Anyone have any Brake Questions?

[CTSV]

OG is there any formula for choosing the caliper piston sizing to maximize total braking in a booster or manual system? I was always under the assumption the front piston area must be 50% greater than the rear for proper bias etc.

[OG_Racing]

OG is there any formula for choosing the caliper piston sizing to maximize total braking in a booster or manual system? I was always under the assumption the front piston area must be 50% greater than the rear for proper bias etc.

yes, there is a formula but it's not a %. you'll need to factor vehicle weight, center of gravity, rotor size, piston size, master cylinder size, pedal ratios, booster advantage, tire size, tire compound, tire stagger, brake pad Mu, and a few other variables.

[67cougnut]

Great thread! Tagging for reference later

[1967ls2]

Question. I'm running a 2005 LS2 from a GTO in my 67 Camaro. I have power disc brakes all the way around. Recently noticed that when I'm at a light intermittently (not every time, in fact it's rare but happens from time to time) and I have the brake applied, the idle will become rough. The idle will also change or improve when I remove my foot from the brake, it will become worse by applying the brake, and can be duplicated as described.

I've checked the brake booster hose and there are no cracks or tears in it.

Do you believe the brake booster is going bad or have any suggestions for diagnosing? Thanks!

[bigdaddychevelle]

Great information. I know this is geared more for racing, Auto crossing. I have a 66 Chevelle Pro touring look not for racing. I have ls1 engine stock. detorit speed suspension. Car weight not sure. My question what would be a good set up for street driving. I looked into Kore3 corvette set up. I'm just confused now.
please help Confused?

[Kiquee71]

My project is a 1971 Nova, LS engine w/ 4L80E, Ford 9" from SpeedTech, ridetech front coilover suspension, rear suspension is SpeedTech torque arm with coilover shocks, 19x9 wheels with 265/35/19, rears are 19x11.5 with 325/30/19. Have Kore3 ZO6 brakes 14" rotors 6 piston calipers, 13" rear rotors 4 piston calipers. Car is originally
a manual brake car and would like to keep it like that. My question is what size MC for this set up, car will be mostly street and some auto cross time. Can I reuse the original pedal or will I have to get another one? I'm sure I've forgotten some details and will get that info when asked. Thanks

[vstol]

My build is below with a C4 brake system. The LS3 427 averages 11 inches of vacuum so I believe the way to go is manual. I have the stock 71 corvette brake pedal for the manual brakes. It's been a very long time since I had manual brakes any suggestions. It will be mostly a street car with several autoX's a year and one road race event per year. Many thanks Kevin

https://www.pro-touring.com/threads/...-replica-build

[72Z/28]

72Z/28,
Believe me, I know how frustrating can be. When building racecars for your first time it's "here is all the parts you can buy, good luck figuring that out". I am unaware of any floating calipers that will bolt to a dialight bolt pattern. Try giving Wilwood a call, they might have something on the shelf that would work.

When PFC was designing the Ford Mustang big brake kit they had to keep the stock caliper in the rear. This Is because the axles would move in and out. A floating caliper was needed to deal with all the changing tolerances. On the front kit was a giant 4 piston mono block caliper, the rears had to have a stock caliper with an upgraded rotor.

that caliper itself that you are using has a .92" offsett. http://www.wilwood.com/Images/Calipe...lite-cm-lg.jpg

Hi again

This is just an update to my old post in regards to the passenger caliper outboard side rubbing against the rotor. So I went ahead and purchased the floating caliper kit from wilwood as per the housing ends dimensions(big ford new style end flange).
Installed the driver side kit without issues. However, the passenger side has exactly a similar problem I had with the fixed type caliper kit. I have not driven the car but the outboard brake pad is badly sandwitched between the rotor and the caliper, making it difficult to rotate the rotor freely.

So basically the new kit did not solve the problem.

I have read in forums and stuff that ford 9" rear end axle shaft lengths are uneven due to pinion location. Passenger side length is different than driver side.
Could the reason be that driver side axle shaft was installed by mistake on the passenger side causing more offset between the housing flange and axle flange?

[72Z/28]

Can anyone please help me to resolve the issue of uneven axle offsets.

[davidb]

i'am doing a ls1 swap in a 1970 Camaro the 11'' booster is to big. looking for a 8'' or 9'' booster. wondering what booster works the best. the last one I ordered the rubber didn't seal up the hole in the fire wall. no one can give a good answer. so many of these swaps being done someone should have a answer.

[Skip Fix]

The 79-81 4WD Trans Ams used a 9" dual diaphragm that has the correct angle for a second gen firewall. '81s used a larger register "quick take up" aluminum MC so the booster is larger to fit it. They also used a lower ratio pedal hole since it provides more assist than a single diaphragm booster.

