How would you build a 10 bolt for cornering?

[WSSix]

Just like the title asks. I'm interested in hearing what changes you feel are necessary to make an 8.5" 10 bolt go around corners reliably. My car is a street car mainly so nothing too hardcore. I'm not keeping my current rear end under the car. I figured I might as well address some of the stock 10 bolt's short comings and build it more for it's intended purpose with the new rear end.

Thanks

[no go nova]

I would think 9" ends with some type of floating calipers, upgrade to 31 spline axles a nice limited slip diff with a aluminum support diff cover.

[glassman]

Trey, when i did my Baer brakes (07?) i convrted the rear from drum, this allowed a "floating" rear (albeit i have a 12 bolt, but same idea)>I've tracked it once and autocrossed it a few times, works very well. Nver had a hint of padknock.
Will see how it goes as i do my new set-up though....

[WSSix]

Thanks Mike. I already have C5 rear brakes, and they are performing well aside from the parking brake but that's for another time.

What I'm mainly interested in or concern about is what I should do to strengthen the rear end and eliminate the c-clips. I'd really like to do something more robust than the bolt on eliminator kit Strange has available. They have their street version which has tapered bearings but it's the bolt on part I'm not keen on. Plus, I believe I can get larger bearings back there with a Ford style end. I'm just not certain on all this so I figured I'd ask.

Thanks no go, too.

[MeanMike]

Strange and Moser have housing ends that take a big 9" axle bearing, but still has the GM brake bolt pattern. So you could run a ford tapered roller bearing and keep your brakes.

Strange H1143 and H1144

Moser 7900

[WSSix]

Thanks Mike. I just found that out off NastyZ as well. That sound pretty much exactly what I was looking for I believe. The only issue I wonder now is what would axles cost me. I'll shoot Moser and Strange emails and see what they say about that. Thanks again.

[MeanMike]

Moser 31 spline 9" axles are $300 with bearings installed. You just need to make sure the brake standoff matches what you have now. That is the dimension from the brake mounting flange to the axle flange. And make sure the the od of the rotor locator matches the rotor inner diameter.

[WSSix]

No idea on that dimension. I'll keep it in mind when I go to get this all done. Just have to also find someone that can do the work for me.

So do you think changing ends like this would be a good way to achieve my goal?

[MeanMike]

For the GN's the 8.5,31 spline axles are good into the 6-700hp range drag racing. They typically don't use the tapered bearing because they aren't concerned about cornering, but that is a solid setup in the 9" rears. Unless you have plans of over 700hp, this should be plenty. Buy a 31 spline trutrac if they make it for the 8.5. If not the eaton 31 spline clutch posi is tough to beat.

Once you get good axles (33 spline ) and a spool in an 8.5' the limit becomes the ring and pinion itself. But that is way up ther in cars drag racing with transbrakes making 900+ hp and weighing 3500lbs.

[WSSix]

Thanks Mike. I appreciate the info. I'll only be making about 500hp/tq at the flywheel and really don't see myself ever making much more.

[Vince@Meanstreets]

I'll just add one thing.
If you go with the moser ends and axles run the 7900fm for a flush mount seal. You can use your brake backing as a retainer plate.
Not sure what you have planned for rear brakes but the manufacture will know what axle offset you would need. Tobin at Kore 3 makes a nice C6 based kit.

Tru track and 31 splines is perfect for you.

[WSSix]

Thanks guys. I'm only finding a Truetrac with the stock 28 splines though. Think that's still strong enough?

[Rod P]

I built mine...with a Detriot Tru-Trac, Factory TEN Hardened c-clip axles and have raced it for 4 years now and have yet to have a failure

The truth is the 8.5-inch 10-bolt is almost as strong as a 12-bolt since its ring-gear diameter is only 0.375 inch smaller than a 12-bolt (8.50 versus 8.375 inches) and the pinion gear shaft is an equal diameter.

Even better, the 8.5 rear axle assembly was the universal rear end for millions of GM cars and trucks from 1971 through 1996, that means there CHEAP to find named the GM 8.5 corp diff

[Vince@Meanstreets]

Thanks guys. I'm only finding a Truetrac with the stock 28 splines though. Think that's still strong enough?


i'd go 30 in tru track DTL-913A481

[WSSix]

Thanks Vince!

