RCR #010 Build Progress

[Bill Musarra]

Bill,
I had the same exact problem, except it occurred while just moving the car around for some work. The motor wasn't even cranked. Pulled it and the bearing had seperated from the housing. Don't know if it was a bolt or poor manufacturing. Showed it to my Corvette parts guy who builds and sells Corvette parts. He never heard of this happening. Be sure to use NAPA/GM replacement parts. They are garanteeded. Check with the parts guys.

Bill

 

[Randy V]

Bill,
I had the same exact problem, except it occurred while just moving the car around for some work. The motor wasn't even cranked. Pulled it and the bearing had seperated from the housing. Don't know if it was a bolt or poor manufacturing. Showed it to my Corvette parts guy who builds and sells Corvette parts. He never heard of this happening. Be sure to use NAPA/GM replacement parts. They are garanteeded. Check with the parts guys.

Bill

I've worked on a lot (LOT) of C3 through C5 Corvette racecars... The C4 bearings are actually pretty stout but I've replaced a fair number of them just the same. The failure mode of the C4 bearings was generally the inner collar that retains the inner race of the inside bearing. The collar would somehow move and cause the bearing pack to loosen. Then the repeated hammering of opposing corning forces, curbs, et al - would eventually push the bearing apart...

I think that maybe Bill's "Seizure" issue could have been caused by the rotor and caliper.

Not ruling out failure of the cast 3-bolt housing at this point either...

 

[Bill D]

Couldn't sleep this morning thinking about the wheel problem. I got it up on jackstands, removed the wheel, and brake caliper to find this...

All the studs are either loose or broken. All the little pins that screw to the lugs were off (?????).

Pulled the rotor and the inside looks like this...

You can see that parts were slamming around and caused some superficial damage.

What do you think caused this type of failure?

 

[Jeff Hamilton]

The studs appear to be full factory length. When you use pin drive the studs need to be shortened or the pin drives can't be torqued.
Jeff Hamilton

 

[Bill D]

I received the car with the pin drive adapters already mounted. I assume the studs were shortened by Fran before the kit was delivered.

 

[Randy V]

The studs appear to be full factory length. When you use pin drive the studs need to be shortened or the pin drives can't be torqued.
Jeff Hamilton

X-2

Unless - somehow - you were able to torque the pin-drive adapter sleeves without cutting the studs to length;

 

[Jac Mac]

Looks like that might be a difficult task going by this pic, not withstanding that Bills drive pins may not have been properly tight or the studs too long, this item needs a rethink. An external hex machined on the drive pin to enable proper torque up without regard to stud length might be a better idea especially in light of the large offset that Bill is running @ the rear as per the second pic.

 

[Bill D]

I checked the studs and they have not been shortened. However, I was able to make a tool that tightened them The ends did not stick out past the recessed hex. So the $60K question is, how could they have been pressed out?

 

[Jeff Hamilton]

If the pin drives where not tight enough the wheel could have pushed the studs out. As the wheel turned it took slop from the top studs to the bottom stud. When the wheel wobbled it pressed some studs in and the others out. As the drives got looser the studs pushed out the back until it made contact.
Jeff Hamilton

 

[Fran Hall RCR]

Bob at Vintage wheel actually states on his website that when using the knocks off wheels that the Corvette studs be shortened....http://www.vintagewheelsus.com/tech.html

Your car was originally shipped on stock size temporary wheels...while we waited for Jongbloed to come through with their wide 14 inch three piece wheels...which they never did to anyones satisfaction.
So at that time we could not have known that you would end up using Vintage Wheels and hence could not have known that the wheels studs would need to be trimmed...

As an aside "Last Detail Corvette" , our bearing vendor/supplier has recently stated they will directly replace any bearing shown to be faulty through manufacture...they request the bearing be returned and a replacement will be sent back.

 

[Allen English]

Wow Bill - Your lucky the wheel didn't come off and damage anything else. When I built my cobra with pin drive I also had to shorten the studs and then I torqued the alignment pins to 70 ft. lbs. per TRIGO. Well any way it looks like a small set back and you should be back up and running in short order.

