1967 oem 4 piston disc brakes

[nicks67camaro]

Does any one have any experience with the 1967 4 piston OEM disc brakes. They were originally installed on my car and me being cheap want to make them the best they can be. I'm using all braided lines, hydroboost, and I recently rebuilt them. They grab quite well but after a hard brake application the car then tracks to the right when I apply the brakes again. I just did an alignment on the car using the fasttrax....I'm thinking either when the car goes "level" the alignment is changing...or the pad are not grabbing equally...or after they head up the properties of the pad changes....or a combo of any of the above. I have a non-contact thermal gauge on order to see the rotor temps..Any insight is appreciated. Porterfield offers a better pad then ones that I have from year-one, are they worth the $165.00 for pads?
Thanks

[nicks67camaro]

Sorry the application is 1967 Camaro

[6'9"Witha69]

There are several possibilities for this. Basically being that the right front is grabbing ahead of the left. You can either have a sticky piston(s) in the right side or be getting knockback in the left. Or an obstruction on the left side lines.

Most guys I know who used these calipers extensivly had wear/pitting issues with them. THey would bore them out and sleeve them. That solved a lot of leaky and sticky piston issues.

Hope this gives you some info.

[nicks67camaro]

I had an issue with one where sleeve to piston clearence was WAY off and it pressed the sleeve out when I applied the brakes. I replaced that side with a new caliper. I keep them cleand and check for leaks they appear to be leak free. Can you define Knockback for me I haven't heard that term before.
Thanks again

[6'9"Witha69]

Read Here. A great explanation by one of our sponsors.

https://www.pro-touring.com/forum/showthread.php?t=17850&highlight=Knockback

[nicks67camaro]

That is a great article. What I'm getting is that after I make an aggressive stop the car will pull to the right on the next application and other to follow. The pedal feels great still.It almost appears that once the brakes "cool" to normal temps the car tracks better during braking. I just took a quick cruise around the block and the brakes felt great. I'm curious what the rotor temp's are once the new gauge gets in.
Thanks for the direction.
(buy the way I like the centerline daggers!)

[chicane67]

Sounds like a hung piston... or an air leak in that one caliper.

Ill tell you what... the OE four pots work bitchen when you get them dialed in. I guess you could say I have had a little time with this exact system. I finally got them dialed in and all I can say is... WOW.

My 67 with the four pot fronts and OE drum rears were part of my early developement years with brake systems. At first they just plain sucked... fade, glazing, balance, bias... you name it. They sucked. Then I got busy... and started to figure them out. When I was done, the chassis would do 60-0 in about 116ft. That's on par with the C4 Corvette's and their 13" PBR based systems I was dealing with on a daily basis.

When I worked for Guldstrand I got to do some pad compound developement with Porterfield. I worked with Andy specifically with the R4 and R4-S compounds while playing around with different combinations. I will say that the R4-S pads are more than worth the money. The Porterfield R4-S pad and Porterfield semi metallic shoe combination are perfect for normal everyday street driving as well as a max effort street/intermediate road race compound.

My system at the time was as follows:
Front:
OE Delco D3 four pistons
Porterfield R4-S pads
Stainless Steel braded lines (one off's. no one made them back then)
OE distro block
OE residule pressure valve
1976-78 WS6 Master cylinder (1.0")

Rear:
OE 9.5 x 2.0" drum
Porterfield semi metallic shoes (swapped leading and trailing shoes to change bias. (an old road racers trick))

I would however, stay away from the R4. I ate about 0.285" off each rotor in about 90 days... of street driving. Not enough heat for street driving to go into an "adhearent mode".

I then was the first to stuff a 13" PBR system into a Vintage Wheel Works 16x8 V45. That didnt last too long... since then we have stepped up a notch or so... Id say...

https://www.pro-touring.com/forum/attachment.php?attachmentid=11814&d=1154576747

[nicks67camaro]

chicane67, any tricks on these from your experience? I have access to a decent machine shop is it worth opening the piston bore and putting some larger sleeves and pistons? Do you know the bore to piston clearance they look kind of loose even after the "rebuild". I'm not afraid to modify this stuff but I'd want it to be worth the work. Also is there ANY performance rotor around for these dinosaur brakes?
Thanks again..

