Let me run this by you guys.....

[AintQik]

I got my brake setup from a former sponser and while I am glad I got all my parts, I'm now unsure its the correct combination. I will admit my brake knowledge is rather limited. 67 Camaro, dyna 6 piston calipers up front, the standard dynas in the rear. Manual 7/8ths Wilwood master cylinder. I am running the Wilwood proportioning valve.

Hard lines are run correctly according to Wilwood info, fronts (most braking suface) on the "A" circuit, rears on "B".

Master was bench bled, there is no air in the system. I've reverse bled, and bled, and bled again. No air anywhere.

I've not driven the car on the street yet, but the brakes do work in the shop. My issue is the pedal is soft, or very easy to depress. I can't say if they work at 80mph, but my concerns at this point are ONLY based on the pedal "feel". My other manually braked car is much stiffer.

Does this sound right for those of you who have the Wilwood cylinder? Maybe its just easy to depress? (Yes I realize this is subjective) Compared to my original manual cylinder, it takes about half the force to depress.

The pedal is not bottoming out. If you depress it all the way you come to a stopping point. If you crack a bleeder, the pedal will move another 3".

If you pump the pedal there is really no change in pedal feel. It might seem a bit stiffer, but it might be that I'm insane. Its very close.

I do understand hydruallics and brake workings. My real confusion is with the specific Wilwood cylinder and its "feel"... maybe this is normal and I'm used to having to stomp the hell out of a manual brake car.

The pedal will travel more than half way before any real braking occurs... and this is at driveway speeds. I have done some searching and read about stroke and all that but I'm not sure I understand how that works and how or more importantly IF I need to fix this.

Wilwood says I probably need to bleed it more (which I expected) but honestly its got no more air to give.

Lines are new and the little bit of flex I am running are stainless braid and not swelling (that I can see, but it would have to be a lot to account for an easy pedal halfway through the stroke).

I also understand that many of you, myself included if I was reading this, will point to air in the system. However I can find no evidence. I've bleed the top bleeders, disconnected the master again and moved the piston by hand through the stops with a master bleeding kit and there is simply no bubbles anywhere.

I also realize that "go drive it stupid and see what it does" is a perfectly sound response but the car is not ready for the road and its winter here in NJ. My gut tells me something aint right and the gut is usually right whether I like it or not. So, I thought I would generate some conversation here with you smart folks.

So, I hope I can get a few comments to guide me or generate some better thought in my small brain. To sum it up I'm uncomfortable with the ease and distance I have to push this pedal. Before I "get used to it" I want to make sure its right.

[dontlifttoshift]

Until you drive it it is hard to say if there is really anything wrong but here is something to check that I didn't see mentioned.

How much free play between the pushrod and master cylinder? If you are running the stock return spring and haven't adjusted the pushrod it is possible that a large portion of your pedal travel is not even operating the master cylinder at all.

[AintQik]

Thanks Donny. I did check that and forgot to mention it. The pushrod is butt up against the cylinder. With the push rod in the stock location on the pedal, the pedal was about 3" higher than where it should be. I had to adjust the pushrod to put the pedal in the right spot. Before it would physically bottom out about 4" from the floor, now its much closer. I'm running it right now with no return spring to ensure I'm only feeling the master. As a comparison I've got the manual master in my 50 set up with no spring like I said about 50% of the force to move the Camaro.

I honestly think it is the 7/8ths bore master. Its probably completely normal to have this "feel", but just uncomfortable to me. All of my stuff is like stepping on a brick. I might experiment with a 1" bore and see if things get better.

[Apogee]

Could be normal, but before you go and change anything, I would suggest that you do two things. First, plug both outlet ports of the master cylinder and stroke the master cylinder either by hand on the bench or by applying the brakes. The MC should hydraulically lock with minimal travel, just enough for the seals to cover the compensator ports into the reservoirs. If the master cylinder feels spongy at all, then you still have air in the MC and it needs additional bleeding.

Second, invest in a caliper pressure guage kit and measure your caliper pressures with your current MC bore size. You can calculate the pressure/volume differences associated with an alternative bore size MC (15/16", 1", etc), although it's approximately 11% to 12% per 1/16" bore diameter in that size range. Once you have caliper pressure information, you should be able to make a much more informed decision regarding your pedal feel, hopefully without fixing one issue only to create another.

Tobin
KORE3

[AintQik]

Tobin, you bring up two very good points and I will explore both.

To help me understand the second let me ask a few questions. I did actually ask Wilwood about pressures and was told that all of the manual MCs put out about 1200 psi of pressure, but do so in different ways. The bigger bores will do it quickly ie "stiffer pedal" and the smaller will do it with more pedal movement "softer". Perhaps they were saying this knowing what calipers I'm running? What would having the caliper pressure kit show me? Wouldn't it be around 1200 psi no matter what, just get there a little differently with each MC? Please understand I know you know what you are talking about and am eager to do what you say. I just want to understand how measuring a caliper pressure would be helpful given what Wilwood told me. They maybe over simplified the explanation of "1200 psi no matter what". I'd like to understand where you are going a bit more as it will definetly further my brake knowledge.

