Review - PMB Performance 308 alloy rear brake calipers

Back in May I wrote up a description of cleaning up and refurbishing my 308 rear calipers while I was replacing rotors and pads: http://www.ferrarichat.com/forum/308-328/446474-refurbish-not-rebuild-308-rear-calipers.html

One of the points I noted initially was

Well... two weeks after finishing the rear brakes, I noticed a drip of blue brake fluid on the garage floor (I was using ATE Blue purchased last year before the ban on blue!). A bit of investigating found that the right rear caliper was dripping a bit. It wasn't the bleed screw or the rigid pipe, so it appeared to be dripping from the bottom of the handbrake lever shaft. I would guess that either a) I cleaned up dirt that was preventing a leak, or b) a seal started leaking when the pistons were fully retracted, a position they hadn't been in for many years, or c) used a bit too much brake cleaner and created a leaky seal on the handbrake lever shaft (per Eric Shea in this post and others:

). Some of the rear caliper rebuild threads say "use lots of brake cleaner!!", but I'd now suggest a bit of care in brake cleaner use.

So, with a leaky rear caliper, I started researching choices...

1) try and find all the seals etc. needed to rebuild the rear calipers myself. It seems this isn't necessarily easy, as nobody sells a complete rebuild kit for this rare units.

2) send my rear calipers off for rebuild. A viable option, there are a few shops that offer this service, and from research here it seems the best shop is PMB Performance: We Don't Rebuild Your Brakes... We Restore Them , and they charge $325 per pair to restore the rear calipers: Ferrari 308 Rear Caliper . The downside to this option is downtime - having finally got my 308 in a drivable state, I didn't want to take it off the road for a month in our very short summers while waiting for rear calipers to return from service.

3) purchase replacement calipers, ready to bolt on. This option is not as easy as it sounds, as nobody offers this rare ATE caliper for sale, or they want a core exchange up front - you send them your calipers before they will ship rebuilt calipers. For the price vendors were asking, it would be cheaper and likely far better to just go with option 2 and have PMB rebuild my own calipers.

3a) BUT when looking through the PMB web site, I found this intriguing option - "Vintage Brakes" 308 Alloy Rear Caliper PMB is offering an aluminum alloy version of the 308 rear caliper that weighs barely half as much as the stock caliper. Even better, they happen to be on sale now - $899 per pair, rather than the original price of $1,595 per pair. At the $899 price, they're cheaper than buying used calipers that would require rebuilding. If I was inclined (I'm not), I could probably sell my original rear calipers for more than that price.

After a bit of thought, I ordered the PMB Performance 308 alloy rear calipers from their web site in June. PMB Performance replied promptly to my web order, and kept me updated on shipping and tracking - great service. The calipers arrived in an extremely well packed and padded sturdy box, no issues.

I finally got a spare afternoon to install these yesterday, so here's a few comparison photos and installed photos. There are three visible differences from the stock rear calipers - they are gray, not plated zinc yellow; the bolts holding the halves together are slightly sturdier than the stock bolts; and there are two bleed screws on each caliper, rather than one. This is because the caliper is also used on the back of the Porsche 914-6, but oriented with the handbrake arm to the bottom, and the OEM Porsche version has the bleed screw on the other 'end' of the caliper. With this alloy replacement, having two bleed screws allows the same caliper to be fitted to either a 914-6 or a Ferrari 308.

I am extremely happy with these calipers and the service from PMB Performance - highly recommended. I know they were more expensive than having my stock calipers rebuilt, but the convenience factor (and saving 10 lbs of unsprung weight! ) are important. If I decide to send my stock OEM rear calipers to PMB to be rebuilt, I can likely re-install them on my car and sell these alloy calipers for close to what I paid for them...
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I'd love to be able to claim that I can feel the difference of a 5 lb reduction per corner in unsprung weight... But I can't. . On my Miata that I have tracked regularly I have noticed improvements in ride quality and suspension response with a similar reduction in unsprung weight, but I don't know my 308 that well yet.

 

Bill,
The experience has been very positive, in that I haven’t given them a thought! Aside from a bleed/flush every 2 years, along with checking the pad thickness, they just work.

Hand brake action - well… same as OE, which on my car means that it will prevent the car from being blown away in a strong wind on level ground, but it’s still pretty ineffective on any sort of incline. I’ve worked on, adjusted, all parts of the handbrake system, and it’s never been good, with OE or replacement calipers. I know some cars have handbrakes that work well, some have useless handbrakes, mine is in the latter category no matter the caliper.

No downsides.

PMB doesn’t list the alloy versions any more, but they do list the 914-6 GT versions caliper again (it has a wider spacer between sides than the 914-6 version, to accommodate the vented rotor on the GT versions- so it bolts right up on a 308. https://pmbperformance.com/products/reproduction-porsche-914-6-or-914-6-gt-rear-caliper-set-with-dual-bleeders?variant=40539603501234

For parts availability, it looks like PMB still has components for rebuilds available on their 914-6 / 914-6 GT page https://pmbperformance.com/collections/porsche-914-914-6-products

Gordon