Brakes

[pedro]

Car is 69 Camaro with Wilwood 1 1/8 MC, small vac booster, 6 piston front, and four piston rear. Today was the first time the car was driven on the street with the new brakes.

Brakes feel like they have no power assist. With the car off the pedal is solid after an inch of travel and really doesn't move much more than that with out extreme effort. Car running its a little easier that first inch but after that it is the same. I don't think it is a problem with air in the lines (I vacuum and presure bled the brakes several times).

I measured 15.5"vac at the check valve. The booster is holding vacuum once the car is shut off (I pulled the check valve and hear air rushing in, I also swapped check valves for one off my truck).

I believe it is adjusted right. 1/8in of free play, pedal will go all the way to the floor during bleeding.

I think the booster is bad.... anybody else have any thoughts? Could I pick a new one up at napa? I was suposed to take the car tomorrow and get it tuned, but I dunno if they will drive it with the brakes like this. It stops, but you have to stand on the pedal.

Thanks
Pete

[68sixspeed]

with the car off, pump the brakes a couple times to make sure you have no power assist. Hold your foot on the brake and start the car, if the booster is good, when you start the car the pedal should drop some as the assist kicks in. If that checks ok, your bleed sounds good, I'd check the pedal ratio, or maybe go to a 1" bore master cyl. Pedal ratio- camaro's usually have 2 holes on the pedal, the one closer to the pivot will result in more pedal travel but less effort. good luck, Dan

[pedro]

Thanks Dan,

After pumping the pedal then turning on the car the pedal drops 1/4-1/2.... seems like it should be more. After that the pedal is stiff as a board.

I have the pushrod in the lower hole which I thought was for power brakes. I will try the upper first thing in the morning.

Pete

[pedro]

Swapped to the upper hole, made a huge difference in effort. Pedal travels much further now. Still no noticable difference in effort between car running and off..... Also the pushrod is at a pretty severe angle.

Either way brakes feel good enough to drive it dowon to get tuned.

Thanks
Pete

[ProdigyCustoms]

Got your email this morning and seen this too.

Wrong hole. The upper hole is a higher pedal ratio for manuel brakes. Using that hole is a crutch and will work to get it to the tuner. But we need to look at that booster once you get it tuned. I will send you another one out.

[68sixspeed]

what booster are you running? If it's a dual 7" that may explain the heavy pedal with ~15" vac. I changed from a dual 7 to a dual 9 and it made a huge difference in the pedal feel/effort.

[ProdigyCustoms]

He has a dual 8" we use quite a bit, think he got a weak one. I won't even sell the 7s

[Apogee]

Which Wilwood calipers are you running? Seems big on the master cylinder bore, but I'm used to working with mostly C5/C6 stuff.

Tobin
KORE3

[pedro]

SL6R in front and S4R in back.

Pete

[JRouche]

Ok, just thinking of ideas.

Did you bed the new pads in? That IMO isnt necessary for decent stopping, she should feel great without a proper pad bedding. But I had terrible braking till I limped the car to a nice stretch of road and bedded them in. After that I was able to toss my head out the windshield with some serious braking if needed, or any irritating passengers for that matter.

And I dont even have the nice setup like you. I have junk yard Cadillac MC and booster. Not a massive booster, from a Seville. And my engine doesnt make alot of vacuum. And I still have some nice brake feel, not over boosted. That might be a fluke. Larger booster and low vacuum. But I got lucky, it works. I still havent really slammed the pedal yet. Maybe for fear of ripping the control arms out of the car

Sounds like your vacuum is in order. Properly placed parts.

I would check the booster, you have a good vacuum going to it which is fine.

Remove the vacuum line and plug it. Start the car and drive it. Does it feel similar (it should feel ALOT harder to brake). Does it feel not that much harder? If so the booster isnt doing its job.

And the parked while depressing the pedal while starting the engine check? The pedal should drop by at least 1 to 1.5". With no additional force, it should just basically drop from yer foot, like you lost brakes. You wouldnt think a booster could apply that much additional pressure but they do. Kinda crazy. JR

[JRouche]

Ok, just thinking of ideas.

Did you bed the new pads in? That IMO isnt necessary for decent stopping, she should feel great without a proper pad bedding. But I had terrible braking till I limped the car to a nice stretch of road and bedded them in. After that I was able to toss my head out the windshield with some serious braking if needed, or any irritating passengers for that matter.

And I dont even have the nice setup like you. I have junk yard Cadillac MC and booster. Not a massive booster, from a Seville. And my engine doesnt make alot of vacuum. And I still have some nice brake feel, not over boosted. That might be a fluke. Larger booster and low vacuum. But I got lucky, it works. I still havent really slammed the pedal yet. Maybe for fear of ripping the control arms out of the car

Sounds like your vacuum is in order. Properly placed parts.

I would check the booster, you have a good vacuum going to it which is fine.

Remove the vacuum line and plug it. Start the car and drive it. Does it feel similar (it should feel ALOT harder to brake). Does it feel not that much harder? If so the booster isnt doing its job.

And the parked while depressing the pedal while starting the engine check? The pedal should drop by at least 1 to 1.5". With no additional force, it should just basically drop from yer foot, like you lost brakes. You wouldnt think a booster could apply that much additional pressure but they do. Kinda crazy. JR

Oh yeah, what he said. You should use the bottom hole on the brake arm, that one is for boosted brakes, it allows more fluid that the boosted system needs (bigger MC). The manual MC needs the upper hole for leverage. The boosted system needs the bottom hole for more stroke for brake feel and fluid flow due to the bigger MC. The upper hole is too fast for a proper boosted brake system, it gets too touchy if the system is working as it should.

[pedro]

JR,

Frank is sending a new booster to see if that is the issue. There is a slight difference between car off and running. Pedal drops only a slight amount (1/4-1/2in) when I start the car. As for beding in the pads... they are not, only 46miles on the car before it went to the tuner. The stopping ability gets better and better, so I am sure they are still breaking in, but the effort remains very high.

Pete