E450 Rear Brake Pad Replacement - long post w/pics

[CloudDriver]

I recently finished replacing the worn rear disk brake pads on our 2003 E450 chassis and thought that other DIY folks would be interested in the problems I encountered and the tricks I learned.

I have been doing brake jobs on my cars since the 60's and the change from drum brakes to disk brakes has made replacing the friction material, aka brake pads, so much easier than replacing brake shoes on the old drum style brakes. I figured that the brakes on the E450 were just larger, heavier versions of what I had seen on cars. While this is true, there are differences that made the job more difficult.

The first problem occurred after I had jacked up one side of the rear axle and removed the lug nuts. I discovered that the wheels wouldn't come off. The inside diameter of the wheel rim is a snug fit over the axle hub and rust that had formed in the tiny gap prevented the rim from moving. Application of Liquid Wrench, prying, hammering, etc. did nothing to break the rusty bond. After a half hour of struggle, I recalled reading about a trick to break rusted rims loose. I put the lug nuts back on finger tight, dropped the MH off the jack and drove a short way down the driveway. A sharp application of the brakes resulted in the wonderful clunk sound of the rim breaking loose from the axle hub. This trick works because the holes in the wheel rims are over sized for the lug bolts, so loose lug nuts combined with sharp braking causes the rims to move slightly against the hub.

Picture of oversize lug bolt holes and tight fit of rim on hub


After jacking the wheels back off the ground, I was able to wiggle the outer rim and after about 10 minutes of effort finally got it off.

Picture showing rust on hub before removing inner dual. The inner dual also required lots of wiggling to get it off the hub.


I had chocked both front tires as well as the duals on the other side before jacking, but I don't trust jacks. So I used the wood ramps that level the MH when it's parked in the driveway to catch the axle hub if the jack should fail or the MH fall off the jack.


The next problem was getting the caliper off. All of the cars I had worked on had caliper bolts to hold the caliper in place. The E450 rear brakes have caliper pins, which must be driven out of slots in order to remove the caliper.

Outer end of upper caliper pin circled in red.


There are raised bumps on the ends of the caliper pins to prevent the pins from working themselves out when going down the road. The service info I had downloaded from Ford said that there is a special tool to squeeze the end of the pin so that it can be driven out. The local Ford dealer didn't carry special tools, so I came up with another way to squeeze the end of the pin. In the picture below, the two flat blade screw drivers tapped in with the hammer act as wedges to squeeze the end of the pin, allowing the raised bumps to clear the edge of the slot.


A 3/8" ratchet extension was the perfect size to drive the pin out with some hammer taps.


Close view of end of pin with raised bump circled. The bump is shaped with a slope on the outer end so the pin can be driven into the groove easily when assembling the caliper. The sharp edge on the inside prevents the pin from sliding out. The pins are constructed as `a sandwich consisting of shallow V's of stainless steel with rubber bonded between.


The outer brake pad is attached to the caliper. This made it necessary to do some hammering and prying to get the caliper with pad off past the slightly thicker outer rim of the brake disk.

On the driver's side, the brake hose was long enough and had enough flex to allow the caliper to be removed from the disk. On the passenger side the hose was shorter and it was necessary to remove a support bracket where the hose was attached to the metal brake line.

Once the caliper was free, it was hung with wire to keep strain off the brake hose.


After removing the outer brake pad, a C clamp and a block of scrap wood pressed the two caliper pistons into the caliper.


A comparison of the old and new brake pads. The old pads had almost 81,000 miles of use and still had about 1/4" of friction material remaining. Might have been able to go another 20,000 miles.


Before installing the new brake pads, I cleaned the caliper pins and lightly sanded the caliper pin grooves and caliper surfaces that come in contact with the pads to remove rust. These surfaces were then given a thin coating of caliper grease, with care taken to keep the grease off the pad and disk friction surfaces.

Picture of the reassembled caliper.


Before installing the wheels onto the axle, I lightly sanded the rim/hub mating surface and applied a thin coat of caliper grease, in the hope that the wheels won't be rusted to the hubs the next time.

Inner wheel on greased axle hub.


Since I hadn't disconnected any brake lines in doing the job, there was no need to bleed the brakes. A few pumps of the brake pedal extended the caliper pistons against the new brake pads. A syringe removed the excess brake fluid that had been sent to the master cylinder earlier when the caliper pistons were compressed.

After finishing the other side I took the MH for a short drive. Brakes work fine, good for another 80,000 miles.

[Kurbennett]

My plan was to pull the rear and front calipers, clean and re-grease the pins, and put new pads in. Then bleed and flush the system. The RV has about 23000 miles on it but had been sitting awhile before I bought it. The brakes seem to work ok but they do drag a little. It this a good plan and sequence or??
Also is there a recommended replacement pad or will anything for a 2004 E450 super duty work?

Thanks again for all the info.

[j-d]

Trying to remember what I was working on recently, but a brake bleeder or two was plugged with rust. They can be cleaned out, or replaced. If something you're trying to do just doesn't seem to be progressing, take the bleeder all the way out and check it. The hole you can see from the outside may be OK, but the holes that feed it might be blocked.

[CloudDriver]

The pins in your second picture are the caliper slide pins. I just cleaned mine up with some emory paper, cleaned up the slide grooves in the caliper and bracket, lubricated the pins and the grooves with caliper grease and drove them back in.

Your picture of the pads looks very familiar. Pretty sure mine were tapered on the leading and trailing edges too. The taper is visible in your picture on the axle side of the pads and the pads were made that way. this taper is not due to wear, as it is impossible to wear pads to produce that type of taper. As long as the remaining pad thickness is not tapered from the leading to the trailing edge you are OK. If they are significantly tapered, a caliper piston or slide may have been sticking. In the second from last picture in my original post, you can see that the thickness remaining on my old pads has essentially no difference from one end to the other.

[j-d]

The pins you picture are an earlier version of caliper side and retention hardware. It irritates me that the fronts on E450 are the newer slide bolt setup and the rears are this old design.
From what I see here I believe something is sticking. Those pins wedge the calipers into slide grooves in the caliper mounting bracket. Either those slides, the caliper surfaces or the pins are dirty/rusty, and/or...
The caliper pistons are sticking. Either or both can leave the pads in tight contact with the rotor. Tight contact will cause damage to the pads, the rotor or even the caliper itself from heat of friction.
I think you need to find out what's sticking and free it. This could involve rebuilding the calipers or replacing them. Change the hoses too. The pads are shot, even if they still have thickness.

[Kurbennett]

Ok all,

A little help here. I have attached the pics. This is from a 2004 Ford e450 right rear brake caliper. First questions are the 2 silver pins also what the caliper slides on? I did not find any slide bolts or pins. Second question is the leading and trailing edges are wore away, but the rest of the pad looks pretty good. Is this normal? The disc itself looks good with no grooves or pitting,

[gkainz]

I remove my stuck wheels with the loose lugnut trick, but just leave the truck on the jackstands, spin the wheels with the engine (doesn't have to be very fast, maybe 5-10 mph) and then tap the brakes. The momentum of the wheel/tire will shift enough to break the rust/corrosion bond between wheel and hub. Also works to break loose the drums that my Dodge wears on the rear.

[Kurbennett]

Old thread but started on this same project today. I want to bleed the brakes as well. The caliper has the same type of bleeder as the one in the photos. I have a 2004 Ford e450 chassis. My plan was to connect my mityvac to the bleeder valve but not sure how you would do it with the one pictured.

Any insight from those who have done this would be appreciated.

Thanks!

Kurt

After some more digging on the web it looks like the valve pictured is a rubber cap over the valve, never saw a cap like that. Im good.

[Normk]

j-d wrote:
Adjusting the belts on our MerCruiser stern drive takes about 5 wrenches/sockets and some are english, others metric.

And, of course that has never resulted in the use of bad language?:B

[j-d]

Adjusting the belts on our MerCruiser stern drive takes about 5 wrenches/sockets and some are english, others metric.

[Normk]

A person doesn't get very far on vehicles these days without metric tools. When I had my tool business, inch sized tools were on the wane excepting in the heavy truck, equipment & agriculture equipment fields. Not that people weren't buying some but the bias was in the metric direction for both new tool aquisition and replacement.

