Lighter (substitute) C3 power brake booster?

Weighed a spare C3 brake booster today. I got 8 pounds on my scale. I'm just adding this to my wish list of parts to replace with lighter items if I happen to find an acceptable substitute.
Just mentioning it in case someone has some possible candidates.

Thanks.

Edit: I managed to find a partial picture of a C5 engine compartment. The booster looks compact. Anyone have a picture of one out of the car to see what the bolt pattern looks like, and the weight?

I do not have the weight but the C5 booster and plastic m/c is lighter than the C2/C3 version. We adapted one for a resto mod project on a C2. If I remember correctly the C5 bolt pattern is the same width but the bolts are further apart vertically. I took a piece of C channel and welded studs at the position for the C2 on one side and C5 on the other. The only wrinkle was cutting the C5 pushrod down and re-threading for the end fitting. Even with it lined up to the C2 pedal pin (to maintain the pedal ratio) the hood still closed but it was very close to the m/c cap. We used some Aeroquip metric to sae adapters and it worked great.

You CERTAINLY don't want a Hydroboost unit (for weight anyway).
Haven't installed mine yet and it weighs in at 13.5 pounds!:banghead:
BUT its sexy looking and there is still the weight and additional plumbing to add to the Power Steering pump to consider.
Bolt Pattern looks like a perfect fit though.

Cheers - Jim

If you have the correct HB mounting plate it's a bolt in deal

The C5 booster is plastic indeed and pretty small compared to a stock C3 unit. Not sure about the stud pattern, the stock ones goes through the pedal box and the metal plate sandwiched in the fiberglass, shouldn't be too hard to modify it for a new bolt pattern.

Twin_Turbo said:

If you have the correct HB mounting plate it's a bolt in deal

The C5 booster is plastic indeed and pretty small compared to a stock C3 unit. Not sure about the stud pattern, the stock ones goes through the pedal box and the metal plate sandwiched in the fiberglass, shouldn't be too hard to modify it for a new bolt pattern.

Click to expand...

Well, I'm hoping I can find a C5 booster at a swap meet in the near future so I can take a close look at it.
If nothing else, perhaps I'll make a junkyard run sometime this winter (one of the very FEW upsides of Florida) and look under the hoods of a few dozen cars to see what might be out there.

pcf_mark said:

I do not have the weight but the C5 booster and plastic m/c is lighter than the C2/C3 version. We adapted one for a resto mod project on a C2. If I remember correctly the C5 bolt pattern is the same width but the bolts are further apart vertically. I took a piece of C channel and welded studs at the position for the C2 on one side and C5 on the other. The only wrinkle was cutting the C5 pushrod down and re-threading for the end fitting. Even with it lined up to the C2 pedal pin (to maintain the pedal ratio) the hood still closed but it was very close to the m/c cap. We used some Aeroquip metric to sae adapters and it worked great.

Click to expand...

I looked at a few C5 boosters on ebay, and it definitely looked like the pedal pushrod would need to be shortened and adapted to the stock pedal. That's pretty straightforward. I'm a bit unclear about the mods you did to the studs, though.
I'd like to figure out how to get some measurements of the C5 booster stud locations to compare to the spare C3 booster I've got on the shelf here. Anybody know an easy way to get those measurements?

Well, I've made a couple requests to the C5 crowd for measurements on the mounting stud spacings, but I've got no replies back. Any suggestions on how I can get these dimensions?

Ask someone on ebay who is selling a booster.

Twin_Turbo said:

Ask someone on ebay who is selling a booster.

Click to expand...

Well, I've done it there, and in a couple other places, and no responses to date.
I'm beginning to think that this is some big secret in the C5 world, and we lowly C3 people aren't supposed to know about such things. :amused:

Try this one -- currently on eBay:
"...you are bidding on a 97-04 corvette c5 power brake booster and master cylinder off of a 2004, this part is used but in very nice cond. any questions call 1-954-564-0808 or bradscorvettes.com"
Pricey 199 but includes the master cylinder:
http://cgi.ebay.com/ebaymotors/97-0...r_Truck_Parts_Accessories?hash=item518c5f094e

Cheers - Jim
BTW I'm gonna get a C5 Master cylinder for the hydroboost I picked up. They mate ok to each and the hydro to the firewall and steering/pedal box.

Well, I've pretty much given up on getting a response from portions of the C5 crowd. Several requests sent out, but squat for replies.
There's a big swap meet next month at Daytona. Perhaps I'll just look around there and see if I see any C5 boosters, and then measure them myself. (Gotta remember to measure my spare C3 booster beforehand so I have a baseline.)

Sorry I did not get back to you on this I lost track of the thread. Attached are some photos of the brackets and booster we used for a C2 conversion. The C5 booster studs bolt to the brackets and the brackets bolt to the firewall using the C2 mounting position.

Three more photos

pcf_mark said:

Three more photos

Click to expand...

That's a pretty looking project there....:thumbs::smash:

Thanks! That is what I can do with a small fortune of someone else's money! This car had no expense spared from new LS7 Z06 engine to six piston Bear monoblock brake and custom wheels. Frighteningly quick, corners great and stops traffic everywhere it goes. Perfect.

pcf_mark said:

Thanks! That is what I can do with a small fortune of someone else's money! This car had no expense spared from new LS7 Z06 engine to six piston Bear monoblock brake and custom wheels. Frighteningly quick, corners great and stops traffic everywhere it goes. Perfect.

Click to expand...

OPM is the BEST kind....

wish I had some .....

:sos:

Got a reply back from a guy I bought my C5 master cylinder from. The booster housing mounting stud placements/dimensions he supplied look encouraging, so I'm going to buy the booster from him and try for an installation over the winter.
The stock C3 booster is just shy of 9 pounds, and I'll put this booster on the scale for comparison.

I got the C5 brake booster today. Nice and shiny piece, for sure. To my disappointment, there hasn't been much improvement in boosters in the last forty years. My old spare C3 booster comes in at 8.9 pounds, while the C5 unit comes in at 8.6 pounds. While I love taking weight out of my car, I don't know if I have the time and energy to contort myself under the dash and swap things over for a net reduction of 5 ounces. If in the future the present unit takes a crap on me, I'll seriously look at putting the C5 unit in it (it's paid for, obviously). The bolt pattern looks close (within a sixteenth of an inch), but the pedal rod bellows is a touch bigger diameter. (Don't know how big the firewall hole is.)
Oh well, at least for now, my curiosity is satisfied knowing that I haven't left any serious weight reduction options not looked at.