71 master cylinder issue

[Bob H.]

I purchased a reproduction 68-72 m/c 5460346 only to find when removing the old incorrect m/c that it used a short pin approx.2 3/8 total length where the repro m/c is going to need one about 1/1/2 inches longer. First question is should the repro require the long pin? I ask because I see 3 different 5460346's based on later years. I am wondering if one of the other 5460346 for 73-74e or 74l through 76 have the shallow one.

So I don't know if I just need a longer pin or I should have gotten a m/c that uses the short one. Help!

PS: The booster was changed just before I got the car so who knows what it is!

[Joe L.]

Re: 71 master cylinder issue

I purchased a reproduction 68-72 m/c 5460346 only to find when removing the old incorrect m/c that it used a short pin approx.2 3/8 total length where the repro m/c is going to need one about 1/1/2 inches longer. First question is should the repro require the long pin? I ask because I see 3 different 5460346's based on later years. I am wondering if one of the other 5460346 for 73-74e or 74l through 76 have the shallow one.

So I don't know if I just need a longer pin or I should have gotten a m/c that uses the short one. Help!

PS: The booster was changed just before I got the car so who knows what it is!

Bob------


1968-76 Corvettes with power brakes used a master cylinder with a "deep bore" primary piston. This, in turn, required the long push rod.

1977-82 Corvettes used a master cylinder with a "shallow bore" primary piston. This, in turn, required the short push rod.

[Bob H.]

Re: 71 master cylinder issue

Thanks Joe. Would it be ok to get a long rod? Perhaps I have a later booster?

[Joe L.]

Re: 71 master cylinder issue

Thanks Joe. Would it be ok to get a long rod? Perhaps I have a later booster?

Bob------

I don't know that the later booster, even if used with the longer pushrod, is otherwise compatible with your brake system. I'd be very reluctant to try it.

[Bob W.]

Re: 71 master cylinder issue

Bob, Call Ken at LONESTAR Caliper. Maybe he can help you out. In his catalog there is a short rod 2-1/2 and along rod 3-3/4. His number is (903)-829-8400.

[Bob H.]

Re: 71 master cylinder issue

I'll do that. I just heard from cssb. Options were to replace the booster with the correct one or order a repair kit for a 78-82 m/c and install that in the repro m/c I purchased. The last option is to buy the 78-82 m/c which would not look correct although the part number is the same. There are no bleeders on it. So, I am going to get the repair kit the 78-82 and install it in my 68-72 repro m/c. Should solve the problem