Not disputing j-d's posts at all but simply making an observation. In the larger sizes the sizing becomes so close to identical that it doesn't matter so many of we old timers are light in the metrics above one inch while the young guys are often the other way.

For the home hobby type wrenching, it might be worth while to emphasize j-d's excellent point regarding the ability of 13/16" to make a tight fit onto 21 MM as this technique can be very useful in both directions in dealing with rusted or partially rounded heads. One can often tap a smaller sized socket into place to deal with a damaged head.

Another trick which should be part of everyone's tool kit is to use a tin of valve lapping, sometimes called "valve grinding compound" which is carbide grit in a water or grease carrier. Go out to your local auto supply store and buy a tin! Also buy some blue Loctite as is at least as useful.

The valve lapping compound is a tremendous help in dealing with damaged screw heads, rounded bolt/capscrew heads, especially good when one has to use an open end wrench. The additional grip is equal to spreading sand onto an icy sidewalk. Seriously! Get some as a tin will last forever in normal use.

Have a tight screw in a plastic light housing or dash panel? Push hard enough to make the Phillips screwdriver grip and you will likely break the plastic. Dip the screwdriver into lapping compound and no problem to get enough grip without hard push.

How about all the different "Phillips type" screw heads? Add to that the likely that you don't own professional quality screw drivers. Use lapping compound. Done!

Brilliant when used on power screw driver or cordless drill bits.

Loctite (blue) is usually misunderstood as something which makes things very difficult to remove but on new threads only adds about 10% to the break away torque (the effort needed to start the screw turning). On used threads, especially when there might be some corrosion, the Loctite prevents corrosives from entering the threads and so often makes for easier removal.

HIH

[j-d]

I wondered why I'd gone out and bought a metric socket when the english ones will usually cover in the larger sizes. I went back out with 13/16" and 7/8" six-point Craftsman sockets. The 13/16" will just tap in place and would have done the job. I think 7/8" would slip at the torque the fastener calls for. I probably bought the 21MM to have the exact tool in my "travel" tool box.
Props to Bryan. He was able to quote 21MM for this job, apparently from memory.

[j-d]

You're more than welcome!
There was corrosion on the bracket bolts as well as being so tight. So I wanted to be able to get them off if I ever had to "in the field." I think I used a 3/4" drive stepped down to that 21MM socket to get them loose at first. Also, when I simply replaced the pads, the contact pattern on the rotors was really spotty. So I took them off to have them turned and I re-packed with new seals for reassembly. I don't worry too much about torque on things like those bolts. The goal's to German-Tork them: gutentite...

[CloudDriver]

j-d - Thanks for going to the effort of checking those items. I know my front caliper pins are Torx. IIRC size 30, but I have a full set anyway.

The maintenance schedule said to repack the front bearings at 60,000 miles. I bought the seals, but never did the job due to the high torque on the bracket bolts. My torque wrench only goes to 150 ft-lb. The bearings are still smooth and quiet when I rotate the front tires so I'm comfortable that all is still OK.

[j-d]

A two-day rainstorm just ended and I was able to find:

Caliper Bracket is 21MM
Tie Rod Adjust Sleeve is 15MM
Caliper Slide Pin is 13MM (although I believe the ones I took out were Torx)

Hope this helps.

[j-d]

Yeah, the bottle jack is going to have to lift more than what a "corner weight" would be. Although a six-ton can lift nearly the whole weight of a 24' Class C, the force it takes on the handle would be more than we can generate laying down, reaching in, etc. With the sway bar brackets and the attachment for the track bar, I'm running out of jack points on the axle!
You can take the front calipers off with a wrench, unless the slide bolts happen to have TORX heads. My slide pins weren't damaged, but I used the new ones that came with the new pads because thay had ordinary hex heads, albeit metric.
You can replace Pads, Calipers, Hoses easily, but if you want to pack both the Outer and the INNER wheel bearings, the Caliper Mounting Brackets have to come off. They're a large metric Cap Screw and I think the head size is 21MM. Which I didn't have so I had to go buy one and it took a breaker bar to get them loose. The torque spec for them is pretty high. I can check socket size and torqe spec if you need.