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Need just a little help with rear brake pads

roadrunner777

Full Member
Joined
Aug 7, 2018
Messages
44
Location
Bemidji, MN
2002 AV Z71 1500 4x4
Option code for brakes: JC5 Brake Vac Power, 4-Wheel Disc, 7,200 lb -- also option G80 locking diff
17" wheels

So, first of all, I apologize now, I suspect this info is somewhere in other threads or just obvious to some.  I had a very early long workday, and I'm a little braindead.

Here's the thing:  I started getting minor noise from the rear that I recognize as most likely worn out brake pads.  It's a light grinding noise, it starts on braking and then quiets down as I continue to drive.  It just started this morning.

I looked through the spokes in the wheel, and the rear discs look good from the outside.  I'll get into this more tomorrow, get some light in there, try to get a visual on the inside disc surfaces, but I mean, I know it's gonna be new pads, that's fine.  I just looked at a YouTube on the job, and it's easy, other than dragging my monster floor jack through the snow, and all that. I lost count of the disk brake jobs I have done... it's north of 50 for sure.

But my mystery is this:  The discs have a considerable outside margin, like maybe 1/2 inch, where the brake pads are not contacting.  It is as though the disks are a little larger than designed for the pads.  Ok, so I go look online for rear brake pads, and there are apparently 2 designs, one longer and maybe more narrow than the other.  So, my tired brain is saying, buy the longer narrow ones, but I'd love to get confirmation and some explanation on how this could be.

I do not have a second vehicle available, and I'd really like to figure out which pads I need, and get them before I start tearing things down.  Maybe I should buy both and return the wrong ones... LOL

Also, a more general question: I have no idea what kind of pads are on the front, but they are relatively new by previous owner.  I will have to choose between organic and ceramic pads for the rear, with unknown fronts.  Given unknown front pad type, which should I go for?  I guess, moneywise, I'd rather go organic, cash is tight at the moment... but if that's a disaster, I'll find the extra money for ceramics.  Thoughts?

And, I guess while I am bothering you with this, one other question: I have been getting intermittent brake sensation like the ABS is activating, on clean dry pavement.  Maybe 1 stop in 20.  Ideas on that?

Again, I'm truly sorry to ask about things that are probably already here.  If it's any consolation, I'm planning on becoming a supporting member with some extra cash coming in January.

Thank you for your thoughts and patience.  I'm going to keep reading threads, maybe I'll find it and if so, I'll mark this solved.

~RR

Edit: So, having learned a few things, I checked and now know my rear calipers have two pistons each.  And, for that, you want the long and narrow pads.  I guess someone installed single pad rotors... they fit and work, they just don't utilize the entire braking surface.  So, I think I am peace with this.  I did trip over a single comment that the rotor surface offset may be different, but I'm not going to address this until I need new rotors, which hopefully will be never.  I may get the parts guy to drag out one of each type rotor just to see if there is really an offset difference.

I'm still interested in organic vs ceramic where the front pads are an unknown type, and thoughts on unexpected ABS activation...

Thanks!

~RR



 
 
look for ones made for 2 piston calipers which you should have on rer since of the locker but do confirm.

exampe:
https://www.autozone.com/brakes-and-traction-control/brake-pads/duralast-gold-brake-pads/582262_428659_3773

might want to check parking brake shoes as on 2002 they moed around and wear out the inside of the drum hat and can cause the rotor to come off if really severe wear as shoe cuts the metal away as you drive.

 
Oh...
So, on the parking brake... that's interesting.  See, I got this AV about 6 months ago, and when I tried the parking brake, the cable snapped.  So, I just tucked the cable ends into holes in the frame because I read here earlier the parking brake is useless anyway.  This makes me wonder if this noise might be parking brake parts gone wacko inside the drum hat, and not pads at all.

Ok.  Well, now the better path is to take the time to get the wheel off and really inspect it.  Yeah.  I can use the wife's car to get parts.... ok.  Plan!
 
ifit kinda sounds like swoosh swoosh

or if ever worked in a machine shop....

the sound of someone turning a brake drum final cut....
 
Yeah, that's about right...  Well, it's pre-dawn here, so I'll know in a few hours.

