Compressing caliper pistons, changing piston boots.

I was trying to change my front brake pads and had difficulty compressing the pistons so I could fit the pads in. I ended up tearing a piston boot in the process.

I have a couple of questions.

1st, does anyone know of an easy way to compress the pistons? When I pushed one piston in, the other one would pop out. I ended up pushing one piston in and inserting half of the brake pad while I pushed the other piston in. Just seems like there should be an easier way.

2nd, I ordered a caliper seal kit from Toyota. Can I change the piston boots without taking the whole thing apart?

 

Take the worn out brake pad to use to push both the pistons back in at the same time. You can not press one at a time. This will push the other piston out as you have found out..To push the pistons back in, use a big pair of caliper vise grips. this works great.. To put the piston seal kit back in you will need to pop the piston that was pushed to far out completely out. To put the new seal kit back in, 1 seal & 1 dust dust boot.. Then fill system with fluid & purge all the air. To pop the one piston out block off the good piston with a piece of wood and then use some compressed air on the open bleeder screw or supply hose this will push the piston out .. Do not use a lot of air pressure,,,just enough to push it out.
Note: If ever you can not push the piston back in with normal pressure, the caliper should be replaced or rebuilt.

 

My favorite way is to push them back with the bleeder open. Since the worst fluid is usually in the caliper, it really helps with the bleed process. Beyond that, you can do it with just hand pressure for most calipers.

 

And Harbor freight has a nice brake caliper set, if pistons do not go back easily: I also open bleeder screws when pushing the pistons in, to get old, more likely to be overheated, fluid out. Also, in my experience, pushing pistons in, by hand, without bleeder screws open is very, very hard, since piston is pushing back against the un-compressible brake fluid.

PS I have this kit, since it covers all possible makes, models and caliper sizes. I've used it on 6 different brands (Japanese, Korean, US), and it had matching pads for all.

 

Good stuff.

The one that really messed me up was a combo caliper with parking brake. Screwing it in while pressing was . . . fun.

 

My Kia had one of those. That's then I bought the kit. Front of the piston was smooth, except for for 2 notches at 3 and 9 o'clock. I could not push that piston in to save my life, and trying to turn the piston, while pushing it, was worse than catching a greased pig. I put old brake pads on, after fighting with one caliper fr 2 hours and ordered the kit via mail (no Harbor Freight in Alaska). A week later I did both wheels in less than an hour, with the kit.
Kit had a plate that matched Kia's piston perfectly.

Second kit has two pushers, left and right hand threaded (labeled LH and RH), so it will work on all screw in and push in pistons.

 

Yeah. It was on a Mazda 3. I got them with some old needle nose pliers. Haha!

Never even expected an issue before jumping in. I sure do like these combo calipers, but that little issue did trip me up.

 

$20 JOJOY LUX Brake Caliper Press Tools, 360 Degree Automotive Swing Ratchet Expander Wrench Brake Pad Spreader Tool with Extra 2PCS Large Plates for Single Twin Quad Sextuplet Piston Disc Brake Caliper

https://www.amazon.com/dp/B08LY4NCHG

This is what I use. Cheap, easy, effective.

 

Same here, I have used it on multiple vehicles and it works like a charm.

 

Or this:

$60 Lisle 29100 Quick Quad Pad Spreader

Amazon.com: Lisle 29100 Quick Quad Pad Spreader : Automotive
and others like it.

 

I use the Quad pad. It makes life a lot easier.