1957 Thunderbird Master Cyl. Push Rod

1

1967 Camaro

Member
This is the push rod as it came out of my '57 master cylinder. I've seen a couple different ends on these. A flat end with what looks like an o-ring and a rounded end with the same o-ring. Which one is correct? The pic to the right is the rod as offered from NPD.
 

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Ridges. At first I thought they were threads but nope. So the push rod end cap is what I need? Should it fit tightly into the receiving bore of the master cylinder spool? Should some type of adhesive be used to secure it onto the rod end? Thanks so much.
 
1967 Camaro said:
Ridges. At first I thought they were threads but nope. So the push rod end cap is what I need? Should it fit tightly into the receiving bore of the master cylinder spool? Should some type of adhesive be used to secure it onto the rod end? Thanks so much.
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You just need the little cap, it's a friction fit on the end of the rod. The tip on the rod sits in a shallow cup inside the master cyl.
When it's installed there should be a very slight amount of front-to-rear end play of the rod so the MC can release completely.
The bolt that holds that rod to the brake pedal has an eccentric shoulder for the large / open end of the rod. Rotate the bolt to adjust the end play and lock the bolt into position with its locking nut.
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The top one/w ridges is what was on my 55 T-bird's master. Yes, there should be a nylon/plastic tip on the end. The fit was pretty snug. I did not see any adhesive.

I converted to Wilwood front discs, using Wilwood's 15/16th master cylinder and proportioning valve. The Wilwood pushrod was too long for my application, so it was cut to length and re-threaded. Had I bought their Mustang master cylinder, I think the pushrod would have been the correct length. The Wilwood pushrods are adjustable, but the one that came with my master was still too long.
 
I found the plastic tip stuck inside the old master cylinder spool. Fitting the rod back into the old master cylinder, I found that the end of the rod slips into and out of the tip rather easily. Hopefully the new tip I've ordered will hold securely into the counter bore of the new master cylinder spool. Thank you very much for the insight.
 
1967 Camaro said:
I found the plastic tip stuck inside the old master cylinder spool. Fitting the rod back into the old master cylinder, I found that the end of the rod slips into and out of the tip rather easily. Hopefully the new tip I've ordered will hold securely into the counter bore of the new master cylinder spool. Thank you very much for the insight.
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The plastic tip fits onto the end of the rod with enough depth that it will stay in place once it's assembled, or you can use the new one and keep the old one as a spare.
 
The old tip was very tight in the old master cylinder. I pretty much destroyed it during removal. It is what looks like white nylon.
 
Just wanted to put this out there in the event someone else runs into a problem like I did. The master cylinder push rod end cap (see pic) should fit snugly into the bore of the master cylinder spool. My previous one was stuck and effectively did not allow my brake pedal to have any free play despite where I spun the eccentric adjustment bolt. The new one did slip in the bore with little effort. I did remove some flashing from the cap with emery cloth until I was satisfied with the fit. Now I can adjust free pedal play and I'm well on the way to be driving the car safely. I did get my new cap from NPD. $7 for the part and $11.50 to ship it!! Couldn't find it locally. Thanks to everyone for the advice.
 

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I know this is an old thread but i,m changing master and it appears the total depth of the hole is quite a bit deeper , about 5/8 - 3/4 deeper .. I had a hard time getting the master off , it was grabbing so tight on that bushing that is no way coming out of the old master .. Can I just play with the length of a spacer till it seams good. Right now my pedal seems to go about 2-3 inches before I feel it contacting the piston thanks Fred
 
ff, is your new master an OEM-type, or are you upgrading to a dual reservoir? In either case, I would use a new rod that is intended for that master cylinder. If that's done, just leave the stuck rod in the old master.

I'm not sure what shims you're talking about. Although I have a 55 Tbird, I don't think there's a difference. There is an adjuster bolt where the rod attaches to the pedal assembly. There should be some play, but I would have to check the manual to see if 2-3 inches is excessive. 1 inch seems more correct.
 
Check the free play at the master. Should be about 1/8 to 3/16 This allows for fluid expansion when hot. If the pedal has excessive free travel after that, then the rod needs to be changed
 
I’ve got this blurry memory of buying a new master cylinder and it had a metal “plug” that went in the bore. The master was used with the plug on a power booster, and without it on a manual. Or visa versa? Anyone remember that clearly, it sounds like ff is about that far off.
 
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