Brake Master Question

Suspension, including wheel, tire and brake.
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James
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Brake Master Question

Post by James » 23 Apr 2019 13:55

I thought I would throw this out there and get some feedback.

I have a fairly stock 1972 2 door - running SU's. I would love to run the stock SSS air filter housing -as I have one. I also want to keep the dual reservoir/system master (I have a NOS early single master - but not a fan of the lack of redundancy).

I don't want to cut or dent the housing for clearance (as I've read used to be common practice with our LHD cars).
I haven't done a bunch of measuring yet - but I don't think even grinding the tips off the bleeders will really get the clearance.

My question is - would it be possible to port the opposite side for the bleeder screws and run a flush plug in the existing ports. I don't know a lot about the internals of the Master, but it makes sense to me that it would work. From a machining standpoint how hard would it be to do?

Any insight would be greatly appreciated. Something I started thinking about a few weeks ago.....
Last edited by James on 24 Apr 2019 22:34, edited 1 time in total.
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RMS
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Re: Brake Master Question

Post by RMS » 23 Apr 2019 16:16

you could also run a 90deg bracket like funwithmonkeys
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icehouse
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Re: Brake Master Question

Post by icehouse » 23 Apr 2019 16:46

Doesn't Troy Ermish sell RHD master cylinders for that exact reason?

I had a comment about carbs but why repeat myself :)
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James
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Re: Brake Master Question

Post by James » 23 Apr 2019 16:51

I will check out Ermish. 90 deg. bracket - don't understand - but will check out that build. I understand the carb thing. But I'm old - and I want my kids to understand what a manual choke is.......
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RMS
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Re: Brake Master Question

Post by RMS » 23 Apr 2019 19:29

ImageImageImage
two_68_510s wrote:I guess our donkeys are quicker then your sled dogs!

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MikeY
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Re: Brake Master Question

Post by MikeY » 24 Apr 2019 07:14

There are masters with the bleeders on the other side. I've often wondered if RHD cars got those. Maybe.more common in Australia. I've got one and ground off the boss to make clearance. The flattop Su airfilter has a dimple in it and fits with no nipple. I've bled and cut the tip of the bleeder nipple off. And on all I have to loosen the master from the firewall to move it out ot the way, and drain the front resiviour and remove it, to install the air filter in the housing. So it can be done.

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James
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Re: Brake Master Question

Post by James » 24 Apr 2019 10:23

Thanks for the info. Yeah I checked out the 90 degree thing. Looks very cool. I've actually read through that whole build (just hadn't paid attention to the BMC) - nice car

So ermish does have a 7/8" master with the ports on the other side. That would increase pedal effort and reduce pedal travel and feel a bit - correct? (still on stock brakes at this point). Anyone with experience on that change want to dissuade me? Seems like an easy solution and I can handle the manipulation Mike Y is describing - I was assuming all of that to make it happen.
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MikeY
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Re: Brake Master Question

Post by MikeY » 24 Apr 2019 13:46

My son now drives the car with SU'S. He has stock rears and zx front, and a 7/8th master with the opposite bleeders. Brakes seem just fine. A large syringe to suck up the brake fluid comes in handy to remove the front resiviour. It a hassle but for the look it's worth it for me. There is no hidden cavity in the unused boss. Grind away and it cleans up easily to look like it was never there. It is still very close and with the engine moving around it still might tap the housing occasionally. No guarantee implied. Lol. Just the only fix I've seen. Other than a hack or the 90% turn.
Currently doing the hack on the old flattop box.

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James
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Re: Brake Master Question

Post by James » 24 Apr 2019 15:23

Thanks for the info. I think I will head this route - will end up with a different pedal feel as I have stock calipers. If its an issue I can always go back the 3/4" and the K&N filters. Or get to fabrication and do the pivot....Nothing is perfect on my car - so I can "massage" as necessary.
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James
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Re: Brake Master Question

Post by James » 27 Apr 2019 11:47

Been doing a little more research. From the math I have done and seen - the change from 3/4" to 7/8" master - changing nothing else - will result in a 36% increase in pedal stiffness. This may be fine - and if/when I got zx brakes will be beneficial. Wondering what downside would be in either extending pedal arm length as in bertvorgon's build - or raising the master connection point an equivalent amount to increase pedal travel for the same pressure. I haven't done the math on that - nor studied the effect of potential off axis pressure on the rod and internals with the raised connection point.
Thanks in advance for thoughts on this.
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indy510
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Re: Brake Master Question

Post by indy510 » 27 Apr 2019 13:00

I got a 7/8" master from rock-auto, for a 260Z, because their picture showed the bleeders on the other side. I think 260Z and 280Z are the same, but 280ZX is 15/16" and the mounting holes can vary from horizontal to vertical.

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bertvorgon
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Re: Brake Master Question

Post by bertvorgon » 27 Apr 2019 14:34

I have minimal brake pedal travel with my 2" extension. Unlike a full on race car brake set up, where there is zip for pedal travel, I have enough to "feel" the brakes. Maybe hard to describe if you have not felt a lot of different brake pedals and their travel.

One of our club members pedals was like steppin on a brick. You do need to be able to have a lineal feel as the grip and temp goes up too.

Depending on how or if you heel and toe, you need to match the kinda final travel of the pedal with still being able to roll on the gas pedal in a comfortable way.
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James
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Re: Brake Master Question

Post by James » 27 Apr 2019 20:09

Heel/toe is different for me - I wear a size 13. I'm also 6'-6" - with my seat mounted back I'm comfortable. I have a converted from auto car, and the accel pedal is closer to the brake pedal (I'm good with it).

I'm going to get a 7/8" and try it and see what it does. Then I can mess with it from there and can always regress.
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bertvorgon
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Re: Brake Master Question

Post by bertvorgon » 28 Apr 2019 05:44

Wow......and I thought I am tight in my car at 5'7". With my roll bar where it is, any one much taller than me would have to do a new bar.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

Keith Law
1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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JordanTr
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Re: Brake Master Question

Post by JordanTr » 28 Apr 2019 07:09

I'm doing some nerd math on this. Anyone have the dimensions of the stock brake pedal? Pivot to clevis, clevis to pad center?
Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

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