Rear caliper seized?

[GT_MTL]

Hello!

Was u der the car this morning and I notice that the inner side of the rear brake disc was like it never saw à brake pad for decades (unless a very thin line)

The other side of the disc is normal, and the pas are still ok (car has 30000 miles and is almost daily Driven).
I guess my caliper is stuck, due to previous winters and salt on the road, but I wonder if you guys have any ideas or advice.
Thanks!
Yves.

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[sk47]

Hello; Had similar issues on the rear disc brakes of a Chevy pickup. However, the pad wore down much more quickly on one side that the other, o your issue may be different.
Over a few years i tried some things but finally replaced both rear calipers.
I am guessing you have what is called a floating caliper. That being one which moves on pins to squeeze the pads on the rotor. First thing to try is to make sure those pins are lubed well with good brake lube grease. They make a synthetic lube now days. Clean then lube the places where the pads rest or move.
Of course you will have to clean up the rotor surface some to get rid of surface rust. Do not worry too much if you scratch the rotor surface a little.

You may have a caliper piston issue. I did the above and still had the issue of one pad doing most of the braking. Next thing i tried was honing the cylinder walls of the caliper. I broke down the calipers and remover the piston. ( Only a one piston caliper) I used a hone to smoothen the cylinder wall so the piston moved freely in and out. Helped one caliper but not the other. Also was a lot of time consuming work.

My issue was easier to spot as it was the disc surface on the outside which had the narrow shinny ring. Yours is on the inside. One other thing catches my attention. That being the pads had even wear after 30,000 miles. Had a Ford van i worked from. Was leaving a job and stopped to talk to the boss. Van was stopped and i had my foot on the brakes. Yet one rear wheel was slowly spinning in the wet grass. Turned out to be a bad wheel cylinder on the rear. The front brakes were doing all the stopping. This was a rear brake drum setup. My thinking is you may have some sort of restriction.

Good luck.

Note: If you decide to do this job yourself check to see if the brake line is attached to the caliper with a banjo bolt. If so you will need a way to stop the dripping out of brake fluid. I learned the hard way to have a proper sized bolt and nut and some brass washers on hand. the bolt needs to fit inside the banjo bolt. I may have made a thread about this and posted on this site.

 

[GT_MTL]

Yeah, this is a single piston caliper in the rear. The moving axle is free of any blocking and slide back and forth nicely. Before changing everything ( and yes, block the brake line so it doesn't drain out which is tricky on those abs/esp car like S550) I'll try to move the brake cylinder and see if there's any improvements.

 

[Optimum Performance]

Judging by the level of corrosion in the picture it appears the caliper is not sliding. Removing it and replacing or cleaning up the caliper slide pins so the caliper actually moves as designed. At this point new pads and rotor, throughly clean the rust from all the mounting surfaces and replace all brake hardware so the pads can freely move. Also this may have started due to not keeping the parking brake adjusted properly. Periodic 5 backing up and pulling the parking brake adjusts the rear calipers to compensate for wear.

 

[sk47]

Judging by the level of corrosion in the picture it appears the caliper is not sliding. Removing it and replacing or cleaning up the caliper slide pins so the caliper actually moves as designed. At this point new pads and rotor, throughly clean the rust from all the mounting surfaces and replace all brake hardware so the pads can freely move. Also this may have started due to not keeping the parking brake adjusted properly. Periodic 5 backing up and pulling the parking brake adjusts the rear calipers to compensate for wear.

Hello; I did not know this. Thanks.

 

[WildHorse]

Wow.. what kind of mutant salt do they use in Quebec ?
Wow.. quel genre de sel mutant utilise-t-on au Québec ?

 

[GT_MTL]

Hello; I did not know this. Thanks.

Yeah, actually it wasn't set properly. I adjusted it.
But the piston seems really stuck, so I'll have to go through changing everything.
I read the Ford documentation and they said to move the hand brake as well when pressure bleeding the rear brakes due to the "complexity of the brake fluid circuit inside the rear brake".
Thanks!

 

[Sig556]

If this was my car with 30,000 miles on the clock. I would replace both rear Calipers, Rotors, and Pads. Then flush the system.

