Help, 08 Gt500 Front End & Steering Wheel Shudder When Braking

[HGT500H]

Hi all. I have been researching around the front end shudder issue a lot but I still cannot sort out what's the real cause is.

 

The front end is shimmy horribly when I put brake pedal, and the vibrations appear to be stronger and higher frequent at higher speed.

 

One noticeable symptom is that the steering wheel shudders more with slight pedal efforts( shudders very horribly) than heavy one at 65~75mph.

 

So far, to me, I would assume it's warped rotors. However, I cannot really conclude it simply because It's been the same with different new rotors sets.

 

I had shudder when I had a stock brembo set up and when I put entire new baer 6p system.(had to replace it to another new one because it was leaked

 

thru pistons) I also replaced recently the another new entire front set of baer 6p extreme including new rotors and it stated to shudder again after the

 

break in period. So I am completely panic now and have no idea where to start to kill the issue. If it's really coming from warped rotors, how can my

 

car keep making rotors warped? is it even possible?

 

If it's not a problem of warped rotor, can anyone address what would be the real issue here?

 

I think secondary culprits could be tie rods, bad steering box or worn out steering bushings.

 

I am sure it is not a problem of EPSA? EPA? programing error since 08 gt500 uses hydraulic steering system.

 

Please help me. Any input would be appreciated.

 

 

 

Best,

JC

[54First]

Did you bed the pads? Google "bedding brake pads".

 

Steve

[HGT500H]

Hi. Steve.

 

In addition, I don't feel vibration through pedal at all, but do feel through whole front end cabin and somewhere on either wheel or tie rods.

 

Jason C.

[HGT500H]

Did you bed the pads? Google "bedding brake pads".

 

Steve

Hi. Steve. I haven't go through a specific bed procedure for both front sets of Baer as they mentioned on their web page. I didn't also put excessive heat on the rotors or do any hard driving at first couple hundred miles. Is the beding procedure mandatory to avoid rotors warped especially for shelby/baer rotors?

 

For those of who have SS with Baers all way around, has any one experienced rotor warpage with moderate driving?

Thanks for reading.

 

Jason C.

[54First]

You may find that after bedding the shudder goes away. Your rotors may not be warped.

 

Steve

[Imatk]

You should have bed the pads in properly, I'm not sure if this is your issue, but it may be.

 

Also if it keeps happening then you MAY be warping the rotors by riding the brake.

 

Do you ride the brake when going down hills? If so it's possible that you are warping the rotors.

[HGT500H]

You should have bed the pads in properly, I'm not sure if this is your issue, but it may be.

 

Also if it keeps happening then you MAY be warping the rotors by riding the brake.

 

Do you ride the brake when going down hills? If so it's possible that you are warping the rotors.

Hi. Imatk. I do ride brake on downhill sometime but not too much or anything. You can imagine me as very smooth and easy driver and many times I even drive slower than those of v6 mustangs. I personally believe if baer rotors really get warped with my riding style, it shouldn't be used as performance parts at all.

 

I drove it yesterday again. I exactly took a big mountain uphill and down hill. When I was going down the hill at 70~80mph, even with very slight brake pedal effort, the car front end shuddered fiercely ( feels like something is hammering my front end consistently) and it was as if some kind of metal plates( sounds like brake duct plate) were touching something and making faded hitting sounds with the same frequency of shuddering around the rotor area in the moment I put pedal. Also, I figured out that car front end shuddered entirely rather than just brake pedal. I think I don't feel any vibration from brake pedal, but I do feel it from entire front end so it made me feel like I was feeling the vibration through the pedal.

With above 75mph on the downhill ( about 35 degree down hill) , it was literally impossible to apply brakes because of forceful vibration. And it was too intense and strong to even slow down the car.( just give up braking) It seems the vibration get much crazier at the down hill braking.

