VERY hot front hubs

[4x4blaze]

Hey guys, I have been dealing with the front hubs getting extremely hot while being unlocked.. I drove less than 10 miles tonight in two wheel drive with front hubs unlocked, and by the time I got back home they were red hot. Earlier today, I put all brand new bearings inside of two brand new hubs and put new ceramic brake pads on while I was at it.. I torqued the hub nut to 50 pounds, then backed off to 35.. Went for a test drive and they were super hot.. Came back home, and read my Haynes manual and it said to torque to 35, and then back out another quarter inch. Followed this step, and still the same results.. I'm totally baffled at what could be causing this.. It was also getting extremely hot with the old hubs & brake pads. & by the way, theses are on my 87 k5 that is my daily driver.. This truck is almost all stock and has been lightly off roaded very few times.. I love this truck but this issue is driving me out of my mind..... Any help would be greatly appreciated!!!!!

 

[375 H&H]

you have too much bearing pre-load. front wheel bearings are supposed to run with a tiny bit of slack, not pre-load. even hand tight with a spindle nut socket is too tight. my shop manual says to set up the front wheel bearings with an indicator to something .001" to .002" play. can't remember the exact specs, but I tried for .001" and have had zero issues.

if you need, I can post up the procedure from the Chevrolet shop manual later.

 

[Stomis]

you have too much bearing pre-load. front wheel bearings are supposed to run with a tiny bit of slack, not pre-load. even hand tight with a spindle nut socket is too tight. my shop manual says to set up the front wheel bearings with an indicator to something .001" to .002" play. can't remember the exact specs, but I tried for .001" and have had zero issues.

if you need, I can post up the procedure from the Chevrolet shop manual later.

While I agree that his preload is too tight, any bearing has to have preload. A bearing cant have slack in it or it will not correctly ride on the race.



Ive had outers off and on a million times. Run the inner nut in until it hits the bearing, spin the hub by hand. If it will complete a revolution or two and feels basically unobstructed when you go to spin it but with no wobble its good. If it spins and then stops abruptly its too tight. The lock nut gets torqued down pretty good to stop the first nut from backing off.


I dont understand the haynes instructions btw. How do you torque something to 50ftlbs and back it off to 35 ftlbs w/o breaking it loose completely and re-torquing it? Id be willing to bet if you gave the correct preload a numerical torque value it would be in the inch pounds, certainly not 35 or 50 ftlbs.

 

[diesel4me]

Perhaps the caliper pistons are now sticking,seeing they had to be shoved back in all the way to allow the new pads to fit over the rotor ?..

I have always adjusted the wheel bearings using the "book" method--tighten the inner nut to 50 ft.lbs while turning the rotor,to fully seat the inner races--then back it off and tighten it just enough to eliminate all "slack" when you pull in and out on the rotor at the 12 and 6 o'clock position--then install the lock ring (which might require moving the inner nut a bit to align the dowel pin with the ring's holes,I usually favor tightening the nut a tad rather than back it off)--then install the outer lock nut..

I've found it a good idea to check the bearings for play a few miles later too--I've had a few "loosen up" mysteriously by themselves--I think the inner races were not seated fully until I took it for a ride..

 

[Zeus33rd]

The tighten to 50, then 35 thing is to seat the bearing in the race, (mostly applicable to NEW bearings/race sets) then to back off the preload to ZERO. Wheel bearings should have as close to zero preload as you can achieve. I think the 35lbs thing is just a more or less arbitrary/guideline number they (haynes) chose to get as close to a safe way to achieve zero preload as possible, in an easy to print in words way, that makes sense to the most people. 35lbs on a new bearing/race set will generally loosen up to where it should be/proper spec after some use. If you do that 50/35 thing on old bearings, that could just be too tight. On used bearings, I always tighten till I can barely spin the hub (no tires attached) half a turn, (pretty damn tight) then loosen till a good one handed spin will get 5 or 6 revolutions. Then tighten very slowly till no more than 2-3 free spins. Set and forget at that point. No need for a torque wrench or to over think it.

