I’ve a '93 subaru impreza. It’s brakes are powder, so I bought new pads.
Lower pin out
Caliper swung up
Old pads out
Piston pushed back
New pads in
###!swing caliper back down
So the caliper swings up and down just fine, but won’t slide in and out on that pin due to some nefarious dried blood material that grew between the pin and threads. I guess the boot was slacking, the pin is rusted.
So I spray on the PB. I knock/bang/attempt to pull/wish I could pry/curse. I repeat. I repeat. I repeat. I wait a day. I repeat.
Question:
Do you have any magic methods for freeing up a caliper with a rusty pin? Or a way of getting the bloody thing over the new pads?
Kinda depends on how bad the rust is. If it’s really bad, you should probably just think about replacing the caliper. Otherwise, try a wire wheel on a dremel. Light pressure. You don’t want to score the pin itself, because if you do, you need a new caliper.
I’m not familiar with that caliper but if it is like a GM, more force is required. It needs to slide so need to get it out and cleaned up I believe. Air torque wrench or extention on the ratchet handle and bang the handle with a 5 pound hammer. There isn’t much clearance with new pads so you have to make sure the piston is pushed all the way back, but if it doesn’t slide, it won’t function properly anyway. Make sure the car is properly supported with jack stands and bang away on it.
Why not just remove the upper pin? Just because you don’t have to doesn’t mean you can’t. Also, if it has any rust on it at all, you will need to replace it, and you should be able to do that without buying a new caliper, although I would question the condition of the rest of the caliper if the pin is frozen.
Just to clarify, I thought it was the second pin that wouldn’t come out and I was talking about using sufficient force with a hammer to get the pin out. Then either clean it up or replace it.
When I run into this issue, I find the only good way to deal with this is to use heat to get the pin out of the caliper anchor. Heat, twist, pull, pry, and do whatever is necessary to get it out. Not using heat will increase the likelihood of damaging something with brute force. MAPP gas is hot enough to do the job, and is fairly cheap and readily available. Don’t try propane; it’s not hot enough to do this job. Be careful to avoid damaging anything sensitive to heat, like hoses, grease seals, and wiring. Once the pin is out, clean it up, as well as cleaning out the cavity it mounts in, and apply plenty of brake lube to prevent it from seizing again. Also replace any damaged or missing seals and boots to prevent water intrusion which can cause this to happen.