Brake pedal rod for master cylinder - which to use?

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Rocket

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I have a replacement master cylinder to use for my 69 Barracuda. I am looking for the rod that connects the brake pedal to the master cylinder that will work with this master. The rod that was in my car originally is bolted to the master and has a rubber boot over where it mates to the back of the master.

For the new replacement master it appears the rod does not attach to anything and just rests inside the recess of the piston plunger (plunger has a recess of around 3/4 inch). The rod would need to look the the end of a pushrod. I guess the brake pedal cannot move back sufficiently with the correct length rod for it to back out.

Any ideas from which vehicle I can get the right rod?

Thanks
 
If it is a direct reaplcement it should fit with a new rubber bushing to go on the end of the rod that inserts into the master cyl.
 
I suspect my replacement master is from a later vehicle. THe replacement cannot accept the bolt on flange that goes with the existing rod and rubber boot assembly.
 
Do you have any pics rocket? I used a disc master on my 65 Cuda and all went together well.
 
Here is a picture of the master I took off. I have not been able to remove the rod. That is why I was looking for a replacement. The bolted flange holds the piston assembly in the bore and does not hold the rod in place.
What is the best way to get this rod out of the bore? My next step is to destroy the piston assembly to get at the rod.

Master and pedal rod.jpg
 
Chuck the end of the rod in the vise and bang the flange on the master cylinder with a BFH. If you hit it hard enough the rod should pop out of the old master cylinder. The only thing holding it in is a rubber retainer and years of grunge.
 
As stated, the rod is held with a rubber safety retainer that fits into a machined groove inside the piston bore. All you need to do is get physical with it.
 
Rocket said:
Here is a picture of the master I took off. I have not been able to remove the rod. That is why I was looking for a replacement. The bolted flange holds the piston assembly in the bore and does not hold the rod in place.
What is the best way to get this rod out of the bore? My next step is to destroy the piston assembly to get at the rod.
Click to expand...
The two bolts come out and you can remove the rod. May take some doing since it hs a rubber collar on it to keep it from popping out. Once out, chuck the plate with the 2 bolts and go to www.magnumhp.com or Year one to get the boot and a new collar. The new master cylinders don't need the plate on the back since the boot stretches over the end of the cylinder bore.

Larry
 
OK I will get more physical with it and us a bigger BFH. Using a screw driver throught the pedal ring and all my weight against the bench it would not budge. A regular hammer was useless also. Mini sledge hammer time!

Are the rubber gromets to hold the rod in available and if so where?
 
I have on a couple of occassions had to use a die grinder and cut the piston from around the rod. After many years of crud building up there, plus brake fluid possibly leaking onto the collar and swelling it they are a real pain in the butt.

Magnum HP and Year one both have the collars.

Larry
 
lhearold said:
I have on a couple of occassions had to use a die grinder and cut the piston from around the rod. After many years of crud building up there, plus brake fluid possibly leaking onto the collar and swelling it they are a real pain in the butt.

Magnum HP and Year one both have the collars.

Larry
Click to expand...

This is how I got the rod out:

Used a 1/2" threaded rod, or bar stock about 18" long thru the eye hole. Cut a block of would about 1/2" longer than the distance between the back of the flange and the bar. Clamp the master in the vise, and pry. The rubber collar usually come with a new master. You must use it!

I never put the boot back in.
 
As I understand it, the sole purpose for the rubber retainer is simply to prevent the push rod from popping out of the back of the piston if your foot slips off the pedal and it snaps up. Otherwise, when will there ever be an upward force on the rod???

As a simple substitution for the retainer, I was told to squeeze a glob of RTV silicone sealant into the cavity and seat the rod in there while mounted to the pedal. Once the RTV sets up, it will have the rod captured, the machined groove in the piston filled, and, in effect, lock everything together. There you go, no popping out of position and causing great excitement.

Anyone ever do it this way?
Jerry
 
Success. Clamping the rod in a vice and using a BFH did the trick.

Thanks to all for recommendations.
 
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