Customs OK, I give up. DeSoto wagon brake issue.

The distribution block came with the booster and master from Speedway for a disk/disk system.


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Is the cylinder vent absolutely at the top, or merely just the bleeder being in the 'up' position, which isn't necessarily the same. Subtle but important difference that might explain your bleeding issue. Or not!! There's a good diagrammatic am online of this somewhere, and repeated here somewhere too on one of the many brake threads. Need to follow the path of the drilling from the bleeder to where it enters the cylinder.

I'd expect the rear brakes should be pretty effective even with a portion of the pads not being in use. Not really a problem either so long as you don't allow the pads to wear to the extent that the unworn sections on each side get to meet each other, thereby negating the braking effort. Don't ask me how I know this!! Remove pads and correct with a rasp and refit. But that's for the future!!

Chris

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Ford welded the caliper brackets on the axle tubes, so they're as up as they're ever going to be. I'm getting a brake pressure gauge kit. I suspect there's a faulty new part to blame, be it the master, the distribution block, a line, or the calipers. $50 on a gauge beats just buying random, more new parts.

I briefly thought maybe the torque converter wasn't unlocking, but since the car will set on gr*** and idle in gear without spinning the tires, I don't think that's it. I'm not taking it out in the snow though...

 

The caliper anchor bracket is not welded from the factory. It bolts to the housing. The caliper sliding bracket bolts to this.

Something in your combination isn't right. The pad should not be out of contact at the top of the rotor like yours. Sure, it might still stop the car..... But it isn't right.

 

Post some photos of the front view of the rotor and caliper and a rear view of the same. Can't tell much from your photos.

 

I am following this closely. I have a 2000 Exploder rear end for the 55. It's all new as well. Just waiting to go back in.

 

I bought one of those speedway corvette MC and double diaphram kits for my diamond t project and never could get it to work right, Decided there was not enough volume being pushed. Trashed it and went to the wrecking yard and found a stock dodge truck setup that had the same basic brakes as mine and it worked fine.

 

Is it possible the proportioning valve has shifting out of center blocking fluid to the rear? I fought this problem once before I found the cause.

 

A little update: I found today, after checking with my buddy at the salvage yard I got the axle from a year ago, that it is a 2003, and, it's from a "Sport-Trac" (a cutesy little pickup/SUV) that uses, surprise, surprise, completely different brake parts than it's Explorer brethren. I snagged a core rotor and caliper from one in another U-Pick yard this morning ($37 for junk, but hey, at least I can compare) and have, hopefully, the correct parts coming. I've also ordered a brake pressure gauge kit.
We'll start at the back and work forward. When I got the axle, I thought he'd told me it was an '03, but '03 Explorer parts didn't work on it, leading me to get rotors that would mount, and calipers, as it turned out, for an '01, because that's what "fit". But they don't work together.

As for the caliper mount on the axle, yes, they're bolted on, but they're in the location Ford put them. That wasn't part of the problem

 

It isn't out of the realm of possibility, for sure. Hopefully a pressure gauge will tell the story on that.

 

Yeah, one of the downsides of retaining mounting bolt patterns across models. Some parts all bolt on, but will not work together.

A 2003 Explorer has independent rear suspension (started in 2002), and as far as I remember, different diameter rear rotors, closer to 12", or so. Some of those parts swap over, but won't work, either.

Explorer Sport Trac rotors are 11.83" in diameter, versus the Explorer at 11.22". I think they have the same hat offset.

That will put the edge of the rotor 0.305" farther up into the caliper.

 

Todays search in the U-Pick yard found the Sport-Trac, with it's complete, limited slip rear. I may buy it just to have one around. You're right, the parts bolt on, but are much different between different years, models, and this combined with me listening to a counter person at O'Reilly's and believing him when he said, "They all use the same rotor, my list says so" lead to me outsmarting myself. I think I'm on the right track now, at least.

 

Check the 1A auto video on YT how to replace ford explorer 1995-02 rear disc brakes, see what looks different on your set up....

 

Hey Brian, glad you're finally starting to get it figured out, you've gotta be frustrated at this point. Do all of us who have been quietly following your adventure a favor and post some pictures and explanations as you get it together. I'm totally unfamiliar with the later Ford rear ends as I'm still working out of my stash of old 8" and 9" rear ends but it never hurts to learn the pluses and the pitfalls of the newer stuff.

 

That is great! Keep us posted.

 

Does the prop valve have a switch in it that operates the brake warning lamp? If you have any su****ions of the prop valve you may be able to test it easily by checking it for continuity thru the switch. If it reads open the piston inside the valve is still properly centered in the bore keeping the warning light off. If there has been a hydraulic imbalance condition in the valve the piston will move which will actuate the switch, closing the circuit and turning the brake light on.

I seem to recall that at least some prop valves were not really designed to be easily reset to their "neutral" position once they detected an unbalanced condition. At least not without some special tools or fixtures.

 

Correct rotors, calipers, pads. All new. Re bled. No air in rear, or front. No change. No rear brakes. Waiting for the pressure gauge set and we’ll see what the line pressure is, to determine if it’s the distribution block/proportioning valve and/or the master cylinder, or the booster. I spoke with the supplier of the transmission controller, it’s his feeling, and mine, that it’s a brake issue, not the torque converter being “locked”. It’ll set in gear, brakes set (at least the fronts), which holds the car without the engine laboring or stalling.

Frustrating. And getting expensive.


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Subscribed. Have a friend that chased the issue of no rear brakes as well with Ford rear discs. He never found an answer but thinks all is good now because he installed a hydo-boost system. I told him that didn't fix rear brake issue just because car stops now.

 

There were some that couldn't be reset at all... Replace only. I know AMC used some of those. I'd be a bit surprised if this is one of them.

There's a perception that these are 'required' for proper brake operation which isn't true. Before 'split' braking systems became required in '67 you didn't see these used on single-circuit brakes, even the early disc/drum systems. I can name you at least one OEM manufacturer who didn't install one even after split systems came in. My personal opinion is these were primarily used to give a point to install the warning light, with the 'proportioning' used to allow variations in front/rear pressures without activating the light under normal use. Some did offer additional 'safety' features like closing a port that lost pressure seal to allow the remainder of the system to function but the few times I've used that 'feature' it didn't work very well.

The first disc conversion I did was on a single-circuit system and I didn't convert to a split system because of space considerations. This was a variation on a factory system and I used the 'correct' single-circuit disc brake master. I was talked into an aftermarket proportioning valve (plumbed into the line to the rear brakes) and no matter how I adjusted that valve couldn't get the brakes to work right... until I removed the valve. YMMV

 

Well, at least you have a good chance of having rear brakes now!

 

There is a simple pin tool that threads in where the warning light switch goes. It goes in before bleeding, to keep the switch piston in the center position while bleeding.

The quick check to see if the switch valve is out of position already is to do a continuity check between the contact on the switch and ground. If there is continuity, the valve will need to be reset, as it is pushed to one end already.

 

If you have already verified that the rear pistons are moving when the pedal is pushed, check the master cylinder.

I have had a number of them, new in the box, with an internal byp*** leak. Sadly, this has not been a rare occurrence.

The symptom of this is the transfer of fluid from one reservoir, to the other. You can force this test by making sure all of the bleeders are closed, and then cycling the pedal a whole mess of times. Then check the fluid levels. If one went down, and the other up, the master cylinder is bad.

The problem is that the brakes kinda work when bleeding with this problem. The fluid takes the path of least resistance, which is out the bleed screw, when one is open.

When one is closed, it is down the faulty bore/seal of the MC, and into the the opposite reservoir.

 

Just curious on what you see, with the lid off of the m/c, when depressing the pedal. No air bubbles?

 

I just half an hour on phone with a Speedway tech guy, who VERY patiently listened and went through this problem. He asked what pedal I was using and what the ratio is. I didn’t know the answer to that, and measured the stock Challenger pedal. 3.5:1. Not the 5 or 6:1 it needs. It simply doesn’t generate enough pressure to brake against the engi. Which makes sense and explains the very hard pedal with very little free play and total travel. I’m waiting for the gauges before I tear into it, but we may have a handling what’s happening. Mismatched components. My fault, again, for using what I had available, just because I had it.



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Good find. That would hamper things.

 

Is there enough room between the pedal pad and the floor to make the business end of the pedal arm longer?

Even an inch can add a lot of leverage.

Also, that booster may not be of much help, given the diameter. If you can swap in a larger one, like a big GM unit from the yard, as big as will fit, that will certainly help.

 

Yes, lots of room.



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Don't feel bad, you had multiple things working against you!

 

That will fix right up then. Pretty easy too.

 

Thanks for listening and the ideas for things to check. There's a lot I don't know about brake components, and mixing and matching different bits certainly has shown itself to be a serious pitfall. I'll get it, I'm sure, I'm learning as I go. As an aside, my usual build has involved using ALL the components from whatever donor car I got the engine and trans from, I'd use the rear end, the MC and booster, prop valve and all, so stuff always has worked fine. This time I've gotten myself in a trick bag, and it's totally my lack of knowledge, including not knowing exactly what components I HAVE, and mixing other stuff with them. It's a good thing this is all in fun...