C3 car/early C4 booster/C5 m/c

69427

69427

The Artist formerly known as Turbo84
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Clinging to my guns and religion in KCMO.
Was doing some suspension tweaking work on the '69 when my attention deficit disorder kicked in (self diagnosis). I noticed some spare C4 brake parts (plastic booster and master cylinder) in a box, and started thinking about things. I like how light the C4 boosters are (about 4.5# lighter than a C3 booster), but the master cylinder bore is awfully small. I measured the diameter of the booster, and it was appreciably larger than the C3 booster (about an inch and 5/8 bigger), so that wasn't going to package very well. I looked at my '84 and noticed that the booster on it was different (in appearance, and it was metal), and made a measurement of the diameter. It was smaller, within about a quarter inch of the C3 booster. Hey, that might package okay. But what about my present (C5) master cylinder? I tried a spare C5 m/c, and it looks like it would bolt up to the (plastic) C4 booster with a touch of ovaling of the m/c attachment holes (hopefully the early C4 boosters are identical in the attachment area pilot hole).
The booster mounts (to the firewall) are different (two studs versus four on a C3), bit the C4 booster is about two inches shorter, so that leaves plenty of room to make an aluminum adapter to change the bolt pattern.
I'm just looking for opinions here. It sounds like a PITA to change the booster, but I'm kicking around rebuilding the pedal assembly eventually, so while I'm in there I might just as well change the booster, and also install the lighter weight stamped steel pedal hanger. It could be another 8-9 pounds of weight reduction (total) combined into the one painful R&R.
Thoughts?
 
cough....Hydro boost for brakes that work....aluminum m/c and call it a day....

maybe machine up a aluminum HB system?? that would be cool....

have to add lead to hold the car down....


:2nd::twitch:
 
mrvette said:
cough....Hydro boost for brakes that work....aluminum m/c and call it a day....

maybe machine up a aluminum HB system?? that would be cool....

have to add lead to hold the car down....


:2nd::twitch:
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Gene, honestly, ENOUGH! I'm tired of hearing about that cast iron wonder you're in love with. Just drop it! My car fucking STOPS JUST FINE! I'm talking about weight reduction stuff here. Try to stay on fucking topic.
 
69427 said:
Gene, honestly, ENOUGH! I'm tired of hearing about that cast iron wonder you're in love with. Just drop it! My car fucking STOPS JUST FINE! I'm talking about weight reduction stuff here. Try to stay on fucking topic.
Click to expand...

Old men tend to repeat themselves alot. I've got no other explanation other than he's trying to irritate us on purpose.

I think we've discussed it before but the booster on my old Buick GN was electronic. I don't know if that is lighter.
 
turtlevette said:
69427 said:
Gene, honestly, ENOUGH! I'm tired of hearing about that cast iron wonder you're in love with. Just drop it! My car fucking STOPS JUST FINE! I'm talking about weight reduction stuff here. Try to stay on fucking topic.
Click to expand...

Old men tend to repeat themselves alot. I've got no other explanation other than he's trying to irritate us on purpose.

I think we've discussed it before but the booster on my old Buick GN was electronic. I don't know if that is lighter.
Click to expand...

The GN booster thing is new to me. I'll have to check into it. Thanks.
 
I meant to say manual brakes as a weight reduction and a means to make the pedal feel a little better too I thought your car was mostly a track car, no need for a booster IMO

The hydrobooster is a bandaid and a heavy pig too with poor pedal return and a funky pedal feel. I tried it and removed it within a day, not for me. It's for a truck.
 
didn't the 90-96 ZR1 use a different plastic brake booster then the base 90-96 vette? I vaguely remember it using 4 bolts through the fire wall verses the 2 found on a base vette.

But not sure if it was plastic.
 
Yes, you're right...the zr1 used a different master too. Wonder if the grand sport got the same 4 stud booster
 
Twin_Turbo said:
I meant to say manual brakes as a weight reduction and a means to make the pedal feel a little better too I thought your car was mostly a track car, no need for a booster IMO

The hydrobooster is a bandaid and a heavy pig too with poor pedal return and a funky pedal feel. I tried it and removed it within a day, not for me. It's for a truck.
Click to expand...

Well, the car is actually a full interior street car, I just haven't gotten around to getting it licensed lately with having it torn apart so much, and the move from Florida to Missouri. Assuming I don't have problems with any inspection stuff this spring I'll be putting plates on it again.

I looked over at the ZR-1 section on CF, and those guys want 250-300 bucks for those boosters. I can't justify that many dollars per pound of weight reduction.

So, in the meantime I'll kick around the possibility of manual brakes (a cheap eight pound reduction). Heaven knows it would make life a lot easier when removing/replacing the left side valve cover. Dealing with the lower rear bolt on the valve cover has been a major PITA due to the booster being in the way. I'm curious what the rod setup is (between the pedal arm and the master cylinder) on manual systems. What keeps the pushrod from slipping out of the master cylinder when the brake pedal is released?
 
Another vote for manual brakes... Id be interested to see what you come up with concerning keeping the pushrod in place with the C5 master. Hood clearance is also an issue so Ive been told.

I just got the stamped steel steering column piece too... I need a better excuse to pull the whole dash apart just to save a few pounds.
 
You will need a longet pushrod and a master with a deep hole. Maybe machine the c5 mc piston. That's what keeps it from falling out

Sent from my GT-I9000 using Tapatalk
 
Twin_Turbo said:
You will need a longet pushrod and a master with a deep hole. Maybe machine the c5 mc piston. That's what keeps it from falling out

Sent from my GT-I9000 using Tapatalk
Click to expand...

This is a truism of life, longer rods stay in better, not as much fallout....

:rofl::rofl:
 
69427 said:
Twin_Turbo said:
I meant to say manual brakes as a weight reduction and a means to make the pedal feel a little better too I thought your car was mostly a track car, no need for a booster IMO

The hydrobooster is a bandaid and a heavy pig too with poor pedal return and a funky pedal feel. I tried it and removed it within a day, not for me. It's for a truck.
Click to expand...

Well, the car is actually a full interior street car, I just haven't gotten around to getting it licensed lately with having it torn apart so much, and the move from Florida to Missouri. Assuming I don't have problems with any inspection stuff this spring I'll be putting plates on it again.

I looked over at the ZR-1 section on CF, and those guys want 250-300 bucks for those boosters. I can't justify that many dollars per pound of weight reduction.

So, in the meantime I'll kick around the possibility of manual brakes (a cheap eight pound reduction). Heaven knows it would make life a lot easier when removing/replacing the left side valve cover. Dealing with the lower rear bolt on the valve cover has been a major PITA due to the booster being in the way. I'm curious what the rod setup is (between the pedal arm and the master cylinder) on manual systems. What keeps the pushrod from slipping out of the master cylinder when the brake pedal is released?
Click to expand...

A lot of GM cars use that plastic booster. I replaced the one on my 97 camaro and it was metal I think cant remember but it was pretty light and sticks out kinda far like a C3 booster. What about a C5 booster?
 
300 bucks is cheap, check ebay there's a new one on there for around 700 or so
 
Twin_Turbo said:
You will need a longet pushrod and a master with a deep hole. Maybe machine the c5 mc piston. That's what keeps it from falling out

Sent from my GT-I9000 using Tapatalk
Click to expand...

I tried that a couple years ago when I was first putting the C5 m/c in. I had a spare (beatup) C5 unit, and was trying to find out if I could get by without shortening the booster-to-m/c pushrod. I started to drill a deeper pocket for the pushrod, and I didn't get far before I drilled through it. Just not much thickness there. I ended up having to shorten the booster pushrod instead.
 
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