308-Precision Brakes - "Mr. Parker" caliper?

Please be patient, it is the weekend and many guys lurk here during the week, too. Have Brembo front with their stock FM1000 pads and use Ferodo DS3000 rear pads and Girodisc's matching alum/floating slotted rear rotors o balance the braking. The car is used on the street and extensively on the track. Stops at about 1.2G using street rubber (Mich Pilot Sport PS2). On Thursday am changing to Mich Pilot Cup and will see if/how much the stopping G's go up. Go slotted or solid rotors, drilled is just a game of connect the dots IMHO and from other track guys i have spoken with.

 

With a setup like Steven's and mine using Brembo or Girodisc big front brake setup and Girodisc floating hat rear rotors, with high-temp brake fluid and "balanced pad" combination (different than Steven, I use Porterfield R4S pads front and EBC Greenstuff rear but it makes for a similar balance) there's really NO functional reason to change out the rear brakes to a multi-piston setup. Try upgrading your front setup first and I'm sure there will be no lack of stopping power and no brake overheating/fade problem on track days.

www.ferrarichat.com/forum/showthread.php?t=39712

Of course, if you use multi-piston larger rotors both front and rear, you can use the same pads all around, but there's not much advantage unless you're a track-only car, and still only barely then, and in that case you don't need a parking brake anyway.

 

Greg,

You and I have discussed the 308 brake upgrade situation before. I just looked at the Mr. Parker caliper on-line and it reminds me of a Wilwood unit. It probably is possible to modify or adapt Mr. Parker to a 308 but at almost $500 per pair it IS a little risky. Do you even know what the mounting dimensions are? It would be a lot easier to adapt if it was made to mount radially. In that case an aluminum adaptor bracket can be made to fit almost any caliper to almost any up-right.

I have Brembo calipers front and rear with a Tilton tandem master cylinder set-up on my 77 308GTB but to date have no parking brakes. I shaved a lot of metal off of the original ATE rear calipers in an attempt to save only the parking brake function but they still weighed a ton so I didn't want to use them.

Wil

 

I told lil' Amanda to run and fetch a big rock from the ex's landscaping....it worked fine......

She was a little nervous getting it back out when I left, but she'll catch on.....


Back to greg328's quest........

 

So did I when I first put them on. If you don't figure out the solution for the bigger rears and parking brake issue, you can definitely get proper balance with either pads as Steven and I have done, or a brake bias valve.

Yeah, I know they look dwarfed by comparison. But you'll find that kind of diameter difference on many cars, including Corvettes!

 

Hi Greg, at it again huh? This is deja-vu

AS posted 10-17-2005 In response to this same question.......There is still no magic solution Greg.


Hi Greg,
I have been over this issue with a fine tooth comb.
It is possible. It will be time consuming and difficult at best.
The reality is that there is NO bolt on, no worries, comes in a box setup.
You are basically going to have to re-engineer the whole rear corner assemblies from the upright out. If you are ready for the challenge, then its mission impossible time.

Here are some of the main considerations:

1. Parking brake caliper. Which one? Make shure it can work with the rotor diameter and thickness you choose. This is critical. There are just not many of these on the market, and you will need to find the critical mounting dimensions before you buy. You may find that it wont work with the rotor size and offset you have chosen. If not start at number one again.
2. The upright has identical mount bosses on the front and rear sides. Only the rear bosses are face machined to mount the OE caliper. You will need to find a competent machinist to face mill and drill the face is critical in placing the parking caliper axially, so make sure you know the dimension. your design needs to take radial and axial dimensions into consideration.
3. Placement of parking caliper. Do you place it in the front, 3 o clock, or rear, 9 o clock position? Is the parking caliper you choose a pull type lateraly or longitudinally? Consider how you will get a cable to it. And if you move the main caliper position, consider that you will eed to engineer a new rear hydraulic brake line.
4. Mount bracket, you will not find a parking caliper with dimensions that will allow you to bolt it in place. Some type of bracket will be required between the upright bosses and the caliper mount flange. Better hope there is enough radius in the rotor you choose to allow space for a bracket, or start with step one again.
5. If you can use the OE cable assembly or not. A new cable will require brackets and proper length adjustment capability. The OE will likely be too short or long, so check for modifying that as well. know the ratio of pull at the lever vs pull at the caliper. The new e brake caliper may require more or less pull than OE.
6. If you use a one-piece rotor, this will dictate the axial placement or offset. Hope it doesnt screw up the plans for the bracket and cable run, as well as whatever the main caliper bracket mount dimensions are.
A two piece rotor can be tailored to suit, but they are not on the shelf anywhere as you need. So this is another custom part.

I have been through this routine. I have done several designs for this type of system for the 308. In the end, the total cost of the machine work plus parts is completely over the top for the benefit. This is why we settled on a rear two piece rotor with great pads for the Girodisc kit.

There is an outline of the mission should you choose to accept it.
It can be done. It will not be easy. It will cost more than it should. It will take many hours from your life. etc...

But anything of value always does.

