New Pads and Rotors Binding?

[SoCalManche]

So I made a mistake on wanting to change my brake pads. As I pulled the calipers and pads, I decided to inspect the rotors as well; wouldn't you know it- the driver side rotor is practically fused to the axle, and the passenger side too some serious handling to remove as well. I got a fantastic deal on a pair of new Bendix rotors to swap in, so I decided to just knock it out. Upon installation of rotors, the new Wagner pads, and calipers, the rotors are loud and proud when I drive; I'd say it's more prominent with speeds over 40mph. Anyways, vibrations are now there as well, and I'm wondering if I just need to throw on a pair of fresh calipers as well? What is everyone's thoughts on this? My MJ is much less driveable now, and I'm just looking for some outside eyes to steer me in the right direction.

 

Other notes: Brake fluid is dark and needs changing. Yesterday I swapped only the pads and the brakes stopped fine, yet today when I threw on new rotors, the brakes are floorboarding now. Oh, and after driving for a bit on the highway and checking the rims, they are cool to the touch.

[ghetdjc320]

When you removed the old rotors did you get all the rust and debris off of the unit bearing so you get a nice clean seat for the new rotor? I’d take the rotor off and compare it with the old one also.

[SoCalManche]

Just now, ghetdjc320 said:

When you removed the old rotors did you get all the rust and debris off of the unit bearing so you get a nice clean seat for the new rotor?

I definitely did my best to take a wire brush to the studs, but I may make that my project tomorrow to hit even harder. 

[ghetdjc320]

1 minute ago, SoCalManche said:

I definitely did my best to take a wire brush to the studs, but I may make that my project tomorrow to hit even harder. 

Also, with the wheel off, try turning the rotor by hand and see if the contact with the pad is consistent. 

[SoCalManche]

2 minutes ago, ghetdjc320 said:

Also, with the wheel off, try turning the rotor by hand and see if the contact with the pad is consistent. 

Contact is pretty consistent. But with the new pads, resistance seems kind of high (in my opinion) when rotating the rotor.

[ghetdjc320]

Hate to say it also but new rotors on old pads is not a good idea. New pads have a sacrificial later that embeds into the pad and help increase braking. If you threw on new pads and then added new rotors latter the sacrificial layer is no longer present on the pads and it will be difficult if not impossible to brake in your pads onto the new rotors

[Dzimm]

I'd also check to make sure your pads are seated correctly in the caliper and try to see if its the front or back of the rotor that's touching the pads.

[SoCalManche]

So update;

 

My fluid was pretty bad, so I decided to clean out the master cylinder and bleed the lines before I continued on to cleaning the rust off the wheel studs and mating surface for the rotor. Good thing I did because wow, there are some nice chunks in there!

 

 

Then I moved on to the wheel studs and gave them a good brushing with a wire wheel.

 

 

Needless to say, the rotors mount flawlessly now, and uncovered another problem...a busted brake pad!

 

Back to the store I go so I can get this taken care of, and then to see if I've taken care of the loud rotor problem and the floorboard-y brakes. Lots of lessons being learned over this past weekend and today...

 

[JustEmptyEveryPocket]

47 minutes ago, SoCalManche said:

Lots of lessons being learned over this past weekend and today...

Welcome to MJs! ~30 years old means you can't trust anything anymore. Inspect and clean everything, every time.

 

I daily drive my MJ, and any time I plan a project I estimate how much time and money it will take. Then I double those numbers and add in two extra trips to the parts stores. Usually that gets me in the ballpark for what it will actually cost and how long my main vehicle will be down.

 

Still in the end its fun.

[SoCalManche]

24 minutes ago, JustEmptyEveryPocket said:

Welcome to MJs! ~30 years old means you can't trust anything anymore. Inspect and clean everything, every time.

 

I daily drive my MJ, and any time I plan a project I estimate how much time and money it will take. Then I double those numbers and add in two extra trips to the parts stores. Usually that gets me in the ballpark for what it will actually cost and how long my main vehicle will be down.

 

Still in the end its fun.

Yeah, I thought my TJ gave me a run for my money, but I tell ye' what....there's a new sheriff in town! 

[ghetdjc320]

2 hours ago, SoCalManche said:

So update;

 

My fluid was pretty bad, so I decided to clean out the master cylinder and bleed the lines before I continued on to cleaning the rust off the wheel studs and mating surface for the rotor. Good thing I did because wow, there are some nice chunks in there!

 

 

Then I moved on to the wheel studs and gave them a good brushing with a wire wheel.

 

 

Needless to say, the rotors mount flawlessly now, and uncovered another problem...a busted brake pad!

 

Back to the store I go so I can get this taken care of, and then to see if I've taken care of the loud rotor problem and the floorboard-y brakes. Lots of lessons being learned over this past weekend and today...

 

Good find on the brake pads. Don’t buy any of those “lifetime warranty” pads. The compound is far to hard. Also, make sure to break in the pads correctly instead of just mounting them and running them. I always run either Centric posi-quiet or black magic pads. Looks like you have the newer style knuckles with the brake pad wings. Here are the pads that work excellent with those: https://www.shop.blackmagicbrakes.com/Front-Black-Magic-Brake-Pads-477-Upgrade-to-Stock-Brake-Pads-F-BMBP-477.htm

[SoCalManche]

My goal down the line is to afford those for both the TJ and MJ; until then, I have to make due, especially during these times.

 

8 minutes ago, ghetdjc320 said:

Also, make sure to break in the pads correctly instead of just mounting them and running them.

