need help with rear brake

[Mitsueagle]

need help with 90 tsi awd. my caliper siezed so i got a new 1. i have never done a rear brake before. i got the tool to twist the piston in and compress that part but there is no room for the pad and a rotor . do i need a c-clamp or something to compress this other part of the brake? I have a picture of the old caliper, but our new caliper has the piston twisted all the way down now. do i have to compress the rest of the brake?

 

[Mitsueagle]

the piston is compressed and not in the way, it is the red part highlighted in the pic that is in the way. does the brake compress when the rubber is, circled in blue on my pic?

 

[Achelea]

Okay, I'm assuming this is the passenger rear brake caliper.

Not sure what you're asking, but I can help a bit. I did both rear brakes on my car.

Using your picture as a reference; The bracket, which you have outlined in green and red, bolts to the hub. The caliper assembly slides on the slider bolts. You have them circled in blue. When you apply the brakes, the piston pushes against the pad in front of it. When the pad contacts the rotor, the whole caliper assembly slides along the slider bolts, and the other half of the caliper, (The red bits) press against the other side of the rotor, applying braking force.

To remove the caliper from the bracket, you loosen the bolt until the caliper can swing away on the other slider bolt. The other slider bolt slides out, but you have to remove the little rubber nipple on the brass section. If it is seized, it may take some persuasion, mind you, it took a hammer and good swings to separate mine, but that resulted in new slider hardware. IE Bolts, boots, and slider bearings.)

Thing is, when you try to push down the piston, it has to be rotated. I would suggest trying to find a way to compress the caliper before putting it on the car.

If the caliper in the picture is the 'new' one. The reason the pad won't fit is you haven't compressed the piston yet. it looks to be nearly full extension. The piston with the > < marks on it needs to be pushed into it's housing.

Hope this helps. . . Assuming some one else didn't answer this while I was typing.

 

[jbramble2]

You need to compress the piston into the bore. Everything should fit nice once you do this.


After re-reading your post it sounds like the pic is of the old caliper. If the new ones piston is already compressed everything should fit. The slides (circled in blue) should not be an issue. You should be able to remove the caliper, via slides, from the bracket. Maybe you have the wrong caliper if this does not work?

 

[LKWTSI]

You can't just press the piston back in. You have to rotate the piston at the same time you're pressing back on the piston. You do this with a special tool that has the correct ears that fit in the "v" grooves on the piston face.

You can buy the tool at the local auto-shop for less than $10 and it has multiple styles of ears for different vehicles. just rotate the tool around until you get the right ones. The tool looks like a cube with pointy corners and the center is hollow that that actually takes a 3/8" drive on a ratchet extension.

The best way to do it is fasten the caliper to the car and then split the caliper at the slider and rotate the caliper half up towards the wheelwell. Then, with the brake reservoir cap "off", press the tool onto the piston and start ratcheting the piston, ALL the same time as you are pushing on the piston. I can't remember for 100% but I think you turn the piston clockwise to screw it back in. (sorry, I might be wrong, but you'll know quickly if you're going the wrong way), in that case just ratchet the other way. The piston will go back flush with the caliper body and the rubber boot around the piston will look somewhat squashed but nearly flush as well.

Now comes the easy part. Drop your pads in and lower the caliper half you rotated out of the way back down. It'll take a little wiggling, but you'll be able to line up the bolt hole and you're down.

repeat for the other side.

Didn't see "achelea" quote, so disregard my breakdown off the caliper, BUT YOU WILL need the tool I mentioned.

 

[Achelea]

^^^^ He's got the better description.