Master Cylinder Push Rod Question

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RichardJ916

RichardJ916

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I have a 1972 Duster Manual Brakes, I just replaced the Master Cylinder and need a picture on how to re-install Push rod parts, the push rod has a rod with a ball on the end a rubber o ring and a smaller spacer made of rubber, do I have to remove push rod from inside the car to put together before the master cylinder is replaced. I may have to reach behind the master cylinder to hold up the push rod to fit inside the cylinder as I slide it on the 4 bolts. Can someone show me a picture of what order the space and rubber go on the rod.
Please help,
Richard
 
I don't have a pitcher, but the rod is held in the MC with a spring pin. Just rip out the old rod and jam it the new MC until it snaps in

There is a cross pin that retains the rod to the brake pedal, that you will have to remove
 
Most Chrysler master cylinders have just one tiny sheet metal finger holding its piston in the bore. Try to pull the master off the rod in the car, the finger bends/fails, the piston pulls out, fluid flows everywhere. I separate the rod at the pedal, pull master cylinder and rod together. Block the piston in while pulling the rod at the workbench to prevent a fluid mess there too. Rubber collar goes in master cylinder first/alone, then rod goes into it.
Most difficult step is going under the dash with tools to get that bolt out at rod to pedal.
Don't forget to disconnect neg' battery cable so brake lamps don't drain battery.
 
RedFish said:
Most Chrysler master cylinders have just one tiny sheet metal finger holding its piston in the bore. Try to pull the master off the rod in the car, the finger bends/fails, the piston pulls out, fluid flows everywhere. I separate the rod at the pedal, pull master cylinder and rod together. Block the piston in while pulling the rod at the workbench to prevent a fluid mess there too. Rubber collar goes in master cylinder first/alone, then rod goes into it.
Most difficult step is going under the dash with tools to get that bolt out at rod to pedal.
Don't forget to disconnect neg' battery cable so brake lamps don't drain battery.
Click to expand...
So are you saying that the larger rubber collar needs to be put in the rear of the master cylinder then insert the rod, also should the rod be attached to the master cylinder before attaching the master cylinder to the firewall

BPR-A.jpg
 
RichardJ916 said:
So are you saying that the larger rubber collar needs to be put in the rear of the master cylinder then insert the rod, also should the rod be attached to the master cylinder before attaching the master cylinder to the firewall

View attachment 1715307037
Click to expand...
Yes sir. Hang the master cylinder loosely, check that the rod is on correct side of pedal arm, carry on.
 
I put the rubber sleeve on the pushrod first, insert rod into piston bore, install MC onto firewall with the pushrod as an assembly. Attach pushrod to pedal.
Make sure your MC has the recess in the bore to accept the rubber sleeve.
 
KosmicKuda said:
I put the rubber sleeve on the pushrod first, insert rod into piston bore, install MC onto firewall with the pushrod as an assembly. Attach pushrod to pedal.
Make sure your MC has the recess in the bore to accept the rubber sleeve.
Click to expand...
Do all new master cylinders have the recess to except the rubber sleeve.
 
RichardJ916 said:
Do all new master cylinders have the recess to except the rubber sleeve.
Click to expand...
A power brake master cylinder doesn't use same rod w/ ring so that's kind of yes or no. We can't know if all aftermarket mfgrs put the ring groove in all pistons for all applications.
 
RichardJ916 said:
So are you saying that the larger rubber collar needs to be put in the rear of the master cylinder then insert the rod, also should the rod be attached to the master cylinder before attaching the master cylinder to the firewall

View attachment 1715307037
Click to expand...
After watching the following video I can now see what that the rubber collar locks the rod inside of the back of the master cylinder but what does the o ring do, and where on the shaft does it go...

 
RedFish said:
A power brake master cylinder doesn't use same rod w/ ring so that's kind of yes or no. We can't know if all aftermarket mfgrs put the ring groove in all pistons for all applications.
Click to expand...

I can see that the collar locks the rod into the back of the cylinder but what does the o ring do...
 
Yes, you usually install the rod into the MC before putting the MC in the car. Most manual MC come w/ the rod (see rockauto), at least for my 1965. There should also be a rubber dust-bellows on the rear of the MC that the rod fits thru. The metal base of it serves to keep the piston from backing out of the bore. Best to have a new rubber bushing. I bought one somewhere (Dr Diff?). Re how it locks inside the piston, I don't know if an internal ring is necessary. See my post using a 99 Breeze MC for manual brakes in my 64 Valiant. In a test fit, I put the rod w/ bushing in the piston, then couldn't remove it. I had to beat it out, tearing apart the bushing. I needed to remove it to add a dust bellows. That MC is for power brakes so doubt they put an internal retaining groove in the piston.
 
Does anyone know the nut size of the bolt(s) (4) holding the master cylinder to the pedal bracket?
 
Clip the rubber retainer to the end of the push rod first, then insert the rod into the back of the master cylinder. The retainer incorporates a trough for the air to escape during installation.
 
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