setting backlash
 

ive been looking around for a good thread that goes in depth about setting backlash. i will be building my axles here soon this is my shy area. in case it matters i will be doin it on a HP30 and an 8.8

bryan

I believe it's around .008

im good on the tolerance its more of the how to. ill be switching ring and pinion to run 4.88 well pretty much a complete rebuild. so a "how to set backlast correctly for dummies":confused: is what im lookig for.

Well, the placement of the shims differs with some axles. I have found that starting with the original shims gets you close. It can be a pain to get your correct backlash and a good tooth pattern. You'll need a dial indicator and a micrometer. Some of the shims are behind the side bearings, which need a puller or press to remove. I've read many how to articles online about it. I've done it about 7 times. I say read up a lot and dig in. Reading the tooth pattern tells you what it needs.

probably a stupid question but the shims are on the pinion correct. so wouldnt you have to unload it then load it again?

by the time all this goes together i will be out of the military (june this year) so might hav eto have a garage party with someone who can teach. id like to do it right the first time.

there can be shims on the pinion pending the type of diff your dealing with(i know hp30 and 8.8)just giving a general answer there but you will need to start by setting pinion depth and bearing preload (rotating force one the bearings in inch pounds). preload will also change if your using new or used bearings. once that is set then there can be shims on the sides of the carrier bearings(again diff specific) some behind the bearings (pita) some between bearing and housing that will set your backlash. when installing those shims it needs to be tight where the shims go in or it will compress and change the backlash number. there is alot of detail and im not trying to scare you from trying it but if its a street vehicle they are either right or wrong, trail only rigs give a bit more forgivness but not much. typing cramp hope this helps :thumbup:

Scott is right, there are a lot of variables. The hard part to me is changing the shims behind the pinion or carrier bearings. It is common to have to remove the bearings and change the shims multiple times. I usually make setup bearings out of the old ones. I grind them out a little so they come off easier. Research your specfic axle online and see how they do it. Way to much to list here.

thanks for the info. im not goin to let the info scare me, cause its something i would like to learn. if i do it once more than likely i will again and again and it will be good to know how to do so.
i still have 2 months before this happens so i have time to do more research for the HP30 and 8.8 but even with all the reading i will be doing i will prolly still seek hands on help from someone who does this often to learn any little tips and tricks i can the first time.

They are not to bad after you have done them. You also need some marker dye and a acid brush to check your pattern. The pattern can tell you allot about what needs changed. Backlash is just the distance the gears travel when you hold the pinion and move the ring gear. The pattern tells you where the gears meet each other. You get the backlash and pattern close and proper running bearing preload and nail it down.

thanks for the insight. hopefully i can get all this together. ive been waiting to long for 36s, but i know if i make that move before the axles i will destroy the d35 in a hurry.

Always get a second set of NEW bearings to make set-up bearings... It makes a huge difference!!!! trust me on this one, the old bearings will be warn causing you to use too much shim, then when you press the new ones on you can have issues getting the carrier back in the case! :eek: this is a fun ghost to chase for a few hours!

I have made set-up bearings for dana 30, dana 44, dana 60, and Ford 8.8 keep them in the garage for future axle projects.

Good luck! :thumbup:

i didnt even think about that. maybe when i get everything together if you wouldnt mind walking me through the rebuild process of the axles and setting them up, should be easy they wont be in the jeep yet so i could drive them up in the truck and buy ya a 6pack or a 12 or something to help compensate your time.:beers:

I've never had that problem...

my 60 set-up set where made out of the old bearings too. Of course I'm also not setting up gears that will be used for a DD either. I think gears that don't see extended use at highway speeds have a whole lot more tollerance... One old timer told me "instead of getting a case spreader, shim it until the carrier is just snug to slide in by hand and then add another .004" before the final assembly"

Either way, a set of set-up bearings will make you a much less stressed out person when the time comes. Have fun. :beers: