[kjmccarx]

I installed the TF rear disc kit (#4354425) over winter.

Just wondering what size rotor and pads I need when I replace them in the future. There doesn't seem to be too much info about this online already (hence the new thred, not just a post in the what I did to my TJ today, so other people can find it easily).

Will the 8.8 pads, and centric rotors work with these calipers and backing plate drum?

 

[kjmccarx]

Since I hadn't heard anything back here, I asked terra directly. Of course they sell replacement rotors and pads, but they also let me know what pads and rotors to get, if I want to go aftermarket, which was pretty sweet of them.

Their OEM pads and rotors are:
#8624 - https://teraflex.com/shop_items/528ffa7fead962f416e7300f
#8622 - https://teraflex.com/shop_items/528ffa7fead962f416e7300d

But the pads fit a 1998 For Explorer Rear, and the rotors are from an '04 Rubicon.

Why they didn't just use standard rubicon pads... idk. But there you go!

 

[Black Magic Brakes]

Since I hadn't heard anything back here, I asked terra directly. Of course they sell replacement rotors and pads, but they also let me know what pads and rotors to get, if I want to go aftermarket, which was pretty sweet of them.

Their OEM pads and rotors are:
#8624 - https://teraflex.com/shop_items/528ffa7fead962f416e7300f
#8622 - https://teraflex.com/shop_items/528ffa7fead962f416e7300d

But the pads fit a 1998 For Explorer Rear, and the rotors are from an '04 Rubicon.

Why they didn't just use standard rubicon pads... idk. But there you go!

Minor correction but the pads fit a 98 Explorer caliper. The reason they don't use a Jeep TJ rear pad is because the Explorer caliper has a steel piston and the rose clip is much larger to fit into the larger hole in the piston.

Jeep TJ rear calipers have phenolic pistons with smaller holes and the pad has a smaller rose clip.

I removed some pads from a Tera caliper and laid them out next to 8.8 pads and a set from a TJ.

 

[kjmccarx]

Minor correction but the pads fit a 98 Explorer caliper. The reason they don't use a Jeep TJ rear pad is because the Explorer caliper has a steel piston and the rose clip is much larger to fit into the larger hole in the piston.

Jeep TJ rear calipers have phenolic pistons with smaller holes and the pad has a smaller rose clip.

I removed some pads from a Tera caliper and laid them out next to 8.8 pads and a set from a TJ.

Thanks Blaine! That's awesome of you to lay out all the different pads like that. Looks like the '98 explorer pads that terra uses are the same as the 8.8 rear pads that you make/sell, unless there's subtle differences I'm not noticing.

I kind of wish the terra kit used pads with a larger surface area, but the upgrade was worthwhile. I'll definitely get some black magic pads when it's time to replace them in the rear.

What's the pros/cons of the stock TJ Rubicon brakes vs the Terra kit, do you (or anyone else) know?

 

[Black Magic Brakes]

Thanks Blaine! That's awesome of you to lay out all the different pads like that. Looks like the '98 explorer pads that terra uses are the same as the 8.8 rear pads that you make/sell, unless there's subtle differences I'm not noticing.

I kind of wish the terra kit used pads with a larger surface area, but the upgrade was worthwhile. I'll definitely get some black magic pads when it's time to replace them in the rear.

What's the pros/cons of the stock TJ Rubicon brakes vs the Terra kit, do you (or anyone else) know?

The Tera caliper is larger in the body only and interferes with some rims.
The Tera caliper has steel pistons which are less desirable especially in salt zones.
The later Tera calipers have 2 bleeder screws so you can't put them on upside down and as long as you remember to use the top screw, you can always get them bled.
The internal parking brake is similar and interchangeable between the two.
Due to using the older 8.8 design, the pad is smaller on the Tera kit.
All the Tera calipers I've seen are zinc plated which is very good.
Tera calipers are new not reman.

 

[kjmccarx]

The Tera caliper has steel pistons which are less desirable especially in salt zones.