[MikeJ67]

Hey Johny C - I have a question on my project. I'm building a '67 Camaro and have the CPP Big Brake Kit. I'm only installing the front brakes at this time (as the new rear end needs to be finished) but my question is this, do I "really" need the disc brake dust shields on the brakes? My set did not come with them and I need to know if I "really" need to go buy them before the brakes go on next week.

Thanks

[Crashflow]

Hi and Thank you. I have c4 hybrid brakes up front and ls1 era rear discs on the rear of my 68 Chevelle convertible. I am using a booster and MC from a 95 firebird . Do I just plumb everything to the MC or do I need A proportion vavle or something like that?

[craigs73]

so when i bought these brakes a few years ago they came in a box completely apart... how do these clips go in i know seems like a dumb question...but i have never used these on any vehicle

[stab6902]

It'd help if you mentioned what the brake calipers are off of (C5 Corvette? "LS1" calipers? something else?)

If they're C5 calipers, check out the picture in this link: http://www.performanceforums.com/for...rattle-springs

[craigs73]

They're of of a 4th gen camaro

[modular93fox]

Hi, I was going to create my own thread, but on the first page there was one similar and then I seen your thread OG Racing and wanted to ask you a question about the brakes that I am going to be putting on ... mostly what to expect and what I probably am missing.

Vehicle: 1987 Silverado 1/2 short bed, sticker on door says 5600#
Stock combo valve
Stock Master cylinder - 1.125" bore

Current brake setup is stock front caliper and c5 or c6 caliper.. forgot which one I bought 7 years ago from Tobin at kore3
Front Stock caliper @ 2.9" pision
Rear C5 caliper @ 1.77 piston
online Brake bias calculator showed this to be at 70%

Stock combo valve
Stock Master cylinder - rockauto says 1.125" bore

Never had any brake issues, but since Im doing a Gen5 LT swap and wanted more woa power figure upgrade the brakes.

Engine: Stock Gen5 355HP/382TQ
Tires 265/55/17 (pretty sure)

Recently seen Wilwoods c-10 pro spindle and picked up a set for a good deal) to incorporate the c6 front brakes (no research, just impulse buy) ... hours of research and ploting info into autocad - found out its not possible to mount that caliper to their spindle... after some autocading 07+ Silverado calipers might work. Few templates later, got the 07+ Silverado 1500 calipers to bolt up on a 12.9" x 30mm rotor. (stock rotor is 13"x30mm)

So the new brake specs
Front: 2 piston 2.0" on 12.9" rotor
Rear: 1 Piston 1.77 on 12" rotor
stock brake pads
online Brake bias calculator shows it to be at 73%

07+ trucks show to be a 1.25" bore master cylinder, which the 3/4 ton c10 tuck / suburban is offered, but in ugly cast iron assembly :( from research larger master decreases pedal travel and lowers brake psi.... the trade off.. Also offered is a 1" bore master cylinder - increase pedal travel and psi..

As far as what to expect - do you think it might be necessary to remove stock combo valve and install and adjustable combo valve? change master cylinder. once installed, I will have a feel what the brakes are actually doing, but I am just trying to plan ahead for what to look for and what I might expect.
Thanks,
Clint

[dkar26]

1970 Chevelle coupe.
I just got a 4 wheel Wilwood disc conversion with new 17” wheels professionally installed. New brake booster, too.

The car doesn’t feel like it stops like it’s supposed to:
A. I can’t get the wheels to lock up when I stand on the brakes.
B. When I do stand on the brakes, the car has stalled.
C. On downhill slopes, the car doesn’t stop as briskly as I feel it should. Subjective yes, but my DD F-150 stops better on same little hill. Also, the car’s braking doesn’t feel as good as it did with rear drums and front discs.

I’ve sent it back to the shop who tells me: “the brakes stopped very well”, “I can get them to lock” and “ you don’t want them to lock with a ‘balanced’ brake system”.

I asked him specifically to test the booster vacuum yesterday. He’ll get back to me early next week.

Any other suggestions?

Thanks!

[79T/Aman]

OG Racing has not been here in 3 years.

[boss_hoss]

I've got one for ya. I've got a hard, short pedal. I'm running a right stuff detailing big brake kit. It has 13" rotors with mustang calipers in front and 11" gm style rear brakes. 1 1/8" master with dual diaphragm 9" booster. The brakes work but like I said the pedal is hard and short. The brake also won't lock up if I really stomp on it either. I completely replaced the booster and master with no improvement I suspect it could be the combo valve but the warning light on the dash hasn't come on. Any thoughts.