Hi,

I have a bit of a rarity for a vehicle. It's a 2000 Bigfoot E450 Class C, but it is a factory (Bigfoot) 4WD. It looks like they didn't get a 4x4 chassis, but rather got a 4x2 chassis and added the front axle in house. This has created some issues in finding parts, but I have figured out that parts from the pre-unit bearing ford Dana 60s fit, like the '92-'97 range.

Anyhow, what started the whole saga was having the front passenger wheel bearing give out on the highway. I replaced the wheel bearings on both sides, and did a whole brake job while I was there, new rotors, calipers, lines, and pads. Both the old front rotors were unevenly worn, especially the front passenger side. I am not sure if that occurred during the bearing incident, but it looks like there was an ongoing and unaddressed issue. With the new brake components, it seems the front calipers are dragging and getting really hot on short test drives. The calipers are new and I can adjust them manually with a prybar, the sliders are lubed and the calipers move around on the slide bolts when not under pressure. With the engine off, the brakes can be applied and released and the caliper seems to release. However, with the engine running, once applied the front calipers don't fully release and are indeed dragging. Some other weird things are this vehicle has the hydroboost, but is the 6.8 V10 gas motor, and it appears to have 4-wheel ABS, but the front sensors are not present. I'm not sure at what point they were removed, be it factory or a previous owner. I have ordered a new master cylinder no rule it out, but I am suspect of the ABS system keeping pressure on the front lines. The brake lines go from the master cylinder straight into a metal block, with three outputs - one for each front side and one for the rear. I assume that block is the ABS controller module. Is it possible this can keep pressure on the lines? There is no ABS or Brake light illuminated on the dash, but it seems strange that it has the ABS unit there but no front sensors connected. I'm not sure if there was an incompatibility of the older axle with the newer chassis, or if a PO just yanked them off. I'm going to go through the fuses and see if they're in place, I don't know if there is no ABS warning light because somebody disconnected them intentionally.

If it turns out to be the ABS unit causing the residual pressure, what is the solution? Does anyone rebuild them? It looks like they are hard to source and largely unavailable. I was thinking of by-passing the ABS controller all together and using a Wilwood proportioning valve instead, but will this cause any other issues? I'm really at a loss here and the mish-mash of parts on this thing makes it even tougher to figure things out. I don't know which is from a pre-'98 Ford, and which is from a 2000 E450. When was the 4-wheel ABS an option, only after the '97?

Any ideas?

Thanks!

 

Did you replace or check the rubber flexible lines to the calipers? They've been known to degrade internally creating a fluid restriction when the brake pedal is released which keeps the pads rubbing against the rotor more than it would normally see.

Typically if the ABS control module fails a code is present and the dash light illuminates. You may be in need of what's called a "service bleed" which requires a device that connects to the DLC and walks the ABS control module though its steps which assures the entire system and ABS block are completely trapped air free. (I'm not overly familiar with this process but someone on YouTube has posted something far more descriptive and informative.)

 

Hi,

Yes, I replaced the rubber lines as well. I'll look into the bleed for the ABS module. It's just so weird that the chassis has 4-wheel ABS but the front axle seems to not.

 

I have a fraction of the knowledge these guys do so grain of salt and all. Given the calipers release with the motor off and do not with the motor running I'd suspect the booster. Perhaps a kinked vacuum line or something given the work you did and it didn't happen previously. My understanding with the abs module is air can become trapped in it resulting in a soft pedal, not the opposite. Furthermore I've been told by multiple techs that the module in vans is an "open system" and does not require activation to be bled.

 

Hi,

It has hydroboost, not a vacuum booster. The booster seems to be working OK. Brake pedal is smooth, easy, and has good firmness. I thought maybe the pushrod needs to be adjusted and it was too long keeping constant pressure on the brakes, but neither the brake pedal to hydrobooster rod nor the hydroboost rod to master cylinder are adjustable. I spaced the MC away with some washers, and the front brakes are still engaged. With the MC totally disconnected from the booster, the brakes are still engaged. With the lines removed from the MC, the brakes are still engaged, but only slightly. I can turn the rotor by hand, but it won't spin freely and I can hear the pads dragging. Normally I wouldn't worry too much about it, but the slight dragging gets the rotors VERY hot. Since the brakes still seem slightly engaged with everything disconnected between the pedal and the ABS, I am thinking it has to be something going on with the ABS. But I have no idea how the ABS is not throwing codes with no front sensors even connected. I agree air would not normally cause this type of issue, but maybe the air is expanding as the system warms up and applying pressure.

 

There is no Ford factory 4x4 E series chassis. All 4wd Ford vans are conversions that are done afterwards by aftermarket companies.
Does your ABS light illuminate when you turn the key on? Do you have a scanner to check for codes. If not, get a Bluetooth code reader and download the Forscan app. It will allow you to do some self tests. Also, how do you know it has 4 wheel ABS?

 

Hi,

I'll double check that the ABS light illuminates with the key when I get it all back together, I'm 99% sure it did, then went out as it should along with the "brake" light. The 60A ABS fuse is installed in the power distribution box, I'll check the under-dash fuse block for those ABS fuses as well. Right now the battery is disconnected because I had to move the power distribution box to get the master cylinder out.

