okay, I installed lg motorsports brackets, hawk hps pads, and some c5 rotors from autozone. Immediately after the install, I would get an intermittent grinding when going straight, increasing in loudness when turning right, and completely disappearing when going left.

I've torn that side apart twice since the install. I've found the outer most edge of the rotor (on the inside face) is rubbing on the stock caliper bracket (at the lower portion of where the bracket crosses over the rotor. At first I thought it was just the rattle clip but I've noticed that it's actually caught the bracket itself from the looks of things.

After each tear down/ put back together, the noise seems less severe.

After just doing it right now, the car only does it when turning right, above ~10mph. This led me to believe mabe a wheel bearing going bad, so I checked the wheel for looseness at the 3/9 o'clock position and 6/12 positions, there is a bit of looseness at the 3/9 more so than at the 6/12. I had the tie rods replaced ~25k miles ago with baer units so I dont think they would cause the slack. Also the ball joints, shocks/springs and control arm bushings have all been replaced this summer with moog units.

I don't know what's causing it! I don't know why the clearances would be less on the bottom inside, I mean it is really really close. It does not make the noise with the wheel off, rotor torqued down and turned to the right. It only does it with the wheel loaded turned right, and moving. It's almost as if I need a 1/16 wheel spacer between the rotor/hub to move the rotor out but this doesn't seem right to me, also it wouldn't explain the lateral movement when turning to the right.

Okay my question is? does this sound like:

a bad wheel bearing?
bent bracket (lg or stock)?
maybe a warped rotor out of the box?
maybe a stack up of tolerances of both brackets, and the rotor that all favor contact?
something else?

Sorry for the long post, I don't want to have to put my stock brakes back on. I just haven't seen anyone have this problem with the lg brackets.


The attached files show that inside and outside clearances for the lower portion of the bracket. At the top portion of the stock bracket, the inside/outside clearances are almost symmetrical.

 

Looks like you might need some shims I was worried mine would rub cause they were really really close.

 

where would i go to get shims? or should I just try using big flat washers? thanks!

 

Flat washers would be too large ill have to see where everyone gets them. A lot of guys would have to use them on thirdgen.org I remember when switching to disc in the rear.

 

I sent an email to a guy that should know where to get some. Is it rubbing on the back side of the rotor hard to tell in your pics.

 

yeah it's the backside of the rotor. the first is the outer lower clearance, the second is the inner lower clearance. the top is fine on both sides.

 

By this:
Do you mean that the clearance is fine between the top of the caliper bracket and the rotor? If so I would have to suspect something behind the caliper bracket, i.e. the adapter bracket, steering knuckle or quite possiblely the caliper bracket itself.

Can you get a picture of the full inner? Meaning both the top of the caliper bracket and the bottom.

 

I just took both fronts apart, and swapped the caliper brackets left to right. This made the clearance better, still hear the rattle clip scraping on the rotor but not nearly as bad. Sorry, I didn't take pics. the clearance on the upper inside is 2~3 times that of the bottom inside.

On a side note, I'm beginning to wonder if there is something wrong with my wheel bearing/hub units. I noticed that on the PASSENGER side it's going bad (i.e. it makes a grinding sound when spinning the flange with no rotor on it so I know it's going bad. I'm wondering if since that one is going, maybe my DRIVER side one is going as well and this is allowing the slop that causes the rotor/bracket to grind when the wheel is turned. As i figure it, if the wheel is turned to the right, the ground is exerting a lateral force (to the right) on the wheel. If there is any play, this would cause the rotor to be pushed to the inside of the car, causing the interference. It's the only moving part that could cause the parallelness of the rotor/bracket to change. The car does have 90k miles on it. Does this sound plausible?

 

Sounds like you just might be having issues with the shims. Try moving them or getting new ones if you dont have them already.

 

okay, this may sound like a stupid question....what shims are you talking about?

 

The brake pad shims sorry. The metal ones that go on the caliper bracket before you install the pads.

 

okay, that's what I've been calling the anti-rattle clips. Those scrape a little bit, but before, it was the actual bracket that was grinding on the rotor. The shim is only scraping on the little ear that keeps it from sliding inboard/outboard and only on the bottom bracket crossover. There's something definately wrong with the clearance though because the top is fine and the bottom soooo tight on that one side

 

Shims and anti-rattle clips are two completely different things.

Shims can be used to align the caliper to reduce interference with the rotor. Although if you have excessive play, the bearings (or other axle components) may be worn.

Anti-rattle clips do not perform this function. They don't even go in the same place.

 

Huah we wernt talking about that just that the clips might be rubbing.

 

whoops. Since I swapped the brackets left to right, the rotor hasn't rubbed, just the shims but the tight clearance has to be indicative of another problem, I don't seen why it would be fine on one side (and the top) but jacked on the other side (and not right on the bottom)....weirdest thing i've seen working on this car.

 

are you sure you put the brackets on correct and used the correct bolts.... the orientation and which bolts to use is very unclear with the LG bracket as they ship with no install diagrams.... i have the same kit...

 

well not to revive this post from the dead but i've got a break from school again so I'm going after this problem again. Since last post, I've replaced both wheel hubs w/no effect on interference issue. It's as though the rotor is too thick, the pad abutment bracket opening for the rotor is too small, or the LG bracket is too thick. I don't get it, the pass. side fits beautifully. I've come up with two options:

1. VERY VERY SLIGHTLY grinding the pad abutment bracket @ point of contact (like 1mm deep)

2. drilling the LG brackets (like greenherb I think) to accept the larger bolts of the vette PAB and using it because of the wider space where it straddles the rotor.

 

I have LG brackets too = no issues.

I don;t beleive these can be installed on the wrong side since they are left and right specific brackets but I could be wrong.

Do you have the calipars mixed - the bleed screw must be facing up not down.

Are the calipar pins well greased?

This is a pitorial on LG bracket install:

D:\Documents and Settings\robertbartsch\Desktop\LG Motorsports C5 Brake Install.htm


Follow this carefully and you should not have issues.

 

Yeah you can't mix the LG brackets up left to right. The calipers are on the correct sides but it's not them that hit. It's the driver side caliper abutment bracket that hits and only on the lower part where it goes over the rotor and at that it's only the inside face. Check the second thumbnail, there's only a little bit of clearance but when the wheel is bolted down, and driving, any right turn causes the two to contact at the outer most radial edge of the inside face. The pass. side is perfect.

 

I've seen a few, random occurences of this phenomenon when the customer installs the thicker C5 rotors and uses the F-Car abutment bracket.

Because of the thicker rotor, tolerances are significantly tightened and rotor rubbing the bracket has occured on a few, not very many, but a few customer cars.

It's typically the flashing where the molds seperated or on one the side.

Rotor run out, wheel bearing play, bracket mounting tolerences (or a combination of all 3) are the likely culprits.

Solutions:

Install C5 abutment brackes or gently remove the flashing.

HTH
(not affiliated with LGM)