ZINGGG

What are the pros and cons of each? When I did my front pads and rotors yesterday, I realized that the OEM caliper pistons on my 96 XJ 4WD are not metal.

From what I've read, metal pistons reduce brake fade but corrode more quickly if not maintained properly while the OEM phenolic pistons reduce heat transfer and are all around cheaper and are better for those who tend not to keep up with needed maintenance.

So would swapping to calipers with metal pistons be an upgrade as long as they are properly maintained? Are they more reliable than phenolic?

ZINGGG

Wanted to bring up this thread again. I'm going to be doing my calipers and brake lines this weekend. So same question as above

DieselD

How do you properly maintain a caliper's piston? Rebuild the caliper?

ZINGGG

I had posted this a year ago and had done a lot of research at the time. I think I remember at least a few different places saying to apply a thin coat of grease to them fairly often.

I might be making that up though, as it's been a while

DieselD

I didn't see the original post's date.

I honestly didn't know they weren't metal or that there was an option.

Greasing them wouldn't be a problem I guess, but you'd have to remove the wheels and pull the calipers. Not really hard but is it worth the gain? I don't know how much better metal would be.

Are you having trouble stopping? What other brake upgrades have you done?

Willys55

the only reason manufactures went to phenolic caliper pistons was cost of manufacturing and reduce pedal effort as compared to steel pistons. I have never in my 30 years of auto repair heard of someone doing "maintenance on a caliper piston" Not only that, but most rubber products tend to swell when they come into contact with petroleum based products ["grease"]

belvedere

By maintenance, I'm guessing he means flushing/changing the brake fluid regularly, so the absorbed moisture doesn't cause corrosion.

DieselD

Just get phenolic lol. Why add maintenance for what seems like very minimal gain.

Do a rear disc swap, get a WJ master cylinder and booster, call it a day.

Willys55

that would make sense, nearly all manufactures recommend flushing the brake system every 30,000 miles or so. In my Jag I would be effecting my warranty if I neglected to do so.

Brake fluid being hygroscopic allows it to cause corrosion in the brake calipers, wheel cylinders and master cylinder.

ZINGGG

Brakes is the one area I have yet to do any real upgrades to yet.

I have had stainless steel braided lines that have been waiting to go in for over a year now so I'm finally going to do them this weekend. When I did my pads/rotors a while back, the calipers looked pretty sad. Had some rust on em and what not.

Just figured I'd replace them since I have to bleed the brakes when doing the lines anyway

ZINGGG

But I appreciate the responses and info, sirs

Willys55

when I got my XJ last year, the calipers were nearly rotted away. Hard to believe they could hold brake fluid they were so bad. Gotta love the Jersey road salt crews in the winter..LOL

ZINGGG

Haha crazy. Don't have that problem here in CA thankfully. I take it you went with phenolic piston calipers?

MtnHermit

Me too. I have zero body rust and only thin rust on the calipers. The rear drums have some rust inside and out, but not enough to affect braking. Never changed brake fluid on any vehicle I've owned over fifty years.

ZINGGG

I did my rear wheel cylinders last weekend and that was the first time I'd ever dealt with brake fluid. It's nice and clean now. Now that I have the hang of bleeding, I'm ready to do the fronts