Rattling brake pad and piston clip

Hi,

I have been on a rattle hunt for the last couple of weeks, and I now have 2 out of 3 solved. First was the retaining spring/pin for the driver's side parking brake pads that had somehow worked loose and was twirling away inside the disc drum. Yesterday, I finally found the time to implement WarCamp's glovebox fix and my dashboard is blissfully silent again!

My last annoying rattle was initially masked by the parking brake issue, but is now pretty obvious. It is coming from the driver side rear and happens whenever I go over bumps. It is definitely not the parking brake (adjustment or cable knocking against struts). However, I was under the car once again this morning looking for the source and it seems that the inner brake pad on that side is very loose and jiggly. With the car up, I can bang against the wheel or caliper housing and the brake pad rattles loudly. If I hold a finger on the brake pad, no rattle. The brake pads on the passenger side seem solidly in place, so I am guessing that this is the sound I am hearing.

I am about to go out and tear the brake apart, but my guess is that the clip that holds the pad to the piston has either come loose or has somehow broken? These pads are Porterfield R4S's that only have 10K on them and have a lot of life still. If I do find a broken clip, is there anything I can do short of buying new pads? I'm guessing the answer is no. Any thoughts on what might have caused this or any repair ideas are much appreciated!

Originally Posted by DaveZ

Hi,

I have been on a rattle hunt for the last couple of weeks, and I now have 2 out of 3 solved. First was the retaining spring/pin for the driver's side parking brake pads that had somehow worked loose and was twirling away inside the disc drum. Yesterday, I finally found the time to implement WarCamp's glovebox fix and my dashboard is blissfully silent again!

My last annoying rattle was initially masked by the parking brake issue, but is now pretty obvious. It is coming from the driver side rear and happens whenever I go over bumps. It is definitely not the parking brake (adjustment or cable knocking against struts). However, I was under the car once again this morning looking for the source and it seems that the inner brake pad on that side is very loose and jiggly. With the car up, I can bang against the wheel or caliper housing and the brake pad rattles loudly. If I hold a finger on the brake pad, no rattle. The brake pads on the passenger side seem solidly in place, so I am guessing that this is the sound I am hearing.

I am about to go out and tear the brake apart, but my guess is that the clip that holds the pad to the piston has either come loose or has somehow broken? These pads are Porterfield R4S's that only have 10K on them and have a lot of life still. If I do find a broken clip, is there anything I can do short of buying new pads? I'm guessing the answer is no. Any thoughts on what might have caused this or any repair ideas are much appreciated!

Inner pad? The one against the caliper piston? Either that calipers psiton is not extending or the caliper is not freely moving on it's mounting pins (the ones you undo with a hex wrench to get the caliper off). Check to see if anything or everything goes tight when the brakes are applied. Nothing goes tight - Caliper piston; Only the outside (under the clip) goes tight - Caliper is not moving freely. JMHO

Originally Posted by HaqDeluxe

Inner pad? The one against the caliper piston? Either that calipers psiton is not extending or the caliper is not freely moving on it's mounting pins (the ones you undo with a hex wrench to get the caliper off). Check to see if anything or everything goes tight when the brakes are applied. Nothing goes tight - Caliper piston; Only the outside (under the clip) goes tight - Caliper is not moving freely. JMHO

Yes, it's the pad that clips into the piston. I just took the brakes apart, and indeed the clips on the back of the inner pad are completely mangled and unrecognizable. In fact, I think that 2 of the 3 prongs have broken off, since I only see 1 left, all crumpled against the back of the pad. You talk about the calipers not sliding right along the guide bolts, but I can see nothing wrong in this respect. I am wondering if it is the reverse. Somehow, the pad itself got stuck along its outer edges and did not slide when the piston retracted. I had painted the calipers at the same time I installed these pads about 1-1/2 years ago. I am now wondering if a blob of paint along those "outer edges" of the caliper that the pads are supposed ride along somehow obstructed the pad from moving. In any case, I discovered that I still have some old EBC Red pads that I will use to replace the broken one. It pays to save everything you take off the car!

I am hoping that the different pads, right vs. left rear, will not cause a dangerous situation under hard braking. I will order a new replacement pad, but it will probably take a week or so before I get it.

Originally Posted by DaveZ

Yes, it's the pad that clips into the piston. I just took the brakes apart, and indeed the clips on the back of the inner pad are completely mangled and unrecognizable. In fact, I think that 2 of the 3 prongs have broken off, since I only see 1 left, all crumpled against the back of the pad. You talk about the calipers not sliding right along the guide bolts, but I can see nothing wrong in this respect. I am wondering if it is the reverse. Somehow, the pad itself got stuck along its outer edges and did not slide when the piston retracted. I had painted the calipers at the same time I installed these pads about 1-1/2 years ago. I am now wondering if a blob of paint along those "outer edges" of the caliper that the pads are supposed ride along somehow obstructed the pad from moving. In any case, I discovered that I still have some old EBC Red pads that I will use to replace the broken one. It pays to save everything you take off the car!

I am hoping that the different pads, right vs. left rear, will not cause a dangerous situation under hard braking. I will order a new replacement pad, but it will probably take a week or so before I get it.

I think you have found the exact root to your problem! The piston does need the pad to clip in properly to pull it back. Now knowing this, I would agree that everything else is working as it should. I don't think you will seriously change your stopping power fro the short time you plan on leaving it this way. Glad it was a simple one..

The spring clip is NOT neeed for proper brake operation. They are needed only for quiet brake operation.

I would call Porterfield and ask them to either replace the pad, assuming you are SURE the install was done properly. Or at least go halves with them to send the defective one back for their analysis.

You can change only the one pad.

Originally Posted by Pinecone

The spring clip is NOT neeed for proper brake operation. They are needed only for quiet brake operation.

I would call Porterfield and ask them to either replace the pad, assuming you are SURE the install was done properly. Or at least go halves with them to send the defective one back for their analysis.

You can change only the one pad.

Thanks for the info, I did end up changing only the single pad for an EBC Red that I had lying around. My Z is now blissfully silent, so the rear end rattling plaguing me was definitely the de-clipped pad. I drove 15miles over local roads last night and did not notice any adverse braking effect from the pad mismatch, so I am a bit relieved about that. One thing I did notice when I replaced the pad is that the Porterfields fit much tighter against the "outer rails" of the caliper than the EBCs. I am now wondering whether this tight fit prevented the pad from retracting somehow with the piston. I have never put any lube/anti-seize compound on these outer rails because I never felt it was needed and I was always concerned about it making its way to the braking surfaces. Maybe I should reconsider... Anyway, I am definitely going to take your advice and give Porterfield a call today and see what they have to say.

I'll be real interested in what Porterfield has to say. Just had my car teched for a track day and was told that my RR brake pad was loose.
Haven't pulled the brake apart but suspect that the clip is missing or mangled just like yours. I've got about 12K and 20 or so track days
on the pads. They are 50% used, don't want to replace before the end of the season, so I'll probably pull it apart get rid of the remainder of the clip and run the rest of the season or 3-4 track days.

Just talked to "Tim" at Porterfield. They said they would replace the clips on the back of the pad and turn it around the same day if I sent it to them. Will do so tomorrow. He had nothing much to offer in the way of tolerance info or possible fitment problems. So, for the price of one way shipping and some close attention on my part when I reinstall the pad, I think this is the best outcome possible.