rebuild diffs?
 

hi! i have 2 questions.

1. do i need to rebuild my diff? its favoring the left side. so when i floor it on rocks and sh!t it spins more on the right side.

2. if so, where can i find a guide on doing that seeing as i havent done it before.

little things: its a HPI savage with metal diffs and a highly modified Peak .28.

The brg on one side of Sav diffs is undersized for the load - the side on ring gear. IIRC that brg is on one side in the front and the other side in the rear, so I could be causing the prob.

Maybe its just a bearing prob. I wouldn't assume its diffs unless the connection between wheels and F to R has been lost.

You might be thinking about a different truck. The sav bearings are equally sized on each side of the diff. I think you're probably right about it possibly being a bearing problem though. The bearing on the ring side HAS been giving people a bit of trouble lately, but a little shimming seems to help quite a bit. A friend of mine went through 3 ring side bearings in a week, till I finally convinced him to let me touch his truck long enough to shim the diff for him. I believe the excessive slop allows the shallowly beveled ring gear to exert enough lateral force on the bearing each time the throttle/brake is applied, that it eventually pounds the inner race right out of the assembly. You'll always have that lateral force due to the interaction between the ring and pinion's teeth, but minimizing the slop is like shortening a hammer's swing.

You might check your axle bearings as well. I've seen a few savages lately that have had rusty axle bearings right out of the box.:(

Here is HPIs .PDF on how to rebuild the Savage diffs. Kinda depends on what you're after, it's ok for general use. A couple of things I would add though are, grease the inside of the housing/gearbox to catch any foreign material that might make it's way in and seal the skidplate to the housing with RTV.

Click on this Google link and select the first result for a kinda generic how-to on diff shimming.

Good luck and have fun with it!:smile:

ok thanks all. i took apart my diff and the umm... 2 gears were cruched up pretty bad. so i ordered rebuild kits and shims and grease.


thanks alot!

Didin't say anything about brgs being diff sizes.

Once you've shimmed them properly and put diff in alum diff case in alum bulks, brg on ring gear side is weak link. Shimming Sav diff how to -

http://www.savage-central.com/module...wtopic&t=55122

nope all bearings are the same size and all new. i ordered shims to.

thanks.

Ah, pardon my retardedness, I misunderstood your post.

I've already posted a link-to-a-link to that page so....HAH!!! I WIN!:smile:JK

oops... so did i:eek:

well all the bearings were fine and all the axel bearings are brand spankin new.

whats the best way to get rid of the grease?

A lot of people use naptha. You can use just about any solvent really...gasoline... I use wd40 by the gallon in a little parts washer,

http://www.harborfreight.com/cpi/pho...6999/96952.gif

http://www.harborfreight.com/cpi/pho...099/44007.gif"

as long as it's not something that's going to effect the plastic parts (safety first of course, and dispose of used solvents properly). Sometimes I use a little Marvel Mystery Oil to clean up bearings, and then re-lube them if they need it. You might have to let stuff soak a bit and maybe even take an old toothbrush to some of it.

Even though your bearings are new, I'd at least check them for free rotation, cuz like I said, lately I've seen a couple of savages that came brand spankin new with rusty bearings.

well i soaked them in alcholo over night and scrubbed them this morning and they were really chewed up. ive decided im just goin to buy new diffs out of a savage SS with the hardened steel drive cups.

but thanks for the help guys.

Sorry yours were that tore up, but those are supposed to be better diffs. Of course you'll still be shimming them??

When you beat one of these hard - lots of jumping - big air, nasty landings- both on and offspeed, diffs take a pounding. After you've made them good and strong - my diffs are in gpm alum diff cases (same ones as in the SAV how to) and inside gpm alum bulks so there is no twisting under load, start to see the ring gear side brgs wear more than other side. I've had them frag - fail badly, open it up and pieces of brg race and balls everywhere. I replace that brg every time I'm in there for whatever reason.

One fix - take ring gears to machine shop and have brg boss cut down to run 1/8th buggy brgs, 8x16x5mm instead of stock 10x16x5mm. The stock brgs use smaller balls while buggy diff brgs use bigger. Enough diff to fix prob. Nothing I run with 7.5 style buggy diffs (SuperMaxx, Lightning and FLM BL Emaxx) have ever had probs with those diffs or bigger brgs). I was disappointed to see my new Flux using same brgs.

Other fix is some kind of adaptation of one of the CEN diffs. Not familar with that one - yet.

yes i will be shimming them for sure

i really dont bash as hard yet but when i finish my MT track i plan on doing primarily strength upgrades. im saving that post so i can remember to do it later:nod:

I know you're waiting on parts to repair you diffs, but though I'd include this - bestr writeup I've seen on the CEN diff modd for a SAV. Man that stuff is beefy!! This is the way I'll be headed if I run into trouble with my Flux diffs.

http://www.rcbasher.com/savcendiffs.html

i tell you wut...if these diffs fail, im buying them 4sure!!!

Some time has passed since anyone has posted on this thread.

Are the CEN diffs the way to go in the Savage's? The mod sounds cool and easy enough.....:tire:

I have a Savage X and I keep blowing the rear diff. I bought the upgraded diff kit, HPI 86922. I smoked it, probably because I didnt shim it. I want to fix it for good this time.

How tight is too tight when shimming your diff? Is like seeting mesh on everything else?

Or is this the way to go?
Instead of the CEN mod.

http://www.hpiracing.com/products/en/102692/