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Old 05-23-2023, 07:18 PM   #31
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Perhaps a stupid idea… let’s see ;-)

Piston, pressure, valves…
For now you tested “on the bench” vs on the rotor right?
Did you try to simulate the pressure by adding a strong clamp in your “bench setup”? This might simulate the pressure from the rotor and therefore perhaps also change the movement due to the valves?!

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Old 05-24-2023, 08:22 AM   #32
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Interesting, this happened on the old axle too,
I think this bit of info is a big deal right here. Since this has happened on both, new and old axles and symmetrical on both sides I would direct my investigation away from anything brakes hanging on the axle. Specifically I would do an engineers assumption that everything beyond the hydraulic tee on the rear axle as "good".

I'm still in the camp that thinks this is hydraulic not mechanical.

What, to your knowledge, is not original to the van's brake system up stream from the tee? Brake lines metal and hose? ABS unit? Master cylinder? Vaccuum booster? Peddle linkage/rod? Peddle return spring paraphernalia? Peddle swing freely? Master cylinder vent cap? Just some thoughts without a van in front of me. I'd say nothing is off the table as suspect that is common to both old and new axles in the van and has been changed from original first.

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Old 05-24-2023, 09:41 AM   #33
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I'm still in the camp that thinks this is hydraulic not mechanical.



- Eric
I agree that any symmetry indicates a common cause. Apparently dragging piston side pads is one of several common faults but the link I posted did not indicate why.

I had a friend recently that was fighting a front motorcycle brake. Essentially the brake caliper was not released after being engaged. The theory was that something can get into the lines which are pushed out of the way under compression but act as a check valve when pressure is released and the master cylinder spring tries to retract the pistons.

I don't know what is in there but there is a fairly large brake system element in the underhood Anti-lock brake control system module.

I have a 2000 FSM and it provides some troubleshooting on page 206-00-5 under "brakes lock up during light pedal force" and "Brake Drag"

The first includes common Anti-lock brake control system but the second points to wheel-specific problems.
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Old 05-24-2023, 04:06 PM   #34
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[QUOTE=ShuttlePilot;321459]I think this bit of info is a big deal right here. Since this has happened on both, new and old axles and symmetrical on both sides I would direct my investigation away from anything brakes hanging on the axle. Specifically I would do an engineers assumption that everything beyond the hydraulic tee on the rear axle as "good". I'm still in the camp that thinks this is hydraulic not mechanical. /QUOTE]

Well, I know for a fact that this is a common problem on these vans, I know more than one person who has had this issue, so it might not be such a surprise that it has happened on two different axles. One of my buddy's actually swaps the pads from side to side to even the wear. It also happened on my last SMB, but not to the degree I'm seeing now. As for the hydraulics, everything from the hard line connection point back to the rear axle is new including new SS flex lines. So far, the fronts have been wearing evenly, and since they share the same master cylinder and brake booster I'd guess they are ok. It could be that the ABS unit is holding pressure on the rear calipers, but if that was happening, it still shouldn't account for uneven wear, just accelerated wear. I'm still thinking that one sticking piston in the caliper could cause the caliper bracket to twist and prevent any sliding. When I removed the slider pins from the old caliper, they came out easily, were well greased, and moved freely once the caliper was unbolted. I'm hoping this latest set of "remanufactured" calipers are a better quality, but I won't really know for several months.
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Old 05-24-2023, 04:12 PM   #35
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I have all the parts I need for a 2008+ front dist mod including all new rotors, flex lines F/B/M, booster, and master cylinder. I have rebuilt kits for the factor calipers.

I think before I start taking it apart, I think I will flush everything out from the master to each wheel just in case there is something in the lines that I don't want to subsequently pump crap into the new parts.
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Old 05-26-2023, 12:18 PM   #36
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I think before I start taking it apart, I think I will flush everything out from the master to each wheel just in case there is something in the lines that I don't want to subsequently pump crap into the new parts.
That’s an excellent idea. In addition, brake fluid tends to degrade as it absorbs moisture. Periodic flushing is recommended.
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Old 05-26-2023, 01:47 PM   #37
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That’s an excellent idea. In addition, brake fluid tends to degrade as it absorbs moisture. Periodic flushing is recommended.
I picked up an older low mileage (4800 miles) DRZ400S, I flushed the front it was very dark. The rear was forming a gel in the reservoir.

It probably had never been flushed, but that was enough to make me notice.

I ordered one of these to help with bleeding.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Pretty sure I tested this using one of the Harbor Freight manual Brake bleeders (put it upstream of the hand-operated pump

https://www.harborfreight.com/brake-...RoCUvAQAvD_BwE
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Old 05-26-2023, 02:38 PM   #38
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wrong link
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Old 05-26-2023, 03:32 PM   #39
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wrong link
fixed .................
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