RDX-Rick

After owning my 2016 RDX for 2 years I decided today I would service the brakes. There is still plenty of life in the rear pads, but I still want to lubricate the slides.

I was able to remove the 2 bolts holding the caliper, and found the caliper would not even wiggle until I gave it a slight tap with the hammer to loosen the rust. The problem is that I cannot lift the caliper entirely off of the rotor.

It is completely loose, and I can pull it away 1/2 " from the hub, but it is being held back by what feels like a clip. At least the springy feeling seems like a clip. My best guess is that there is a clip on the back of the inner pad that fits inside the piston. If that is the case, then it seems that I would have to remove the inner pad as I removed the caliper (i.e. allow the spring to remain in the piston). The problem is that with the corrosion buildup, the pads don't want to slide out easily, and I can't really pry them out using a screwdriver with the caliper still over them.

Despite the fact that if feels like there is a clip, it doesn't make sense because that would also make assembly more difficult. I have tried both rear wheels with the same result. I don't want to apply any more force for fear of bending a clip and not being able to back out of the procedure. I have watched many YouTube videos about Acura rear brake pads, and in every one, the caliper just lifts straight off as expected.

Can anyone confirm what might be holding the caliper from being totally lifted from the rotor?

justnspace

iTrader: (1)

I would try to remove the pads first.
if that means, bolting the caliper back up, so be it.
bolt the caliper back on and remove the front pad

Brown13

I would first remove the brake master cylinder reservoir cover and then take a screwdriver or flat edge like a pry bar and put pressure on the brake pads to compress the piston.Remove two screws for caliper and it should lift off with no problem.

RDX-Rick

Thanks, I appreciate the reply, but I'm not sure I understand. My brain is tired from trying to figure out the brake problem.

Normally the pads cannot be removed without first lifting off the caliper. The attached drawing (not mine BTW, just a Google search result, and it's a front caliper at that ) shows that the pads are contained under the caliper and cannot escape without first removing the caliper.

If someone can confirm the presence of a clip on the backside of the inner pad that reaches into hollow of the piston, perhaps I could use a piece of thin metal to shoe-horn it out.

justnspace

iTrader: (1)

oops,! i was mistaken!! i was thinking of the brembos. I'm sorry!!!!!!

RDX-Rick

Yes that might work, assuming that I am correct and it is a clip inside the piston holding things back. The pads look like they have little wear, so I don't know how much of a gap I could create, but it's not that hard to try. I've given up for today, but may try that on my next attempt.

Thanks

RDX-Rick

OK, I found a YouTube video showing the replacement of a CRV rear rotors and pads.

When he removed the caliper in the beginning of the video, there were no clips reaching into the piston. He was able to remove the caliper as I would expect by just lifting it off. The pads remained in the caliper mounting bracket. However the new pads definitely had large clips that reached inside the piston. He had to place the inner pad on the caliper first, while the outer pad was positioned normally on the bracket. He then had to position the caliper into place with the inner pad already attached.

This YouTube video is cued to start at the point where he installs the new pads. I guess I just need to provide some extra assistance from my screwdriver to move the inner pad against the friction caused by the rust.



https://www.youtube.com/watch?v=Wr4y...youtu.be&t=414

RDX-Rick

Well the brake job is now completed. It turned out that my inner brake pads did have 3 clips attached in a triangular configuration which fit into the piston, as was shown on the YouTube video.

The job turned out to be a real "catch 22" situation. There is no way you can just lift the caliper from the bracket (as is done in every YouTube video ever made). The caliper and inner brake pad must come off at the same time. The problem is that the "ears" on the pad are wedged so tight in the caliper bracket is that they will not easily slide out. You definitely need to pry them out with a screwdriver. The problem is that the caliper covers the pads so completely, that it is difficult to position a screwdriver to pry out the pads.

I tried to follow Brown13's suggestion of using a screwdriver to pry back the piston, but that wasn't as easy as it should have been either. There is a spring clip snapped into the normal "window" in the caliper, (the hole where I usually view pad thickness). There were only very limited points where I could get a small 1/4" blade screwdriver in, to pry against the piston. I eventually gained about a 1/4" of movement between the piston and the pad and I used a screwdriver and hammer to push the pad back and forth over that 1/4" gap until it became loose enough that I could slide it out along with the caliper.

Once I got the caliper off, I cleaned the hardware where the "ears" on the pads rest, and checked the pads for proper fit. The fit was so tight that the pads could not be placed into position without tapping them with a hammer. I decided to grind a little metal off each "ear" of the pads so that they could be dropped into position without requiring a hammer. I then lubed everything up and reassembled the caliper to the bracket. Before re-seating the piston (using the brake pedal) I checked and found the caliper now slid very easily. Before starting the job I found the caliper was frozen to the bracket. It looks like there hadn't been any movement there for quite some time.

