Question about the C5/C6 brake upgrade for G-body

[Stg1Regal]

I found this thread awhile back.

http://www.turbobuick.com/forums/brakes-suspensions-tires-wheels/172762-ls1-brake-mod.html?referrerid=1864 (http://www.turbobuick.com/forums/brakes-suspensions-tires-wheels/172762-ls1-brake-mod.html?referrerid=1864)

Was wondering if anyone hasn tried this ( machining down the hub) to accept C5/C6 brake rotors for the brake upgrade, instead of tring to find those ZQ8 spindles?

Seems, In My Opinon, All one would hafta do is make a braket for the caliper.

Same thing right?

Would it increase the front track width?

It would be a cheaper alternative..........

Thanks guys

[first64]

I'm in the early stages of this swap, machining down the hubs doesn't seem to big of a deal to accomplish. You use the original spindles so the track width increases only by the thickness of the rotor mounting surface if I understand it correctly. Flynbye.com sells the brackets to mount the calipers if you don't want to make your own. The other benefit of the "LS1" is no sealed hubs, to replace the ZQ8's hubs are pricey.

[Apogee]

You're correct, it's not that complicated...sometimes. In the case of the G-body, we haven't offered a kit for that particular spindle because the dust shield mounting hole bosses, the upper one in particular, is undersized and tends to yield over time and use, causing other potentially bad outcomes as a result. The best solution IMHO is one where you would machine a new mounting pad/boss into the spindle, but it requires good core spindles and finding decent G-body core spindles without bent steering arms can be tough. The afermarket replacement spindles made by Dorman are quite costly, so it's typically easier to adapt to the 98-03 Blazer spindle or upgrade to the AFX setup.

Tobin
KORE3

[nullshine]

Tobin:

Just to make sure I understand...
It's the spindle itself that's failing over time and use?

https://static1.pt-content.com/images/noimg.gif

If you chop off the caliper mounts and attach an adapter bracket through the dust shield holes, what might happen? The upper hole (starts to rip)rips out???

You said the boss is undersized, is it the depth/thickness of the material at the boss... or not enough meat around it? Something else?

I was keeping this exact swap in mind, but was unaware of the potential durability issues!

[monteboy84]

The Blazer spindles and hubs aren't that spendy...

http://cgi.ebay.com/ebaymotors/S10-Blazer-Sonoma-Dual-Piston-Calipers-Hubs-Spindles_W0QQitemZ260502787910QQcmdZViewItemQQptZM otors_Car_Truck_Parts_Accessories?hash=item3ca72d1 746

(http://cgi.ebay.com/ebaymotors/S10-Blazer-Sonoma-Dual-Piston-Calipers-Hubs-Spindles_W0QQitemZ260502787910QQcmdZViewItemQQptZM otors_Car_Truck_Parts_Accessories?hash=item3ca72d1 746)The way I went about it, was to purchase the full Blazer setup of ebay, bought some NAPA rotors for the Blazer application, and run that setup until I'm ready (have the money ;) ) to install the Corvette pieces. You won't have your big brakes right away, but the dual piston Blazer calipers should be far superior to the tiny stock pieces.

[ironhide]

I did this mod to my 70 camaro with xlr brakes . They are pretty much the same thing as c5 . Worked out fine .I did cut them on a brake lathe tho . I think it makes a difference in tolerance stack up .

[monteboy84]

I did cut them on a brake lathe tho . I think it makes a difference in tolerance stack up .

That's an excellent point, centering the hub via the bearing races should give you much less runout in the OD than what a hub fixtured like in the other thread will have.

[Apogee]

Tobin:

Just to make sure I understand...
It's the spindle itself that's failing over time and use?

https://static1.pt-content.com/images/noimg.gif

If you chop off the caliper mounts and attach an adapter bracket through the dust shield holes, what might happen? The upper hole (starts to rip)rips out???

You said the boss is undersized, is it the depth/thickness of the material at the boss... or not enough meat around it? Something else?