Can you tell me the proper break-in procedure for brake pads? I see different sources saying different things, and you seem to know your stuff with brakes.

[ghetdjc320]

3 minutes ago, SoCalManche said:

My goal down the line is to afford those for both the TJ and MJ; until then, I have to make due, especially during these times.

 

Can you tell me the proper break-in procedure for brake pads? I see different sources saying different things, and you seem to know your stuff with brakes.

Here is the break in procedure for bmb. It is the same procedure I use in most applications unless there is an application specific procedure from the pad manufacturer:

http://www.justaddrocks.com/blackmagicbrakes/Black Magic Pads Iinstructions.doc

[ghetdjc320]

The goal is to embed or seat the friction material onto the rotor without glazing. The break in procedure greatly improves high speed or panic breaking. 

[SoCalManche]

4 minutes ago, ghetdjc320 said:

Here is the break in procedure for bmb. It is the same procedure I use in most applications unless there is an application specific procedure from the pad manufacturer:

http://www.justaddrocks.com/blackmagicbrakes/Black Magic Pads Iinstructions.doc

Sweet, I will do the break-in procedure and get back to this thread tomorrow.

 

So it's safe to say that not doing this procedure will still transmit a sound that is similar to a wonky rotor? I spun the tires while it was still on jack stands after replacing everything, and they sound freely and quietly. This was before I pumped the brakes to engage the pistons and tighten the brakes. Once I did that, I took it for a quick test drive, and above 35mph, I hear the rotors still. 

[ghetdjc320]

Does it sound like a metal grinding? If so, check your brake pad clips for interference with the rotor. 

[ghetdjc320]

It’s also possible you have a bad unit bearing. Is it only one side or both that make the noise?

[Minuit]

Some brake pads are loud (cheap pads are loud, and "performance" pads can be really loud), but the anti-rattle clips can cause noise if they aren't put on right. Also, check the dust shield to make sure it's not hitting the rotor. Do you have the FSM?

 

Some varieties of this brake setup have "inside" pads and "outside" pads that are tantalizingly close to being the same, but will cause horrible brake noise if mixed up. Not sure if your truck is this way, but the '91 2WD setup is. Don Hornbrook and I both had problems with this on 2wd 91s.

 

That's officially the most disgusting brake fluid reservoir I've seen, and I've seen some nasty ones. You did good getting that out of there. That was going to cause a lot of problems down the road, and might already have.

[SoCalManche]

22 minutes ago, ghetdjc320 said:

Does it sound like a metal grinding? If so, check your brake pad clips for interference with the rotor. 

So it doesn't sound like grinding; but more of a "wwooOOOooowwwwwwoooOOOooowww" noise if that makes sense. Sounds like someone driving a car that has bashed on the brakes for the last ten years and their rotor is about to go out. I can't tell which side it is coming from either; it's just happening from the front end.

 

7 minutes ago, Minuit said:

Some brake pads are loud (cheap pads are loud, and "performance" pads can be really loud), but the anti-rattle clips can cause noise if they aren't put on right. Also, check the dust shield to make sure it's not hitting the rotor. Do you have the FSM?

 

That's officially the most disgusting brake fluid reservoir I've seen, and I've seen some nasty brake ones. You did good getting that out of there. That was going to cause a lot of problems down the road, and might already have.

No, I don't have FSM; and yes, I'm glad I uncovered that crazy gunk at the bottom of the MC. Happy it's out!

 

Dust shields are out of the way, and as I mentioned earlier, the wheels were spinning freely and quietly while she was still on jack stands. I need to go put each wheel back in the air now that the calipers have been primed and they are pushed up against the brake pads, and see if they still spin freely and quietly.

 

[ComancheKid45]

Check your unit bearings for play also, may have one ready to give up which would cause that noise.

[SoCalManche]

I'm going to stick my GoPro under the front end tomorrow and do a test drive so you guys can hear the sound produced. I really hope it isn't the unit bearing...that's not a cheap fix lol. How do I check for play?

 

13 minutes ago, ComancheKid45 said:

Check your unit bearings for play also, may have one ready to give up which would cause that noise.

 

1 hour ago, ghetdjc320 said:

It’s also possible you have a bad unit bearing. Is it only one side or both that make the noise?

 

[ghetdjc320]

The unit bearing is about a $65-85 fix and about 20 minutes with the right sized sockets. 

[SoCalManche]

16 minutes ago, ghetdjc320 said:

The unit bearing is about a $65-85 fix and about 20 minutes with the right sized sockets. 

And how does one determine which unit bearing might be an issue?

[ghetdjc320]

5 hours ago, SoCalManche said:

And how does one determine which unit bearing might be an issue?

If one is going out than replace both. 

[AZJeff]

Concerning that rasty looking master cylinder reservoir:   I would place bets that the stuff you see in the reservoir is probably scattered throughout the brake system, and none of that will help make the brakes function as designed.   As "Minuit" mentioned, that is some of the nastiest looking brake fluid I have ever seen, and is a good indication of the condition of the rest of the hydraulic system.

 

I would take the MC off the vehicle and disassemble and clean it.  If the seals and bore look OK, then reassemble and reuse.  If you see damage inside the bore, then get a new MC.    While the MC is off, now is the time to flush all of the lines with compressed air, to push out the old fluid and the crud that is probably floating in it.  I would also give serious consideration to replacing the front calipers and wheel cylinders.  

 

I would also consider removing the rear load sensing bias valve and clean that thing as well.

 

Putting new pads/rotors on a brake system that had that much crud in the MC is sort of like painting over the rust holes in the body.