Repeated the procedure on the other side and went for a test drive. Everything feels good, and there are no unusual noises as a result of grinding the "ears" on the pads to make them fit a little looser..

On my last vehicle (a RAV4) I also noticed that the rear pads fit very tightly and could not be removed by hand. I also needed to uses a hammer and screwdriver to remove them. Fortunately the RAV4 didn't have the strange set of clips that locked the inner pad to the caliper. The caliper just slid off in the usual manner. I ended up grinding down those pads as well without any ill effects.

rosen39

I usually compress the piston back into the caliper while it is attached to the mounting bracket with a large "C" clamp. Then you will have enough room to get by the clips on the inner pad. Not all brands of cars allow you to do this. If the caliper is also used as a parking brake mechanism, then the piston has to be "screwed" back into the caliper with the appropriate tool. Does the rear mounting bracket have stainless guides the pads ride on? I get new hardware each time rather than trying to clean up old stainless guides. Yes, the "ears" on some brands of replacement pads are too big, cause the pads to bind up, and not retract when you take your foot off the brake pedal. Then you have an overheating issue. I too file them a little at a time, and fit to caliper mounting bracket.

RDX-Rick

I don't think it would be possible to push the piston back far enough to entirely clear these clips. I'm guessing that they reach into the piston by 3/4 of the total depth. They are 2-3 times deeper than the thickness of the friction material on a new pad. The pads would have to be pretty worn to allow that much space when compressing the piston into the caliper.



Yes there were stainless guides for the "ears" to ride on. I brushed them clean with a brass brush and found they were in decent shape. I also like to replace the hardware when installing new pads, but when just performing a routine check up and lubrication (like today) I just reuse the existing hardware.

Your thoughts about the overheating is why I wanted to do today's maintenance. Over the last few weeks I began to notice a vibration when applying the brakes. It felt like the classic symptoms of a warped rotor, except that the vibration was never there when the brakes were cold. Because the steering wheel didn't vibrate, I assumed it was a rear rotor. That lead me to the conclusion that I may have a sticky caliper or pad which only caused the rotor to warp after some extended driving time. I only worked on the rear brakes today. and I will wait a few days to see if the vibration symptoms have been resolved.

YeuEmMaiMai

I see that the OP got the job done so where is general advice

typically I will use an impact tool and remove the caliper bracket and then remove the caliper from the bracket after using a C clamp to compress the caliper a bit first. This will allow easier access to get the inner pad out as you can use a hammer to gently tap out the outer pad and then pry the inner on out.

Do not reuse stainless clips and make sure that you clean off all rust for any mating surfaces

also outside of where the pad ears contact the stainless hardware you would grease every metal to metal surface with brake system lubricant

Tech

The latter part is important and often not done. The rust that sits in the cavity under the stainless steel clips that the pads ride on, results in inadequate clearance and a sticking pad. I always use a fine file and file the rust away which when severe ends up appearing as flakes of iron oxide. Others will cheat and file away at the pad ears to provide the necessary clearance.

I also change my brake fluid regularly and as a bonus, my bleeders never seize. I also pump the pistons out at least half way, lift the silicone dust boots and clean the area under them with alcohol moistened swabs till ultra clean. I then apply the appropriate silicone grease. Same for the sliders.

Fifteen years later, no seized caliper pistons and I only need a brake job (discs and pads) about every five years.

Abe W

RDX-Rick - I'm having the same issue removing the caliper body to replace (2015 RDX) rear pads and rotors. The caliper body won't come off the pads (flange bolts removed), it seems to be held by the pad spring (spring clip), and I guess the inner pad's clips into the caliper piston? Is this the best, easiest, only solution? Seems like there has to be a better way to get the caliper body off and the new pads back in. I've never run into this issue with a simple pad change on other vehicles. Any help or suggestions much appreciated!

RDX-Rick

With any model of car, it is not unusual for rust to develop on the brake pad "ears" or under the stainless steel mounting hardware where the "ears" hang from. This results is the pad being jammed into the caliper bracket, and a screwdriver and hammer are required to bang it loose.

So the normal procedure is to slide the caliper off of the bracket, and hammer loose the stuck pads.

In the RDX, you can't slide the caliper off of the bracket by itself. The inner pad needs to slide off with the caliper because the spring clips on the backside of the inner pad, are inside the hollow of the piston. The problem is that if the pads are jammed into the bracket due to rust, similar to other models, there is very limited access to work the pads loose while the caliper is still mounted.

The only solution is brute force. You need to stick a screwdriver into any access point you can find and try to force the piston back into the cylinder just enough to gain some space. Afterwards try to wiggle the pads free of the rust, and then lift off the caliper with the pad clips still inside the caliper piston.