So today i installed new rear brake pads and rotors on the '15 150. It has the electric parking brake system. Before anybody asks...yes...i did the procedure and set the epb in service mode. My issue im having is the rubber dust boot that surrounds the caliper piston. When i compressed the piston the rubber boot didnt compress like it should have. I used a flat blade screwdriver ever so carefully to pop it back into position. Having no luck with that i thought maybe a bit of lube would help it retract. Before anybody asks...yes...i sprayed WD-40 on my fingers and rubbed it on the boot. That helped a lot to get it to relax back...but...during the course of this it tore. Or maybe the WD has compromised the rubber. Now there is about a 1/8 inch tear in the boot. I've read a few forums and the general consensus is NOT to spray WD-40 on the boot. I need to replace the boot. Just looking for thoughts from other members on replacing the whole caliper or just replacing the rubber boot. Or if anybody else has had this issue.

 

WD40 Silicone or other silicone spray on rubber parts.

I personally, due to past experience with caliper parts, would go the quick route and purchase a new caliper.
But if you're looking to save money and don't mind tearing it down again, spent $20 or so on the rubbers.

 

Yeah, you should always replace the boots. And WD-40 isn't just silicone... it's a solvent, and it can attack certain rubbers.

I wouldn't replace the caliper if that's the only problem, but if you have any concern about it functioning properly, then swap it. You did grease the slide pins, etc., correct?

 

I did grease the slide pins. The whole job was as normal as expected except one rubber boot and the rotors being rust welded to the wheel hubs. Had to wedge a pry bar between the caliper hanger and the rotor to knock them free. It wasnt due to lack of maintenance on my part. I picked up the '15 150 second hand at 88,000. Looks to be the factory brakes. I think im going to keep my eye on it. Watch for drips. Im hoping the amount of WD I used wont seep down and compromise the piston seal. If the boot is there to keep rain out im good for a while. No rain is expected here until October.

 

We were not allowed to uses it or have it in our shop. Very light use item. US Naval Aviation.

 

The local parts supplier says they cant get just the soft parts. I have to swap complete caliper. 80$ plus 45$ core. Ugh...after almost 400$ in brake pads and rotors....lets just say im lucky the CEO doesnt look at the books.

 

There's a high temp caliper grease specifically for that. I think Valvoline makes a good synthetic one in a little tube or the CRC stuff in the ketchup packets.

Caliper repair kits with seals are $5 at rock auto, can probably get them at the parts store. Dealer doesn't carry repair parts....they carry replacement parts.

 

FWIW, the Power Stop Z36 rotor/pad kits include the boots, caliper lube, etc.

 

Interesting... didn’t know that... I guess I’ll stop spraying the rudder when it sticks.

 

I thought that was all the military needed? WD-40 for things that don't move but should, and duct tape/bailing wire for things that do move but shouldn't?