It's interesting that you say this. When I was looking online between steel and phenolic pistons it seems like most people recommend steel, if you have the choice.

Why do you think that they're less desirable, apart from the fact that they rust easier?

 

[freeskier]

The Tera caliper has steel pistons which are less desirable especially in salt zones.

It's interesting that you say this. When I was looking online between steel and phenolic pistons it seems like most people recommend steel, if you have the choice.

Why do you think that they're less desirable, apart from the fact that they rust easier?

Usually comes down to people's universal (often incorrect) belief that metal is always better then plastic.

 

[tangofox007]

Usually comes down to people's universal (incorrect) belief that plastic is always better then metal.

I would have thought that the "universal belief" would be to favor metal over plastic.
In any case, I have had far fewer problems with steel caliper pistons than phenolic.

 

[freeskier]

Usually comes down to people's universal (incorrect) belief that plastic is always better then metal.

I would have thought that the "universal belief" would be to favor metal over plastic.
In any case, I have had far fewer problems with steel caliper pistons than phenolic.

That's what I meant, somewhere between my brain and fingers in got reversed.

 

[tangofox007]

That's what I meant, somewhere between my brain and fingers in got reversed.

Nothing like a mind with a good grip.

 

[Black Magic Brakes]

It's interesting that you say this. When I was looking online between steel and phenolic pistons it seems like most people recommend steel, if you have the choice.

Why do you think that they're less desirable, apart from the fact that they rust easier?

Anyone that recommends steel pistons for brakes has little understanding of how brakes work.

 

[kjmccarx]

Anyone that recommends steel pistons for brakes has little understanding of how brakes work.

Hahaha. Doesn't really answer the questions, but I'll take your word for it.

I have MUCH more experience with mountain bike brakes, and those use ceramic pistons with very high temp brake fluid (Dot 5.1 or special mineral oil). Ceramic works really well for those, but if you don't know what you're doing you can easily crack the piston, which might be part of the reason it never caught on in the automotive world, where you get a lot of people doing things that they probably shouldn't be doing.

 

[Black Magic Brakes]

Hahaha. Doesn't really answer the questions, but I'll take your word for it.

I have MUCH more experience with mountain bike brakes, and those use ceramic pistons with very high temp brake fluid (Dot 5.1 or special mineral oil). Ceramic works really well for those, but if you don't know what you're doing you can easily crack the piston, which might be part of the reason it never caught on in the automotive world, where you get a lot of people doing things that they probably shouldn't be doing.

Phenolic got a bad rap early on due to some of them not being as well made as they should have been. After a while, the manufacturers got the problems sorted out and the problems went away.

They reason they were looking for an alternate material is due to the bad things about steel. It transfers heat to the fluid at a prodigious rate. It corrodes quickly, and it typically costs more.

I work with a couple of big rebuilders and manufacturers of calipers and I've discussed this with them a few times and they are pro phenolic, very pro phenolic.

Be wary of any rebuilder that offers a choice between the two types in the same caliper. If a caliper was designed to have phenolic piston(s), it would be unusual to find piston seals for it that were designed for steel pistons. The seals are not interchangeable between the two and they don't work the same. The inverse is also true, if a caliper was designed around steel pistons, it would be very unlikely to find a seal for it that works with phenolic pistons.

If you dig around online and avoid the subjective stuff and dig down into the info from manufacturers and suppliers, there are some good articles and papers about the importance of keeping them design correct.

 

[tangofox007]

Anyone that recommends steel pistons for brakes has little understanding of how brakes work.

Evidently, brakes are incredibly complicated. Engineers were able to put men on the moon before they succeeded in introducing the phenolic caliper piston.

 

[Black Magic Brakes]

Evidently, brakes are incredibly complicated. Engineers were able to put men on the moon before they succeeded in introducing the phenolic caliper piston.

I suspect they appear that way to those who struggle with simple hydraulic circuits. In reality they are very simple with very simple rules that you should pay attention to.

If you need some help to understand them a bit better, ask away and I'll remove some of the mystery for you.