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This past weekend I won some track time at a local road course. The car runs very well with its modified motor and Webers, but it doesn't stop nearly as well as it still has the original brakes. I had HRE build me 17" front and 18" rear rims, so there is room for larger diameter disks. I've seen a variety of opinions on this site regarding how much improvement can be accomplished  and what the best brand choices might be. Money is an object, but I'd rather not compromise my safety.


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...Before You Buy...take a Look at what SACC Restorations (top of this page), has to Offer. The 6-Piston Front Calipers work Great for Me, and the Price is Right! Call and talk to Scott, he can build custom Calipers for the Most Huge Brakes. You'll be Very Happy You got-rid of the Lame Factory 'Solid Rotor' Brakes.


Last edited by marlinjack

This is a comment by Scott at SACC regarding the proportioning valve and stock brakes:

"David Nunn is absolutely correct. The question is IF you have upgraded your rear Calipers. If the answer is no then DO NOT remove the stock p-valve. If you have an upgraded rear Caliper then by all means, removed the p-valve.

Someone said you don't have a stock car so remove it. But I think you said your brakes were stock. What isn't stock is you have bigger rear tires. That doesn't help the situation, it makes it worse. You have more braking potential in the back than you did when the car was stock. So improving the fronts by removing the P-valve will also cause the back to be less effective.

We have done lots of testing to prove this theory. People still want to debate it but this issue has been tested and there is no question that a car with stock rear Calipers will have better braking performance with the valve in.

Those that claim their cars braking was better with the valve out and stock rear brakes are likely incorrect. It may feel like the fronts are stronger at the expense of the rears doing almost nothing. Measure actual braking distances and you will find a stock braking system is better balanced with the p-valve in place."


From a braking standpoint I have not helped the car. The brakes are bone stock. I did replace the pads about a year ago even though the first and only set it ever showed little wear after 27,000 original miles. However, the motor is considerably stronger now and tires are 245/17 front and 305/18 rear on a set of custom HRE rims. I've looked over the SACC brake packages, and some look just right. However, without pulling a rear wheel, I believe that it is necessary to dismantle the wheel assembly in order to change to larger disks. I recall a former brake inquiry that indicated that merely changing calipers will not provide a significant brake improvement.


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Tom, when it comes to brakes, front to rear balance is everything! The problem with the OEM pressure reducing valve in the front circuit is, it gives you a less responsive pedal and makes it more difficult to bleed all the air out of the system. In some cases, those valves are 50 years old now! I wonder if they still work as designed? If you want to upgrade your brakes but don't want to disassemble your rear uprights to do it, just have Scott at SACC put a kit together for you that uses the OEM rear rotors. For street or occasional open track use, most drivers would never be able to tell the difference between vented and non-vented rear rotors. You'd have a firm, responsive pedal too. That would also allow you to retain your OEM parking brake. You can always do a rear rotor upgrade in the future.

@dougm posted:

Changing to SACC rear "Wilwood" callipers with stock rotors will provide a substantial and noticeable improvement in braking performance.

Doug M

have done it ..
1) valve off!! new pipe and fittings, can be done self made just need a simple tool
2) SACC rears "Wilwood"with 4 pistons per caliper TOP class braking. Nice balance on my  205/305*15" on STOCK Rotors rear. Worst case follow Bosswrench's advise above.
3) added also SACC hand brake "motorcycle" "Wilwood" calipers instead of keeping the Peugeot crap in parallel to the "Wilwood" rears. Nicley to adjust with stock brake cable.

.. good investment!  smile!


Glad it worked out. The reason I suggested a manual proportioning valve is, the OEM part is not adjustable and was designed to balance '70s OEM tires- which were (at best) 185-70-15" & 215-70 x 15" radials, or C-60 belted bias Arrivas in the rear. You may luck out with all the changes working together but its just safer to adjust braking bias for any combination of parts without the OEM valve , using a manual proportioning valve. Likely once set, you'll never need to touch it again- until your 305 rear tires become unavailable, and you're forced to find a new tire combination- which may then need rebiasing.

The oft-repeated Cliffs-Notes sentence of "changing calipers does not improve braking" is an extreme condensation of multiple 3-page discussions on rotor OD & thickness, pad compound and caliper position, plus amount of booster assistance. In any case it applies only to the perfectly adequate Girling front calipers. Replacing the toy sized rears with something larger & lighter- then balancing the brake bias- is nearly always a good idea. Wilwood's drum e-brakes built into the rear rotors is an adaptation of the stock 55-yr-old Corvette system and works well. I put it on my 4-wheel-disc-brake Corvair in the previous century. I've seen poor-boy copies built using early motorcycle drum brakes. OK as long as you know what you're doing.- as with any brake redesigns.

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