 

[GT_MTL]

A little head's up on this.
I removed the pads, pushed back the piston and brush everything, along with a hand brake adjustement. The piston was actually moving freely back and forth so I guess the issue was more due to rust preventing the pad to come closer enough to the disc.
I now have a slight friction noise and the rust on the disc is going away.

Anyways, I've ordered new discs, pads, and calipers, along with dust shields and will fix this properly soon.

 

[sk47]

A little head's up on this.
I removed the pads, pushed back the piston and brush everything, along with a hand brake adjustement. The piston was actually moving freely back and forth so I guess the issue was more due to rust preventing the pad to come closer enough to the disc.
I now have a slight friction noise and the rust on the disc is going away.

Anyways, I've ordered new discs, pads, and calipers, along with dust covers and will fix this properly soon.

Hello; Good to hear. Over time the rust on the disc will be worn away by the brake pads. While all new parts is not a bad way to go about it, you may have already solved the issue. Give it a little time to see if the disc surfaces clean up and become shinny. If so only some new pads will be needed after a while.
NOTE - while the rust is being cleaned up some braking efficiency will be lost. Not as critical if the fronts are working properly as they do 70% + of the stopping. Good luck.

 

[GT_MTL]

Hello; Good to hear. Over time the rust on the disc will be worn away by the brake pads. While all new parts is not a bad way to go about it, you may have already solved the issue. Give it a little time to see if the disc surfaces clean up and become shinny. If so only some new pads will be needed after a while.
NOTE - while the rust is being cleaned up some braking efficiency will be lost. Not as critical if the fronts are working properly as they do 70% + of the stopping. Good luck.

Yes I thought about keeping it like this for a while but this is SO rusted. The dust shield is litterally falling appart :-( As the car won't see winter anymore, I'd rather "restore" this and be relaxed !
I'm due for a brake bleed anyways as well so ...

 

[sk47]

Yes I thought about keeping it like this for a while but this is SO rusted. The dust shield is litterally falling appart :-( As the car won't see winter anymore, I'd rather "restore" this and be relaxed !
I'm due for a brake bleed anyways as well so ...

Hello; Makes perfect sense. Be cautious when changing out the caliper and try to not let too much brake fluid leak out. I was not set up properly when i removed a caliper on my 4x4 truck. I did not have a bolt +nut and copper washers on hand to stop the brake fluid from leaking out of the banjo fitting. I had bought some rubber plugs which were supposed to stop the leak but did not. I went ahead and replaced both rear calipers, bleed the brake lines and thought I was finished.

When i started the engine and did a test drive the brakes were soft and a warring light was on. I had allowed too much fluid out and had air into the antilock power valves. I was going to have it in a shop with the special tools needed to bleed the air out of the antilock but found a way to do it myself. I wrote the method up and will try to find and post such.

 

[sk47]

Hello; Makes perfect sense. Be cautious when changing out the caliper and try to not let too much brake fluid leak out. I was not set up properly when i removed a caliper on my 4x4 truck. I did not have a bolt +nut and copper washers on hand to stop the brake fluid from leaking out of the banjo fitting. I had bought some rubber plugs which were supposed to stop the leak but did not. I went ahead and replaced both rear calipers, bleed the brake lines and thought I was finished.

When i started the engine and did a test drive the brakes were soft and a warring light was on. I had allowed too much fluid out and had air into the antilock power valves. I was going to have it in a shop with the special tools needed to bleed the air out of the antilock but found a way to do it myself. I wrote the method up and will try to find and post such.

Learned a trick about anti-lock brake systems. | 2015+ S550 Mustang Forum (GT, EcoBoost, GT350, GT500, Bullitt, Mach 1) - Mustang6G.com

 

[GT_MTL]

I'm planning to bleed right away after swapping the caliper, starting with right rear.
Then I'll bleed them completely to change brake fluid ;)
I might upgrade the brake lines as well while I'm there , idk ...

 

[GT_MTL]

No I didn't.
But I'm not sure what you meant. You don't really see the pad on the picture (caliper on top, then disc, then dust shield). picture has been taken from the bottom up.

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