1madss

iTrader: (10)

A few questions on setting up a 12 bolt.

Do you HAVE to measure the pinion depth or can you just use the gear pattern? It seems that the measuring just gets you close to the correct depth and then the gear wear pattern fine tunes the pinion depth. Is the accurate?

Is .009 too much backlash on a used set of gears?

Does pinion depth effect backlash? It seems that it would to a small amount being that the gear tooth on the pinion is thicker towards the rear of the gear.

I'm asking because I am having some odd noises after having my pinion seal replaced. The shop found some shims under the yoke that they thought were mistakenly put there instead of behind the pinion bearing to set the pinion depth. No other changes were made other than moving these shims. I saw the shop check the bearing preload so I thought everything was okay. A couple of days later the rear started making a lot of noise that is best described as "slop". Gear whine has not changed much, it just sounds like there is a lot of play in the rear. I took it back and the pinion nut had backed off about a 1/16th of a turn. This was tightened back up and lock-tite was used. Last weekend I checked it and it had not backed off again and I checked the backlash. It was .009. This weeked I am going to get a basic kit and replace the crush sleeve, pinion nut and check to gear pattern with compound (I could not get any last weekend). I'm really worried about tearing up the pinion bearing as I am driving aver a 1000 miles a week right now. I'm thinking that either the pinion depth is not right (should be close though) or the pinion bearing preload is too loose.

Any suggestions. I know the "right way" to fix this is new gears and bearing, but I can't afford that right now.

kp

iTrader: (34)

the shims were there to set the bearing preload if it has a solid crush sleeve which it most likely does if it had shims. When they tightened it and set the preload without the shims the bearing most likely wasnt bottomed all the way on the sleeve and thats why it came loose. Not to ask a dumb question but why didnt they put the shims back in?

edit: Oops, re-read your post and seen the shims were behind the yoke, not the bearing, not sure why someone would put them there..



I would guess the pinion bearings are probably getting trashed, especially if they really cranked down the pinion the second time. If it had shims in there with a regular crush sleeve then the sleeve should have been replaced.

I have set up many rear ends without doing the pinion depth and just by gear pattern. They dont tell you to check the pattern after setting the proper depth for no reason. The pinion depth method for is just a major timesaver and it works out about 80% of the time.

.009 should be fine on a used of gears, just make sure its .009 all the way around

1madss

iTrader: (10)

Thanks for the reply.

I talk to Jason at Thunder and he told me that he had run into the shims behind the yoke on a Moser rear with the billet yoke (which I also have). He said that they were there because the yoke was bottoming out on the pinion and was not able to get any preload. The shop I went to was not aware of this and thought they were there by mistake and moved them behind the bearing, which also leads me to beleive that the pinion depth might be off. I'm worried that by not putting the shims back that there is little to no preload on the bearing now. What confuses me is that I saw them check the preload when reassembling. I guess that the only way to know for sure now is to check it myself.

Would too little preload cause the slop in the rear?

Thanks again.
Mark

kp

iTrader: (34)

Those shims wont change the pinion depth, only the shims behind the bigger bearing will

That makes sense why they put them there I guess. If the preload was very loose it would make some noise, sort of what it did when the nut loosened up. If the Yoke is bottoming out on the pinion before it hits the crush sleeve its bound to have way too little preload. I would put a new crush sleeve in, put the shims back on the yoke and check the bearings.

1madss

iTrader: (10)

I've ordered a basic install kit that includes the crush sleeve, pinion shims and nut. I'll check out the bearings after I get the pinion out.

One more question. The guy at NAPA recommeded using white lithium grease as a marking compound. Will this give a readable pattern? I'm having problems finding marking compund without buying a complete gear installation kit.

kp

iTrader: (34)

I have painted all kinds of things on ring and pinions to check the pattern but the stuff that comes with the kits is the easiest to use. I have a large bottle of some orange lead based paste I have had for like 15 years - still havent used it up yet

gonz

go to your local drugstore and pickup some diaper creme (Desitin, etc.). it works fine and the cost is considerably less than other pastes, paints, etc. coming from a papa that's set up many rears, it'll do you just fine.

Jorday

I didnt have a depth setup tool to install my gears on my other car. I used the stock pinion shim and adjusted from there with the shims in the kit until I got a gear pattern that was acceptable.

kp

iTrader: (34)

Forgot all about that one Diaper rash creme has zinc-oxide..

Camaroholic

iTrader: (1)

Huh, I was wondering about the gear paint myself. Hadn't thought about raiding my daughter's room. (She'll be 2 next month.) Good idea.

(doesn't come out of the car budget, I like it )

z-ya

iTrader: (1)

At the nationals at brainerd I was told by mosers rep Shane StMyers to set the rear end up by the numbers and ignore the pattern.This was on the 4th ring and pinion of the summer while in front of their display with me demanding an explanation.My installer Don Winter refused to do it this way,leaving me to do it on my own.
Nailed the pinion depth with a td tool,and set the backlash to 8 thou with a so so
patern.Holws like the ex wife on payday.So much for mosers tech support.