Took a break from the Saab and wrenched on this instead. Things didn’t go quite as expected, but it all turned out for the best in the end...
This ’88 F-250 (7.3L diesel) came in with a customer complaint of poor brake feel, accompanied by some parts that had fallen off in his driveway (!). Those parts turned out to be the guide pins from one of his front brake calipers.
Further inspection revealed that on their way out, the guide pins had lightly gouged up the inside of one of his front wheels. Ugly, but still serviceable:
But as I looked closer, more problems revealed themselves. Despite a healthy amount of friction material, the pads were starting to crack and crumble. The dust boots on the caliper pistons were torn, and only one piston (this truck has 2 per caliper) would retract fully to accept new pads. I even found some chunks of metal missing from one of the pistons. The brake hoses were showing some cracks and starting to flake off pieces of rubber, too.
The owner responded well to my suggestion to replace the hoses, calipers, and pads. The rotors, however, were in such good shape that there was little need to resurface them. I’m not usually comfortable doing “pad slap” brake jobs, but these ones looked really great, without even the slightest lip around the edge. I swapped the new parts on, and pushed some fresh fluid through the lines.
Satisfied with my work, the owner asked if I’d check the rears too. So I pulled off one of the drums to find this mess:
Everything inside the drum was soaked: the linings were completely saturated, and everything else had a layer of shmoo over it too. I puzzled over whether it was oil from an axle seal or brake fluid from a blown wheel cylinder, until I saw the swollen dust boots on the wheel cylinder. Well, no wonder paint was starting to flake off the springs... Strange that the brake fluid level wasn’t low, though. Come to find out- the owner had topped it off previously.
So, armed with some new shoes, some brake cleaner, and a fresh wheel cylinder, I proceeded to take the brakes apart. I set aside the old shoes and wheel cylinder, and cleaned everything else up.
Once it was all back together with fresh shoes and wheel cylinder, I bled the line and moved on to the other side. At little over $10 a pop, the owner didn’t hesitate to have a new wheel cylinder ready for this side too. But when I removed the drum, everything looked just as messy as the first except for one thing: the leaking fluid wasn’t coming from the wheel cylinder.
No, this one was still good. It was actually the axle seal that was leaking this time. And it was safe to say that the axle seal was probably contributing to the mess on the one that I had just put back together, too, just masked by the mess left by the wheel cylinder. Doggone it!
And lo and behold, the local parts store didn’t have these seals in stock. Welp, guess who’s not getting his truck back quite yet
I proceeded with replacing the brakes and wheel cylinder anyway, which went a lot quicker now that I had a reason to get that big full-floater axle hub out of my way. Or it would have gone quicker, if the brake line going to this wheel cylinder hadn’t insisted on twisting as I turned the flare nut. Fortunately, I still had a roll of bulk NiCopp on-hand to fab up a replacement, and was able to salvage the flare nuts for re-use:
With the brakes all reassembled and bled, I used my handy-dandy new shop press to push the old axle seals out of the hub. It was tricky, and I ended up shoehorning a flat-bar under the ram & through the hub to apply pressure to the seal. I’m not proud of this sketchy setup, and put up a spare sheet of bulletproof glass that I had nearby just in case.
It worked! Nothing jumped out of place until the seal dropped out from underneath. I proceeded to do the same with the hub from the other side, too. The new brake linings that I had just put on that first side hadn’t yet been contaminated by the still-leaking axle seal, so there was no need for another new box of shoes.
While waiting for new seals to come in, I did some research and learned that Ford added an “oil slinger” to these hub assemblies on later models. This allegedly helps direct oil away from the seals so that they don’t have as much oil to hold back, at least not while the truck’s in motion. Alas, fitting such oil slingers to this older truck would mean installing new bearings, and the owner was already starting to weary of project creep, so he declined the upgrade.
The new seals (National FTW) came in, and my new press made sliding them in a piece of cake (man, I can’t believe how life-changing this contraption is). The axles, bearings, etc. all got generously lubricated during assembly, and went back together without a fuss. Of course, a final top-off of axle fluid was in order. To my relief, the fill plug didn’t need much persuasion to come loose.
(As usual, I got carried away and didn’t take as many pics as I would have liked. If you’d like to learn more about the process of changing axle seals on these Ford 10.25 rear ends, check out this video I found on YouTube.)
The truck could still use a little TLC in some other areas, but it’s back to doing truck things!