Brake upgrade for contemporary cobra.

[Mils]

So i'm not happy with braking performance with these small front discs and single piston calipers.

I'm not sure what upgrade options are available but would love to get into a Brembo or Wilwood kit.

Looking for options, opinions, gotcha's, etc... I'm kinda blind here with this...

Thanks in advance!!

[mickmate]

All kinds of upgrades available from just a 4 piston Wilwood caliper and bracket to vented larger rotor kits.
Jaguar E-Type & XKE Performance Upgrades| Jaguar Brake Upgrades & Parts

[cycleguy55]

The type of braking system will depend upon how much track use you're planning and the speeds you'll be running (autocross vs road racing). I did a similar conversion on my car a year ago. When I bought it in 2014 it had the original 9.25" Mustang II discs on the front and 11" drum brakes on the 9" rear end and was just not going to work for me.

I used a 'universal' kit on the back that works for the various types of Ford 9" rear ends, and I believe it also fits the 8.8" axle. It comes with 3 sets of brackets to fit the different rear ends, and uses the GM 'large calipers' with integral parking brakes and 11" solid surface vented rotors. The only glitch on the installation was there was interference between the calipers and brackets and the rear sway bar and it's brackets. The solution was to rotate the brackets 180° on the axle ends and use the right caliper on the left and vice versa - this was necessary for keep the bleed screws on the top of the calipers.

The parking brake cables were a bit short, but I was able to extend the 5/16" NF threaded rod on the parking brake lever to engage the cables. It was about 1.5" too short, so I used a section of 5/16" NF bolt plus a coupler I made from some steel tubing - a few minutes of threading it with a tap and it was ready for use. Be aware that you need to use the parking brake regularly on the GM calipers to keep them properly adjusted.

On my MII front end I went with a Wilwood 4 piston setup with 11" solid surface vented rotors. You will need braided lines to connect to your existing plumbing, plus adapters at both ends (1/8" NPTM to AN -3 for calipers, 3/8" x 24 TPIF to AN -3 adapters with clip groove for hard line connection).

Why not Wilwoods all around? 1) the front brakes do most of the 'heavy lifting' and the rears very little, so didn't feel I needed more stopping power than the 'large' GM calipers; 2) Wilwood uses an internal drum for their parking brakes, my kit uses the same piston and pads as the brakes. My wife and I have internal drum parking brakes on our daily drivers and I'm not a big fan.; and 3) Wilwoods with integral parking brakes are significantly more $$ than brake kits using the GM calipers. [Note: there are kits with GM 'metric' calipers and others with the so-called 'large' calipers - mine are the latter and the ones I'd recommend]

As noted above, my rotors are solid surface vented, with smooth braking surfaces. Why not drilled and/or slotted? I did a lot of reading and research before making the decision. My first inclination was drilled and/or slotted rotors, but the more I read, the more I became convinced drilled and slotted rotors were more for the 'cool look' than for actually providing improved performance. Tire Rack even states "Slotted, drilled or dimpled rotors offered as OEM replacements should not be considered appropriate for high-speed track use."

Some references on this issue:
https://www.tirerack.com/brakes/tech....jsp?techid=87
Rotors: Blank vs Cross Drilled vs Slotted and Warping | Automotive Thinker - Discussing the finer points of automobiles

I had a combination valve in the brake system (distribution plus proportioning valve for the rear brakes). I removed the proportioning valve mechanism from the combination valve and installed a manually adjustable proportioning valve in the rear brake lines but, to date, have found no need to dial back the rear brakes. I guess the combination of the GM calipers and wider tires on the rear works well with the 4 piston Wilwood calipers in front, but the adjustable valve is there should I ever need it.

I put speed bleeders in all of the calipers - highly recommended. The Wilwoods have 4 bleed screws, but you only need speed bleeders in the upper pair on each caliper. It took a while to bleed the brakes, especially the rear ones, as I pretty much drained all the brake fluid from the system.

The first few stops on new rotors all around were a bit scary as there is little braking power until you start getting them bedded in. It took 2 or 3 light applications of the brakes before I could feel the brakes getting progressively stronger. Once the bedding process was done it was obvious the new brakes were MUCH stronger than the old brakes. I'm really happy with the results - much better than the old system and well worth the investment.

[Mils]

Thank you for a wealth of information! I'll be looking at a Wilwood upgrade kit and have a few things to consider.

I do question drilled/slotted/dimpled rotor theory however. I say this only because my previous vehicle, 2008 Corvette Z06 at 592HP (stage 2), I had drilled rotors. I felt the braking and reduced fading was excellent. How much of that had to do with a 6 pot caliper, I don't know? I did use racing pads when tracked but thought the holes helped with heat dissipation therefore allowing for better braking.

