Has anybody experienced this?? Our X is pulling, pretty hard too, to the left upon braking. What gives? Is it just a bad rotor, or is there some problem with the hydraulic part of the brakes not actuating the calipers evenly? Any input would be appreciated. The front end acts normally in all other conditions. The truck only pulls when you apply the brakes.

 

Your RIGHT-SIDE caliper is probably frozen. BTW, you may as well replace both ( L & R ) while you're at it.

 

Shiver me timbers, I have not even thouht about that possibility. I bet you that is what's up. I will have it up on jackstands in the am to check this. Thank you for your insight.

 

It also may be the caliper sliders. When I replaced my front brakes, I found both sides were dry as a bone. It would cause the caliper to stick as well.

 

My Excursion will tend to pull left under heavy braking at high speeds. F'rinstance, I hav repeatedly found myself at 70mph+ and the traffic in front goes all red, so I start braking, then increase pedal pressure to the point of full pedal to the floor lock-up and the X will pull the steering wheel and veer left no matter the road, surface, road crown or whatever. I recently swapped tires from the factory stuff to full snow (Blizzak) tires and the same thing. I expect there's a steering effect when the front suspension compresses. It's relatively easily controlled from the helm, but suffice it to say the Excursion is dangerous at high speed with heavy braking.

 

Well, all the brakes appear to be working as they should. I pulled the calipers off both sides and checked that they applied and released freely. They did. The slides are working fine on both sides. This is puzzling. If you take your hands off the wheel and apply the brakes briskly at speeds as low as 10 mph, the X lurches almost violently to the left. When I do the same in reverse, the front wheels turn to the right and the rear end swings around to the right. I have not inspected the rear, but they seem to be working correctly. Could there be something in the brake system (portioning valve) that could be malfunctioning? What else do y'all think it might be??

 

Turn the front rotors first, then check the back brakes. Was your X new or used?

 

I am not doubting that this could alleviate my problem, but how could this fix the pulling problem? Also, the X is a 2000. We bought it used. I see that both front calipers have "reman" stickers on them, so they have both been replaced since new. Thanks for your input.

 

From what you're suggesting -- "violent" even at 10mph -- it sounds like you have either zero hydraulic pressure to the right front brake or you have a steering/suspension problem. I can't think of how this symptom alone would arise from steering or suspension troubles and you'd have tire wear by now. Sounds to me like a kinked/crushed/bent brake line, maybe a collapsed flexible line (all of which is cheap and easy to fix and find) or you get into the more expensive master/slave problems all of which can rust and cause this problem when people aren't clean doing a brake job and introduce air (water) into the system. I'm afraid the next step is to start incremental disassembly until you spot the culprit or find some rust.
I haven't read the whole thread. Did you flush the fluid completely? Assuming so, was there discoloration?
Try removing the brake line from the right front caliper and depressing the brake pedal -- compare the release of fluid (force and volume) to the same test on each of the other calipers. If you enjoy a mess, try it with the engine running to get the boost up ...
I'm still optimistic this is a bad hard line.
Another simple test you might already have tried is to have the engine off, then pump the brake pedal until it goes flat/hard, then keep the brake pedal depressed and start the engine, the pedal should drop down further.

 

Thanks for the optimism!! I flushed/bled both front lines, only a small amt. of discoloration. Could this be a problem with the ABS? Are both left and right controlled with one computer?
Thinking of going to a Ford Mechanic tomorrow. $$$$$$ Trying not to!!
Thanks all!

 

I'd agree it's just about time to take it to the best local brake specialist shop and they should be able to diagnose the fault for free and give you a sensible quote on the repair or at least identify the part or parts you need to source for yourself.
But I still think a kinked/bent line could be the culprit. If it were ABS, you're below ABS cycle road speeds anyway. It could still be a failure in the ABS block, but probably not in the eletronics. I don't know that much about Excursions specifics, but I'd assume it has a "simple" three-channel system (one circuit for both rear calipers and one for each front caliper.) This would allow a fault to effect just one wheel on the front and lead to the pull you're describing.
In flushing the system, you should remove old fluid from the reservoir first, then flush new fluid through each line.
Mild discoloration is a combination of over-heating and rust/oxidation. If it's still a uniform fluid with no "flakes" or grit/debris, then it's just old, crappy fluid and probably not carrying too much rust.
I'm curious to know if you observed equal pressure and flow of fluid from both sides.
Also, when a caliper appears to move (the piston) at low pressure, it can behave quite differently at high pressure under boost, so the slave could still be failing.
I'd be more inclined to get a free diagnosis from the best nearby brake shop than pay a "Ford" shop to look at it. A good brake tech should be able to diagnose the cause for free (or at least very little time.)
The remanufactured calipers suggests someone already went after this problem and did the usual "replace the easy stuff and keep replacing stuff until the problem goes away" which is the easiest way to fix a problem without understanding the problem and a good way to take money for nothing.

 

i bet you 10 bucks its alower ball joint!

 

Hmm .. interesting diagnosis. I'll bite, but you have to say which side lower ball-joint is bad. (hee-hee)

 

I've had a similar, but not as violent pull to the left. I've had it in to the dealer three times for the problem. They've turned rotors, changed pads, replaced rotors, switched rotors and pads to the other side, bled the brakes and they still can't find the problem. My biggest pull comes when driving at any speed highway or city the first initial step on the brake will pull the steering wheel to the left and if I'm holding it tight enough it won't pull the vehicle to the left. It will then stop straight it doesn't keep pulling. I have had a few times it's almost pulled me into the left lane... My dealer says these big 4X4 trucks will pull, but I say bunk. keep us posted if you find a reason or a repair that will fix it.
I think it could be in the ABS. I don't know how far the dealership will go to repair this problem, but I haven't stopped pestering them. I think they may need to start replacing the components till the problem stops...

 

Well I have a few new things to check tomorrow. Thanks everyone. One really frustrating thing I have found is the fact that when someone posts a thread, the reults(the fix) is not posted. I found many similar posts here with several different diagnoses but not what actually fixed it!! I will pull the brakes off again and look at the hoses for kinks etc... Then off to the brake shop as suggested. Hopefully tomorrow I can post a fix!!!