[jpgolf14]

Tobin, you bring up two very good points and I will explore both.

To help me understand the second let me ask a few questions. I did actually ask Wilwood about pressures and was told that all of the manual MCs put out about 1200 psi of pressure, but do so in different ways. The bigger bores will do it quickly ie "stiffer pedal" and the smaller will do it with more pedal movement "softer". Perhaps they were saying this knowing what calipers I'm running? What would having the caliper pressure kit show me? Wouldn't it be around 1200 psi no matter what, just get there a little differently with each MC? Please understand I know you know what you are talking about and am eager to do what you say. I just want to understand how measuring a caliper pressure would be helpful given what Wilwood told me. They maybe over simplified the explanation of "1200 psi no matter what". I'd like to understand where you are going a bit more as it will definetly further my brake knowledge.

Using a 7/8" master with manual brakes and a 6:1 pedal ratio would take a 120lb push on the pedal to get 1200psi into the fluid. That is doable but is a lot of effort. But it really depends how much pressure you need.

The beauty of testing the pressure at the caliper is it can help you eliminate potential problem areas. If you test the pressure at the caliper and get a good reading (> 1000psi) you can be sure you don't have have any weird problems like blockages in the hard lines, blockages in the soft lines, blockages in the calipers, soft line collapsing, ect.... You can also ensure you are getting equal pressure on the left and right side.

On top of that, by blocking the master, you can identify if you have any issues with the master.

If no issues are found, then the issue is simply with the design of the system, the hydraulic side or the mechanical side. Both play a part into brake torque, pedal travel, pedal effort. The setup you are using is quite long in travel, especially with the 7/8" master, and high in effort when compared to modern brakes.

John

[TheJDMan]

Well here is my story. I installed my brakes with C6 Z06 calipers and the Wilwood 7/8 MC. Same as you I bled and bled and bled the brakes. Pedal was just a tad soft. I got sidetracked on a different project and the car sat for nearly two months. When I got back to it the plan was to bleed the brakes more but when I tested the pedal it was firm and has remained firm to this day. The only thing I can think of is that allowing the system to rest for two months allowed some bubbles in the MC to percolate out.

[AintQik]

Steve, well I can always hope can't I? lol

When I get in the garage this weekend I'm going to calculate the pedal ratio and see how far off it is from 6:1. I know the Camaros have a long pedal.

Plugging the MC is a simple thing to do and to be honest I never thought about it. So, I'll do that and look for hydro lock. That will rule out any air in the MC.

Everything is brand new but you know how that goes. I'll look into the caliper pressure kit and see what I got.

[Apogee]

RJ, Wilwood is correct that any master cylinder can produce 1200 psi technically, however the question should be with how much effort and travel at the pedal, since that's what impacts you as the driver. Ultimately what you like is going to be a fairly subjective target. First, I would check that the MC is fully bleed and I wouldn't worry about caliper pressures until you've done that and eliminated it as the potential issue. Caliper pressures come be valuable in further troubleshooting the system should it be required.

Tobin
KORE3

[Skip Fix]

So any of the caliper pressure gauges come with adapters for the tiny Wilwood bleeders? And how do you get the air out between the adapter and the gauge? My longacre dash gauges have a bleeder at the top of a T to the guage to do that.

[Apogee]

Wilwood sells adapter fittings specific to their bleeder design, 220-0971 (http://www.wilwood.com/LineKits/LineKitsProd.aspx?itemno=220-0971).

My experience with the Longacre gauges is that they're meant to be permanently installed for feedback and monitoring purposes in a track car, so they need the bleeder valve to remove the air from the system so as not to negatively impact the pedal feel. From a troubleshooting perspective, a little air won't impact the gauge reading once it's compressed by the fluid, so it shouldn't matter in this instance. Aside from the slightly lower pedal while the gauge is attached, it should return to normal once you remove it so long as the bleeder is at the top of the caliper and air isn't allowed to enter the system or fluid escape.

Tobin
KORE3

[Skip Fix]

Thanks for the adapter # Tobin. Those little dinky bleeder Wilwood uses(Longacres used the same one for their gauges) bugs me. Getting a 1/4 wrench even a boxed end 6 point I feel I am going to round off the corners tightening them!

Working on the kids old high school daily '81 TA brake system now and might get a pressure gauge. Cleaned it up to let them drive it for Thanksgiving(been in storage while they have been at college) and when I drove it and had to stop hard(idiot drivers) it made a hard left turn-darned rear ratchet caliper quit ratcheting on one side. So start pulling it apart for a new caliper(love that lifetime Oreilley warranty I got in 1991:) )and rotors are to thin, then check the axles and they have too much end freeplay in- so now another snowballing project!! SO much for a quciky caliper chaneg and surface the rotors! Figure I'll freshen the rear while it's out too. Got front brakes so the whole system can be fresh-put a new booster and MC on it about 6 years ago.