[Hammered]

I have put a lot of effort into my original 4 pistons and am going to ditch them for a PBR type setup. I've had them sleeved, had Hawk make a more aggressive pad for them and they're doing similar things to what you mentioned. I've bled them several times with a pressure bleeder and they work great until they get hot from one quick stop or several in short succession.

In summary, they work great when they work, but they require too much attention to keep working. You can also have the seals go if you don't use them enough (like over a winter). That happened to me and was the final straw.

The pistons do fit very loosely in the bore which I understand was done to compensate for lower machining tolerances of the day. In other words, thhe loose bores made caliper to rotor alignment less critical.

The loose bores also allow the pistons to rock enough that the seal can be momentarily broken. I've been told that .002 runout is sufficient to cause this problem.

If you stick with them, you can take any C3 Corvette performance pad and grind the corners off to make them fit your calipers. Just take your existing pads and use them as a template for grinding down the Corvette pads.

I have ID info on 4-pistons here: http://john.my67.net/Disc%20Brakes.htm

[chicane67]

chicane67, any tricks on these from your experience? I have access to a decent machine shop is it worth opening the piston bore and putting some larger sleeves and pistons? Do you know the bore to piston clearance they look kind of loose even after the "rebuild". I'm not afraid to modify this stuff but I'd want it to be worth the work. Also is there ANY performance rotor around for these dinosaur brakes?
Thanks again..

I used stainless D3 sleeve's and pistons from Vette Brakes. I can pretty much assure that it nullified the piston rock from it being a tighter tolerance... or you can just trade them out and use your older ones as core's. The OE tolerance was about like the Grand Canyon... but that was because if the materials used back then. The newer stainless stuff is much better and can hold a tighter tolerance without growth issues.

The best rotors... are solid rotors. Which are available thru Classic Industries (p/n E 231 for the 6.5" OD or p/n E 239 for the 5.75" OD). Or you can go thru the ropes of doing an alloy hat and rotor set-up. But... I just dont think that its worth the time and money to do so. For $119/ea... the new one piece rotos are phenom. I have had probably 20+ set's of pads on the new rotors (within 5 years of pad development) and havent surfaced them once... and they are still in perfect condition.

I got my set from the cat that took the newer one-piece design to production. He then brought in Classic to fill a mass production order to bring the cost back down. I think back in '93 I paid $100/ea for mine. Classic now sells them for $119/ea.

All I did was have the new rotors machined to accept ARP 1/2 x 3" wheel studs (p/n 100-7704) and dropped the R4-S pads on them after the Vette Brakes sleeve's and piston's.

Is all of this worth the effort though ?? I mean... you can throw 13" PBR brakes on it for cheap.

Other things... ditch the backing plates, get new bearings and seals and green bed the rotors before you do nay kinda of fun driving.

[nicks67camaro]

I guess thats the question make the stock brakes better or just buy a set from PBR and forget about them. Thanks for the help!

[Skip Fix]

So what about Chevelle vs GTO 4 piston calipers, any info? Man those buggers are heavy! Old 2 piece rotors also.

[Hammered]

Skip, last time I checked, Vette Brakes only o-ringed the Chevy 4 pistons so us Pontiac guys are out of luck there.

The rotors can now be had for a lot less through a Raybestos dealer. I think they're about $69/side.

[Skip Fix]

I'm not sure if the setup I got is actually a Chevelle or a GTOs.

I know years ago Guldstrand converted second gen spindles to use the Vette calipers.

[Hammered]

Skip: You can ID them from the casting numbers I have listed here: http://john.my67.net/Disc%20Brakes.htm Once you know what to look for, they are easy to identify by the casting features. The big cars used the same castings, but less was milled off the mating faces to allow for a thicker rotor. The only way to tell is to measure the distance between the halves.

[nicks67camaro]

So I played with the car last night...Ct has been rainy and nasty..I purchased from Northern Tool a temp tool...LOVE IT. Drivers side 190 degrees F, Passanger was 230 degrees F. This was measured after some aggressive stops. HMM is the drivers side not working correct or is the passanger side working to good? I love this stuff. The system is bled well new rotors pads calipers new seals orings bla bla bla... Any thoughts?(other than buying a new setup not in the budget right now)