 

[EGLITOM]

Hi Bill,

sorry to see what happened, but to be honest i just don´t understand.
For sodablasting your uprights, everything had to be completely dissassembled.
For reinstallation you just would have had to follow the RCR build manual which states the following ( plus showing the following pics):

Before assembling the knock off hubs, the studs must be shortened by 0.155" (3.94mm). Post shortening, the stud should end
at the end of the threads in the drive pin as shown below right.

Now install drive pins and torque to 75 ft/lbs (101 N/m).
Additionally, Loc-Tite® and torque to spec rotor mounts.

Pretty clear to me.​

Additionally the Vintage wheels description is also linked there, where the same is stated.​

MY clear reco ( and sorry to be so harsh). READ THE BUILD MANUAL AND FOLLOW THE INSTRUCTIONS, they are there for this very reason. After reading it redo all the critical installations with the manual on mind.​

I don´t give this reco because i want to be the smart ass. It is just my honest desire to help you and see you as an healthy unheart member of this community in the future,​

Thanks for your understanding
TOM​

 

[Dean Lampe]

Glad to see that it will be an easy fix. This is what it means to shake down a car for the first time. I use a red paint pen to mark every bolt when it has been tightened for the last time. That why I can tell if I left something loose. You will be back on the road testing soon.

By the way, one of the previous post seems to infer that Fran or RCR is responsible for this. Thats not really fair. Tom is right on this one.

 

[Randy V]

Studs may also have not been fully seated as well...

I **never** trust a factory installed stud to be fully seated..

I **always** put a mandrel on the stud along with a lubricated washer and nut - then torque to 100#.
Note - do NOT lubricate the threads.
Then remove, clean threads and then put into use.

I'm thinking that I may well also tack weld the stud to the hub.

The great offset of Bill's wheels is a large lever arm on those studs and the bearings themselves.

 

[Rob]

Bill,
Sorry to hear about your misfortune. It's a drag for sure. We've all had shake down issues, and know how frustrating it is to miss stuff. The good news is the wheel didn't brake loose and go through the body.

Might I suggest what I call "silent runs" to you. When I am doing an initial shake down, I will run silent to listen for noises. There are two hills in my neighborhood that work well for this. At the top of the hill I will shut down the motor and roll at different speeds, give hard steering inputs, brake etc and listen carefully for any noises. Certainly such an exercise would have caught this situation.

I agree with all Dean's remarks. I also utilize the same practice of paint marking of torqued joints. It is especially important on a build that will take long durations of time. As we forget where we left off......

Last point to mention, is I do NOT suggest welding wheel studs. Wheel studs are heat treated, welding them will affect the heat treat.

Best of luck Bill. Car looks fantastic man!

 

[Randy V]

Last point to mention, is I do NOT suggest welding wheel studs. Wheel studs are heat treated, welding them will affect the heat treat.

Tack welding with a MIG welder puts very little heat into the hub and stud. If left to cool on its own the heat-treating is basically not affected...

Put a GR8 bolt in your vice and hit it with a hacksaw. Now put a little heat into it and left it cool - try the hacksaw again. You'll find that it's just as tough as it was to begin with.

BTW - I also mark fasteners and fittings.. I use a slash "/" on the first torquing and when doing the re-check, I use the opposite slash "\"... With the exception of the lug nuts, every fastener / fitting has an "X" on it or the car doesn't hit the track.
During cleanup after the race, all "X"s are wiped off and the drill starts over again with the Nut-N-Bolt during the service cycle..

 

[Dave]

For reinstallation you just would have had to follow the RCR build manual which states the following ( plus showing the following pics):

HA, who reads the build manual??????

 

[EGLITOM]

HA, who reads the build manual??????

the ones that are bold and smart enough to admit, that they don´t know everything.

TOM

 

[Dave]

the ones that are bold and smart enough to admit, that they don´t know everything

My coment was meant in jest Tom.....:drunk: But I guess you're used to stating the obvious.:lipsrsealed:

It's ashame that all these comments about reading manuals and the like are ruining I would say the best build thread this forum has seen and really the mods should remove all of them so the thread can continue in a pure form IMHO.

 

[Fran Hall RCR]

Bills thread has hopefully enlightened and educated him and others to many situations during his build.......one of the reasons forums like these exist and are so popular is the interaction not just the pictures...IMHO.