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Master cylinder rods
jeffw - 4/4/11 at 05:34 AM

Is it possible to shorten the rods out of the master cylinders (I have two seperate MCs)? I'm trying to move the brake pedal further down and have run out of adjustment.

whitestu - 4/4/11 at 06:51 AM

Mine is just made out of some threaded rod, so I should think shortening or making new ones should be pretty easy.

Stu

foskid - 4/4/11 at 07:16 AM

Why not just get a die on them to increase the thread length on the existing rods.

Cheers John.

Mr Whippy - 4/4/11 at 07:38 AM

my only concern would be side loads on the first piston if the rods were really short which could cause much more wear. Try to get the lever force as close to the center line of the MS as you can

jeffw - 4/4/11 at 08:41 AM

I was only thinking about reducing the length by 5mm or so. Maybe threading it is the way to go, although the balance bar fitting only has a limited thread depth. I'll give it a go.

Peteff - 4/4/11 at 09:13 AM

Get a bolt something like the length you need and cut the head off, round it off and viola

HappyFather - 4/4/11 at 10:37 AM

I have done it, if I understood correctly what you're asking. If I hadn't done it, the brake peddle would tilt towards my feet.
I didn't use the proper tools, but my blog post from that day shows what I have cut of, if it may be of any help.
http://happyblade.blogspot.com/2010/09/brakes-and-lhd-specificities.html

Have fun!
HappyFather

bimbleuk - 4/4/11 at 11:43 AM

quote:
Originally posted by jeffw
I was only thinking about reducing the length by 5mm or so. Maybe threading it is the way to go, although the balance bar fitting only has a limited thread depth. I'll give it a go.


I've done it on my pedal box install in an RX7. If I didn't shorten them then the pedal is sat too high. Try to retain the supplied rod as it's got a dome shaped end in the MC which spreads the load to the back of the piston and keeps the rod in the MC!

britishtrident - 5/4/11 at 07:10 AM

A few caveats.

(1) The pedal angle of the pedal and line of action of the pushrod should be carefully considered.
(2) Best not to thread the whole length of the rod -- it greatly weakens it in compression.
(3) If making a new pushrod the mushroom end must allow the piston in the master cylinder to come fully back --- even 0.5mm can lead to brakes binding on due to hydraulic locwhen the fluid expands due to heat.