CRG Discussion Forum

Model Specific Discussions => Trans-Am Camaros => Topic started by: 369 on September 24, 2017, 02:29:58 PM

Title: JL8/J56 or HD Service rear end setup question
Post by: 369 on September 24, 2017, 02:29:58 PM
Hello all......I'm putting together a disc brake rear end with the "fixed mount" J56 corvette style calipers. I'm shooting for .005" axle end play......I know this will require custom c-clip thickness which will change as the posi clutches wear..I'm trying to get an idea of how often this will need to be adjusted or reset on a road car. I figured if anyone would know it would be someone here. Any guesses?

-So from what I've read, Penske would change his rear end every race so no issue here...

-the lesser funded guys...How often was this checked/changed? Was the pad knock back tolerable enough to make it thru a season?

-what about the JL8 owners.....I can't see this being a "dealer service" adjustment every other oil change or anything right?

Ok thanks guys.....Tyler
Title: Re: JL8/J56 or HD Service rear end setup question
Post by: Jon Mello on September 27, 2017, 01:09:08 AM
No idea, really. Probably not a lot of miles put on the car and not a lot of heavy abuse so you probably could go a couple of years with no problem. Just a guess.
Title: Re: JL8/J56 or HD Service rear end setup question
Post by: 69Z28-RS on September 27, 2017, 01:55:40 AM
I've a good friend who ran a service rear in his '69 Z28 in SCCA and later IMSA races.   He's told me that he had the rear end gears changed very often, before essentially every race, depending on the track and the speeds anticipated.  I don't recall him saying anything about having to adjust for brake wear...  I'd think there would be sufficient pad thickness to not be anything close to 0.005" tolerance... The pressure on the sides of the rotor should be essentially equal even if one pad was wearing faster than the other.
Title: Re: JL8/J56 or HD Service rear end setup question
Post by: firstgenaddict on October 13, 2017, 07:02:02 PM
With the fixed mount calipers yes there is plenty of tolerance for axle end play, if you are worried about thickness of the C clip then set up every thing with rotor and caliper sans pads, insert different thickness C clips and check where the rotor and caliper are in relation to one another... I think you are going to have .375+ inboard and outboard of the rotor.
Title: Re: JL8/J56 or HD Service rear end setup question
Post by: 369 on October 21, 2017, 03:25:29 PM
10-4.....thanks for the input. Im starting the assembly here this weekend so we'll see how it goes!
Title: Re: JL8/J56 or HD Service rear end setup question
Post by: 69Z28-RS on October 22, 2017, 02:18:38 AM
take some photos, 368...  help to educate us... :)
Title: Re: JL8/J56 or HD Service rear end setup question
Post by: 369 on October 25, 2017, 04:41:03 PM
Yea-I'll shoot some this weekend.

So....interesting tidbit here...I downloaded and printed the "chassis preparation manual" that jon mello posted up here (thanks jon btw)......they list the axle end play spec as ZERO to .015".......ZERO!....playin' with fire there once that whole deal heats up to racing temp.

I know..I know........way over analyzing  but I just thought that was kinda cool