Brake Calipers

BryanEstep · Jun 18, 2017

Can the guide pins wear or be too long and let the calipers move around? The caliper moves and when it moves, depending on the position it moves into, it clamps my brakes and make my wheel drag. Or maybe its just that my piston need to be pushed in and out? I've done it like three times and i was gonna do it again but i cant get the pins out this time. the notches wont let off

ericbphoto · Jun 18, 2017

The calipers do move. The piston simultaneously pushes the pad on one side and pulls the caliper (with the other pad) towards the other side of the rotor. When you release the brake pedal, it relieves the hydraulic pressure. The pads may still rub the rotor, but not with any significant force. If you're going fast enough, some air may squeeze in between the pads and rotor to give a little more clearance.

If your brake hoses are old, they may be swollen (on the inside where you can't see it). When that happens, the brakes will not release properly when you take your foot off the pedal. That is because pushing the pedal creates enough pressure to force fluid through to move the piston. But then the oil is trapped by the swollen hose and can't release the piston. If that's the case, replace the hoses, fill and bleed the system.

RonD · Jun 18, 2017

I replace them, $7 per set/caliper

But no, they just push out and push in, the tabs at either end will hold them in place, a 3/8 extension can be used to push them out

The brake pads should rub a bit, re-bleed the calipers, they should hold firm with brake pedal applied and slide into correct position for the new pads
When brake pedal is released the calipers shouldn't move, just piston pressure is released, pads are still in contact with disc just not clamping it

Mark_88 · Jun 18, 2017

If you grip the end with pliers and tap it with a hammer they should pop right out.

I tend to agree with Ericbphoto about the flex lines needing replacment though. The lines can act like a one way valve on the inside when they get old and that essentially locks the brakes.

They are inexpensive and easy to replace though. Just buy one of those one-man bleeder kits and follow the instructions to bleed them after you change them. Take your time and you will ace that one.

While you've got them apart have a good look at the shock tower where it attaches to the frame and inspect it for cracks or rust. It is one of the weak points that could cause problems down the road so cleaning them up and hitting them with rust converter then some paint will go a long way to prevent further damage.

If they look good then you can mark another thing off the list for now...

Denisefwd93 · Jun 19, 2017

Even I learned the hard way, t brake hoses are often the cause of dragging pads. Had a brake fire on my car.

BryanEstep · Jun 22, 2017

ericbphoto said:
The calipers do move. The piston simultaneously pushes the pad on one side and pulls the caliper (with the other pad) towards the other side of the rotor. When you release the brake pedal, it relieves the hydraulic pressure. The pads may still rub the rotor, but not with any significant force. If you're going fast enough, some air may squeeze in between the pads and rotor to give a little more clearance.

If your brake hoses are old, they may be swollen (on the inside where you can't see it). When that happens, the brakes will not release properly when you take your foot off the pedal. That is because pushing the pedal creates enough pressure to force fluid through to move the piston. But then the oil is trapped by the swollen hose and can't release the piston. If that's the case, replace the hoses, fill and bleed the system.

I bought a new calipers with new pins and the piston wont go back still. and yes i bled the brakes. So i watched the hose and the hose doesnt swell so the hose isnt the case. So then what could it be? when the brake is pressed i cant move the rotor but when its not presses it just drags the rotor.

ericbphoto · Jun 22, 2017

You won't "see" the swollen hose. It is swollen on the inside closing off the flow of fluid except when it is under pressure from the master cylinder. (If that is the problem)

Sent from my SM-G920V using Tapatalk

BryanEstep · Jun 22, 2017

ericbphoto said:
You won't "see" the swollen hose. It is swollen on the inside closing off the flow of fluid except when it is under pressure from the master cylinder. (If that is the problem)

Sent from my SM-G920V using Tapatalk

I bled the brakes and no more air comes out. Just air. Its a new caliper so in theory it should be fixed. lol. The piston will push out and clamp the rotor together but it only releases it enough to have the rotor slide across the pads and drag. I cant roll it and have it roll for a few seconds because if i could then that would mean the piston is compressing. Maybe I have to manually compress the piston a few times? Maybe the cylinder isnt relieving pressure on that break alone? (idk how cylinders work so what i said may be the dumbest thing you've ever heard) Or maybe it is the hose.

Also, with the caliper came two copper rings. I put them on the bolt for the caliper/hose for compression rings...Is that right? I also got a steel thingy lol dont know what that is either....

