Project 3P, Part 14: How to Adjust a Stupidly High Fiat 128 Brake Pedal (Fiat 128 3P Restoration)

Chris' 128 sedan for attention.  (You're probably tired of seeing P3P by now!)

Followers of P3P's progress may remember that brake pedal adjustment was on the agenda.  The pedal was way too tall at about 20 mm above the height of the clutch and significantly further for the throttle, making heel-toe downshift blipping impossible.  This was dangerous, too; the possibility of not being able to hit the anchors quickly enough in an emergency was significant.

This shows how high the brake pedal was when compared to the clutch.  The brake / throttle disparity was far greater!

Why this was so is anyone's guess!   Mine is that there's a non-original part in the system - maybe a close-enough-is-good-enough brake booster from another car - for instance.  Either way, something didn't quite measure up.

An inspection of the set-up that transfers the right-hand-drive pedal action to the left-side-mounted brake booster failed to find the splined shaft that I was expecting.  There wasn't a turnbuckle type thing, an arm with multiple pivots or a threaded end on the booster's actuator pin, either.  I couldn’t find an obvious adjustment mechanism at all!

Neither my trusty Autobooks manual or the internet was able to provide any advice on how the pedal might be lowered.  My mechanic was similarly flummoxed.

Fellow 128 enthusiast Chris got me started, explaining that the same plastic screw switch that adjusts the brake light's on-point also lowered the height of the pedal.  It certainly helped and got the pedal 10mm or so lower.  Close but still that cigar eluded me!   

This switch doubles as a pedal height adjustor and brake light actuator.  Screwing it out - making it longer - pushes the pedal towards the floor.  Care is needed not to overdo this, though; if over-adjusted, it can engage the brakes slightly so that they remain on, even when there’s no pressure on the pedal.

Top-down view, taken from the car's LHS.

So how to lose another 10 - 20 mm?   Time for some lateral thinking!

As mentioned before, there’s no adjustment thread on the pin that actuates the booster.  That got me thinking that if said pin’s travel couldn’t be made shorter, maybe the booster could be placed further away   Something to do with that chap who wouldn’t go to the mountain having the mountain brought to him.  But in reverse, obviously.

But how?  Three 10 x 1mm flat washers on each of the four studs that connect the booster to the bracket that connects the whole shebang to the firewall did the trick.  Simple!  

All that was needed was to remove each stud's nut and to slide the washers in, one at a time.  This effectively reduced the actuator pin's length by 3mm, dropping the brake pedal by a good deal more, bearing in mind that the pedal arm is quite long and good distance from its pivot point.  The nuts still engage fully with the studs, the distal face of each one being flush with the stud ends.  Nothing else had to be disconnected; the booster was pulled free of the bracket without anything falling off or going out of alignment.

As a result, the pedal is at a normal height, making the car far easier to drive - especially when double-de-clutch downshifting into second with its dodgy syncro.  It's also handy to be able to tickle the throttle when the car's cold and on the verge of stalling whilst coming to a stop.

Much, much better!

  

U M P H

(uppermiddlepetrolhead.blogspot.com.au.)