Rear break noise problem (brake)

[luillo]

Rear brake noise

To make my story short I have a humming noise coming from the rear of the car for a long time. Initially had squeaking noise too but I fixed that with new pads shims.

Here is the full story. After a couple of 1/4 mile races in the track with no line lock just power breaking to heat the tires the car started to develop a weird noise on the rear and the noise seam to be more pronounced when I applied the breaks lightly. I though it was the rear end and after getting the gears changed by ford I decided to fully rebuild the 8.8.

The noise continued and it was getting worse, I did not drive the car much at that time because I was mostly in deployments. When I finally started to troubleshoot the noise I turned the rotors and it help it but it came back again.

The noise was very very loud with a strong vibration in the whole car specially on cold weather, when I pull the e-break it disappear so I am sure is the rear breaks.

Today I decided to try something else and I swap the rotors and pads. The car drove fine for an hour until I did a couple of hard pulls and the humming and vibration came back, is a very curious problem because it seams to happen more when I accelerate hard, it is like the pads are binding hard with the rotor. I after I parked the car I check the rear breaks and these is what I found and what I think is the main problem:

The rear left side break was really hot and it smells

The rear right side breaks was a lot cooler than the left side in comparison.

So I think the left caliper is stock or binding the pads hard into the rotors causing noise and vibration.

Please guys let me know what do you think and if you have any other advice of what I should do or anything I miss.

My last fix will be to swap the whole system for the wilwood rear parking break system for my 9" housing ends.

by the way i been using I-pad to type here so sorry for all the autocorrect or mistakes.

 

[luillo]

After searching around the internet for a while and looking at the things I found in my car, could it be a possibility that my break fluid needs a flush?

My brake fluid is very very dark and maybe have some moisture on it. Also my clutch definitely feels like it needs more pressure, what I mean is that sometimes I can put 1st and 2nd gear with no problem and sometimes is like stuck. Almost like I did not pushed the clutch pedal down, then I pump 2 or 3 times and first gear is in with no problems.

Due to the fact that the break and clutch fluid are connected in some way and the fluid is bad, could it be that the caliper is not releasing because the fluid is contaminated?

 

[luillo]

On these morning I just decided to take a quick look at the brake reservoir and I found some type of jelly looking stuff at the bottom of the reservoir. I will flush the brake fluid tomorrow and check on that left caliper fluid to see what comes out. I think is very possible the contamination is not releasing the caliper after I apply the brakes.

Next I will buy a new clutch line and do a full flush of the system and get it installed and check the clutch pedal feels.

 

[luillo]

Well, I couldn't wait any longer and did the break flush. What I found was nasty, a lot of small black particles like dust. All the fluid was very very dirty black.

The bad thing is that my problem still occuring and worst now. The left rear rotor gets extremely hot compared to all other rotors. It almost burn my hand by getting my hand about 1/4 inch close to the rotor while I can still touch the other rotors.

I will assume that caliper is stuck and needs replacement. I even disconnected the parking break cable on the left side to make sure it wasn't the parking break stuck, then went for a short ride about 1-2 miles and it was about burning hot again right side ok to the touch and normal. When I did the flush I also found black particle coming of the line.

Next step will be to replace the rear left caliper and test run again.

 

[stkjock]

Sounds like clutch dust in the fluid.

 

[GIG4FUN]

title edited for success with future search results

"brake"

 

[luillo]

Sounds like clutch dust in the fluid.

That is exactly what it looked like, but how is that even possible. Isn't that line sealed in the brake system it self?

I also don't get how I have a bad caliper in a new car that has been more in the garage than In the road. I did race the car for a while back in 2011 and have never flush the break system since I got the car but to damage a caliper is kind of hard to believe.

 

[stkjock]

Dust can push past the seal in the slave the Z06 had big issues with this happening.

 

[luillo]

Dust can push past the seal in the slave the Z06 had big issues with this happening.

Thanks for the info, i thought i was going crazy looking at dust in it for no reason.
Could it be possible that my left caliper got damaged by that stuff in it?

i will be replacing the caliper a long with better break lines and clutch line too and will post it here if that fix it. I can not see anything else ben bad.