 

Is it still like warped rotor symptom? I personally think it's either bad tie rod or bad bushings or worn out steering rack. Any more ideas? Thank you very much.

 

Best,

Jason C.

[Imatk]

I would take it in to a reputable shop and have them look at the car.

 

Bad bushings would not cause the issue you describe. If you had bad bushings or a bad steering rack the problem would be there all the time, not just when you brake.

 

It sounds like you have warped rotors to me, but it's difficult to diagnose over the internet.

 

If you have brake ducts then they may be contacting your rotor if they were improperly installed or if something on them (a fastner) has come loose.

 

As far as what type of rotor you have... it doesn't really matter. A "performance" rotor is generally larger to help dissipate heat more rapidly, but most of the quality rotors are made from the same material so in theory a larger rotor would take more heat to cause warpage, but if you're riding the brake down a mountain pass then yeah it can warp a rotor. When you ride the brake and don't let off, the system can't cool down... better to brake and let off then just continually ride them.

 

Since you've been through a couple different systems and are having the same issue I would suspect it's your driving habits. Try downshifting on a downhill grade instead of riding the brake. Or apply the brake momentarily to control your speed, but don't "ride" them. Apply... let off.... coast... apply... let off.

 

But I would definitely take it to a shop and have them diagnose it. If the shudder is so violent then your car isn't safe to drive.

[HGT500H]

Oh Thank you very much for letting me know riding brake is so bad on rotors. I haven't really ride brake as much as you mentioned above though. I would say I might have done it just a couple times with extremely slight efforts if I remember. But, I will keep that in mind that all the time. Yea, I will definitely take it to the shop and get diagnosed. Let's say,,,,, since the problem has been the same with 3 different front brake sets, would it be possible the cause might come from the rear because rear has never been changed ever since the 1st front stock set? I was wondering if rear rotors' warpage could justify front end shuddering or the symptom I mentioned above? Thanks.

 

Jason C

[Rattlesnake]

These fellas are right you need to have it looked at but its most likely warped rotors from the heat of riding the brakes. rears are not involved in this issue to my way of thinking.

Listen to what these fellas have mentioned and your on your way to solving the problem.. You may have to replace the rotors if they are real bad but maybe not, Thats why a good brake shop can help you determine if that's necessary.

[Shelby3]

Hi. Imatk. I do ride brake on downhill sometime but not too much or anything. You can imagine me as very smooth and easy driver and many times I even drive slower than those of v6 mustangs. I personally believe if baer rotors really get warped with my riding style, it shouldn't be used as performance parts at all.

 

I drove it yesterday again. I exactly took a big mountain uphill and down hill. When I was going down the hill at 70~80mph, even with very slight brake pedal effort, the car front end shuddered fiercely ( feels like something is hammering my front end consistently) and it was as if some kind of metal plates( sounds like brake duct plate) were touching something and making faded hitting sounds with the same frequency of shuddering around the rotor area in the moment I put pedal. Also, I figured out that car front end shuddered entirely rather than just brake pedal. I think I don't feel any vibration from brake pedal, but I do feel it from entire front end so it made me feel like I was feeling the vibration through the pedal.

With above 75mph on the downhill ( about 35 degree down hill) , it was literally impossible to apply brakes because of forceful vibration. And it was too intense and strong to even slow down the car.( just give up braking) It seems the vibration get much crazier at the down hill braking.

 

Is it still like warped rotor symptom? I personally think it's either bad tie rod or bad bushings or worn out steering rack. Any more ideas? Thank you very much.

 

Best,

Jason C.

 

You can check warpage with a dial indicator. You need to check both sides.

[zoo690]

i have a 07 gt 500 with 7000 miles on it. Front End & Steering Wheel Shudder after hard acceleration then Braking. slow driving,no shake.