[Che70velle]

I built mine...with a Detriot Tru-Trac, Factory TEN Hardened c-clip axles and have raced it for 4 years now and have yet to have a failure

The truth is the 8.5-inch 10-bolt is almost as strong as a 12-bolt since its ring-gear diameter is only 0.375 inch smaller than a 12-bolt (8.50 versus 8.375 inches) and the pinion gear shaft is an equal diameter.

Even better, the 8.5 rear axle assembly was the universal rear end for millions of GM cars and trucks from 1971 through 1996, that means there CHEAP to find named the GM 8.5 corp diff

Rod, your saying your running GM axles? What rear brake package are you running? Do you experience significant pad knock back?

[WSSix]

Bringing this back up because I'm close to getting the work done and want to make sure I understand the process.

I'm looking at using the Moser 7900FM ends since they say that is the end for use with disc brakes. I want to retain the factory dimensions of the rear end even after the new 9in ends are put on. So which measurement is more important, the brake mounting flange distance or bearing distance from the housing? I need the track width to be the same when done so that I have no issues with my wheels fitting. I'm hoping I can reuse my current brake setup with no or minimal changes.

Also, is it worth it to change to an aftermarket/stronger yoke while I'm at it?

Thanks

[MeanMike]

You need to know the current axle flange to axle flange measurement of the overall rearend and current brake standoff. Brake standoff is the measurement from the axle flange to the caliper bracket mounting surface. When you order axles, you order them with the correct brake standoff (tell them you are using flush mount ends). Overall axle length should be the same a stock.

That should make it easy on the rearend guy to place the new housing ends in the correct position. He'll just measure off the existing axle flange back to where the new housing end will weld on.

[WSSix]

I haven't ordered the axles yet. I was actually planning to have the rear end housing modified first then collect the axles components. Is that ok? The person I'm having do the work didn't seem to have a problem with that and understands that I want the rear end to be factory width. I guess what I'm worried about or not understanding is how does using the 7900FM ends affect the bearing placement in regards to the axle flange? Currently, the bearing sits just outside the flange. The picture of the 7900FM makes it appear that the bearing will be inline or inside of the flange. Will this result in more of the axle sticking out beyond the bearing and be unsupported compared to factory GM? Does this matter? I'm probably over thinking this.

Thanks Mike.

[MeanMike]

I'm supposed to take a break from cad during lunch, but a picture explains it so much more. :) Ignore the ford 9" center part, that's just what I have on my work computer.

Since you are sticking with your current brakes, the axle flange to caliper mounting bracket flange dimension will not change. Since the axle flange to axle flange measurement won't change, where the caliper bracket bolts to the housing flange will stay the same.

Whatever the new housing end measures for width, subtract that much from the existing caliper mount flange and then weld new ends on. The bearings will ride further back on the new axles. I would talk to whomever you plan to order axles from to make sure the brake standoff is something they can build. I'm almost positive they will, but it would make for a bad suprise after the housing is modified if they can't.

Old bearing setup on top, new on bottom.
http://i112.photobucket.com/albums/n177/edwardsmt/HOUSINGMODIFICATION_zpsdbaf1c7d.jpg

[MeanMike]

I haven't ordered the axles yet. I was actually planning to have the rear end housing modified first then collect the axles components. Is that ok? YES The person I'm having do the work didn't seem to have a problem with that and understands that I want the rear end to be factory width. I guess what I'm worried about or not understanding is how does using the 7900FM ends affect the bearing placement in regards to the axle flange? Currently, the bearing sits just outside the flange. The picture of the 7900FM makes it appear that the bearing will be inline or inside of the flange. Will this result in more of the axle sticking out beyond the bearing and be unsupported compared to factory GM? Yes, Ford's are typically 2.375" or 2.5", others hang out even more Does this matter? I'm probably over thinking this.

Thanks Mike.