 

[irishpwr46]

I was going to suggest changing out the calipers. doing brake stands has probably destroyed the seals and possibly warped the calipers.

 

[luillo]

I was going to suggest changing out the calipers. doing brake stands has probably destroyed the seals and possibly warped the calipers.

I will definitely change the caliper as soon as I can and the break lines. I am looking at the boss 302 that AMR sales but I need to verify they will fit which I think they will.

These morning I did a one last check. I lift the rear wheels from the rear end, both wheels of the ground, no gear, no e-brake and the e- break on that left side still disconnected.

No I am 100% sure that caliper is bad. Right wheel spins free with no effort one hand easy.

Left wheel tight as hell, two hands and a lot of effort. Also it feels like is warped, it losses and tights it as it spins which explained the howling noise when it gets hot in cold weather.

The reason I will change the break lines is because I want to make sure they are good due to the fact that when I got my rear end beefed up the shop might left the calipers hanging and damaged my lines in some way. Better be safe and change them in the process.

 

[stkjock]

dude seriously....

break = broken, not working

brake = part used to slow the car


please know the difference.

 

[86GT351]

dude seriously....

break = broken, not working

brake = part used to slow the car


please know the difference.

LOL!


Also you can check to see if it is a Caliper or Hose also. Drive the car to build some pressure in the lines. Remove the wheel in question. Crack open the bleeder screw. If fluid "Shoots" out then it is a line/hose. This is an indication that the line is broken down internally and not allowing the fluid to retract back towards the master cylinder. If it dribbles out it is a Caliper.

Are you 100% sure the caliper slides are ok and lubed properly?

If it is the caliper, you might still want to replace the hose with the repair.

Time to do a Stainless Line upgrade!

 

[luillo]

dude seriously....

break = broken, not working

brake = part used to slow the car


please know the difference.

Sorry, I said it in an earlier post that I am horrible at spelling specially using my I-pad. These shit autocorrects and jumps everywhere so sometimes I don't pay attention to what I type.

Anyway, today or tomorrow I will replace the caliper because, the BRAKES are BROKEN.

 

[86GT351]

Sorry, I said it in an earlier post that I am horrible at spelling specially using my I-pad. These shit autocorrects and jumps everywhere so sometimes I don't pay attention to what I type.

Anyway, today or tomorrow I will replace the caliper because, the BRAKES are BROKEN.

 

[luillo]

LOL!


Also you can check to see if it is a Caliper or Hose also. Drive the car to build some pressure in the lines. Remove the wheel in question. Crack open the bleeder screw. If fluid "Shoots" out then it is a line/hose. This is an indication that the line is broken down internally and not allowing the fluid to retract back towards the master cylinder. If it dribbles out it is a Caliper.

Are you 100% sure the caliper slides are ok and lubed properly?

If it is the caliper, you might still want to replace the hose with the repair.

Time to do a Stainless Line upgrade!

Thanks a lot for the advice but I got to read your post too late. I already got a new caliper. I installed the caliper and after bleeding the caliper it still doing the same thing. Drove the car for a mile and same deal getting hit on that side.

Next and final step is obviously to change the line and cross my fingers it solves the problem because I can't think of any other component that could be causing my left rear break to lock up.

 

[TexasBlownV8]

You could have a bad wheel bearing on that side, too. It would add to the heat, and make for uneven rotation. Or even a bent axle.
When you replace the caliper, check for side-to-side and top-to-bottom movement on the axle. There will be a little, but it shouldn't be a lot.
Try turning the axle end, too, and feel for any binding.

 

[luillo]

You could have a bad wheel bearing on that side, too. It would add to the heat, and make for uneven rotation. Or even a bent axle.
When you replace the caliper, check for side-to-side and top-to-bottom movement on the axle. There will be a little, but it shouldn't be a lot.
Try turning the axle end, too, and feel for any binding.

I will double check on that but I think when I put the new caliper on that side the axle felt free.

I will buy all new braided lines and when I get to it I will check on the axles.

 

[luillo]

I received the lines today and they look good. I hope that fixe the problem, once i get the old ones out i will cut them to verify if they were bad.

 

[wbt]

When this happens are you driving around on the Racestar wheels?