I'll post back with after the upgrade and let ya know how it is. Appreciate the input!

[1795]

Slots and holes as for heat dissipation. Unless you are racing, you probably really do not need them, and some racers do not use them.

[1985 CCX]

Wilwood is the way to go.
Easy to swap out. Kits available from Jaguar folks like SNG Barratt.
They are easy and helpful.

[legenmetals]

I feel the more surface area on a rotor the better the braking. Holes were used for off gassing older style brake pads. I use sloted rotors because they act as a shear and keep the pads clean.

[Snake2998]

Be careful of assuming that the rears do very little braking. In a Cobra with a low center of gravity and rear weight bias (Say 48% front and 52% rear or possibly more rear bias) and wider tyres on the rear than the front the proper brake bias should be something like 59% front 41% rear compared to 68% front and 32% rear for a Jag XJ6 - the system you are possibly using.

If you don't make sure that the rears contribute the extra 10% of braking compared to the Jaguar setup you will be losing out on a lot of braking so you have to be careful that you update the system as a whole. Using this extra braking at the rear could lead to overheating in the inboard system in continual heavy use (like track use) so it is best to fit ventilated discs at the rear - preferably with curved internal vanes. Too little bias to the rear will cause early lockup of the front brakes causing reduced stopping ability and possibly instability and squirming under braking - too much at the rear will cause the car to spin and possibly crash so make sure you get the balance right with proper design of master cylinders and disc caliper combinations and careful on road testing.

Disclaimer - the above figures are based on my own calculations and should not be used as a basis of your decisions. Get a genuine expert to design the system for your car using it's individual physics and it could stop much better than an unbalanced system. And stop much better than many kit Cobras whose brake system come unmodified from some donor car.

[mdross1]

I used Wilwoods all around with a better than 48 front 52 rear bias the rear brakes certainly added a lot once the proportioning valve was properly adjusted.

It also took a couple tries to find the right pad compound now can very easily scrub off speed with the right pedal feel. It is all about dialing your ride in to your comfort level brakes certainly are an important part of owning one of these incredible muscle cars.

Another just as important part is having the suspension scaled when running coilovers on all four corners especially if you plan on pushing the car to near it's limits. Also a properly scaled suspension greatly improves braking control.

[Mark IV]

FYI "slots and holes" in rotors are not for cooling , but rather to allow the gas generated by the heating of the pads to escape and prevent the equivalent of an "oil wedge" that restricts the pad's full surface contact with the rotor.

All pads "outgas" when heated, the binders and fillers get hot and produce gases. This is what causes "green fade" in new pads the first few times they are used hard, the outgassing is pressurized (think tea kettle) and keeps the pad from full contact with the rotor. Yes, rotor holes can and do increase cooling, but the amount is so small as to be insignificant.

In most street application the slots/holes are for the same purpose as yellow calipers.....the look.

[Mils]

I'm not comfortable doing this conversion myself [yet]. Who would you recommend in our area that is reputable and knowledgeable about our cars?

Originally Posted by Mark IV

FYI "slots and holes" in rotors are not for cooling , but rather to allow the gas generated by the heating of the pads to escape and prevent the equivalent of an "oil wedge" that restricts the pad's full surface contact with the rotor.

All pads "outgas" when heated, the binders and fillers get hot and produce gases. This is what causes "green fade" in new pads the first few times they are used hard, the outgassing is pressurized (think tea kettle) and keeps the pad from full contact with the rotor. Yes, rotor holes can and do increase cooling, but the amount is so small as to be insignificant.

In most street application the slots/holes are for the same purpose as yellow calipers.....the look.

[Mark IV]

Mils,

Call me. I have friend who has done brake upgrades for us on Superformance and did one on his own Cobra which was a Jag system. I can put you in touch with him.

Likely it will require a master cylinder upgrade as the Girlings for the Jag fronts will not have enough capacity for a four piston system.

I have several Wilwood Dynalite calipers that are Superformance take-offs that I will sell cheap.

[Mils]

Wonderful. You got a deal! Once we know the weather has turned for the better, I'll give you ring and get things setup. As always, Thanks!

[legenmetals]

Here we have a front brake kit put together for me several years back for my Contemporary by Bill Bassett of Bassett Jaguar.

Six piston calipers, hats, rotors, radial mounts all designed to fit type 1 uprights. I believe Bill had to turn down both rotors dia. to fit my 15 inch Halibrands.

The kit is complete including safety wire.

Not for sale - I just wanted to share info.

Caliper part #-120-6112-RS and 120-6111-RS
Aluminum hats#-AS-8386
Rotors# - 160-12286 and 160-12285
Radial mounts are both FW 6309

Rear brake will need upgraded to match this set up - this is a lot of front brake.

Bill told me that this is the set up he used on a e-type vintage racer.