braking ford disc brakes on rear
 
On mine it squeezes down what seems like too far to the floor to me. And it stops but it takes way too long. The rotors and drums get hot so it's definitely at least trying. I'm going to measure my push rod and make sure it doesn't need to be longer to get more push into the MC but I really doubt that's the problem. It has more travel, but I don't want to blow the other side out of the damn MC pushing it too hard. I've been wrong before though. I find it more likely that there is air getting sucked back in from a leak, and by the time I actually drive to test after bleeding it's enough.
 
I suppose the calipers could be slightly shimmed inadequately and misaligned just enough to cause an issue. They appear to be fairly centered to my eyes. I don't know any more. It's driven me so crazy I would believe anything at this point.
 
This is for the original poster. I see that you posted picture on the previous page of the prop/distribution block. Is that the original or replacement? Do you have the adjustable prop valve installed to rear that was supplied with SSBC kit? I see no mention of it?

Thanks
James
 
jmello62 said:
fluid clean power bled system with no signs of air master is 1 inch bore 6 to 1 ratio on pedal master was replaced recently but i am suspecting it may be my problem also have adjustable proportioning valve brakes feel best when valve is set for least rear braking ford disc brakes on rear
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If dialing the rear brakes back with the adjustable prop valve helps then your problem is almost certainly in the rear brakes. You said Ford rear brakes? What size are the wheel cylinders?

And for the op, i agree with PST. The SSBC kit seems to have generated a few threads on here lately with issues.

You have to consider the whole system when you start changing caliper piston sizes, master cylinders, wheel cylinders etc. If you mix and match a bunch of different stuff it's pretty easy to end up with the wrong ratio and poor performance.
 
I didn't use their whole kit, just the at the wheels kit, so calipers, pads, and rotors, and flexible lines for up front. The MC is the doctor diff 15/16, rear cylinders are 7/8, and the prop valve should be the combination valve from an a-body, not sure if it's original or not.
 
72bluNblu said:
If dialing the rear brakes back with the adjustable prop valve helps then your problem is almost certainly in the rear brakes. You said Ford rear brakes? What size are the wheel cylinders?

And for the op, i agree with PST. The SSBC kit seems to have generated a few threads on here lately with issues.

You have to consider the whole system when you start changing caliper piston sizes, master cylinders, wheel cylinders etc. If you mix and match a bunch of different stuff it's pretty easy to end up with the wrong ratio and poor performance.
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Your absolutely right on the mix match mine has disc with 2 inch pistons in caliper but even with rear brakes dialed out can not skid front brakes
 
The only mismatch I can think of on mine might be the pedal ratio but since the manual and power pedal was the same in a-bodies I can't see that being a problem. I am going to try lengthening the rod a bit though, but I'll have to bend the switch back again to do so. Maybe that will help. I haven't tested yet with all of the leaks fixed so we'll see. I think the rod travel into the MC is probably about an inch and a quarter or so
 
I'm an idiot. Earlier in this thread I was struggling with the adjustable rod being too long, and everyone asked if it was hanging up on the switch, which is what i meant by too long. I bent the switch back a bit but i still had to cut the rod. Anyhow, I saw tonite that the brake switch is actually adjustable, and has a slot for adjustment. I'm such a dumba$$. This doesn't explain everything but it probably very much explains why it's almost to the floor and not applying enough pressure.
 
Yep. Although I cut the the rod down I still had some length to give it. Opened it up some and left at least 3 threads in it and locked it down. It works like it's supposed to now. Sigh. I really had no idea there was a slot for adjustment of that switch bracket. It looked from the one side like it was a permanent fixture.
 
killnine said:
Yep. Although I cut the the rod down I still had some length to give it. Opened it up some and left at least 3 threads in it and locked it down. It works like it's supposed to now. Sigh. I really had no idea there was a slot for adjustment of that switch bracket. It looked from the one side like it was a permanent fixture.
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That's great but do the brakes stop now
 
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