New bearings are different. Better to do the 50/35 thing, drive around the block, then re-check. Leave the tq wrench in the tool box at that point and do it by feel. It's easy to feel when it's too tight.

A torque wrench on a giant hub socket is a fail anyways. Reading won't be accurate for sh!t.

 

[Bowtie85]

Id check calipers, mine sieZed up first drive, not solid but just enough to build some serious heat.

I've always just set the wheel bearings to have the slightest drag, seems to work fine.

 

[rjfguitar]

Uh, you packed them with grease right?

 

[chevyfumes]

WD-40, should be fine right?

 

[4x4blaze]

Wow, thanks for all the replies! Im gonna try my best to respond to all of you guys as best I can..

Well first let me start by saying that currently the preload on the bearings is very minimal.. After I backed the nut out a little over a quarter inch, it became loose enough to spin with your fingers.. I then snugged it back down just a little so i could not wobble the wheel. Not anywhere near the 35 pounds that I had it torqued to on the first ride. During my second test ride (with the nut loosened) the hub was still getting just as hot as it was before.

I am most likely going to end up pulling the hubs apart one more time and following your guys ( Stomis, diesel4me, and KidJethro ) instructions and then hopefully have better news to tell you guys..

And Bowtie85, I was really leaning towards the calipers too and still am a little bit, since before I ever even touched the wheel bearings they were still getting way hotter than they should. From the looks of the grease inside, it appears that they could have possibly been the original bearings after almost 30 years. The grease was pretty nasty.. It's just strange to me that both would go out at the same time

 

[4x4blaze]

The calipers for these trucks are also pretty inexpensive, so I may end up giving them a shot.. I'm still planning on pulling the hubs one more time though and loosening the nut since I still believe it is a little too tight.

 

[diesel4me]

I've had old front brake hoses go bad internally,they'll let fluid pass freely to the caliper,but wont let it flow back to the master cylinder ,and it causes the brakes to stay applied some,which can heat up everything..
Its not common for both to go sour at once though..

I've replaced perfectly good calipers before,only to find out after, when the brakes still stayed applied, it was the rubber hoses that were to blame..

I think wheel bearings would have to be adjusted way too tight and the truck driven many miles at higher speeds to get them really hot,and if they did,you'd see evidence of that,the rollers and races would turn a blue color..and the grease would likely boil out of the hub..and you'd hear some crunchy noises too probably..
I think the brakes are to blame most likely..

 

[blazinzuk]

Only thing you didn't change were the calipers. Go for a short drive at night. Hop out quickly see which parts are glowing. I bet it's your brake rotor

 

[paratrooper307]

The tighten to 50, then 35 thing is to seat the bearing in the race, (mostly applicable to NEW bearings/race sets) then to back off the preload to ZERO. Wheel bearings should have as close to zero preload as you can achieve. I think the 35lbs thing is just a more or less arbitrary/guideline number they (haynes) chose to get as close to a safe way to achieve zero preload as possible, in an easy to print in words way, that makes sense to the most people. 35lbs on a new bearing/race set will generally loosen up to where it should be/proper spec after some use. If you do that 50/35 thing on old bearings, that could just be too tight. On used bearings, I always tighten till I can barely spin the hub (no tires attached) half a turn, (pretty damn tight) then loosen till a good one handed spin will get 5 or 6 revolutions. Then tighten very slowly till no more than 2-3 free spins. Set and forget at that point. No need for a torque wrench or to over think it.

New bearings are different. Better to do the 50/35 thing, drive around the block, then re-check. Leave the tq wrench in the tool box at that point and do it by feel. It's easy to feel when it's too tight.

A torque wrench on a giant hub socket is a fail anyways. Reading won't be accurate for sh!t.

^That's how I did mine. The torque values are just to get the bearings seated and get you in the ballpark. Preload can be set by feel with no problems.