is four inches too much?

[shifty]

posting this over here as well, looking for help wherever....

worked on mounting the master cylinder for the T56 today. expanded a pre-existing hole in the firewall at a potentially good location (for the MC, at least)

i'll be honest: my engineering skills and "what will work" meter just aren't too keen. i also don't want to have something bend/break/snap while i'm driving down the interstate, leaving me stranded and possibly dead.

here's my question - see the attached pictures for reference (the MC is to the right of the square hole).

now, my MC rod is parallel to my clutch pedal, 4" away. is this too much to adapt?

if not, help a n00b out - how would you recommend working this out? i have a welder to weld something onto the pedal, but i don't have a clue as to what the best method to make this happen would be - what shape and thickness of metal, if bushings/bearings are required, how to reinforce the bracket properly, etc.

thanks for any and all suggestions! once this is in, i only have two major tasks before i can drive! (slave fitting replacement and minor wiring).

[68 short step]

this is what id do....no, its not a CAD drawing, im that good with paint!!!! then get all thread and screw a eye clevous on it.. then put a bolt in the "hole" and threw the clevvous.... connect the other end to the slave cyl. with the approiate size double nut.. then it would be adjustable too......if this makes no sence to you, its cause im a genius..

[72highlander]

i hope not that's all i got, sorry, had to say it!

[shifty]

haha

68ss, why would you mount above the fulcrum point and not below it?

i was planning on doing exactly what you said, but i guess i was looking for confirmation that I wasn't going to have problems with flex and other crap by mounting it there. it's a great location, though. uses the old choke hole (or maybe the speedo hole, i dunno.

[gringoloco]

Just to expand on 68SS's idea(we use the same CAD program)- I would build it as a triangle and capture the rod-end between two plates. Use 3/16 or 1/4x2 flat bar. So you'll have a bolt going through a plate, then the rod-end, then the other plate. Much stronger this way.

You will also need to determine at what point on the pedal the stroke is equal to what you need, i.e. closer to the fulcrum= shorter stroke, further down the pedal arm=longer stroke. If you are using the F-body MC, it only requires 1- 1.25", any more than this and you will blow the seals...

[68 short step]

Originally Posted by shifty

haha

68ss, why would you mount above the fulcrum point and not below it?

because it has less travel, like gringo said, the slave only requires about 1" of travel...with the lower point you can do the same, just gotta find the sweet spot.....

[68 short step]

shifty im gonna take this one a bit beyond idea's and theories... give me a day or two.

[shifty]

thanks, bud. You pretty much have a mockup of what you'll need if you have any 68 pickup (or cab) in your garage with pedals available.

there are two bolt-holes already available in the pedal that you could potentially get away with not welding anything.

granted - your hole size (in the firewall, pictured) will de different. i used a (i think) 1-1/4" Greenlee knockout punch to expand the hole to a larger size.

NOTE: i an NOT using the stock MC for the T56. i am using aftermarket piece from Wilwood. my bore and stroke are a bit diff't. factory F-body MC requires 15/16" of travel to push volume of fluid required to disengage the clutch.

Stock master cyl = 0.75 bore/1.0" stroke = 0.4417ci = 0.00723816617 liters
Summit P/N WIL-260-1304 = 0.750 bore/1.4" stroke = 0.6185ci = 0.0101353991 liters
Summit P/N WIL-260-2636 = 0.625 bore/1.4" stroke = 0.4295ci = 0.00703824399 liters
Summit P/N WIL-260-6579 = 0.700 bore/1.4" stroke = 0.5388ci = 0.00882935008 liters

I decided to go with the using Wilwood's WIL-260-6579 (.700 bore/1.4" stroke), so i will need a full 1.4" of travel to get this to work properly.

[shifty]

*bump*

if you come up with something, i will gladly trade you for a spare SA-1000 wiring kit I have here at the house.

[68 short step]

i talked with my brother (engineer) and he said this
"The suggestion that gringoloco posted looks good. Just make sure to weld the plate on the front side of the pedal and put some gusseting on the back to reinforce the plates welded on. Or the strongest way to do that 2nd design would be to make it out of like 1x1 angle...I am not sure how much force is actually required to press that MC lever in tho? "
if pry one him to do more, if ya like...

[68 short step]

Originally Posted by shifty

i will gladly trade you for a spare SA-1000 wiring kit I have here at the house.

i have a spare 68 rad support for your sa-001 (dislexais person)...seriously i need to get rid of it comeing up pretty soon... i'll give it the smooth treatment and paint it shine black for ya..

[shifty]

oh hell, you have a deal. i'll pay shipping on the rad support via DHL, since you're doing the xtra work.

[68 short step]

shifty the classic truck gods smile on you.... pick up the classic trucks mag. and on pg 84-88 they are haveing the ezact same problem as you, and see what they did step by step.... pretty much like gringo said..

[shifty]

tought one to find at the local store, but i will look tomorrow. what is on the cover?

[68 short step]

the cover is a red gmc and another covertable truck thats red in the background...

[shifty]

got it! i read half at the store (first half) briefly, then i had to run. it's in my car at work right now, so i can't finish reading. Looks like they used a stock hole like me and aftermarket MC. will be interesting to read the rest.

[gringoloco]

I picked it up too, man those guys are geniuses! That is a very good write-up for ides on how to do your pedal assembly.

[shifty]

the bracket was interesting.

i thought about this in greater detail over the weekend and finally decided I'm going to break down and just install the damned MC here so I don't need to work on hellacious bracing and the crap will practically line up perfectly and be at a good pivot point (mind you, this is a photochop )

i was trying to take the easiest route as far as firewall aesthetics and looks, but ... after reading that story, they said what i needed to hear: there is no lesser of two evils. you either spend time to mount it in a good spot with no good brackets needed, or you mount it in a bad spot and spend time making a good bracket.

[shifty]

Word of advice: GO BUY A HOLE SAW if you want to do something like this. I am a freaking idiot, and just mangled my firewall using a Greenlee punch to try and slam out the slug of metal right there Man, I feel like an idiot.

I have at least a day's worth of work to get this thing looking like someone didn't hack the sh*t out of it.

So pissed at myself!!