New front brakes, inner and outer pad?

[airspeed]

I just ordered some new Raybestos brake pads p/n PGD203M and there  appears to be an inner and outer pad.  The actual pad braking material has a different profile.  The clearly have a different surface area and shape, this is new to me...  Will they only mount one way?  I haven't pulled the old ones off yet to look at them.

[HOrnbrod]

Ah yes, I remember that problem from long ago. Yes, one pad is for the inboard side; the other is outboard, and they will mount either way. If you put them in wrong, they will squeal. Loudly. I had to dig deeply in the FSM for a picture, and there was nothing mentioned  about it in the procedure writeup. Compare them to your old ones and put the new ones back in the same way. If your old inboard and outboard pads are the same, I'll dig up the FSM pic.

 

I also posted about this subject here, and can not find it at the moment..........

[airspeed]

I found the answer at Raybestos web site.  The outer pad is the larger one.  Now that I think about it the inner piston is 2" to 3" in diameter but the outer pad is held by a larger area on the caliper ~ 4".

 

Part Number: PGD203M Brand Name: Raybestos Part Description: Disc Brake Pad Set Inner Pad Size: 6.96" x 2.19" Outer Pad Size: 6.96" x 2.22" Inner Pad (Metric) Size: 176.78mm x 55.63mm Outer Pad (Metric) Size: 176.78mm x 56.39mm Packaged Weight: 4.30" Packaged Length: 9.25" Packaged Height: 6.12" Packaged Width: 2.12" Grade Description: Premium

[HOrnbrod]

Glad you found it. I used Wagner pads when this happened to me and their web site told me nothing. Here's a pic of them.

 

[Strokermjcomanche]

MOST pads are stamped I or O on the backing plate of the pads but not all . I keep track of where the pads are when I remove them but if someone put the pads on wrong before you then I guess you have to do what you did .

[DaveJ33P]

Interesting, I'm fairly certain they will only fit one way on my son's '88 Comanche.

I was surprised because I've never paid attention to pad placement on any of my other Mopars.

Are they always inside/outside dependant and I've never noticed?

[HOrnbrod]

The XJs & MJs are, but I don't know about all models. I've had a bunch of XJs and a couple of MJs and have changed front rotors and pads many times over the years. I can't believe I've been lucky all those times. I did notice in the parts manual that the brake pad set for the 1990-92-1/2 2WD XJ/MJ vehicles has a different p/n than the 4WD set, so maybe it just applies to those vehicles. :dunno:

 

But Airspeed has an 88, so it applies to the earlier Renix models too.

 

This is the thread when I first discovered the inboard/outboard pad difference:

 

 

Posted 30 March 2010 - 05:37 PM

Okay, I'm dragging this up yet once more because I FINALLY GOT THE DAMN THING FIXED!! YAAAA!

I'm gonna tell you all what it was in the hopes that it will save my 2WD MJ brothers the aggravation I've gone through tracking down the damn brake squeal.

First off, the inboard and outboard front disk brake pads LOOK identical, but they are not. The inboard pad has the smaller pad liner, about 3/8" difference in length. BUT they will fit on either way. The last brake pad set I got had three outboard pads and one inboard. I missed it and stuck the two inboard pads on the right front wheel. The problem occurs when you mount up the caliper after fitting the pads and anti-rattle clips (more on these later). When you tighten down the two slide pins that the caliper rides on, the top pin bottoms out just enough to C#*@ the caliper so that it will not ride squarely on the caliper bracket sliding surfaces, thus creating squeal. It bottomed out because I had two of the longer outboard pads on and the extra material on the inboard pad causes the caliper pin to bottom out. Of course, there's nothing in the FSM telling you this, just a fuzzy picture that shows the material difference between the inboard and outboard shoes.

Second problem was the anti-rattle clips. They are shaped like an elongated "C". The open part of the "C" must face AWAY from the rotor, otherwise the pad will rattle around in the caliper. Of course, these clips will go on 180 degrees out too with the open part of the "C" facing TOWARD the rotor (I installed one of them on each side this way) which causes even more squeal. The FSM does say to install the bottom clip with the open end facing away from the rotor, but says nothing about the top clip. Naturally I put them in backwards. :wall:

The cause of the squeal was painfully obvious when I pulled everything down to change out the pads yet again with some new ceramic pads. There were bright shiny spots on the caliper and caliper bracket sliding surfaces. Luckily there was no permanent damage done though. Anyhow, hope this helps y'all next time you change front pads on your 2WD. :cheers:

[Minuit]

Yep. Very VERY easy to mix them up. I always lay the pads on the floor in the position they came from (until I kick them and they get switched around of course)