My previous scanner was really just a code reader and didn't find any codes before. I have purchased a much more advanced scanner that can also do the ABS bleed, I'll see what it finds.

I think it has (or was supposed to, or at least the chassis was supposed to) 4-wheel ABS for a few reasons:

• The brake lines from the master cylinder go immediately into the ABS module/block right next to the master cylinder. When Fords have the rear only, the front line usually just goes to the front calipers and the rear goes to the control unit on the frame rail.
• The connectors and wiring harness for the wheel sensors are in the front wheel wells, but the sensors have been disconnected and are not present. It would seem strange that Ford would pre-wire for it, and install the ABS module, then not use it. I would think they would just send out a RABS chassis in that case, but maybe that wasn't an option.
• The power distribution box has the fuse in the 4WABS spot
• The hubs appear to have the ABS tone markings on them, but I'm unsure if the 2000 E-series sensors can mount to a pre-97 axle and vice versa, but I don't see any pre-97 F350 Dana 60s with front ABS either, so who knows.

 

So here is an update:

There is no ABS or brake light that illuminates when the key is turned on. I am thinking the light has been disabled somehow. All the fuses are in place and not blown.

With the new master cylinder, the issue is the same - dragging front brakes.

I used a better scanner to do the ABS bleed, which doesn't do much, and there was no difference. The scanner did say the ABS warning light should be "on", but it did not find any ABS codes.

So the brakes have been dragging with 4 different calipers and 2 different master cylinders. When the calipers are "stuck", if I crack the bleeder they do not release and there is no spurt of fluid, so that seems to indicate there is no excess pressure going to the caliper. The only thing left that has stayed constant through this is the new brake pads. Maybe they are just a bit too thick? Even with the calipers dragging, I can still turn the wheel by hand. It brakes straight and the brakes feel great, smooth and firm. The calipers are mostly centered over the center of the rotor, slightly inboard on the sliders as one would expect with new pads. The ONLY issue is the heat generated by the barely sticking/dragging pads. Even a short 1.5-2 mile trip with gentle brake action has the rotors over 300°F. I've been doing short trips to see if they break in at all. I may go to the parts store and compare pad thickness and if there is a difference get the thinnest ones.

 

FeCamel. Did you ever resolve your dragging brake issues? I am having a very similar experience on my 2001 E450 RV. 4x2 Thanks.

 

Hi,

Nothing I did seemed to make a difference, so I just drove it. I took a 100 mile trip and when I measured the temperatures the rotors were not hot at all. It seems my neighborhood test runs were putting a lot of heat into the system regardless of the dragging. After the 100 mile "break-in", the brakes still seem to drag a tiny bit, but the rotor temps are acceptable to me now. If I spin a tire, I can still hear the pads dragging, but it's much more minimal and the tire will go around several rotations now versus only about one when I first installed all the new parts. So I'm not sure if that's just how they are or what causes some to drag and others to not, but give it a good break in and see if that makes a difference for you. The difference between dragging and minor contact is fractions of a millimeter.

 

Brake over heat problems E450 Fleetwood 2006 100,000 miles. Ford V10

I bought this used from a CA rental company and it looked amazing good condition.

I did notice that it would overheat the brakes every time I got caught in stop and go traffic. You could smell the brakes but after a cool down would work normally.

About 2019 I shotgun all the calipers pads and break hoses. Rotors back looked good, front not so much but had plenty of life and no detectable runout.

No improvement still overheated in heavy stop and go traffic. I appeared to be getting worse with brakes smoking especially at highway speeds above 50 Mph.

Started research on line and it appeared that people pointed to brake fluid and or power steering fluid which is part of the hydraulic boost system, not vacuum boost.

Both DOT 3 and DOT4 are hydroscopic and can absorb moisture. DOT 5.1 is silicon based fluid much higher temperature rating and not hydroscopic. Drained the master cylinder, replaced with DOT 5, pulled the front calipers out drained the fluid and filled with DOT 5. Bleed the brakes. Test run appeared even worse.

Drained the power steering fluid put in new.

Pulled the back calipers out drained and refilled with DOT 5. During the back brake bleed got a lot of dirty fluid out still in the lines. At one point I crack opened the bleeder when my helper was standing on the brake pedal and collected fluid that was milk white like air or trapped water.

It sat for 30 minutes and did not clear up. If it was air i think it would have risen to the top. continued to bleed the back brakes till fluid was very clean.

System now appears to work normally.

My Opinion is these brakes are the same components as the E350 GVWR 9300 lbs, and the E450 GVWR 14,050. These components are working extra hard in this application.

No more traveling at rush hour!

 

What axle is under the front of you E450? Meaning exactly what truck are you telling the parts man you need brake calipers and other parts for? Is there a tag on the axle?

 

Hi the RV has the Ford twin I beam axel's, rear wheel drive dually. Allways thought I wuould like 4 wheel drive in an RV, it would help but at 31 ft not good for off road vehicle.
JcCamp!

 

I was asking the OP not you, its his post