Evening all. Been cruising the forums the last two days looking for my prob but not finding an exact match, so here goes.

2005 PSD 6.0 4WD Supercrew, 147K miles. Coming back from Fla. this weekend, was 20 miles from home towing a 35-foot 5th wheel. When I stopped to drain my holding tanks, the brake pedal felt kinda scrunchy. Went down further than normal, and really, felt a kind of 'scrunch' when it got there. Said to myself, hmm, shouldn't hadn't of oughten of done that. Oh well, 20 miles out, I'll figure it out later.

Back on the interstate, hadn't gone 3 miles when the ABS light came on. Was kind of a shock as I was waiting for the low fuel light to come on, and I was pretty sure it didn't say 'ABS', just a pic of a gas pump.

When it came time to exit, I let the rig slow down well before, and when I tried the brakes I was glad to see they worked. But again, the pedal went further and scrunched as I pressed harder. What surprised me was the engine down-shifted when I touched the brakes. Similar to going downhill with tow/haul on, which I didn't.

Pulled in to Likes Alot Interstate Paragon of Filling Stations and popped the hood. Couldn't find anything amiss. I was looking for a disconnected vacuum line because that's what this put me in mind of.

Continued the rest of the way home taking it easy but fairly sure now that the brakes were fine but the ABS was out. Experimented a little, touching the brake pedal. Got that downshift each time, and once, the speedo danced, but only once, couldn't duplicate that one.

Dropped the 5th wheel today but the problem remains. Put my Autel MaxiScan MS509 on it but had no codes. Held my foot on the brake and started the truck, and the pedal went down further per normal. Shut it off and pumped the brakes till the pedal got hard and started up again, with the same result. The ABS light goes out after the self-test, then comes back on a few seconds later.

Climbed around under the hood in daylight, found nothing indicative. Pulled the power plug to the HCU, looked fine. All fuses are good. Pulled the plug off the VSS and all seems well there also.

I think that covers it. We bought the truck specifically to tow a 5th wheel, which we've been doing since '07. First problem like this it's had. Pads have been changed once, and both rear calipers were changed in June due to seizing up. Standard Goodyear LT265's (3rd set), no lift. Never in water. Banks Power set-up.

 

The good thing is it isn't intermittent.

I say that, because it'll make it easier to diagnose.

1. What's the condition of the brake fluid? When's the last time it's been changed out.
Probably not your issue, but it's a good idea to check.

2. Check all the hoses and lines to insure no leaks. If there's a small leak it'll allow air into the system and cause spongy brakes etc. Does your brakes pump up back to being firm after the initial depression when they go flat to the floor?

There could be an issue with your booster. The computer should have a code if the abs light is. You might try taking it to an local autoparts place. Sometimes scanners won't read all the codes.

 

I have an intermittent ABS light on my Volvo. The mechanic said it was a sensor issue at the wheel. I think ABS monitors each wheel to see if one is rotating faster than the others (brakes locked, but not on this wheel). It then pulses the brakes.

It seems you have two separate brakes issues, that may trace to a a common failure. You have spongy brakes, and your ABS light is on. I would be more concerned about the spongy brakes.

I concur with Sasquatch that looking at your brake fluid, looking for foam, etc. would be a great first step.

Hope you find the problem quickly, and post what you have found!

 

The power brakes are driven by the power steering pump. The system
is called Hydra-boost and takes it power as a hydraulic system. So you will not
fins a Vacuum line or booster. Have a look at you fluid in the steering system
is it nasty looking or low? Also how well the steering working can be a clue.
You may want to come over to 6.0L Power Stroke Diesel - Ford Truck Enthusiasts Forums
and ask some questions being that you are driving a 6.0. I think that there is
some info about the system in the Tech Folder you should read.

Sean

 

Thanks for the quick replies. Busy day today. Got a septic guy coming to pump my septic, then home schooling the 9th grader and trying to track down a missing package FredRex claims they left on the front porch. Plus it's due to storm later.
I'll have a look at the ps fluid. It was above the fill mark but didn't note the look of it.

Figured it was Hydroboost when I couldn't find a booster and noted that the brake reservoir was mounted to something with ps hoses connected to it. Turns out the service manual I downloaded and was using is for a 2000 F250 I no longer have, hence me looking for a vacuum booster that's not there.

Was gonna post in the 6.0 section but most posts I saw directly related to motor probs, so came here instead.

I'll fill y'all in later today. Happy Monday :-(((

 

A 6.0L is a 6.0L come on over and ask it. We have some Ford guys that that is
what they work on all day. So asking a brake question is not a problem.

Sean

 

Was going to go to Autozone to see if they could pull any codes. When I started the truck, the light went out and hasn't come back on. Tried to duplicate it by changing back to the 'incident' settings on the Banks tuner; also plugged the trailer brake controller back in. Still no light. The one thing I did that might apply is I pulled the plug from the VSS to check for corrosion, water, loose pins, whatever. Didn't find anything but that may have fixed it for now.

I'll keep an eye on it, but for now I'm going to get the brake system drained and flushed per all y'all's suggestion. If it comes back I'll post in the 6.0 forum. Oh, and the folks at AZ said they can only read CEL codes, so no help with the ABS light. Guess I misunderstood some of the posts I read about getting the parts places to read the codes. My bad.

 

Back in the day there was actually two different ports for diagnostics one for engine and one for the abs.

I know the reader I bought at AZ will read both engine and abs codes from my 05 E350 work van.

Maybe the guy at AZ was un knowledgeable?

I'd check the wheel sensors for rocks debris etc. I had an olds achieva (don't laugh) it constantly had abs issues because it was constantly picking up little rocks from the cinders they laid down in winter out east. The brake pedal would go squirly when braking bc it thought one of the wheels was slipping. It'd pulsate the brake pedal and the pedal would sink lower than normal. Fwiw, food for thought.

 

Flyday58,
Pilot ? I hope to be back to turning wrenches if and when my back gets fixed.
A&P by trade

The guy at AZ most likely is not out of high school yet, if ever.
One thing you should do is go get a tube of dielectric grease and some
contact cleaner and clean both sides of the connection. Then put some
dielectric grease in and that should help keep it dry and clean.

Sean

 

It was the AZ manager, and I asked another who I know has been there awhile and he said the same thing. Maybe it's an Ole Miss thang?

Yes, pilot of big-motor people-movers. Also A&P. C130 engine/prop guy for 22 yrs with the Hurricane Hunters.

Wrenchin' is hard and don't pay. Witness all the relations who pull up in your yard asking you to look at their car cos it's making a 'funny noise', can you fix it, I'm low on cash this week, btw I got this light on on the dash what does it mean, your brother-in-law's tellin' everyone he knows you can fix anything ad infinitum.

On Topic, Got to go back to AZ today to get a part I ordered for the FJ ( it's got FOUR lights coming on! ) and will pick up some contact cleaner and grease. Love Spanaway, Bytheway. ('cept u don't hardly need the sunglasses...)

 

Well if you happen to be near I would say come on over and I'll
dig out the Snap-On Solus and we can see what you track is thinking
about in it brain.

Spanaway today Cold damp and blue sky.

Sean

 

Had a abs issue on my superduty a few months back took it to AZ and they let me use code reader told which wheel it was bad sensor. Son had abs light on just recently took it to same AZ they said did not have reader for abs told them I just used it a while back. They told me company pulled them all from them and just had the basic readers now they would not explain why. Maybe they did it everywhere. Just my experience if it helps.