Denisefwd93 · Jun 23, 2017

Replace the hoses!

ericbphoto · Jun 23, 2017

The piston will not retract by itself. That is normal. The pressure inside the piston should be relieved when you take your foot off the brake pedal. This should allow the pads to stop gripping the rotor. But they may still drag. This is normal because there is nothing to make the piston retract. You should be able to rotate the rotor/wheel easily by hand. But it will not keep spinning like a fidget spinner.

You should have one copper ring between the bolt head and the hose fitting (called a banjo fitting). The other ring goes between the banjo fitting and the caliper.

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ericbphoto · Jun 23, 2017

If the caliper continues to grip the rotor with pedal released, making it difficult to turn the rotor, then you need new hoses.

Sent from my SM-G920V using Tapatalk

Denisefwd93 · Jun 23, 2017

I have hoses new for my truck got to get them changed soon. fortunately I don't drive far

tomw · Jun 23, 2017

The O-rings sealing the caliper pistons twist when the piston is pushed out of the bore, and when pressure is reduced, the rings will twist back to their original shape, pulling the piston back a very small amount.
The pads will have very slight drag on the disk when the pedal is released. The drag should be light enough that you can rotate the disk by hand. If there is more drag than that, likely something is jammed, holding the pads tight to the disk.
The slide pins can tend to hold the two sections of the caliper in place if they are corroded, damaged, or bent. Some designs use slide-in caliper guides(metal vee with rubber inside?) that fit into a vee in both caliper and slide. If the vee is rusty, or the guides are rusty, the caliper may not retract properly. A tiny bit of lube should be used on both pins and 'guides', to allow the caliper & slide to move and apply/release pressure on the pads.
If you have 'pins', I'd check that they can move freely in their bore.

When you bleed the calipers, you should get a good flow of clear brake fluid when you open the bleeder and have foot pressure on the brake pedal. If you get no fluid, there's a problem.
You can check for excessive pressure due to failed brake hose by pushing and releasing the brake pedal, and then cracking a bleeder. You should get a very slight burst of fluid as the remainder of the pressure bleeds, but it should be very slight. If you get more than a 'puff' of fluid, your hoses may be damaged. If you cannot flow fluid freely with the bleeder open, when you press the pedal, the hoses may be compromised or the master failing.
If you drained fluid out of the system when replacing the calipers, you may have to bleed the master cylinder to get good brake operation. A bubble in the master will never bleed from the bleeder on the caliper. From my experience, anyway.
tom

BryanEstep · Jun 23, 2017

tomw said:
The O-rings sealing the caliper pistons twist when the piston is pushed out of the bore, and when pressure is reduced, the rings will twist back to their original shape, pulling the piston back a very small amount.
The pads will have very slight drag on the disk when the pedal is released. The drag should be light enough that you can rotate the disk by hand. If there is more drag than that, likely something is jammed, holding the pads tight to the disk.
The slide pins can tend to hold the two sections of the caliper in place if they are corroded, damaged, or bent. Some designs use slide-in caliper guides(metal vee with rubber inside?) that fit into a vee in both caliper and slide. If the vee is rusty, or the guides are rusty, the caliper may not retract properly. A tiny bit of lube should be used on both pins and 'guides', to allow the caliper & slide to move and apply/release pressure on the pads.
If you have 'pins', I'd check that they can move freely in their bore.

When you bleed the calipers, you should get a good flow of clear brake fluid when you open the bleeder and have foot pressure on the brake pedal. If you get no fluid, there's a problem.
You can check for excessive pressure due to failed brake hose by pushing and releasing the brake pedal, and then cracking a bleeder. You should get a very slight burst of fluid as the remainder of the pressure bleeds, but it should be very slight. If you get more than a 'puff' of fluid, your hoses may be damaged. If you cannot flow fluid freely with the bleeder open, when you press the pedal, the hoses may be compromised or the master failing.
If you drained fluid out of the system when replacing the calipers, you may have to bleed the master cylinder to get good brake operation. A bubble in the master will never bleed from the bleeder on the caliper. From my experience, anyway.
tom

I got new calipers, new pins, new rings, and a silver thingy. I CAN spin the rotor but it doesnt go like a fidget spinner lol. I wish i could have you guys feel it for yourself and tell me. Maybe a video would work? If anyone of you have skype, discord, etc etc that isnt personal like FB, Insta, the such then either post your info or PM it and tell me you PMed me and I'll get a video for you.

Denisefwd93 · Jun 23, 2017

How many times and how many told you change the hoses? It's actually very easy.

Brake Calipers

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