Hi I’m new to the group. I’m finishing up a engine and trans swap in a 52 merc. I used a 1984 T5 out of a mustang and put a new HD clutch and pressure plate/ hydraulic throw out bearing from Ram clutch.also used a wilwood 3/4” bore master. The clutch pedal is really hard to depress Any ideas on how to soften the pedal? I have no clue how what ever is in that box is but I didn’t put that in . And some how mikey mike was supposed to be mitey mike
May need to remove springs in the PP. HD might be the issue. I’d check with the PP manufacturer, let them know what you have and pedal ratio, see what they think.
Is the clutch actually working, as in disengaging? If you've not got the measurements and spacers correct the bearing can extend until it reaches the circlip at which point it will be heavy, as in locked solid! But it should hit the fingers long before that occurs. If the clutch is working but is just heavy there must be something funky going on as the 3/4" master is the smallest recommended by RAM, this will give the highest pressure and thus lightest pedal. The stroke on the master needs to be a minimum of 1.1" but the wilwood should have this (I don't know this off the top of my head by the way, I've been looking into my setup which is similar, but has a 1" master and is a bit heavier than I would like). As has already been questioned, what's the pedal ratio? And is there sufficient travel to stroke the master the required 1.1" minimum? Chris
The clutch works fine. No slipping no chatter it’s just a harder pedal than I am used to. As far as pedal ratio I don’t know what that is. I’m using the stock pedal assembly that came with a 52/53 mercury. The clutch begins grabbing about 1/2 way off the floor and is fully engaged in about a1/2”after that. I located the master cylinder as close to center of the hole in the firewall where the old clutch linkage passed through and connected an adjustable piece of threaded rod to the stock pedal location. It’s a fairly straight run from pedal linkage to master cylinder. Thanks to Budget 36 and Happydaze for your input.
foxbody mustangs are well known for their super heavy clutches, but if everything is modified that may not matter. however your factory pedal set may not be setup for hydraulic so it lacks enough leverage. i only know things about lever and Z bar clutches, so i cant really comment on what is needed to fix that.
Pictures, we like pictures! My slave is an external 7/8", same clutch master. I had messed around with it and mounted the clutch master lower on the pedal arm... almost impossible to work the clutch. It was fine in the OG position. Look at that first.
OK, just got on the magic book and googled how to measure for pedal ratio. Length of pedal from pivot pt. To center of pedal pad. Divide that by the length of the push rod from pedal to center of master cylinder piston and that number will be my ratio. 6 to 1 is what I should want to end up with. Thanks guys ,I’ll let you know how I make out and try to post some pictures. Mike
Friend of mine had an old Chevy he paid to have converted from an automatic to manual. They used a Wilwood master cylinder for the hydraulic clutch. From day one the clutch pedal was extremely hard to push in. Then one day the the clutch quit working. After disassembly found the master cylinder bore was scored very bad and fluid was leaking past piston. The culprit ended up being misalignment of the clutch pedal pushrod to the master cylinder. It looked straight but there was some funky geometry as the clutch pedal swung through an arc applying an upward pressure on the forward end the pushrod on the piston in the master cylinder’s bore. The fix was finding a clutch pedal assembly that came stock in the car and going with the stock manual clutch linkage. The guys paid to do the original conversion just took the easiest route proving “if you want it right do it yourself” works great now!
That instruction doesn't read quite right to me. Length: Pedal pivot to pushrod, over Length : pedal pivot to pedal pad. 6 is a good number. Fingers crossed for you! Chris
Back in the ancient times when they taught you things you could actually use in school we learned about levers and leverage in 3rd or 4th grade. The longer my handle is on this side of the fulcrum the Easier it is to lift the rock on the other side. The pivot pont changes with the pedal and clutch pushrod but the leverage factor doesn't. It's been a long time but I remember drivng a couple of those Fox Mustangs when I worked on them in the early 90s and the clutches were a bit stiff. Still if that master cylinder or the slave is just the least bit cockeyed it could cause it to bind up a bit.
While you're under there with your measuring device(s) it's got to be worth checking the clocking of the mechanism too. It's already been mentioned that the pushrod shot into the master needs to be as straight as possible ( thinking rod angularity) but the action around the pedal to pushrod needs to be correct - ish. To get a visualisation of this, consider a clockface and a pendulum from 12 o'clock. The master cylinder is horizontal to (or slightly above) the 6 oclock position, to the left. Without getting into degrees of movement, the swing of the pendulum / pedal wants to be in the 4 o'clock to 8 o'clock region to give the required horizontal stroke. If the start were to be at 6 o'clock ( or later) position, the horizontal movement would be limited and would cease by 9 o'clock, and would also exacerbate the angularity issue. Hope that makes sense. I can't think of a simpler way to explain it in writing. Chris
After taking measurements I see that I have to relocate every thing but the pedal. The stock set up was too low on the pedal. I have to raise the clutch master and move it toward the drivers side because the brake master is in the way. Then weld a bracket to the pedal to line up to the master. Then I’ll have the correct ratio and a straight shot at the master. Hopefully there won’t be any binding. Mike
My Model A was like that, my mistake was using a Hayes clutch, the are notorious for being hard to Engauge. HRP
I made a common plate to mount my brake and clutch masters. The 1st two were from 1/4" aluminum plate, too flimsy but looked nifty. The last was from 1/4" steel and is acceptable. I also moved the clutch master up when I went back to the OG pedal pivot. I'm running a Zoom 11" diaphragm C30-ish truck clutch.
X3. We need to form an orderly queue (that's a line for US folks) for this interesting and vital information! Chris
Humor my good fellows... ratios are ratios no matter what system. I was the kid in 1st grade waiting to learn about upper and lower case NUMBERS...
Ok been away for a while,did some reading and got on with the project. I had to raise the master 2-1/2”and 2”toward driver side. I installed a 1/8”steel plate to stiffen things up.when all was said and done I have a nice pedal. I started out with a 2.2:1ratio and ended up with 4.8:1. Thanks to all who helped and those that were lost are now found. Mike
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