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Discussion Starter #81
Today i take back caprice from service man and start drive with new caprice astro brake rotors mod with PFC pads.
What i say: nothig outstanding or special. All work, no problem, no beating in steering wheel.
But at this moment my rear pads not work. Next week i plan to change my rearend gm8(7.5 2.56) to 8.5 3.08 with same 9" brake drums as i have.

p.s.
Note for other users: I cuted caprice hub(outter diameter) very stiff with innter diameter of astro rotor. So as i think, it is additional insurance that all make propertly too.
That is the point - you get better heat capacity with low cost. The brake feel doesn't change.

Be careful that rust does not lock the rotor and the hub together on the outside radial edge of the cut-down hub. If you live in the rust belt, watch out for this.
 

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15-01-2014
Nothing changed: all work, nothig problem, stops good allways. No beats in stearing wheel when stop the car.
I like how brakes work.
 

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Just installed the Astro conversion on the Blue Wail for Corvette test track at the ISSCA Nats.
Had a buddy cut off the rotor part of the B hub. Took all of 5 minutes on his lathe.
Real simple just used a common 1/4" wheel spacer between the hub and the astro rotor from Autozone.
96 Cadillac J55 calipers at Autozone only $17 each after core exchange.

Rotor fit fine on machined B hub and didn't need any alignment spacers or anything.
Used some ARP 2.5" studs.

Used Performance friction pads, new rubber brake hoses for the heck of it and some blue ATE racing fluid I had.

Left back brakes stock.

Nab
 

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There's a wilwood rotor and hat combo that should work perfect without any spacers. Laterally nor radially. Only thing not sure of is if the rotor and hat is stout enough for a b-body.

It's a 11 3/4 x 1 1/4 rotor. In the 'ultra light' series, they're about 30 bucks a piece. Or if an aluminum hat is good for daily pot hole driving. The hat is some bucks, but that would be a one time cost.

Might give it a try one day. Got two cut rotor hubs waiting.
 

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Vlad, I got your PM--the wide-body GM caliper (9C1/JA9 or Fleetwood J55) uses the 18034582 ACDelco bolt or it's equivalent--the bolt is about 1/4" longer overall. There are many brand sources beyond Dorman--and Dorman may only offer them as "thread repair" bolts, with oversized threads.

Rock Auto has these bolts listed under Caliper Guide Pin

SOURCE: GM PARTS

FRONT
18929239 - BOLT, caliper, JA9 on 9C1, JM4 on 1A2 and 9C6 vehicles (longer) (discontinued--use substitute)
18034582 - BOLT, caliper, ACD Durastop substitute

18022601 - BOLT, caliper, JB9/JM4 on all other vehicles except above
18034593 - BOLT, caliper, ACD Durastop substitute

Front Disc Brake Caliper Bolt (longer)
Part Number: 18K208
Product Notes:
Disc Brake Caliper Bolt
Front, w/Police Pkg, w/Taxi Pkg ; Public Service Vehicles, 2 Per Veh

http://parts-catalog.acdelco.com/catalog/BuyersGuideSearch.php?BGRequest=1&part=18K208&catalog=3752&parttype=4067
http://www.rockauto.com/en/moreinfo.php?pk=112062&jsn=634

Front Disc Brake Caliper Hardware Kit with Pins
Part Number: 18K219
Product Notes:
Disc Brake Caliper Bolt
FRONT,w/o Police Pkg ; Exc Taxi Pkg ; Exc Public Service Vehicles, 4 Per Veh

http://parts-catalog.acdelco.com/catalog/BuyersGuideSearch.php?BGRequest=1&part=18K219&catalog=3752&parttype=4067
http://www.rockauto.com/en/moreinfo.php?pk=112074&jsn=638
 

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Hey all,
I've been running the Astro conversion for about a month now, and finally got a full track day in this last Friday.
All is well, but on the drive home I noticed that whenever I would even nudge the steering wheel just slightly in one direction or the other, I would get a little chirp chirp out of the front brakes.
This got me wondering if my 5mm spacer between the hub and Astro rotor hat that is slightly less than the OD of the hub and ID of the hat is allowing the loads of the wheels when turning to flex the unsupported bit of the Astro rotor at the edges?

Does that make sense or am I thinking way too deep into this?

Attached is a photo for reference:
 

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To flex like you're thinking would require the opposite end to be pulling away which shouldn't happen if your lugnuts are secure. I'd suspect a tight clearance somewhere and some slight looseness in your wheel bearing preload might be the problem.
 

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Bill knows far more about the details, but if you don't mind disabling - or have already disabled - your ABS, you can use the Cadillac Fleetwood V4U's front knuckles, calipers, bearings, and rotors.
 

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MD--Did I post about that somewhere, or share info with you privately???? I don't recall!

Larger inner wheel bearing (Set 5), and a larger outer tie rod is needed, too.

Spindle pin is larger, thus stronger.

Rotors are 1.28" thick, like HD12 - uses "wide body" OE caliper

Wheel studs are 1/2"-20

5/8" lower ball joint

PN 18021054 & 18021055
 

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MD--Did I post about that somewhere, or share info with you privately???? I don't recall!
Most likely I asked you privately, then re-asked you publicly, specifically so that you'd answer publicly, for the benefit of all - but, alas, prior to Aug '09.
 

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Random question: Are the factory brakes from an extended wheelbase Trailblazer anywhere close to adaptable? They have dual-piston calipers and large rotors. They do require 17"+ wheels, but let's assume we are using SS rims.
 

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The TB rotors could be made to work, but it would take some work. The rotor itself has 6 wheel stud holes, so no matter which way they're machined for 5x5, it's going to cut through an existing hole - not the end of the world, but using Corvette rotors is better, IMO. Caliper abutment brackets are similar (with slide pins) but I have zero knowledge of the radial positioning vs what we know is needed to make C5/C6 work. The TB large rotors are 12.8, essentially same size as C5/C6 front, but I would have to confirm thickness. The TB rotor has a larger center bore than B-body, which would call for a centering ring. Unless it's a necessity, I would tend to look elsewhere for a low-budget "big brake" solution.
 

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We're looking at Jeep Grand Cherokee/Commander front brakes now. Very similar to the Trailblazer front brakes. 2 piston iron caliper and 12.9x30mm rotors. They're already 5x5 bolt pattern. The pilot bore is smaller than the stock B car, but you cut the register down when modifying the stock B rotor to a hub. There are hubcentric adapters available off the shelf to return the wheel to hubcentric. The rotor isn't quite as thick as the Corvette, but once the hub modifications are made, it's bolt on. Rotors are relatively cheap, and there's a wide selection of performance pads available.

Sent from my moto z3 using Tapatalk
 
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