 

[89Saleen215]

I'm not sure if this still applies...but a number of years ago when I worked in a shop when the parts people would drop of any rotors or drums the first thing we did was turn them. You'd be surprised how many are warped right out of the box. Yes, we were told by all the parts places and manufacturers that they are true out of the box and you'll void the warranty and blah, blah, blah. It was like about 90% of the time they were warped out of the box. So it's possible the new parts aren't true. One of the reasons why I refuse to run Baer products is because they have historically made it clear that their rotors are a one-time use item - can't turn them. It does sound like a second pair of eyes would be good since you have other issues that don't sound like a typical warped rotor issue. It almost sounds like something in the spindle--rotor-caliper area might not be installed correctly and another set of eyes might catch something that's been overlooked. Let us know what you find - it could help someone else.

[Robert M]

I have read some past posts related to this, and owners have found wayyyy overdue brake system flushing was a portion or all of the problem. As the brakes are used (pads get thinner, caliper pistons extend, brake fluid level goes down), moisture is absorbed into the DOT 3, 4 brake fluid from the air in the M/C. In addition to rust in the brake system, this contaminated fluid also causes braking issues because the moisture (water) in the system does not compress the same as the brake fluid. The ABS systems don't like inconsistent brake pressures.

Shown below is the brake fluid that I flushed out of my 2008 system with just 600 original miles. As seen in the bottom of the bottle, rust sediment is already in the system. At this time my car was 5 years old.......

New/non-contaminated brake fluid is supposed to look like Pee, not Tea (or darker).....

If you look in your mater cyl. and the fluid looks like tea, root beer or coffee, it is well past time for a flush., that brown discoloration is rust. <<<Not good for smooth precise braking. The worst thing to do is during brake pad replacement is to push the caliper pistons back into the calipers before a fresh fluid flush, and forcing all of that nasty contaminated fluid back into the master cylinder and it's seals, but that is the common practice when replacing pads.

If you have flushed you brake system, and the fluid is "known to be good", disregard my reply above.

................and on a side note, the Clutch also shares the brake fluid for its hyd. actuation.........Hmmmm, I wonder why many owners have questioned why their fluid down at the T.O.B. is dark or Black??? Rust finding its way to a low point and through the clutch master and it's seals? <<But that is a different discussion.....

 

R

[Mongoose]

Hey Robert M.,  I think that was a great reply and really something to think about.   Here’s may be another way to go, especially if the car gets stored a lot.  How about stainless brake lines  with Silicone fluid used instead of #4 brake fluid in the master.  This set-up should end the rust and moisture in the brake fluid but it would be a little costly in the beginning to get it all flushed and installed.  J.M.O.             

[Robert M]

12 hours ago, Mongoose said:

Hey Robert M.,  I think that was a great reply and really something to think about.   Here’s may be another way to go, especially if the car gets stored a lot.  How about stainless brake lines  with Silicone fluid used instead of #4 brake fluid in the master.  This set-up should end the rust and moisture in the brake fluid but it would be a little costly in the beginning to get it all flushed and installed.  J.M.O.             

Well, being a previous C3 Corvette owner (decades ago), I tried going that route also, or at least the DOT 5 silicone fluid for the flush.........Problem is, silicone fluid is not recommended for the ABS systems, it is stated on the DOT 5 container and I also looked it up on the internet to verify it was not just a specific brand that was not recommended for ABS, but in general, all silicone DOT 5 fluid is not recommended for ABS.........

The second problem would be all of the pre-bent stainless lines, first from the M/C to the ABS unit and then from the ABS unit to the four corners of the car. I don't think anyone makes such a kit and bending them myself and double flaring each brake line end for a custom installation, well that is not something I would want to tackle......

Believe me, I am with you on the silicone brake fluid, I have spent my share of $$$ with Vette Brakes in Saint Pete Fla. (years ago), but the DOT 5 is a no-go for ABS, supposedly it does not compress in the same way as the glycol fluid for brake pressure in the ABS and also acts strange in higher altitudes in the ABS system.