I was keeping this exact swap in mind, but was unaware of the potential durability issues!

It's not a depth issue, but rather the lack of "meat" around the fastener to support both the preload of the fastener and the loading from the brakes. I should have been more specific in my original post, as the upper boss is too small to support using an M12 or 1/2" fastener, as the wall thickness on the thinner side of that boss gets quite narrow. End result is a small contact area between bracket and spindle and thus high contact stresses in excess of the yield strength of the materials involved. Smaller mounting bolts leave more material and have lower preloads, so may not have the same issues that we found with the larger hardware, but we tend to strive for maximum rigidity in our brake kits.

Tobin
KORE3

[nullshine]

Removed.

[monteboy84]

Even if it's just from a purely theoretical standpoint, and not actual testing, I'd still be interested in hearing it.

Now you're asking for it, let the bench-racing ensue! ;)

I'm still waiting on my spindles and hubs to arrive, but I'm pretty positive that the Blazer spindles, just based on the overall design of them, will be more rigid than the G-body design. The unitized hubs by design have less play (near zero) versus the taper bearing design of the stock spindle. I say this because the stock tapered bearing arrangement is properly adjusted by tightening to snug, then back off to the next pin groove on the castle nut. This means that in the ideal situation the conical bearings will have play, up against the unitized bearings where play means it's time for replacement.

[nullshine]

Now you're asking for it, let the bench-racing ensue! ;)


lol, yeah I just figured that no one had actually done any "scientific" testing on them, so I'd have to just settle for suppositions and wild conjecture!

Thanks for the reply. Yeah I could see the conical bearings being a little "looser" at rest. I wonder what would happen under load?

[monteboy84]

I got my new spindles and other goodies last night, they're much nicer than the stock spindles, with a beefed up steering arm and what I consider a much beefier build overall. I got mine from the same seller as the link I posted, they took an offer of $175, and the parts are fantastic, very low mileage.

[ironhide]

On my fatman fabrications 2" drop spindles I did not have this problem with not being beefy enough .

I don't think it will matter to much . The caliper just wants to go around with the rotor not sideways .

Back when I used to wrench I seen a caliper come in with only one bolt holding it there . Still stopped fine just sounded real bad .

[nullshine]

Hey Matt:

Could you do me a favour and measure the OD of those Blazer hubs?

:)

[Apogee]

Hey Matt:

Could you do me a favour and measure the OD of those Blazer hubs?

:)

James, the OD on the Blazer unitized hub flange is the same as the 4th-gen F-body at 5.75" with a .08" x 45 degree chamfer on the face.

Tobin
KORE3

[monteboy84]

What he said :)

[nullshine]

Thanks again, Tobin!

[MonzaRacer]

Well guys, I have an S10 spindle 5 lug conversion on my Monza, and after looking at them I totally agree with Tobin, spend little more, use the ZQ spindles, HECK the twin piston stockers work great and there are a few different pads out there that the Sy/Ty group love.
I am right now looking around for spindles, had them found with everything, local for $50 a side and the Extreme rearend, as it was 8.5 and I have swapped in a 7.5 S10 rear. Though I had empty 8.5 4x4v rear found, reason is I need wider housing to swap in newer wheels instead of old school deep dish 15s.
Also working a deal with a wheel repair shop here in Indiana that might be able to help narrow Vette rims and make them look decent or even do colors. But thats me, always trying to do stuff the hard way. Especially Since name of car is Cheap Trick,,,

[79-TA]

So, getting back to one of the original concerns of this old thread, does anyone have an answer for how much the Blazer steering knuckles change the trackwidth relative to stock on a G-body?


Also, how about steering range?

[nonosv6]

Well I just installed my blazer spindles and c6 brakes with the kore3 adapters on my t type. Compared to the ls1 camaro brakes which pushed the wheel out like a 1/4" , these appear to have brought the wheel back in some. The kore3 kit was very nice also and Tobin is a very knowledgable guy who is very willing to share! Joel