Front Brake Upgrade Makes Soft Pedal

[mikracer]

I mentioned the ABS module a little while back. There's an easy test to check whether the module is letting fluid pass by. If I remember correctly, there 2 rubber grommets that cover a pistons. You take those off and stick like a straightened out paper clip or something long and straight. You have someone start the van then press the brakes while another person checks to see if the paper clip or whatever gets pushed out. If it pushes out, your module is bad.

My buddy that's a mechanic at a Ford dealer diagnosed and fixed mine. I too had a soft pedal that went to the floor and erroneously swapped out the MC thinking that went bad.

[Youngster]

Originally Posted by mikracer

I mentioned the ABS module a little while back.
...My buddy that's a mechanic at a Ford dealer diagnosed and fixed mine. I too had a soft pedal that went to the floor and erroneously swapped out the MC thinking that went bad.

I feel your pain. The unidentifiable problem that is a black money hole.

My van had the exact problem. I replaced the MC, still the same, peddle to the floor, but my van would still brake to a stop.

After a bunch of inconclusive research, making my best guess I rolled the dice and picked the most expensive option, replace the hydraulic control unit / ABS module. Problem solved.

After reviewing your thread it seems you have tried everything but the HCU. Test the HCU!
It's a chunk of $$$ but it could solve everything.

[jage]

No shop 1 did the HCU a month ago after the first two MC didn't work.

Is it possible the calipers are on upside down (wrong sides)? I mean it doesn't explain why MC 2 tested bad but it fits everything else, e.g. Air trapped in calipers that never bleeds completely, seems better or worse depending on the bleed but never completely out?

Also shuttle if you really want to help coming up here next weekend I could use help with my winch and now delayed OBA install. Don't have the van this weekend, it's at shop.

[karma]

Originally Posted by jage

So after weeks of runaround from the first shop I took it to the second $$$ shop that said the MC tested bad. They put a third brand new MC in and did a whole fluid flush and about 40 minutes ago I just went and picked it up. I asked, it's good right it's done that fixed it? And they said, yeah took it for a test drive it stops fine and everything. Paid my bill, got in, started it up, pushed on the pedal and it's softer than ever. Right to the floor.

They're like well it stops fine and I'm like yeah there are freaking brakes on there for an F550, the brakes would stop a loaded dumptruck that has never been the problem.

Needless to say I'm a little bit angry. We've topped $3000 in parts and labor and that's after the actual cost and install of the brake upgrade kit. All that's gotten me is worse than ever. I'm maybe more than a little angry, like I'm out of my gourd, what the heck is going on.

I left the van with the $$$ shop, I don't even know and didn't ask what they're going to do just that they are going to look at it first thing Monday. I'm starting to worry about an upcoming trip, I mean forget that I was going to spend the rest of today and this weekend packing but I'm now wondering if I'm even going to be able to take the van back to Indiana this year. It's literally been offline for months and I've missed a trip to Palo Duro and several spring camping opportunities, but going back to Indiana is a not optional- we have a rented house and plane tickets locked in and bringing the girls halfway across the country in the van is a pretty crucial piece of the trip.

I don't know what else to say, I'm mortified. I've lost hope. I think this might have killed the van for me.

I had exact same experience on a different vehicle. I changed all calipers, bled and bled and bled..... still no change. changed MC did bench bleed and then bled some on vehicle as well still no change. Had an upcoming move 2,500 miles with trailer attached..... $h1t scared i gave it to a shop thinking may be they know something i don't ....... lost a chunk of money still no change...... walked out pissed and had no choice but to take it on the trip.
Kept like 10 car distance from traffic the first day of trip, 700 miles. Rented a motel at night and went to sleep. Next day morning when I started driving i noticed the brake got firmer and felt way better. By the third day the whole sponginess/ pedal sinking was gone.

I've no idea what happened, i guess driving fixed it. Not suggesting anything but sharing my experience

[jage]

Everybody cross your fingers, I'm going, again, to pick up the van, again.

Guy worked on it for two days and I we're on the fourth new matter cylinder. I asked what was different and she said "the shop owner told him to do two things and it worked."

What two things I don't know because they're out on a part run for someone else. My brakes have become real life click bait...

[MadScience]

Jage: Good luck!!

Originally Posted by karma

I've no idea what happened, i guess driving fixed it. Not suggesting anything but sharing my experience

Some pads can be squishy until they bed. I think that's been ruled out in this case though.

[jage]

Nope.

Master cylinder #4 and "bled the hell out of it" and it's the same. Actually it's ever so slightly better than when I dropped it off, but it didn't address the problem at all.

Before you ask, what were the two things? They didn't tell me. He put another MC in, they were very clear I didn't need to pay for that one, and then "bled the hell out of it". Apparently the two things the owner told him to do he "didn't need to do" because it, of course, stops fine.

So here is where we are, 4 master cylinders, 1 Hydrolic Control Unit, lots of bleeding, different results of pedal stiffness each time and always the same problem- the pedal sinks to the floor in an emergency stop or if you just apply pressure.

One real problem with this as I discovered on the way home, I hit a bad yellow and hard stopped and my foot hit and depressed the accelerator on the way to the floor. Sure it "stops fine" but that is very dangerous- something I've actually had happen with large boots on before.

Two more bits of information:
1. when you shut down the van the pedal is rock solid and does not sink.
2. I asked them to have the mechanic double check the calipers to ensure they didn't go on upside down, you know, trapping air because the bleed valve is up compared to most of the caliper. They said he said they were not. I am really annoyed that I never once had a single word with the actual mechanic- I absolutely loathe the telephone game and lord knows what information was lost in translation.

So shop #2 is done, they've done all they can apparently and "aren't charging me" for the second MC after all.

My next move is the dealership. At this point ABS malfunction and/or new HCU not being correctly purged combined with "well maybe they'll know what the frick is going on". I'm torn because I can go Thursday to a local dealership or I can drive it across the country like this and take it to the one in Indiana I actually like. Bonus for driving it, I might wake up one morning and have everything be fine.

Any other thoughts?

*Edit: The counter girl at Medved (local dealer) mentioned the brake booster bleeding into the master, since I've had 4 MCs and no better results. Seems like a pretty obvious next step right?

[Twoxentrix]

Been monitoring your thread to see what the end result of your predicament turned out to be - partly for educational purposes, and partly to see if the resolve validated my choices.

I had similar about 3 months ago. Braking system was OK, but I had to romp the pedal quite hard to the floor for quick stops but had to maintain a good force on the pedal to get the Van to stop - and it always gave up a little at the end (also mushy).

Dealer had just replaced both Front end Brake-Man rotors, calipers, and brake pads (all at their expense). At that time I also had them replace the rear rotors, calipers, and pads (didnt even charge me for that because of the snafu that prompted them to fix the same on the front). It made the brake system better than what it was, but like you it still didnt have the response on the pedal that it should have.
Brought it back and Dealer said it was the Master cylinder and vacuum boost (believe they said that they both piggy back on one another when installed, so do both at the same time).
So bit the bullet and had both replaced - Fixed my issue altogether...feels like a whole new brake system now.
I would say do the Brake Vacuum booster

[jage]

Originally Posted by Twoxentrix

Been monitoring your thread to see what the end result of your predicament turned out to be

ME TOO

[Gooseberry]

This is going to sound strange but take it to a dirt road and activate the abs a few times to see if it changes anything. My brakes have done it and I went through the same process but while pissed I nailed the brakes on a wet surface at a good speed and I got a solid peddle.


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