See above in RED

[WSSix]

Thank you, Mike. I appreciate the CAD model. I figured it would make more sense to me if I had the parts in front of me. I'm glad to know the axle sticking out further from the housing won't be a problem.

I emailed Moser about axles explaining what I was planning, including putting a 30 spline diff in the car, and the response I got was just order the axles with the 9 inch bearings. The sales tech that replied didn't indicate it was a problem. I intend to call them when I order so I'll double check then as well.

[glassman]

Ummm, are you not updating your "freshly arrived" build thread? LOL, yep givin you a bad time....I'm going through these same questions and issues with Keith (Custom works) as we type. But i have a 12 bolt.....gettin close. Just want to drive it....

Great info here though. And i haven't heard Rodney complain of any padknock....

[WSSix]

Oh, I will Mike. I typically leave my build threads for build updates and not questions like this. I figure anyone else who might want this info in the future isn't going to go searching for it in project thread pages.

Glad your car is moving along. I've been driving and enjoying mine for the most part. I have a high speed vibration I need to figure out. I'm almost certain it's in the drive line. Figured I'd really go at it to get it solved once I get the new rear in place.

Thanks

[Vince@Meanstreets]

Thank you, Mike. I appreciate the CAD model. I figured it would make more sense to me if I had the parts in front of me. I'm glad to know the axle sticking out further from the housing won't be a problem.

I emailed Moser about axles explaining what I was planning, including putting a 30 spline diff in the car, and the response I got was just order the axles with the 9 inch bearings. The sales tech that replied didn't indicate it was a problem. I intend to call them when I order so I'll double check then as well.

Its pretty standard for them.

I would fill out the custom order axle sheet and specify, what ends you have, the brake offset and width. Also don't forget you will need the axle flange (disc surface 5.9" and center hub for your rotors) get all the info and fax it to them.

[WSSix]

Thanks Vince.

[Pete68]

You should consider changing your rims. The wheel spacing is close but its not the same and you are putting lots of stress on those old wheel bolts. Its not a good idea.

Also, Im running the 8.5 in my camaro, you can shim the c clips a bit to minimize pad float.

Of course solid axles suck for handling!

[WSSix]

Thanks Pete. I currently have Moser axles, 1/2" ARP studs, and adapters on the axles in order to have the BMW rims on there. I'll be doing the same with the new rear end.

[TheJDMan]

Trey,
I'm just curious how much you anticipate spending for all this work to your 10 bolt by the time you're finished. The reason I ask is because I suspect for the same money you could buy a complete custom built Moser 9" rear end and have a stronger rear when your done than the 10 bolt will ever be. Moser will build rear ends in any width you specify with the correct mounting brackets already welded on and you can buy ready to install reman 9" center sections all over the place for reasonable prices. I would have a hard time justifying spending any money on a 10 bolt when there are better alternatives available. Heck, I have a 12 bolt posi that I was going to use but by the time I paid to have the housing ends replaced, new axles, bearings and ring/pinion it was still more cost effective to go with a complete Moser 9".

BTW, I have a 12 bolt posi for sale.

[WSSix]

Well, I figure I'm going to push nearly $2k since I'm looking at buying quality parts. This is a once and done deal for me. I'm in for $530 at this point. That includes the new to me housing, 9in ends and installation, and having the tubes welded after straightening.

I looked at a Moser 12 bolt and to have it built by Moser the same as my 10 bolt would set me back well over $3k. A junk yard 9 inch would be about the same as what I'm spending on the 10 bolt. That doesn't include changing the rear brakes I have to work on the 9 inch. I decided to stick to the 10 bolt because it's lighter, robs less power, and can handle all the power I'll ever throw at it. A proper rear is going to cost me a lot no matter what. Unless something doesn't work right with the changes I'm making, then it's everything I need. Thanks for the feedback, Steve. I do appreciate it. Keep your fingers crossed for me, lol.

[Rod P]

Rod, your saying your running GM axles? What rear brake package are you running? Do you experience significant pad knock back?

never had that as an issue, knock back means the axles are moving, a good rearend shop will shim the axles to reduce movement when they shim the Tru-Trac