Wilwood master cylinder ?

[carbondaddy]

I'm replacing my boosted MC on my 69 Camaro to a manual Wilwood MC. Question #1 - Do I use the stock distribution block or do the brake lines go directly on to the new MC. If I don't use it what do I do with the brake light switch? #2 - What do I use for a pushrod? #3 - Wheres a good spot for the proportioning valve? #4 - There is a brass thing in the rear brake line under the drivers seat. What is it and do I reuse it? Thanx in advance for your help.
Craig

[ProdigyCustoms]

Question #1 - Do I use the stock distribution block or do the brake lines go directly on to the new MC. If I don't use it what do I do with the brake light switch? Use the distriution block if you want

#2 - What do I use for a pushrod? The manual master comes with a longer push rod

#3 - Wheres a good spot for the proportioning valve? Anywhere in the rear brake line

#4 - There is a brass thing in the rear brake line under the drivers seat. What is it and do I reuse it? Make it go away, that is a residual vavle and needs to go bye bye.

[carbondaddy]

Thanx Frank. Alls good but my master cylinder did not come with a push rod :(

[ProdigyCustoms]

Then it is not a 260-9439 manual master?

[carbondaddy]

They sold me a 260-8555

[ProdigyCustoms]

Who is "they"

[ProdigyCustoms]

The 260-9439 7/8" master is designed to be a manual master and comes with a extension rod required. The 260-8555 is a 1" bore and some use that but I prefer the 7/8" with my manual set ups.

The 1" bore will work once you exteend the push rod, but is going to have a much firmer pedal feel (to firm in my opinion), then the 7/8" bore.

[carbondaddy]

I talked directly to a tech at Wilwood and that was what he recommended to me. He gave me that part # and I had speed tech bring it into Canada as I bought other stuff from them.

[ProdigyCustoms]

There are a couple guys at Wilwood that prefer the 1" bore. It will work, but not the one I would choose. You will have to make a extension rod for it to fit your car.

[carbondaddy]

Would you advise drilling a hole a little further (1/2"?) up the brake pedal to get more leverage on the piston?

[Vegas69]

That's probably won't work. The housing get's tight unless you modify it. You also won't be able to have a full piston stroke. Personally, I'd modify the housing and drill a hole just a bit higher and use the 1". I'd like to run a 1" to decrease pedal travel in race of high load conditions. If you just hot rod it around, take Franks advice on the 7/8 and be done.

[ProdigyCustoms]

Would you advise drilling a hole a little further (1/2"?) up the brake pedal to get more leverage on the piston?

As Todd was saying you may run into a bind. However, Any little teenie bit higher you can drill the hole will make a dramtic effect on pedal ratio. Just a quater inch could make a 6:1 pedal in to nearly a 7:1 pedal. Taking 50LBS of pressure from your leg into nearly 350LBS with 7:1 instead of 300LBS with the 6:1

[Vegas69]

A teeny bit meaning 3/16 to 1/4 above the existing manual hole puts the clevis pin very close to the housing. You basically only have the opportunity to move the mounting point about 3/4 of an inch due to the clevis diameter and needed thickness in the brake pedal. It can be done but not without mods in my opinion. I measured the piston travel difference and looked at the possible interference but never tested it with the master in place without brake pressure. I'd want some clearance to be safe with the side to side movement in the brake pedal. Moral of the story, mock it up before you bleed out the brake system and measure you pedal stroke. I decided to try a better brake pad before switching masters. I may very well have all these answers for you if I'm still not thrilled with my brakes soon

[killer69]

I normally would be with Frank on this one, also Dustin from Wilwood would recomend a 7/8 master, where did we get the part # from? i think you were dealing with Roger were you not? the 1" may work depending on caliper piston diameter, at this point give me a call on monday and we will go through it and figure it out

Blake

[ProdigyCustoms]

Blake, I an certain you guys did nothing wrong and am certain he got that info from someone at Wilwood. A couple sales guys there do recommend 1" bore. In reality either will work. But as you know Blake, the 7/8" is the way to go. Only exception is possible on some big caliper front and rear kits like Todds, who is a gym rat with strong legs, maybe, MAYBE could use more volume. but the jury is still out on that also. Also, we run into issues with people using factory big brake kits, Corvette, ZO6, etc, which are built as power brake systems, require a lot of volume and have very soft pedal with 7/8" and to firm with anything else.

We just finished a car with a Baer Claw kit (Corveete caliper relabled) and it has a 15/16" bore master that was supplied with the kit, and the pedal is just to firm. So a new Wilwood 7/8" is going in.