96 t100 rear brake drums

hello everyone, i am having trouble with these rear brake drums. i have had four sets put on and they egg shape in a few weeks.also i have used different brands and still the same thing. i have checked that nothing is sticking, and seem to have found nothing. i do not ride the brakes and we have also changed brake shoes also. i was wanting to know could it be a bent axle or axle bearing out? or possibly wheel lugs, or they over torqued my wheels? any help you can give me would help. i have done alot of mechanic work so i understand alot about them, maybe overlooking something, at wits end thanks raven:headbang:

If it was the axle bearing...you'd know from all the noise/vibration or the seal letting go and you gitting gear oil all over the brakes... ;)

If the axle was bent, you should be able to jack the rear and spin the rear tires. If it was that extreme, you'd be able to see the tire wobble...and you'd git some terrible tire wear back there.

If it was the wheel lugs, I don't think you'd be able to put the drums/wheels on straight without some pounding...that or they would've broken off by now. If you are that concerned about them, pull and replace all 12 of them...maybe $20 in parts from AutoZone?

Got piccies of the drums that are gitting egg-shaped? What brands have you used? Are you sure yer putting the shoes on correctly? What components have you replaced/repaired? What precluded the drums being replaced? Were the old ones doing the same thing? Are you applying the parking brakes when the drums are hot? Maybe yer LSPV isn't working correctly?

From a website...
Out-of-round or an egg-shaped drum can result from applying the parking brake when the drum is hot. The locked position of the shoes prevents the drum from contracting normally as it cools resulting in permanent distortion. This can cause a pedal pulsation when the brakes are applied. Drum runout should not exceed .005 in. If the run-out cannot be removed by resurfacing, replace the drum.

hi bam, i first would like to thank you. i have tried auto zone,smyth auto and can not remember the rest. they look good,no heat checks,burning, blue spots, streaks or nothing. as you would know to get egg shaped something is getting hot. i do not even use the parking brake,cold or hot, so i have ruled that out. i went down the road about 50 miles an hour put the truck in neutral and pulled slightly on the e brake and it will shake your teeth out;) so i know it is in the rear. i had the drums turned but the guys said they werent that bad, so i am at a loss. my next thing is to get the old dial indicator out, turn the hubs around bolt them backwards, and see how bad it is out..... do not know what else to try. have tryed everything. you mentioned the lsvp, what could it be there?? thanks a million bam looking forward from hearing from you. ready to get a hammer out lol raven:headbang:

I take it that you got yer truck this way? How are those tires looking? Any indications on there with the wear patterns? BTW...is this a 2WD or 4WD? Have you looked at the axle tubes? Any mods to the truck at all?

Are both drums going out of round or just one side? Are you replacing both drums with the same brand at the same time? BTW...who's doing yer work fer you? Are they charging you fer all these drums? I just figure after the 2nd set of drums..I'd be looking at all the components.

One of the tests that I use fer the LSPV is to jack up the rear by the differential (make sure you chock those fronts) and spin the tires. Step on the brake and see it the wheels stop. If it doesn't...it could mean yer LSPV could be clogged up.

Got any piccies of the truck and the rear axles? They sure would help... ;)

hi bam, thanks for replying, no honestly all this just happened the last few months. as for the tires they are not too bad. this is a four wheel drive ext cab with no mods, completely stock. i am beginning to believe that it is only one wheel, but i am going to check it with a dial indicator. by the grace of the good Lord this set they are not.:clap:bam i am really looking at everything this go around, i honestly believe that part of it is the steel they use anymore it just plain sucks. i am starting to believe some of it may be in something sticking, i have been using anti seize on the brake shoes and i am wondering if after it gets heated then cool if it isnt letting the shoes retract back right. i am also looking to make sure the springs are not weak and pulling right, as of now i have no pics of nothing, i went and got new shoes and exchanging the hubs and try again. if i may ask what is the lspv, is that the proportion valve?? just looking at it, thanks bam for everything in advance. raven;)

LSPV = load sensing proportional valve... As the bed gits closer to the differential, the rod changes the rate at which brake fluid is distributed to the system. In other words, as you load more weight on the back of the truck...more pressure is supposed to transfer to the rear brakes.

Um...you should stick to using brake grease fer the brake shoe contact points as directed in the service manual...not sure what the melting point of the anti-seize yer using.

So what changed on yer truck a few months ago? Loaded something in the truck? Went through some water? New driver(s)?

Did you try yer coast test with the normal brakes after you tried it with the e-brake? Did it give you the same shaking/noise?

Did the brake shoes git adjusted correctly fer both sides after the new drums/shoes were installed?

hi bam, thanks for your reply. as for the truck i have done nothing out of the ordinary. i have not had a chance to look at it yet,but i will saturday i hope:clap: i am doing everything i can do to it and hopefully it will be ok. i am going to order new springs and all. the brakes were both adjusted correctly ,BUT i am going to look at the bellcrank real close.;) adn take your advice on the anti seize and get some brake lube.;) i will stay in touch bam!!!!!!! we will see:thumbsup:

hi bam, well yesterday was the day. i will tell you what i found. the shoes that were on the truck i do not think where sliding right, heres why> when i took the shoes off, the brake part of the shoe was past where the pads meet the back plate! when i got too looking the brake pad itself was what it was pivoting on not the metal part of the shoe but and we know the brake pad is meant to grab to help stop, bam that was the only thing i seen in my opinion. i also torqued the wheel with a torque wrench so i also could rule that out also. but we'll wait and see, hopefully get to drive it some today:clap:. let you know more! raven:D

Piccies...piccies!!

Was this at the top where the wheel cylinder is at or at the bottom where the adjuster is at?

PICCIES!...please. :D