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My mechanic pulled the front unit bearing and said everything looks perfect and there is no play in the needle bearings. He said he had 2 different techs look at it and both said the unit bearing is fine. This leads me to believe that the problem is in the auto hubs. When it's locked I don't have any issues, but when it's on auto I start having problems. I guess my only option is to pull it apart and see if it's repairable or replace it. Although for some reason I'm a little skeptical about my mechanics findings.
There are TWO bearings in the hub. The needle bearing and the main center bearing. You cannot see the center bearing to inspect it, unless you borescope it through the ABS sensor. I did the same thing your mechanic did. Pulled it, inspected it, thought it was good and put it back on. It was not good. Failed completely in short order and started making a very noticeable grinding/growling noise at very low speeds.
Right but the main bearing is just supporting the wheel itself. My issue is there is extra play in the axle itself which is causing the axle to move up and down. Or maybe I'm not understanding something..... I think I'm gonna pull it all apart myself one weekend and have a look.
There can't be play in the axle shaft if the inner, main bearing is healthy. The play in the axle shaft is from the inner, main bearing being worn out. Any idea how many miles are on the hubs?
The needle bearing that rides on the axle shaft plays a minor role compared to the inner, main bearing.
I did some messing with it today and discovered that the snap ring on the outer axle shaft wasn't pushed back all the way into it's groove. I got it back into it's groove and I immediately noticed a huge difference in the amount of up and down movement on the axle. Also, the axle seal is separated in two, going to need to change it. I ordered a new unit bearing (moog), new axle seal and dust seal (timken) and some other small parts from rockauto today. Hopefully the weather will be nice next Sunday and I'll swap everything out.
Started pulling apart the front end. Checked both unit bearings. Passenger side is total foobar. Tons of play in all directions. And not surprisingly my pads are almost gone. Problem now is the rubber boots on the piston in the caliper are degrading. Otherwise they work fine. It looks like there's an outer rubber boot and an inner rubber boot/seal on the caliper. Can I drive like this or are they about to grenade as well?
If someone could take a look at the pic and let me know before I put everything back together it would be a great help. TIA!
If that were mine, I would replace the calipers if they looked like that. We have enough issues with sticking slide pins alone to not want to deal with a leaky seized piston. I would get reman calipers and let someone else deal with the rusty ones.
So here's a rundown of how everything went today. As soon as I pulled the passenger side front wheel and brake caliper I knew right away it was the unit bearing. There was so much play in all directions that frankly I'm shocked it held together. And as I beat it off the truck it seemed to get even worse.
My brake pads were almost gone, a little more then an 1/8" left on all the pads, was relatively evenly worn. But there were some pieces of pad material coming off on the edges so it was a no brainer to replace. I was a little surprised to find that the dust boots on the pistons were starting to crack as I did not have any stuck calipers, the brakes were working perfectly fine. I had a stuck caliper in the rear that I replaced November/December time but that was it. So I cleaned and greased the slide pins and made sure they were still working porperly and reused the calipers. Nothing was leaking, they were totally dry, and they pushed back into the caliper smoothly with no issue so I guess I will be leaving them until the next brake job. The rotors had plenty of life left as well.
On to the rest. The unit bearing was total junk, the needle bearings were gone as was the hub seal. And the thrust washer with the 4 grooves in it was installed backwards. Also, the inner axle dust seal was toast but no surprise there. There was so much gunk caked into the bottom of the knuckle/carrier that I couldn't even remove what was left of the seal without scraping it all out first. There was a bit of goop in the inner axle as well but mostly just near the openings. The splines on the inner axle were perfectly clean and the gear oil was clear as a can be so I'm not worried that anything got in the diff or that the bearing in the diff is bad. I cleaned the goop out as best as possible.
I put in a new inner axle seal, reinstalled the axle, put on a new hub seal, then the thrust washer in the proper direction, then greased up the needle bearings in the unit bearing (came with new studs and o-ring) and installed it, the three washers, a new snap ring, and the auto hub. The auto hub didn't want to go in at first but a few taps with a rubber mallet did the trick. At this point I checked to see if there was any play in the axle (my original issue) and there was none! Then I checked for proper auto hub operation and they worked perfectly!
At this point I took a break and ran out to get new brake pads. When I got back I threw everything back together and went for a test drive. No more thunk thunk noise. Then I went on the highway and took it up to 80. I previously had a vibration that started at about 72 and got really bad at about 75 - 80. Now I only have a slight vibration that starts at 75, it's no where near as bad as before. Makes me wonder if the drivers side is on the way out and that's what I'm feeling. But it looked totally fine, no play in the axle or the bearing itself, the only thing I noticed with the drivers side was the inner axle dust seal is missing but we know that doesn't really do much. Also, I noticed the orientation of the drivers side abs cable was wrong so it was sticking up almost touching the brake rotor, I flipped it so its now sitting in it's groove and away from the rotor.
The few hiccups were; the brake caliper bracket bolts would not come off even after soaking in pb blaster so I put my jack under the arm of my breaker bar and jacked it up, believe it or not it worked like a charm. I didn't have a hub seal install tool nor did I make the home depot version, instead I just used a large pipe and alternated hitting each side until the seal was in past the vacuum port. Then one of the nuts would not come off of the stud from the old unit bearing, it needed to be torched, but I guess if I had no other choice I could have just reused the one old stud. And the last hiccup was forgetting to put the o-ring on the unit bearing, I remembered after I had already torqued down 2 nuts.
What I learned from this is that my mechanic (or his workers at least) is clueless when it comes to these trucks. Just last week he said he had 2 of his techs check it out and they couldn't figure it out. Either that's not true or he just wasn't interested in doing the work.
Here are some pics for your enjoyment:
A needle bearing once lived here.
What was left of the hub seal.
Gear oil looks nice and clean.
Look at all that crud!
After scraping and sanding off whatever I could.
New unit bearing!
Thanks to everyone who chimed in with advice and tips on this awesome forum, I would never have gotten this done without your help.
I didn't have a hub seal install tool nor did I make the home depot version, instead I just used a large pipe and alternated hitting each side until the seal was in past the vacuum port.
You are a braver man than I!
Originally Posted by DidieX
What I learned from this is that my mechanic (or his workers at least) is clueless when it comes to these trucks.
I find this to be true at dealerships too, especially with the engine. The 7.3L hasn't been installed in a truck on the production line (in the USA) for almost 15 years so unless you have a mechanic that's been around the block (or services a fleet of school buses) then they won't have a lot of knowledge or experience with our engine. That's what FTE is for.
Good work! Saved yourself a thousand dollars at least...
Glad I don't live up there in rusty truck land...
Thanks!
It can make even basic maintenance a royal pain but thankfully this winter was mild so there wasn't too much salt on the roads.
Originally Posted by brian42
Congrats! Glad you got it up and running again.
You are a braver man than I!
I find this to be true at dealerships too, especially with the engine. The 7.3L hasn't been installed in a truck on the production line (in the USA) for almost 15 years so unless you have a mechanic that's been around the block (or services a fleet of school buses) then they won't have a lot of knowledge or experience with our engine. That's what FTE is for.
That's one reason I went with the v10, that and the cheaper entry fee. I drove a diesel mid 90's Chebby 3500 for a company I used to work for and man was it hard to find a good mechanic that was willing to work on it. But FTE has been awesome! Tons of info and helpful folks. I dropped off the old hub at my mechanics scrap metal pile and showed it to him first. His response was along the lines of "now I know which guy doesn't know what a bad hub is."
