I was checking the bearings in my truck today because I noticed when testing the brakes that the wheels would wobble some when hitting the brakes. I took the drums out and the bearings looked in good shape, but when I tried to put things together again I looked in the service manual and it does not tells you what kind of preload to use, it sort of tells how to retighthen the castle nut and the lbs of pressure to apply (33lbs and then back out the nut until the next slot on the castle nut lines up with the hole for the cotter pin, but that is all, not info on preload. For my daily driver 4x4 when I service the front end I use a fish scale and set it to about 12 lbs which is within the range the service manual indicates. Does anyone know what kind of preload to use on the AD trucks? Thanks, ADTije53
There is no pre load on these bearings, just nip the nut up so there is no play at all, probably best done with wheel on then back off to nearest slot. ________ Buy Vaporizer
That's the way i do it. Jack the wheel up so it spins freely. Tighten the nut until you feel resistance when trying to spin the wheel. Then back it off enough to put the cotter pin in. Is it possible that the bearings are not the right size causing the wobble?
Ha ADT__First figure out what style bearings you have ? Roller or New style ? Also when were they last taken apart and packed with new grease ? I would think with that much movement maybe the original style roller. Take them apart check carefully for movement between the roller balls and the outer race cage. If too much replace Best to upgrade to newer non-roller style. If Ok repack and like the boy's said adjust until free play out But make sure you are spinning the wheels while tightening down then back off at the most 1/4 to 1/2 turn line up nut insert cotter key. Also with movement check the suspension. Worn king pins ? Bad shocks ? Weaken springs ? alot of other items can make the wheel movement under load. Keep us posted with your findings Thanks
Could also be a distorted brake drum. Take the wheels off and what ive done before to check drums is to get a long magnet and attach it to the back plate so its edge is very close to the edge of the drum, then by hand slowly turn the drum and see if the gap stays constant, if it gets wider or smaller as you spin the drum its distorted. Or you could go out and buy a magnetic dial guage and do the same! also take the drums off and look at the wear pattern inside, should be nice and shiny all round with minimal ridges and no high low spots, I once had a car with a cracked drum and the only way i found it was with someone else with their foot on the brakes and i just happened to run one hand round the drum and found a raised edge where the crack opened very slightly under pressure, ________ Gang Bang German
Found problem I took both front drums off and checked the bearings and found no problems, checked the drums for warping or out of round, fine. When I put things back together I used the torque wrench and tighten things to 37 lbs and them I heard a small pop, I guess the bearing races for the inner bearings were not all the way in. After that I loosen up the castle nut and tightened back to the specifed 33 lbs and everything is ok now. Thanks, Antonio
Feable attempt at tongue in cheek humor Did anyone pick up on some GM Engineer trying to be funny in the 1948 to 1951 Chevrolet Truck Shop Manual? Section 3 - Front Suspension Subsection 3-7 - Front Wheel Bearings - Adjust Quote: "The proper adjustment of front wheel bearings is one of the service operations that has a definite bearing on safety. Duh!
You may have damaged a bearing or carrier. 37lb seems a bit tight and its possible a carrier has cracked or you have flat spots on the bearings. I would be tempted to dismantle to inspect as you dont want to be watching a wheel rolling away from your fender on the freeway, also check that your bearings slide onto the spindle nice and snug and are going fully home, if they are snagging almost but not quite home you may be adjusting it without the bearings fully seated so allowing play after you drive it, another thing to check is your tires, are they egg shaped or blistered, i had a ply seperation in one spot once and it felt like the brake discs had distorted, also look at the tread as you spin the wheel, sometimes the tire can distort and as you spin it the tread moves side to side like a buckled wheel but not as bad. ________ Medical Marijuana Dispensaries
Bearing Preload ! STOP ! . You're not supposed to leave it @ 33 Lb. Ft. ! that's the spec. to seat the bearing then you adjust it to zero play and insert the cotter pin . Remember : the factory shop manuals assume you're a factory trained journeyman mechanic and know these things and are just looking for the torque spec. for referance . Overly tight bearings is why most wear out in 20,000 miles or so , I have several sets of 40 year old front wheel bearings that are all just fine & dandy , they get annual cleaning , inspection , re-pack and adjustment .
