I just installed the Teraflex slotted big brake kit on my 2011 JKU today with the Teraflex master cylinder upgrade. The brakes look great but I have had a few things come up that I can't quite figure out and was hoping someone in here might be able to offer some guidance.

1. Upon applying the brakes to stop while driving under 30mph I get a pulsing sensation in the brakes and the stop is not smooth but a little jerky...

2. When stopping from over 30mph my steering wheel shakes back and forth like what I would imaging death wobble would look like. I never had any steering issues or death wobble before and didn't touch anything other than the brakes now so I can't grasp what that might be.

3. The brakes don't feel any more firm than stock after the install. In fact, they may even feel a bit softer.

We made sure to tighten everything and bleed the brakes more than I thought was necessary just to ensure there was no air in the lines.

Does anyone have any suggestions? I was hoping for a huge positive change in braking for the cost but I'm stumped as to what is causing the issues.

Do slotted rotors cause pulsing at first? It's been a while since I installed a slotted rotor so I can't recall

Any advise is appreciated.

 

None of the drilled or slotted rotors ive run on my cars have cause any kind of pulsations.

 

I have the same brake kit and it works great I don't have any of the symptoms your describing so I can say the kit does work and is a great improvement over stock brakes. Sorry I don't have any insight as to what might be causing your problems. I would say contact Teraflex maybe they can shed some light on your situation. In gonna guess its something to do with the master brake cylinder... Good luck!

 

Just a thought... did you spray down the rotors with bake cleaner and keep grease from your hands away?

 

Ill just clarify that I know this is a great kit and I'm looking forward to it working as I expected but right now I was just describing how it is currently functioning in hopes that someone might have a clue as to why it is that way.

I did call teraflex and they said it should not be functioning that way at all. They recommend driving on it a few days to see if there are any changes... So far with about 50 miles on it, no change.

I did spray down the rotors with brake cleaner as well. I may hit them again today a bit to see if it helps. Level is good and no leaks that I can find.

The brakes are showing more stopping power than yesterday today but shimmy is still there.

Also there is a small hiss for about half a second when the brakes are applied. Could that have to do with the seal not being tight on the new master cylinder? Would that cause this?

 

Did you bed-in the brakes properly?


All brake pads must be bedded-in with the rotor they will be used against to maximize brake performance. The bedding-in process involves a gradual build up of heat in the rotors and pad compound. This process will lay down a thin layer of transfer film on to the rotor surface. Following the bed-in procedures provided by the manufacturer will assure a smooth, even layer of transfer film on the rotor and will minimize brake judder. Here are a few things to keep in mind when installing new rotors and pads:

When installing new pads, the rotors should be new or at least resurfaced to remove any transfer film from the previous set of brake pads.

It is critical that the installer clean any rust, scale, or debris from the hub mounting surface thoroughly and check it for excessive run-out with a dial indicator gauge before installing the rotor.



Failure to follow these procedures may result in brake judder, excessive noise, or other difficulties in bedding-in the new brake pads. The pads need a fresh surface to lay down an even transfer film. Residue from the previous pad compound on the surface or an irregular surface on a used rotor will cause the pads to grip-slip-grip-slip as they pass over the rotor surface under pressure. The resulting vibration will cause noise and telegraph vibrations through the suspension and steering wheel. This vibration is known as brake judder or brake shimmy. This is typically caused by an uneven transfer film on the rotor surface or an uneven surface on the rotor not allowing that transfer film to develop evenly. This is often misdiagnosed as a warped rotor.

Bedding-in new pads and rotors should be done carefully and slowly. Rapid heat build up in the brake system can lead to warped rotors and or glazed brake pads. Most brake pad compounds will take up to 300-400 miles to fully develop an even transfer film on the rotors. Following are the recommended bed-in procedures from each manufacturer:

 

I drove around slowly for about 15-20 minutes gradually applying the brakes. Never going over 30. I didn't jam the brakes at all but immediately I could feel the shimmy... The first time I backed out of the garage I felt it a bit. After 20 minutes of slow driving I returned to the garage to take a look at them and noticed a small amount of smoke coming from the passenger side tire area. I was not sure if it was fluid possibly burning off from somewhere but again I never hit the brakes hard and the shimmy was there.

There was a small amount of rust visible on the driver side when the stock rotor was pulled off the we didn't think would cause any major issues and the rotor seated flush when we put it on.

Man in bummed that this isn't functioning right. Hoping that I can just go back through step by step and 're-install' them incase I missed something.

 

Did you bench bleed the master cylinder? The pulsating could be the ABS and you could have air in the ABS now. You need to get two friends and a scanner tool set it so when you step on the brakes it pumps the ABS. Have one friend start at the passenger rear and start to bleed the brakes again. Have the other friend watch the master cylinder and make sure it doesn't suck air. Do all four brakes furthest to nearest the master cylinder.

 

Make sure you aren't getting a ton of bubbles in the master cylinder. You should be able to bleed from the master cylinder as well. Im sure you have tried this

 

the symptoms you are describing sounds exactly like either pad transfer or warped rotors.....

pad transfer is when brake pad material builds up unevenly on the rotor & warped rotor is caused by excessive heat.

neither of these things should happen with a brand new system but something is uneven on your rotor/rotating assembly causing the wobble.... It could even be some bolt you forgot to torque down.

if it was me I would go 0-40mph fast and do a quick series of 3-4 HARD stops... let it cool off for an hour then repeat... see if that burns anything weird off and maybe pads will settle in. Obviously you do this on your own discretion.

after racing cars for over 15 years you get used to these sorts of issues.

hope that helps.