 

R

[Mongoose]

2 hours ago, Robert M said:

Well, being a previous C3 Corvette owner (decades ago), I tried going that route also, or at least the DOT 5 silicone fluid for the flush.........Problem is, silicone fluid is not recommended for the ABS systems, it is stated on the DOT 5 container and I also looked it up on the internet to verify it was not just a specific brand that was not recommended for ABS, but in general, all silicone DOT 5 fluid is not recommended for ABS.........

The second problem would be all of the pre-bent stainless lines, first from the M/C to the ABS unit and then from the ABS unit to the four corners of the car. I don't think anyone makes such a kit and bending them myself and double flaring each brake line end for a custom installation, well that is not something I would want to tackle......

Believe me, I am with you on the silicone brake fluid, I have spent my share of $$$ with Vette Brakes in Saint Pete Fla. (years ago), but the DOT 5 is a no-go for ABS, supposedly it does not compress in the same way as the glycol fluid for brake pressure in the ABS and also acts strange in higher altitudes in the ABS system.

 

R

Hey Robert, when it comes to brakes, your the “Main Man”!   Thanks for your very informative update on the silicone fluid not being able to be used, or recommended for the ABS systems that are out there now, I didn’t realize that.  And your totally right on bending and flaring stainless steel lines for a custom installation would be a real pain in the butt!  I’m more familiar with the older brake systems that used stainless steel lines and silicone fluid for a long lasting fix, especially for cars that have to be stored for a while like the older Corvettes and stuff!

[Robert M]

2 hours ago, Mongoose said:

Hey Robert, when it comes to brakes, your the “Main Man”!   Thanks for your very informative update on the silicone fluid not being able to be used, or recommended for the ABS systems that are out there now, I didn’t realize that.  And your totally right on bending and flaring stainless steel lines for a custom installation would be a real pain in the butt!  I’m more familiar with the older brake systems that used stainless steel lines and silicone fluid for a long lasting fix, especially for cars that have to be stored for a while like the older Corvettes and stuff!

I remember replacing the rear calipers on a 73 Corvette with the Vette Brakes stainless sleeved replacements. I filled the new master cyl. with the Vette Brakes Purple silicone fluid and with a friend started the bleeding process, shortly after the process began, and a couple of refills of the M/C, I noticed a large puddle of Purple fluid flowing out from under the car behind the drivers door...........The main line from the proportioning valve to the block inside the drivers side frame rail had rusted right at the nut where it screwed into the brass Right/Left block, inside the frame.................How fun!!! That did require a front to rear line replacement and then the bleeding process could move forward again....

Vette Brakes - Stainless steel sleeved calipers and rebuild Power Steering control valves.........and then the Purple Silicone DOT5 fluid......<<That is what I remember about them....Fun, Fun, Fun!

R

[Mongoose]

1 minute ago, Robert M said:

I remember replacing the rear calipers on a 73 Corvette with the Vette Brakes stainless sleeved replacements. I filled the new master cyl. with the Vette Brakes Purple silicone fluid and with a friend started the bleeding process, shortly after the process began, and a couple of refills of the M/C, I noticed a large puddle of Purple fluid flowing out from under the car behind the drivers door...........The main line from the proportioning valve to the block inside the drivers side frame rail had rusted right at the nut where it screwed into the brass Right/Left block, inside the frame.................How fun!!! That did require a front to rear line replacement and then the bleeding process could move forward again....

Vette Brakes - Stainless steel sleeved calipers and rebuild Power Steering control valves.........and then the Purple Silicone DOT5 fluid......<<That is what I remember them by....

R

Yes, stuff like that doesn’t make for a very fun day and you really hate to lose all that new Purple Silicone fluid, plus the clean-up involved.  One thing about silicone fluid and full synthetics, if there’s any little leak what-so-ever, those fluids will find it.   Sleeving the older Vettes calipers was pretty popular, but sometimes can be a real headache!