Braking system diagnosis help

[Bandit723]

Another thought I had is maybe I have a leaking at the gasket between the pistons so the fluid doesn't really build pressure and the pistons just moves along the bore...

I would go with this. Seeing you are this far into it. Won't hurt to rebuild the parts. BTW i have that same screwdriver....

 

[suds788]

So...
I found a leak...
I saw there was a paint damage over the prop valve right under the booster. I didn't notice anything dripping from anywhere so it took time to find it but after drying it good and leaving a toilet paper under the master cylinder I saw one drop of fluid on the paper... Just one. I played with the pedal. With and without engine running. The pedal stay not too soft not too hard. And the leaking is up to one of two drops...
Is it possible that such a small leak is leaving me with such a weak brakes?
Another thought I had is maybe I have a leaking at the gasket between the pistons so the fluid doesn't really build pressure and the pistons just moves along the bore...
View attachment 155640 View attachment 155641

Pretty sure COPO covered this in post 12 & 14. I think that's where your problem is from what i'm following in this post. Options get a new master or rebuild the one you have. Note that if you rebuild probably won't be as good as new master. JMO

 

[80Zcorn]

I would go with this. Seeing you are this far into it. Won't hurt to rebuild the parts. BTW i have that same screwdriver....

I will rebuild it that for sure.
And the screwdriver is a couple of decades old it is my grandpa's one.

Pretty sure COPO covered this in post 12 & 14. I think that's where your problem is from what i'm following in this post. Options get a new master or rebuild the one you have. Note that if you rebuild probably won't be as good as new master. JMO

I agree. Currently buying and shipping new MC to my country will be 100 times expensive then replacing 4-5 gaskets and clean it good.
I'll go with rebuilding and at the future will replace it. I'm planning to do 4 discs conversion any way...
But totally agree with the attitude. New one will be safer to go with.

 

[larrylarry]

Another thing I remembered was my break pedal was hanging up, not returning to full up position with foot off the pedal. Look up under the dash an see if it returns all the way.

 

[80Zcorn]

So I'm about to order a new MC.
I'm not looking for anything fancy just replacing my old stock one.
If there's anything recommanded at the same prive level that will be a little better like plastic resorvir etc. I will be happy to hear about it.
For now, all I found are those 2 models. Any recommandation on a specific one or maybe other product that I didn't see at Summit?

1980 CHEVROLET CAMARO ACDelco 19176488 ACDelco Gold Brake Master Cylinders | Summit Racing

Free Shipping - ACDelco Gold Brake Master Cylinders with qualifying orders of $99. Shop Master Cylinders at Summit Racing.

www.summitracing.com

1980 CHEVROLET CAMARO Dorman M76162 Dorman Brake Master Cylinders | Summit Racing

Free Shipping - Dorman Brake Master Cylinders with qualifying orders of $99. Shop Master Cylinders at Summit Racing.

www.summitracing.com

 

[cadillac_al]

I never liked the looks of the plastic master cylinders but other people don't care. I would spring the extra money for the AC Delco Gold one and hope it is better than the cheaper ones.

 

[80Zcorn]

What I posted are metal ones. What are the difference between the AC Delco i posted and the gold one?

All of the cars at the last couple of centuries have plastic reservoir. I think it's a better design since you have the option of seeing the fluid level instead of opening the cover at the metal ones and have the risk of contamination or moisture.

I tried to look on the one i disassembled but not any part number on it.

 

[kenny77]

NPD for brake parts. They have the correct AND proper fitting brake stuff..

 

[80Zcorn]

I already ordered. Thank you.
I hope it will solve the issue and it won't require a new booster since shipping here a new booster will sum up to around 500$