2002, 7.3 Ex
New (front and rear) Motorcraft Blue HD pads, New MC rotors, New Carquest Calipers.
New SS brake hoses front and rear.
Slides are greased.
Brakes were bled at Ford dealer.
Fluid leves correct on MC and Steering Pump

We were driving to WNC with a 6k trailer (rough estimate). First small mountain we were coming down, there was construction traffic and as I went to reduce speed, I noticed pedal felt OK but brakes weren't much braking. Next thing I knew, was at the bottom of the pedal (like normal stopping place, not the floor) and the truck still wasn't stopped and not planning to.

A few hours later, curvy road with some hills and brakes were getting wonky again. Next thing I knew, the front we smoking at a stop light.

Yesterday I broke hard on a gravel hill to make sure the rears were engaging and they were. Also put sharpie on all 4 rotors and it was immediately wiped.

Brakes seemed 100% perfect prior to towing the trailer.

Any ideas?

 

When was the last time you fully flushed out your brake fluid?

 

Never? I've only had the truck a few months.

 

Old brake lines collapse internally causing a locked-up caliper. Very common problem. If this happens to you on the road you can wait until the brakes cool and usually release. Then do not use the brakes till you get to a shop or home!

Your brakes need a thorough going over. Including new brake lines, purging old fluid and new calipers. Most here, including me change out the rotors as well at each brake job.

I have had too many brake jobs on my Excursion to count!

2 locked up calipers up front at different times. My OEM brakes when truck was new in 2001 lasted a long time. After that I have been lucky to reach 30k before braking problems show up.
My problems are always the same. Chattering rotors leading to vibration and poor performance.

I live in S Fl where you have traffic lights everywhere.

My braking problems ended when I was on Rock Auto and saw a great deal on a Powerstop Z36 4 wheel brake kit. Advertised with carbon ceramic pads and slotted rotors. This is a bit misleading as the pad backing material is carbon and the brake pads are ceramic. This is not a set of carbon brakes that you see on exotic high-performance cars.

Over 50 K on these brakes so far and still perform perfectly.

I have used box store rotors and pads, OEM Ford rotors and have tried all the Ford brake pads. Including Motorcraft box store pads, Severe Duty pads and OEM Ford brake pads.

Don't forget the crossover brake line. The rear brakes have 3 brake lines. 2 to the calipers and 1 brake line that goes over the rear pumpkin.

I just checked my service records and have about 55k on this set up. Still perfect braking.

Everybody has their favorite brake parts, so there are many good choices. Above had worked for me very well.

 

Maybe, just a thought, the new pads weren't bedded properly before your first trip with a load?

I mean you have new everything including lines. So you "shouldn't" be having any issues.

If you went and tested them and they were all working properly maybe they have finally settled in. I'd suggest hooking up the trailer and going to a nice empty parking lot and giving the brakes a work out before your next trip. See how they are acting. Hopefully, it was a one time thing and since everything was so new they weren't settled in or possibly had some grease, fluid or something on the pads that has eventually cooked off.

Are you noticing any smells, sounds? The fact that they weren't going to the floor suggests your master has enough pressure or no air in the lines. So, it would appear it's at the calipers, pads, rotors. A sticky slide pin can cause some headaches but you stated those were change/greased. Might be worth checking to see if a slide pin is stuck or not actuating.

Good luck. Hope you get it resolved.

 

As mentioned above, replace all 5 rubber lines. I had them fail internally and they’d pinch off the lines caliper would lock up

also, slide pins. Probably have too much grease. And/or the recess is vacuum locking. I fought my slide pins for months until I learned to properly grease them. They’d vacuum lock engaged (dragging caliper). And sometimes I had a phantom slow engagement issue.

I cleaned them utterly bare, then lightly greased. 100% solved my issue. Even “knowing” what I was doing, I had over-greased them.

 

Thanks. Definitely smelled the fronts.

I drove it yesterday (sans trailer) and they seemed perfectly normal. I tried hard braking in gravel and all for corners skidded - but never felt like the ABS engaged (not sure if it would on gravel).

 

Thanks!

I replaced the 3 drop hoses, but completely brain farted on the rear caliper hoses. That definitely could be the issue.

The grease thing is worth a look - but the rears were done by a 20 year Ford mechanic so I'd like to think he wouldn't make that mistake. I did the fronts so they probably have way too much grease 🤣🤣🤣

 

I'm away from my shop and need to order a set of flare wrenches - are the flare nuts metric or standard? TIA

 

Updating this.

All new hoses, fluid is fully flushed, brakes still seem "off". I missed a turn the other day (no trailer), slammed on the brakes - and it certainly didn't stop in a hurry. For that matter, it didn't even cause anything loose in the truck to shift. I've also been noticing that I can't get the brake pedal to pulsate when I slam on the brakes (on gravel for example) which makes me wonder if the ABS is even working.

 

I would check the temperature of the brakes with a temp gun. Sounds like a fade issue (from heat) to me. The Ex's brakes at best, are just 'fair', IMO. I've found the Ex needs very-very premium brake parts to perform. I tow heavy (8-15K) a lot.

Avoid 'most' ceramic pads. Ceramic hybrids are OK.

Hydro boost?. make sure the system has clean power steering fluid (flush) and filled to the proper level. If the pedal seems abnormally hard, that's often an indication of a problem with the hydro boost.

 

Yes, has HB. Thanks, I am starting to think the brakes just are what they are.

 

Well with proper pads, rotors, good lines, fresh brake fluid, good hydro boost you should be confident enough to tow 10K. Having been through poor brakes, I think I have it about as good as can be done without going to a "big brake kit".

Have you checked temperatures? My brakes run about 180-220* F when just plain-ole-daily-driving and anything over 400* might suggest something is dragging. Towing is different and you need to make sure your load has some braking power too.

Here's what I use
Raybestos NEW calipers, no more rebuilding
Dynamic Friction HD pads for towing
Power stop cryo rotors in the front
Raybestos S-groove rotors in the rear

**EBC red HD towing pads will be something I'll try.

 

New (1500 miles) Motorcraft rotors and HD pads. New calipers. All new hoses. I'll do the temp thing today