Master cylinder push rod length ?

Idaho Stanger · 02-26-2013, 06:50 PM

Hi, I'm in the process of installing the CSRP swap1 kit in my 66 coupe. I was reading the thread by 65 Fastback that describes in excellent detail his installation. I've copied a quote of his below--

"On go the wheels and tires, and I back out of the garage... and the pedal goes nearly to the floor. Crap! Turns out to be a relatively easy fix. There was too much play in the brake pedal before it applied pressure to the MC. CSRP supplied an adjustable brake pushrod with their kit, so a bit of adjustment to lengthen it and press the brake pedal all the way up at rest, and voila! "

I'm wondering two things about this aspect of the install:

#1 Can I avoid this (the need to adjust) by carefully measuring the current distance of my old MC and its pushrod and transfering this distance to the new MC and new pushrod?

#2 Asthe pushrod length can be adjusted, can this be done without removal of the MC from the firewall? (it looks like the pushrod could be adjusted under dash?

Thanks in advance for any and all feedback.

degins · 02-26-2013, 06:59 PM

Quote:

Originally Posted by Idaho Stanger

Hi, I'm in the process of installing the CSRP swap1 kit in my 66 coupe. I was reading the thread by 65 Fastback that describes in excellent detail his installation. I've copied a quote of his below--

"On go the wheels and tires, and I back out of the garage... and the pedal goes nearly to the floor. Crap! Turns out to be a relatively easy fix. There was too much play in the brake pedal before it applied pressure to the MC. CSRP supplied an adjustable brake pushrod with their kit, so a bit of adjustment to lengthen it and press the brake pedal all the way up at rest, and voila! "

I'm wondering two things about this aspect of the install:

#1 Can I avoid this (the need to adjust) by carefully measuring the current distance of my old MC and its pushrod and transfering this distance to the new MC and new pushrod?

#2 Asthe pushrod length can be adjusted, can this be done without removal of the MC from the firewall? (it looks like the pushrod could be adjusted under dash?

Thanks in advance for any and all feedback.

You may avoid having to adjust the push rod by using the old push rod from the existing master cylinder. Of course, you will be limited to the resulting pedal height.

Idaho Stanger · 02-26-2013, 07:06 PM

Ok, that sounds easy enough. So if my current pedal travel seemed OK, then just use the exsisting pushrod form old single MC in the new dual MC? Just figured the lengths between the two would be different. Thanks for the quick feedback and I'm thrilled to be finally installing upgraded brakes (yours) in my old stang.

Bucket Lister · 02-26-2013, 07:15 PM

Quote:

Originally Posted by Idaho Stanger

Ok, that sounds easy enough. So if my current pedal travel seemed OK, then just use the exsisting pushrod form old single MC in the new dual MC? Just figured the lengths between the two would be different. Thanks for the quick feedback and I'm thrilled to be finally installing upgraded brakes (yours) in my old stang.

Its entirely possible the new MC will be different than the old. Many are. that's why adjustable PRs are so popular. I made my own.

Yes, an adjustable can and should be adjusted from under the dash, but it a stretch. Get someone with small hands.

Make sure you leave some free play in the pedal. Don't run the adjuster all the way out tight. If there's no free play, the MC won't detent and bleed off the pressure. After a few stops, your breaks will lock up, so leave some free play.

Idaho Stanger · 02-26-2013, 10:13 PM

Is the amount of travel (distance push rod can move inward) going to be the same between the old, single bowl and the new dual bowl?

degins · 02-27-2013, 11:33 AM

Quote:

Originally Posted by Idaho Stanger

Is the amount of travel (distance push rod can move inward) going to be the same between the old, single bowl and the new dual bowl?

They are the same in this case.

Idaho Stanger · 02-27-2013, 05:39 PM

Thanks for your reply degins. I'll hopefully be a 'bleeding' sometime this weekend.

65 Fastback · 02-27-2013, 06:38 PM

Thanks for the compliment on my thread. In my case I had indeed matched the adjustable rod length to the original and still had the issue. It's possible original condition was no brake engagement until near the floor (originals were bad enough I wouldn't have noticed I think). I was able to remove the adjustable rod from under the dash to lengthen it without removing the MC but then couldn't get it reinstalled. I shortened it again, reinstalled, and was able to adjust its length while installed to take out the brake pedal slack. The most challenging part was reinsertion of the retaining clip.

In my case I didn't leave any slack (not that I put a lot of static pressure outward on the brake pedal) and have driven the car several times without any negative brake behavior.

Fordguy65 · 02-27-2013, 09:54 PM

I had the same issue. My pedal height for the brake was an 1-2" lower than the clutch pedal and felt like it was going to go thru the floor. I solved this with a longer rod from a 1977 Bronco. I had to cut it down a 1/4 inch or so but now my brake and clutch pedal are the same height and work perfectly. I tried the adjustable rod but even that was too short.