Crazy Rear Axle Idea

[CTX-SLPR]

Howdy,

I doubt this is an original idea (I think I read something about it in the Wilwood floater brake thread) but since I'm having to do a bunch of work to swap the rear axle in my '64 Riviera I thought I'd look into this idea with ya'll.

The axle is an 8.5in 31-spline 10-bolt out of a 91-93 Caprice since it comes with the 3.42:1 rear gears I want and is reasonably close in the axle width department to match up with the 18x8in wheels I plan on running. Since I need to change axles over to 5x4.75in vs the stock 5x5in and want to eliminate the C-clips I throught about doing a full floater with the stock flange and axle seal but with the axle sticking through and splined to mate to a C5/6 rear hub that fits on an adapter block that allows the mounting of the whole parking brake assembly and hub and contains the ears for whatever caliper I want to run (thinking 1st Gen CTS-V unit). I have 3/8-5/8in of room to play with per side in adding to the width of the axle so in my mind that would be enough to contain the adapter block and since the car is already pretty heavy, using steel doesn't bother me.

Thoughts?

Thanks,

[Ppd1979]

On lateral-g.net, Mark Stielow has a build up for red witch his 69 Camaro.
He did the exact thing your are talking about, it is on page 79/81 of his build.

[MrQuick]

Machining is cheap, its the axles that will kill ya in cost.

[CTX-SLPR]

I'm reviving my own thread, mainly because I've revived the idea for my own use. Readers Digest version, after talking to brake and axle vendors and reading Mark Steilow's Red Witch build; this is a workable idea and for cheaper and simpler than Mark's mainly because I have room to widen the axle.

I've spent the last week or so working on the general idea of converting my '64 Riviera to C5/6 front uprights instead of continuing to chase the problem of my very low backspacing wheels and horrible front suspension geometry. The side effect was I needed the rear end to have the same bolt pattern and wheels which meant adapters or wholesale conversion to 5x4.75in and high offset wheels. Because the axle I've chosen is ~3in too narrow for the +57mm offset wheels I'm planning on using I have room to work with on the outsides of the axle. I called 4 of the major axle vendors and ran the idea past them. I'll come out and say that Strange was completely unable to do anything for me for the street but was kind enought reffer me to Dutchman who can do most anything. It was Currie who while saying they probably couldn't do anything for me, spent a good 10-15min on the phone talking axle tech and strengths. After talking to a brake vendor (I'll let him jump in as not to wrongly apply his endorsement to the project) we figured out what would likely be the easiest (and therefor cheapest) method to impliment this. Here's the run down.
The stackup is a bare 8.5in 10-bolt housing with no seals or bearings installed, mounted to the housing end is an adapter block with the 10-bolt pattern on the back and the C5/6 pattern on the front with counter sunk holes so you can bolt the hub on. The adapter block will also have the cable retainer and actuator mount for the parking brake and the caliper bracket mounts and be counter bored large enought to fit over the 10-bolt axle tube and carry the axle seal. A stock C5/6 parking brake backing plate is sandwiched under the matching hub. Now the details are that the axle will be splined on the inside end for a 30 spline 8.5/8.625in differential and on the outside for the 30 spline C5/6 hub. To retain the axle instead of using the stock C5/6 male threaded "nub" with nut, there will be a female threaded hole in the end of the axle shaft for a 5/16 or 3/8in bolt and retainer washer much like a harmonic balancer retainer. On the opposite side of the hub there will be a shoulder to get squeezed in the hub, locking it in place. This solves the major expense and complication of the axle from the point of view of the manufactures and both Currie and the unnamed brake vendor agreed that even a 3/8in hole would have a negligible impact on the axle strength, it just might require gun drilling the whole axle to prevent a stress riser at the bottom of the hole. The differential side of the axle would be completely unrestrained with no c-clip bottons so that expansion or tollerance stackup doesn't cause a fight between axle retension mechanisms.

I've now got to do the leg work on finding the exact dimensions of the C5/6 hub, decide if it's worth it to use the ZR1 hubs, get a hold of and measure the 8.5in 10-bolt so I know how much "flange" there is past the housing end, and work with the axle supplier to find the easiest to machine cominbination of OD's for the bulk of the shaft, shoulder, and seal surface. Hopefully I can find a raw shaft close enough to the seal ID so I can use it as the shoulder and seal surface and just have the ends machined down for the splines. If anyone has any of these dimensions I'd love to have it for basic calculations.
Also I've mentally ruled this out but would love for someone to actually confirm why I have. Use the c-clips to hold the axle from walking OUT and the end bolt to hold them from walking IN. In my mind, the expansion and cycling would make holding a good tension that wouldn't shear the head off of the bolt a problem. If it would work long term than things get marginally simpler since you could concievably use a stock axle seal and and not have to worry about the shoulder for the backside of the hub.

What do ya'll think?

[srh3trinity]

Have nothing to offer, but I hope you figure it out. Seems very innovative.

[prosuperstar]

I also have nothing to offer but would like to know why you're really doing this?

Good luck on your little project

[CTX-SLPR]

Well it has to do with needing a wider rear axle to fit a matching set of wheels to the front. While there are a number of ways to wide the axle, this idea also accomplishes the desire to remove the C-clips, adapt on C5/6 brakes, and change to 5x4.75in bolt pattern from the stock 5x5in. While I could get disc brakes and a slightly wider axle by going with an Impala SS axle but I'd still need 3/4in adapter to run the proper wheels and change bolt patterns. While that would be cheaper overall it still leaves me with marginal discs and C-clip axles. I have my own mill and love learning how to do things so I'd be happy build the skill set making up these adapters. The nice thing about the idea is that the axle housing will remain unmodified so I can fall back to the stock setup if needed.

[CTX-SLPR]

Called and talked to Dutchman about using the c-clips to hold the axle from pulling out the hubs and a bolt from them pushing in and they said the cross pin on the diff is designed to hold the clips inplace in both directions so no need for the hub side bolts. Since I've seen threads about not using rear C5/non-ZR-1/GS C6 hubs on the front of the car, think having the axle just splined, not squeezing the hub would be a problem?
Need to find a used hub to mock up with and go get that 8.5in 10-bolt from the yard next month.

[Kenova]

Would this accomplish your goals?

http://www.speedtechperformance.com/index.cfm/page/ptype=product/product_id=356/category_id=235/home_id=235/mode=prod/prd356.htm

Ken

[CTX-SLPR]

I did find that and it made me decide it was possible to do a smaller bolt in the end of the axle to hold the hub in. After talking to Dutchman, they pointed out that the c-clip could do the whole job.
The Speedtech Chicane is just way too expensive for me. I'm far more DIY scale in my budget and I do have my own mill to work with.