The Prodigy is a trailer brake controller, and is electrically based. Wouldn't be able to affect the X's brakes....

To re-hash what I have done on the X's brakes in the past 12 months:

All new brake lines (Read about my near-death experience - in another thread - while pulling the camper!)

Completely flushed the system out with new DOT 3 fluid.

New front pads, rotors, calipers, slide pins, and just last week, new rubber brake hoses.

Rear rotors, pads, slide pins. Calipers were in great shape.

Beats me.....

 

got me beat then , the EX braking system is quite a simple one.

you have not noticed any fluid leaking anywhere ?
or your fluid reservior dropping ?


your brake pedal is firmly attached ( i know this sound stupid ) but may cause a drop when pushed if loose (not sure why only turning right though)

 

cardiac69. sent PM let me know if you got it. computer being stupid.

 

He said when he turns right guys...........

 

Would posting this over in the Super Duty forum help? I might go and post a link to this thread....

 

cant be any worse Bob....


new eyes an all ......

 

If I am reading this right, it doesn't sound like you have the classic mushy feel of a system with air in it, it sounds more like the pedal depresses normal like - but further than normal - and then feels good and solid?

Here's a story and a theory. Most high end motorcycles use "floating" disks (or rotors), in which the disk is allowed to expand radially as they get hot to reduce warping on these ultra thin, ultra light disks. A side effect is the disk can move side to side just a bit.
After a few miles, the disk vibrating ever so slightly side to side will push the caliper pistons back into the calipers a few thousandths of an inch. The next time the brake lever is pulled, the MC has to push the pistons back out and then apply pressure, causing a longer than normal travel at the lever. On one bike I had, after about 100 miles of no braking, the first pull would come almost all the way to the bar.

So.... Is there anything going on up front that would allow EITHER the rotor OR caliper to move with relation to each other during a right turn? Just a little shift could cause misalignment that would push pad and piston back in. This is exactly consistent with everything you described, including how it doesn't happen if you drag brakes during the turn. The light pressure prevents piston from being pushed back in.

Wheel bearings? Caliper to bracket bolts? Caliper bracket to axle bolts?

ps - If I had to check only one thing, I'd start with wheel bearings.

 

I still think something is loose in the right wheel area.

 

I like what you are saying here, but since they have floating calipers, and the slide pins operate smooth as silk, would it still matter?

The pedal feels great when driving straight down the road. Make a right turn, and the pedal goes down another 50%. The brakes still work, but not nearly as well, and it does pull to the right. 2 pumps and they are back up to normal, nice and smooth, no pulling, until I make another turn.


I might have to make a right turn into the driveway, stop with the e-brake, and get it up on jackstands and take a look. Don't know what else to do.

 

Yeah, the nut holding the wrenches....

 

Nice theory!

Like I said way back in the thread, start from the beginning. Recheck everything you did and make sure it's all installed properly and working correctly.

In light of the post quoted above, when you do check everything (if you decide to do so), make sure the wheel bearing nut was set properly and didn't loosen.

To set it properly, tighten it down past the proper torque point, then back it off to the proper torque point, being 12ft lbs. 12ft lbs aint much, but if the bearing nut wasn't set properly first, it can back off, allowing the bearings too much movement, which could (in theory) cause the problem posted by mws.

Stewart

 

Yes.

As significant and abrupt an effect as you describe makes me think the caliper and rotor are "twisting" with respect to each other. Which one is moving doesn't matter, the net effect is the same.

 

Something not mentioned yet is ABS. This system can EASILY cause a 50% drop in pedal pressure. I know someone who was having some goofy pedal-pressure stuff under certain conditions after he installed detroit locker in rear of his PSD. He got very edumicated about this ABS system diagnosing his 'problem'. I'll send him a linky to this thread and see if he has any input.

Have you scanned for ABS codes? Wheel/axle speed sensor issue??

Btw, the reason I suggested 'manual' brake bleeding is I know for a fact that vacuum bleeding does not work well on all brake systems. I realize this must have worked for you before, since you've been into this brake system before, but if you are 'at wits end' - it easy and FAST way to 100% rule air out. I do agree, this is NOT typical of an air problem - but maybe its enough to **** off ABS???

 

Oh yea, I love brake systems. As stated earlier, I'd check for play in the bearings. Make sure all the "stacked" components are flush and tight. (no rust or debris between rotor/hub/knuckle etc.) Next I might look at the ABS.

The symptoms occurring only after a R-turn don't necessarily point to the right side, only that it occurs when the left side is undergoing pos camber acceleration and the right side is undergoing neg camber acceleration as it relates to mechanical movements. Also you have to consider the cycling of the front knuckles to the left and right. This is where you may have issues with the brake lines or ABS harnesses.

Sounds like the hydraulic system is tight. My wag is if it is a restriction, you are "suffering" from it under all conditions "except" when turning right. This would allow the constricted fluid to fill the cavity (or more completely) under that one condition, requiring more fluid, hence the "soft" pedal until equilibrium is obtained. Finally ABS

I believe your X has 4WABS where my old little truck has only RWABS (hence my problems with my locker ) If you had a small short in one of your front pick-up leads, this could be enough to confuse the ABS, but not necessarily set a light during right turn operations. Something to consider, and you could alternately disconnect each front tone ring and take a drive to see if there is any difference in performance during right turn operations.

If I were a bettin man, I'd bet out of spec wheel bearing (as mentioned earlier), second... ABS.

There was some mention of vacuum issues, you probably know this, but in the event of lost vacuum, your pedal would be HARD, with less perceived movement. An easy way to rule out the vacuum assist would be to disable it and retest (in a VERY safe area ) You could just pinch off the vacuum feed to the brake booster, depress the pedal a few times, and test away.

 

For the record, ABS module is also number two on my list, but I'm not sure how to test or troubleshoot it.... short of replacement.