Compressing front brake pistons

[JOKER M1]

I’m sure this has been discussed before but I’ve searched till my head spun. Only asking this because I was surprised to find out the rear pistons had to be screwed in, kinda interesting concept. Anyway, before I started clamping the front pistons in I figured I would ask how it’s done these days. We used to just open the brake reservoir and use a c-clamp to compress the piston, is this how the fronts are done on the S550. I have a GT Premium with OEM calipers, thanks.

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[Anthony 05 GT]

I use an old brake pad or block of wood and the c-clamp. The reason the rears have to be screwed in is for the e-brake. When you pull the brake handle up the hardware rotates the pistons exposed area to apply the brake.

 

[keltymd]

me I dont remove the reservoir cover because it exposes the fluid to moisture and I never top mine off because if it is low your pads are worn out or you have a leak.

Back on subject...... I compress the pistons with the pads in and a spreader because you have 4 pistons not just one.

 

[Marvinmadman]

I just twist them against the rotor by hand. No extra tools needed. Unbolt them, slide off just a tad bit and pull at an angle. Kinda hard to explain.

 

[JOKER M1]

I use an old brake pad or block of wood and the c-clamp. The reason the rears have to be screwed in is for the e-brake. When you pull the brake handle up the hardware rotates the pistons exposed area to apply the brake.

Got it, thanks for sharing that reason. Good to know.

 

[JOKER M1]

[MENTION=26181]keltymd[/MENTION], thanks. I’m guessing the reservoir breathes so when you compress the piston air in the reservoir breaths out the cap?

 

[JOKER M1]

I just twist them against the rotor by hand. No extra tools needed. Unbolt them, slide off just a tad bit and pull at an angle. Kinda hard to explain.

I follow you on the way you do that. I’ll remember that next time as I’m beyond the disassemble process now, thanks

 

[Marvinmadman]

I use an old brake pad or block of wood and the c-clamp. The reason the rears have to be screwed in is for the e-brake. When you pull the brake handle up the hardware rotates the pistons exposed area to apply the brake.

The piston doesn't rotate when applying the e-brake.

 

[jasonstang]

The piston doesn't rotate when applying the e-brake.

You are right it does not but the mechanism is to allow the piston to be backed in only when rotated. That way when you pull the handbrake, the inside pad is pushing against the rotor to hold the car. If it backs in like the front caliper, it will not work.

 

[Marvinmadman]

It's usually an internal screw that is turned by the e-brake that pushes the piston out.

 

[OKC S550]

I have brembos so not sure if it is different on your car but I can compress the pistons by pressing them in with my hands/fingers. I also leave the cap on the reservoir.

 

[JOKER M1]

Alright thanks everyone, I just wanted to be safe and not cause any damage. I did leave the cap on and I did use a clamp, I did try squeezing by hand but no go. Everything went great and thanks again.

 

[Spartanator]

 

[sldghmr]

I used to do it by hand (sometimes still do if I'm not in a hurry), but then got this as a present...

Lisle 29100 Quick Quad Pad Spreader

 

[JOKER M1]

Now that’s cool

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