67-76 master cylinder rebuild question

[Greg H.]

I'm rebuilding my master cylinder, manual brake 1970 car. The AM had me drill out the check valves to replace the springs and rubber. This looks to be the first rebuild of this part ever.

I drilled out and tapped the brass outlet insert as instructed, and used a bolt to pull it out. No problem.

BUT: There were no springs in the outlet holes, no rubber either. Does this master cylinder use the check valves or not?

[Jim T.]

Re: 67-76 master cylinder rebuild question

Greg I have rebuilt master cylinders on my 68 and 70 at least three times that I can remember. Never replaced/changed check valves although they were in the rebuild kits.
I believe check valves are used only with drum brakes. Read that somewhere. Something about pounds of pressure that is always kept on fluid to the wheel cylinders.

[Joe L.]

Re: 67-76 master cylinder rebuild question

I'm rebuilding my master cylinder, manual brake 1970 car. The AM had me drill out the check valves to replace the springs and rubber. This looks to be the first rebuild of this part ever.

I drilled out and tapped the brass outlet insert as instructed, and used a bolt to pull it out. No problem.

BUT: There were no springs in the outlet holes, no rubber either. Does this master cylinder use the check valves or not?

Greg-----


You have removed the SEATS, not the check valves. There are no check valves in any disc brake-equipped C2 or C3. Are there replacements in the kit you have?

[Greg H.]

Re: 67-76 master cylinder rebuild question

The replacements are in the kit - where they will stay. I'm really glad I checked in here. I would have installed them and ooooh that would have been very disappointing to have brakes that would not release!

[Joe L.]

Re: 67-76 master cylinder rebuild question

The replacements are in the kit - where they will stay. I'm really glad I checked in here. I would have installed them and ooooh that would have been very disappointing to have brakes that would not release!

Greg----


I meant replacements for the SEATS. If you've drilled the old ones out, you'll need to replace them. At least as separate parts, the seats are GM-discontinued.

[Greg H.]

Re: 67-76 master cylinder rebuild question

Joe,
Thanks, yes there are replacement seats in the kit with the check valves. I'm in good shape to get it back together. Now to clean up all the brake fluid that dripped down the firewall and removed all my paint - that's another story. Good news is I found out my clutch linkage ball stud was ready to fall off and someone before me left some of the parts on the frame so I can get it back together the right way!