Describing car noises can be challenging.  I work as a vehicle evaluator, and we have to submit written observations, and a lot of the time, that's noises.  But, we are not supposed to diagnose or draw conclusions.  So, for example, I was driving a 2019 Pacifica one day last week, and it clearly had a rear bearing starting to go out.  I mean, I know that noise, it varies with speed, it's coming from a back corner, but I can't write that the bearing is going out.  I have to come up with a written sound.  Or a squeek... there are all kinds of squeeks, tinny, plastic-like, etc...

I gotta think this is pads because it starts with brake application.  I'm really hoping so... there's a lot of rust in the undercarriage and I know the caliper bracket bolts are tough on a good day.  I'm doing this in snow, so I'd really like it to be fast and easy.  Well, like I said, a little more light, a little more coffee, than I'll suit up and see what's what.

Edit: Yeah, inboard right rear pad is toast.  How it just started making noise is beyond me.  There's the little scraper noisemaking tab, and it's ground down too, never heard it.  Back surface of the rotor is real borderline.  If the caliper bracket bolts cooperate, I guess I'll do the rotor.  It's one of those things, I'm laying on frozen ground doing this, and a big part of me is saying... put in new cheap pads and deal with this next summer with new rotors and high-end pads.  There's about 2 tenths of an inch of pad left on the outboard pad... odd.

Later: I'm good to go, I pried open my wallet and got two new rotors, pads, and also, a nice surprise, they had boxed sets of replacement bolts for the caliper brackets, pretty cheap, with pre-applied loctite. Tomorrow is warmer and less windy, and I'm bone tired, got tomorrow off, so that's that. 

Thanks everyone!
 
I typically go ceramic on most vehicles. On my avalanche I believe I have ceramic all the way around. Just bought Autozone severe duty ceramic pads I believe they were, and the Black coated HD rotors they sell. Haven?t had any issues with them, been a couple years now.
 
Yeah... I had to go organic because I ended up buying two rotors and I was already into a budget issue.  I'll be back in there this spring and go ceramic.  I only drive it about 100 miles in a week, and over winter, snow and ice, I don't do a lot of braking, no hauling or towing at all. 

Honestly, I'm still waiting a little bit to see how the truck shakes down.  I bought it 5 months ago, and this is my first winter with it.  There are other issues, nothing serious, but I'm still in the decision phase about whether it's a keeper or if I sell it and move up next summer.  I love it, but I may end up in a newer AV.
 
Honestly I?ve never really noticed much a difference with actual braking capability between the pads. The only difference I would say is that they may wear quicker, and they may begin to make noise but as far as safety and what not I wouldn?t even worry about it! How many miles does it have on it? The 5.3 is a really good engine, the majority of them may have a bit of a lifter tick on start up but that?s pretty normal for these engines, and they also have a bit of an oil consumption issue but I know a lot of guys who have 250k easy.

This site is really helpful, there?s a lot of people on here that have answered questions that you may have and if they haven?t they?re typically more than happy to help you out!
 
Yeah, I have quite a library of odd noises, including the lifter tick.  I just retired a '94 Ford Explorer, and it had the same lifter issue, but it never became anything worse than the ticking.

Ah.... yeah, the AV has around 330K miles on it.  I know the first 5 years, 2002-2007 it was in a commercial fleet of some kind, and it's missing all the Z71 decals.  I put in Mobile 1 Extended in it a few months ago, with a Baldwin filter, and it's been holding 50-75 psi oil pressure.  There's about a dozen odds and ends I need to deal with next summer... that's fine, I like that stuff.

I was, and remain a contributor to the Ford Explorer message board, looking forward to learning more here.

Thanks!
 
I'm going to get a tattoo to remind me never to say I'm good to go until it's done......

Opened things up, one rotor had paint overspray and a glob right in the middle of the friction area.  Of course, I had the truck apart by that time.

Raised heck with Orielly's for it, so they are going to hand deliver a replacement this afternoon.

Used the remaining parts, finished one side, the one that was grinding.  As many times as I have done this particular task, this is, oddly, the first time I have had to deal with a dual piston caliper, and the pistons were tight.  I mean, I tried it with all kinds of rigs, and got it done, but you know, it's outside, 20 degrees... oh well.  There's a tool for this, and I guess I'll get one somewhere down the road.