Ha Nate, you feeling Better ? Starting to sound like your old self. As normal you are correct Books like other forms of information can be dangerous in the wrong hands. Guy's need to be extra careful with these bearings espically the older style roller bearings. Too much preload will not even come close to 20,000 miles. Need to remember a lot of load is sent into the bearings when our old trucks are stopping. Not a coil spring or much of a shock to carry the weight transfer. Keep putting us in our place Nate Welcome Back
Wheel Bearing Service Notes Hanging in there....... Our trucks originaly came with ball bearings in the front hubs and they offer lower rolling resistance and better load carrying capability -IF- they're carefully looked after . if you skip the annual inspection , re-packing and adjustment , they'll poop out on you . I use two different methods of adjustment for the two types of wheel bearings : Ball bearings I snug up to seat them then I adjust to _barely_ unloaded ~ like .001" at most freeplay , some I set to zero freeplay but never , EVER any pre load ! . Roller bearings are an Equine of a different shade : After seating them , I generally put a slight amount of pre-load like a few ounces of pressure but in no case would I ever leave a roller bearing with any freeplay it in and I've never , EVER lost a front wheel bearing yet . Some times the older Castellated bearing nuts don't have sufficient slots to affect proper adjustment , you can usually find a replacement but with more slots in it @ Boat or trailer supply supply stores of from Dorman Etc. , the ' HELP ! ' section of blister packed stuff in your FLAPS often has them too..... Or , you can find a different thickness thrust washer , your old one prolly has the inner tab that's supposed to fit into the slot machined in the threads of the spindle , broken off and that's bad ~ very bad . AD's had a really W I D E washer , that's not necessary as long as it's a hardened thrust washer and doesn't wobble 'round on the spindle . ALWAYS use top quality Molybiumdisulfide (black) disc brake grease ! that's the good , short fiber stuff that'll cling to the bearing no matter how hot you get it . It should be soft & mushy at all times ~ cheapo long fibre grease is crap , usually brown in color and often comes mis-labeled as ' Hi Temp Disc Brake bearing Grease ' . I know the new synthetic greases are supposed to be good too , anyone who's experimented with them please chime in as I bet they're great too . Remember : when you'r seating (torquing) the bearing and whilst you're adjusting it , the hub must always be in motion ~ keep turning it whilst you play with the adjuster nut and use a snug fitting wrench , no pliers nor Crescent ~ in time you'll get a feel for it .
If I Ever Win the Lotto... I know one thing I'll do. I'll build an AD Hall of Fame, have someone make a bust of vwnate1 to put out in front of the doors leading into it, and have CP's name spread around the building as well. Thank you CP for having parts we need, and this web site- and thank you vwnate1 for always trying to help us, or tell it like it is. I've said it before, and I'll say it again- comments like the above mentioned are why I love this site so much. Thank you (everyone) for sharing your knowledge, and most importantly- your time! Please sign the guest book as you enter the AD Hall of Fame! Rub vwnate1's forehead for good luck!
Nate I haven't really used much of the synthetics, just what they gave us at the Chevy dealer. I know some of the guys would use the red valvoline grease in the bearings. You take them apart 10k miles later and the grease really looked burnt and was a little hard. That can't be real good on the bearings I wouldn't think. I had one old timer to give me the moly lube that you described and I've never had a bearing to come back noisey and they always adjusted out properly.
Black MOLY Grease Yup ~ you'll know it's the good stuff when you cannot get the black off your brandy new uniform shirt (TIP : always have your garage clothes overstarched , the grease & dirt cannot get a hold this way) It's always way too thin feeling but that's just the short fibers allowing it to mould and stick to whatever bearing you apply it . A few of our mechanics have boats and they use the...?blue? synthetic waterproof grease and swear by it but if looks too stiff to me . The red synthetic grease , I've been using that in an extremely thin layer on splned shafts to pevent fretting , like the tranny input shaft where it goes into the clutch disc and BMW read hub drive splines , the sliding output yoke that's exposed on my Ural Moto etc. .
Whom To Thank Not to be ungracious but , we have some Law Enforcement , Fire Suppresion Personnel and Military folks here and they're all WAY more giving than I'll ever be . I -do- apreciate you accolades but I value those types of people moreso than a simple mechanic like I . My advice is always free and prolly worth about 1/2 that . -Nate
No slight No no- There are a BUNCH of wonderful people here. Alot know- alot want to know. I just know that when things get real serious, it's nice to call Mr. Wizzard! (Rub forehead for good luck!)
Rub My _WHAT_ ?! Well ; My gut is bigger than my forehead thanx to Mom's good hair ~ Dad went bald by 21 you know I've been nervous about that my whole life . -Nate