-Eric

ORIGINAL POST:
http://www.ferrarichat.com/forum/showthread.php?t=79082

 

Greg,

Have you looked at the Wilwood parking brake calipers? I have no idea how they work because I haven't had one in hand but it might be worth checking out. Unfortunately my experience dealing with Wilwood wasn't too good. The guy I tried to get info from had a real sh-t attitude.

The '98 and later Diablos have nice aluminum parking calipers, made by Brembo, that would probably work very well on a 308. The cable pulls down but the other end of the cable originates in the same area as it does on a 308. Probably the cable could be adapted too. Problem is they are difficult to locate used and probably cost a fortune new from Lamborghini. They would require a lot less engineering than the Mr. Parker units though. I've never checked if Brembo sells a similar parking caliper through it's after-market vendors. That would be much cheaper.

As discussed earlier, there is always the line-lock option. You could operate an electric line lock in the rear brake line with the parking brake switch. This is probably what I will do but later.

I'm in a hurry to get my car on the road so for now I'm forsaking the parking brakes completely but will look into it again next winter.

By the way: I have my rear Brembo calipers mounted on the forward facing mounting ears and have left the rear mounting ears reserved for parking brakes if I ever decide to mount them.

Wil

 

Hi Greg,

I hope you pull it off. (no pun intended) You would be a hero for the 308 guys out there. Its a straightforward engineer and fabricate job.

Brembo makes a parking brake caliper as used on the Viper, F360, F430, Diablo, Murcielago, etc... same unit. It also pulls inboard as you need.
It is available through Brembo NA, however...it cost about $1000 each retail last time I looked. Ill get the part number for you.

Years ago for Brembo, I engineered it onto a bracket designed to fit with the upright after machining mounting faces on the bosses and drilling/tapping them. The cost of a rear kit including exchange uprights with machining, rear calipers and rear parking brake calipers (and brackets) was staggering. We dropped it at Brembo as we knew there was nobody who would pay the expected retail cost of the kit. So we just released the front kit alone.

Anyway, ill get you the part number, or you can call race technologies, who distributes Brembo aftermarket parts in USA.

Eric

 

Many years ago, as a young adult, I worked on the exact same rear caliper off of Two Renault R-17 Gordini I owned. Same exact lever mechanism, everything. I bet it would have diectly bolted on a 308. I would also bet the front brake calipers were the same.

I would think, that if the same basic rear caliper we use is also used on various Porsche, Fiat, Renault, as well as other cars, that if someone manufactured an upgrade brake caliper incorporating the parking brake mechanism, it wouldnt have to only fit a 308.

I have a feeling its the same with other parts, such as brake rotors. The wheel bolt pattern is the same as some Ford and Volvo cars, I have to imagine a rotor off one of those breeds slipping right on. To the point I cant imagine why a upgrade brake system for the front has to cost 4 times what it would cost for a Mustang or Jap car.

I understand a bit of engineering, and I understand some details need to be looked at when contemplating building or selling parts that change a cars braking system. But get real. Most of the brake parts on a 308 are off the shelf parts from ATE that are exact duplicates from 911/914 cars, Renault, Volvo, BMW, Etc... How much engineering did it take to make the hubs to accept those parts. The stopping power was calibrated through pad selection and master cylinder size VS caliper piston size, and how long it would hold up was a simple matter of mass and application. 308's didnt stop any great deal better than most anything else. How could they with the same exact brakes as these other cars?

If I could find some local dealer who had rotors in stock for various Volvo and Ford cars, I wouldnt mind comparing rotors off a 308 just to see what would fit. I already know the 914 front caliper is supposed to be the same, just a possibly different spacing between the two halves. The 914 sites show an upgrade using a BMW 320i caliper, so I can only assume the same upgrade would be potentially possible on a 308. And I believe the 320i caliper is aluminum!

 

Greg

I too have a set of bigger calipers and am looking into the e brake thing. If i recal correctly, the Mr Parker will only handle a 24 or 28 mm thick rotor. I will go through my notes when i get back from work.

hth,
chris

 

Wow, all this is deja vu indeed!

BTW... the Tilton dual setup, DETAILS PLEASE (part #'s, sizes, etc) and pics if you have them.

 

Wilwood unit and Precision can work. It is a bracketing and cable routing job. Dont know about their holding capability however.

Stop Tech has a parking brake caliper too, you should look into that.

I am including pictures of the brembo caliper as fitted to the F360, and F360CS. It is the same as the caliper you can buy from Brembo. It has a built in bracket and pulley to turn the lateral pull into fore/aft. Still looking for the part number. It is heavier than the Wilwood etc. spot type calipers. But you also know that it works. The cost may make it not worthwhile however.

Good luck.
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Chris,

I believe those are split calipers so you should be able to add a spacer in between to accept a thicker rotor. It's an old trick.

Wil

 

Steve,

I'll post more pictures of my braking system soon but I did respond to your request for pictures of the tandem set-up in my supercharged 308 thread.

I'm spray painting my Brembo calipers tonight so they won't say Porsche on them anymore.

Wil

 

Greg,

They could work if you used a sheathed cable with an anchor bracket for the sheath, attached to the back of the upright or the control arm.

Wil

 

How much are the Wilwood units?

Wil