Brakes Is my caliper piston moving enough?

opihinalu · Sep 15, 2022

Hey all.
I am currently trying to get my caliper back on after a suspension overhaul. It looks retracted, though it the pads are still rubbing on the rotor. When I press the brakes, it moves very little. Is this normal? Am I being an idiot and missing something obvious? My car is an 86 5.0 AOD. Here is a video. I press the brake pedal twice in this video all the way down.

View: https://youtube.com/shorts/fzCOIInbty8?feature=share

General karthief · Sep 15, 2022

I don't see anything moving,

opihinalu · Sep 15, 2022

General karthief said:
I don't see anything moving,

Look closely. It is very slight. Does that mean I have a problem? Could I just be missing something? Does key have to be on to get real brake pressure?

dgollem · Sep 15, 2022

Normally they move a lot more than that, they can even come all the way out with no pad and rotor to stop it. UNLESS you have a lot of air in the lines. Did you open the system and let any air in? If so I would put it on with pads and rotor and bleed the brake then check it again.

opihinalu · Sep 15, 2022

dgollem said:
Normally they move a lot more than that, they can even come all the way out with no pad and rotor to stop it. UNLESS you have a lot of air in the lines. Did you open the system and let any air in? If so I would put it on with pads and rotor and bleed the brake then check it again.

I will try though I did bleed the brakes not too long ago and I thought I had everything out. Thanks for The advice

Rdub6 · Sep 15, 2022

I agree with @dgollem . I’m surprised that piston didn’t come popping out. I believe it should have if everything was correct.
There must not be much pressure in those lines at all right now.

opihinalu · Sep 15, 2022

Rdub6 said:
I agree with @dgollem . I’m surprised that piston didn’t come popping out. I believe it should have if everything was correct.
There must not be much pressure in those lines at all right now.

I have been driving for the last couple months and the brakes have felt good for a 40 year old car. I’m gonna check the other caliper in a minute we will see what that guy does

Rdub6 · Sep 15, 2022

All I know is that when I rebuilt my calipers, it took very little air pressure to get those pistons to pop completely out when I had them on the bench.
I would imagine that the pedal and fluid pressure should be much more than to just move it that little bit.

limp · Sep 16, 2022

Put it together, pump up your brake system and bleed it a few times.....

Mustang5L5 · Sep 16, 2022

It shoudl come out more. You don't need the car on, but a few pumps of the pedal should easily start moving that piston out to the point it probably pops out in 3-4 strokes.

It also doesn't look like it's fully seated.

Fox calipers are cheap. I'd just replace that if you question it at all.

General karthief · Sep 16, 2022

I bet the O ring has rolled out of place, you said you rebuilt it right?

opihinalu · Sep 16, 2022

General karthief said:
I bet the O ring has rolled out of place, you said you rebuilt it right?

No I haven’t rebuilt. How do I check if o ring is out of place?

Mustang5L5 · Sep 16, 2022

You have to pop the piston out to do that. At that point, you might as well install a new seal and boot.

Those calipers are $20 for a reman plus core. It's not worth the time.

opihinalu · Sep 16, 2022

Mustang5L5 said:
You have to pop the piston out to do that. At that point, you might as well install a new seal and boot.

Those calipers are $20 for a reman plus core. It's not worth the time.

Maybe I should just do the Cadillac brembos upgrade at this point. Anyone have any experience with this??

Also any suggestions for rear brakes if I decide going this route?

opihinalu · Sep 16, 2022

Mustang5L5 said:
You have to pop the piston out to do that. At that point, you might as well install a new seal and boot.

Those calipers are $20 for a reman plus core. It's not worth the time.

Maybe I should just do the Cadillac brembos upgrade at this point. Anyone have any experience with this??

Also any suggestions for rear brakes if I decide going this route?

Mustang5L5 · Sep 16, 2022

opihinalu said:
Maybe I should just do the Cadillac brembos upgrade at this point. Anyone have any experience with this??

Also any suggestions for rear brakes if I decide going this route?

I mean I wasn’t trying to talk you out of fixing a caliper and going with a full brembo 5-lug swap.

ATS brembos and a rear cobra/Taurus setup is what I’d do, but it’s a big project

opihinalu · Sep 16, 2022

Mustang5L5 said:
I mean I wasn’t trying to talk you out of fixing a caliper and going with a full brembo 5-lug swap.

ATS brembos and a rear cobra/Taurus setup is what I’d do, but it’s a big project

I know haha I’ve just been wanting to do it for a while. Thanks for the info

General karthief · Sep 16, 2022

Thought I read you rebuilt them, oh well, mount the caliper loosely with pads installed open the bleeder with someone pushing on the peddle, if it has a strong flow of fluid replace the caliper, if not replace the brake hose.
Or just do the 5lug swap.

Gs1987GT · Sep 19, 2022

General karthief said:
Thought I read you rebuilt them, oh well, mount the caliper loosely with pads installed open the bleeder with someone pushing on the peddle, if it has a strong flow of fluid replace the caliper, if not replace the brake hose.
Or just do the 5lug swap.

Good call general, it could just be a collapsed brake line. Replacing all 3 of my rubber lines was one of the first things I did when I bought my car.

OP, as noted prior it should move a whole lot more than that, with no resistance in place, one pump of the brake pedal should move the piston most of the way out.

AeroCoupe · Sep 19, 2022

Not a Mustang but your piston should move alot more.

View: https://www.youtube.com/watch?v=_x-j-Lloi-I

Brakes Is my caliper piston moving enough?

Active Member

wonder how much it would cost to ship you a pair

Active Member

Active Member

So while I wait to figure out my rear end issues

Active Member

So while I wait to figure out my rear end issues

wrap a little cheese around it and its a done

That is…until I whipped out my Bissell

wonder how much it would cost to ship you a pair

Active Member

That is…until I whipped out my Bissell

Active Member

Active Member

That is…until I whipped out my Bissell

Active Member

wonder how much it would cost to ship you a pair

Active Member

lube between the nut and the face. I know my lubes

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