Rear disk brake conversion kits

[thesatelliteguy]

My Empi rear disk brakes (with e brake) have seized a caliper piston, again. Another caliper is around $100.

I’m debating between buying another crappy Empi caliper, or upgrading to a better brake kit. So I’m curious, what disk brake kits are people running on the rear?
I understand that most of the higher quality disk brake kits don’t have an integrated emergency brake and that’s ok. I’ve been seeing that a lot of people attach a separate, e brake only caliper. The Wilwood mechanical caliper seems to be choice.
I’d like to get 3x3 arms eventually but for now, I’m just trying to get the Baja running and driving. So a kit that will fit both stock arms and 3x3’s would be choice.

And if I do upgrade to a better kit, will the stock master cylinder push enough fluid? I’m guessing not. Which means I’ll also have to add pedal assemblies to the list?

As always, any help is much appreciated!
Thanks,
TSG
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[baja5]

I run Jamar Pro X on the rear of my thing. However on my Baja I had CNC 4 piston calipers using a single circuit bus master cylinder. Those brakes worked so well that at times coming down hills it would kill the engine if I didn’t push in the clutch. I know CNC is gone now, but whatever you choose just remember that bigger is better. Going from a 2 piston caliper to 4 makes a huge difference. So I would go that route.
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[dirtkeeper]

I have had ghia type discs on the front of my bug for years and they worked well. After I went with type 3 rear brakes my brakes are great. Really solid feel and a little more braking to the rear.

[thesatelliteguy]

Baja5, what master cylinder are you using on the Jamar Pro-x rear calipers?
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Toyotas are so bumpy it makes me sick, literally.

My build Page http://www.thesamba.com/vw/forum/viewtopic.php?t=383878

[baja5]

[BFB]

ive had pretty satisfactory results from empi's rear disks and master cylinder problems will depend more on bore size than anything. on my copper rail im currently running an old jamar rear disk set up. they are just single piston calipers and didn't have much clamping force so instead of buying a new kit i had a machist buddy make me a second set of calipers and i fabbed up some new brackets so i can run dual calipers on each side. works pretty well and looks even cooler heh heh! i did have to change the master cylinder to a smaller bore if i remember correctly....
if you look close you can see them in this pic.

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[dustymojave]

For actual offroad use of the EMPI disc brakes, I've seen trouble with the center of the rotor hub losing splines or cracking around the center due to lateral forces. Not good enough quality in the cast iron.
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Richard
Offroading VW based cars since 1965
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[jimmyhoffa]

Agreed Dusty. I've seen one 'splode in person, broke the caliper bracket too. A good design is a setup like the Jamar brakes with a high quality center chromoly hub and quality fasteners holding well-engineered wheel adapter plates and brake disc hats to that center splined hub. Most one-piece imported cast rotors are an accident waiting to happen.
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My other car isn't ridiculous.

[JWHracing]

https://www.kartek.com/parts/jamar-performance-vw-...r-irs.html

Jamar has a great product. The splined hub is chromoly and replaceable should you ever ruin one. I highly doubt you would though. They have a 2 piston and a 4 piston kit. Obviously more is better, but in my experience, a stock vw style master cylinder is not big enough to work the 4 piston calipers and push enough volume. 2 piston calipers should be sufficient compared to what you already have. If you want full discs expect the need for a dual master cylinder pedal setup.
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[thesatelliteguy]

Thank you everyone for all the info. Looks like a set of Jamar brakes is coming in my near future!

A few more questions regarding my current set up. Could the residual valve I have on the car right now be causing the seized caliper problem? It’s only one caliper, and it moves, it just doesn’t retract very well.

I can’t press the piston back into its bore (I know it has to be turned and pressed bc of the e brake feature in it). Could it be the residual valve preventing the back flow of fluid?
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[jimmyhoffa]

Possibly, what PSI is the maintenance pressure of the residual valve you have in there? Usually lower (1-2 PSI) are for disc brakes and the higher (5 and 10 PSI) line pressure maintenance valves are for drum brakes.

Related to your calipers: I have never dealt with those ones exactly, but every caliper designed like that I've always ended up fighting, whether it be leaks or seizure. On my 2002 Jetta they kept seizing, even the good OE ones from ATE. On my in-laws Pontiacs they just kept peeing fluid from somewhere or another. I like my e-brakes to be either a separate caliper or drum mechanism of some sort, like my BMWs have been. I always fight those combo-calipers with the built-in screw jack e-brake mechanism.

While I'm on my soapbox, those one-piece disc castings are so much weaker because partly because they lose the strength of the drum "ring" intersecting the face of the drum near where the wheel studs are on a traditional drum. That cup shape is so much stronger on a drum brake than the flat plate hanging out in space on the EMPI and similar disc brakes. That's why if you're gonna be stuck with a design like that, which discs force you into, it definitely has to be done right.

Just last weekend I was very sideways and caught a berm hard on the passenger side and popped the car up on two wheels. 1350lb Chenowth, Type 3 rear drums, Porsche 944 rear stub axles in reinforced bug IRS arms. Dad was in the car co-driving for extra weight too, he got a good look at the ground. No damage! Good decision making on the important stuff really makes all the difference there.
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1974 Chenowth 2RL #1244 Street Legal
My other car isn't ridiculous.

[thesatelliteguy]

It’s a 2 psi valve.
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Toyotas are so bumpy it makes me sick, literally.

My build Page http://www.thesamba.com/vw/forum/viewtopic.php?t=383878

[jimmyhoffa]

Hmmm that should be the right setup then! I've used 2PSI valves with great success setting up disc brakes. For scale, that's just a little harder than you can blow with your mouth, so... almost nothing.
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1974 Chenowth 2RL #1244 Street Legal
My other car isn't ridiculous.

[thesatelliteguy]

I’m starting to be very disappointed with my self for not spending a little more to get a better kit. Of course, that was like 6-7 years ago. Ohh well.
_________________
Toyotas are so bumpy it makes me sick, literally.

My build Page http://www.thesamba.com/vw/forum/viewtopic.php?t=383878