ede

anyone have a race they can measure the OD of for me? 7.5 ten bolt. thanks

ede

no one has a race laying around the garage?

onebad82z

iTrader: (7)

I have one I can measure but I wont be able to do so till friday night when I get to my shop to finish the moser rear for my car.I have a 10 bolt in pieces waiting to be assembled for my brother in laws IROC that I will measure the race from when I get there.I will post back with the results.

ede

well so far out of posting on 3 boards this is about as close as i've got. friday is fine. thanks

Ricktpi

According to the GM EPC it measures 2-57/64" & is 27/32" thick. It's a Timken LM501349 cup, if you have a catalog it should give the dimensions.

RBob

iTrader: (1)

The carrier race OD from an original '92 factory rear is 2.890" +- .002", the tolerance is because I used dial calipers. This matches w/Rick's dimension. The race is marked "TIMKEN LM501314 USA YL."

Didn't see your post 'til today, else had it for you last night. . .

RBob.

92Z-666

iTrader: (2)

http://www.timken.com/india/tilbrguid.pdf

The series 3 factory carrier bearing race is:
LM501314 (as expertly mentioned already)
race OD = 73.431mm = 2.89098 in.

Useful data if yer setting pinion depth, after exploding a set of richmonds Don't forget to verify the carrier centerline! I see no decent 'thirdgen.org' tech articles on gear swaps that goes into the process of setup... someone should take care of that.

ede

thanks i've been looking for the diameter for a while now. going to make a pinion setting tool.

Ricktpi

You guys are right the LM501349 is the cone & LM501314 is the cup. It's not marked as to which is which in the EPC.

Ricktpi

Gotta love the Ford 9". You just have to measure from the side carrier cap parting line to the stub on the pinion to set the pinion depth.

ede

only did one 9" and that was a long time ago and i know most of it seems backwards from gm rears. on a gm rear aren't you doing the same thing that you just said about the 9"?

92Z-666

iTrader: (2)

I put a mark-williams 9" conversion in my 11-sec iroc, I found the total package a bit on the heavy side (as far as weight) and common complaints include the one about the efficiency being less than the 12 or 10 bolt. a rebuilt stock trak-lok is still not a real nice posi IMO, and the good stuff (auburn for 9 inch) is $$$!

then again, I was never able to blow it apart like I did the 10-bolt.

Hey, whaddya do when your carrier bearing surfaces are 0.007 different from each other... take an average?? (don't say line-hone.. I don't wanna hear that) :/

ede

the way i use to do it untill i get this new tool made is use a piece of aluminum to span the opening and use it as a datum surface so in effect i would be taking an average of the two surfaces.

Ricktpi

Just opposite here. Have not done a GM rear in quite a while. It may be the same. Just saw a pinion depth kit in Jegs for $100. Not sure if it would worth it to you or not. I run a straight edge across the parting lines & measure with snap guage or depth micrometer.
As far as being .007 out, I would use the straight edge method & take the measurement at the point where the ring & pinion make contact. Then fine tune it by checking the pattern.

Ricktpi

I would agree on the heavy part. I have heard numbers like a 12 bolt uses 2% more power than 10 bolt & a 9" uses 2% more than a 12 bolt. As far as a Trac Lok goes I have no complaints, for $60 you can rebuild them very easily. An Auburn you have to replace the whole unit. $$$

ede

someone posted not long ago about the universal pinion setting tool, it's junk and a waste of money.

Ricktpi

I figured as much. That's why I didn't get one myself. I was just recently talking to an older guy that does drivelines & custom chassis for a living. He said 9 out of 10 12 bolts will take a .030" shim & you are good to go. From anyone else I would say it's BS, but this guy is very detail oriented. ??

onebad82z

iTrader: (7)

That was probably me..I finally got it to work.I am semi pleased with the results..tooth pattern revealed it was close so I guess it paid for itself.Would I recommend it..NO.In case anyone does purchase it..get a good dial indicator..the one provided was a real piece of s**t.Otherwise add a good quality dial indicator to the price...or just save and get the T&D tool.

92Z-666

iTrader: (2)

Not the flat cap surface, although uneven cap surfaces can affect the results of the measurements if you 'switch off' without recalibrating the depth tool... I meant the bearing bowl depth itself. Mine are 0.007 off, one is deeper than the other as measured from ONE cap surface.

If you SPAN the cap surfaces and measure the bearing bowls you're only biasing the reading by the short distance from the cap to the bearing bowl. in my case I might get 0.001 more on one side and -0.001 less on the other.

THats neither here nor there.... theres sooo much wrong with not using one of those cap-seated rear-specific tools if you're an **** retentive machinist. It gets you close enough I guess... the marking compount tells the truth in the end.

Good luck with the new tool... if it is sound machinist engineering I'd pay 75 bucks for it if it included a dial guage that wasn't made in japan.

92Z-666

iTrader: (2)

I'll put my vote in for P.O.S.

I couldn't get it to repeat a calibration, it was off by as much as a boatlength through sucessive calibration passes... 0.003 sometimes. the cal cyllinder surfaces were not flat! they wobbled around and caused the dial to move. It seemed the spot that the tip rested in the cal cyllinder was not flat either.

I up my offer to $100 for a new tool

92Z-666

iTrader: (2)

Mine WAS rebuilt.. that's the last time I let someone else do it for me

If theres a way to get more clamping force outta the 9 inch trak-lok, I can use that info if you have it. I abandoned the whole idea and went back to a 4th-gen 7.625 10-bolt. I'm trying to keep the number of ford parts at zero .. I had to listen to the purists whine...

92Z-666

iTrader: (2)

Oh, if anyone's really po, they can do what I did, but skip all the $$$ dial guage and measurement stuff.

Take your OLD front (large) pinion bearing and have a machine shop hone it out 0.002. Use this 'checking bearing' on the NEW pinion, trial-fit shims (start LOW) and use marking compound. voila, a $10 solution that eliminates multiple press-fits and re-press-fits and eliminates the need for expensive measurement tools and measurement skills. Final step is press-fit the NEW bearing and re-check with marking compound. Note you must be able to diagnose pinion markings to get it right with no dial guage...

an excellent series is here:

http://www.rubiconusa.com/articles/article.asp?artid=97

no, its not mine... but its a nice job!

use as general info, its not specific to my 10-bolt.

Backlask is still a measurement nessecary though.