It's just... I never had a disc out of the box with paint all over it.  Bah.  I'm warmed back up, time to torque the lug nuts and take a spin to check the first side.

 
If pistons tight they may not retract and you get a stuck pad that will stay engaged while you drive wearing it out, warping dics due to overheat and can cause tire to catch fire as brakes get red hot if you drive too long.

so when done take short drive around block and then go feel how hot they are.... shouldnot be too hot for short drive but if cooking and way hotter then fronts you have stuck caliper and need to get new one.
 
Thanks for the good advice.  Oreilly's delivered the replacement for the defective rotor an hour ago, but the sun is setting.  If I'm not called into work tomorrow, I'll get the other side done, and I'll get a good clue in seeing how hard the other side is to retract.  And, I'll do the test you described. 

This paint on the rotor thing is just weird.  You would think the guy doing the paint would say ooops and take it off the line, or any of the dozen or so people that saw it afterwards.  It was the BestBrake brand, so I guess I'm done with that.  And maybe with Oreillys too.  They tried to tell me to install it the way it was and it would burn off the paint.  Morons.
 
I?ve been working in the Industry full time about 8 years now. I?ve purchased parts from just about every large parts house you can think of. I?ve had issues with every single one of them. Autozone, Oreilly, Napa and Pep Boys to name a few major brands. It seems that they?re all just Chinese parts that are sorted into different boxes. At the end of the day, they don?t care, its just about making a sale, and trying to take as few losses as possible, even if it means screwing over the customer. Can?t tell you have many times I?d open rotors and have two completely physically different looking rotors. i?d Call the store and they?d say ?cant you just put them on?? NO! I?m paying for a product to be a certain way, and the customer may not know but i?ll Know, and if it was my car I wouldn?t want it left like that. Enough of a parts rant.

As far as double piston calipers; yes, they are very hard to press back. Even with a double piston caliper tool they?re very tough to push back. So long as they go back completely you should be OK. Just be sure to lube the guide pins up really good, and I highly recommend using blue loctite on the caliper bracket bolts.
 
I keep hearing about guide pins.  These are rear brakes on a 2002, and there are no guide pins as I understand guide pins.  The caliper is held to the bracket by two bolts with 12mm heads, and perhaps 3/4" long, just regular bolts by the looks of them.  Now, there are ears on the pads that engage a groove, and I lubed those ears.  When I got everything apart, I realized there were some sheet metal liners (abutments?) for those grooves and I didn't get those... that's ok, I'm going back in next summer with ceramic pads and I'll replace those too.

The bracket bolts... this was a happy surprise.  I rounded the head of one a little bit getting it off, and often on jobs like this, I replace bolts as a matter of habit.  Back when my first trip for parts, I fully intended to stop at another store to get grade-8's.  But, Oreillys had them as part of the brake part inventory, with loctite already applied, for less than I would have paid for the grade-8's and loctite.

At this point, I have one side done, and all the tools and parts are in the kitchen to do the other side, when the sun comes up in a few hours.  The kitchen?  I'm doing this outside, it will be 17 degrees when I start working on this, about 30 by the time I finish.  So, it's nice not to have to grab a lot of freezing steel.  I am also the family cook, so it's my prerogative.... :)
 
rear has guides... the caliper bracket uses theseguide pins to bolt to theaxle bracket...

They have trhe rubber booty on them to keep dirt out...

to push back to pistons.
put old pad over pistons...in caliper
Then use C-Clamp and slowly squeeze...

now I open bleeder so old fluid comes out.....
and when done I bleed brakes again.
 
Yeah, ok.  I just got there on the 2nd side.  The 12mm bolt threads into the guide pin, which is almost entirely in the caliper except for the the end with the rubber boot.  And, it was well greased when I pulled them out to inspect.  I'm going to assume the 1st side is ok too.... I'm not going back in the 1st side to check.

So..... interesting.  There is about 0.2" of brake material on all the pads except the inboard passenger side, which was down to metal.  And... this caliper compressed much more easily than the passenger side one.

I'm gonna need a new caliper, I think. 
 
Agree on new caliper...
 
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