Some of you may recall the problem with my master cylinder. Common problem, actually, but I wasn't happy with the replacement options. No rebuild kits, no new m/cs, questionable quality rebuilts.

http://www.corvetteguruforum.com/modu ... id=139526#forumpost139526

-=Jeff=- put me on the the camaro/f-body swap since it is cheap and almost bolt on. I liked that idea.

I also mentioned I'd be doing the swap here:

http://www.corvetteguruforum.com/modu ... id=139526#forumpost139526

Well, I finally got a chance to do this yesterday. Here's the rundown:

1) You will need a master cylinder from a 1998-2002 f-body. I think mine came from a 2000 or 2002 WS6.
2) You will need a 3/16" spacer to fit between the new m/c and the booster (I got mine from forum member -=Jeff=- who had a friend who made them a few years back)
3) You will need to reflare the brake lines since they are different sized nuts. There are adapters available but it's not practical, I'll explain later.
4) You will need to bleed the m/c and system.

Here is the problem:



Used F-body replacement m/c:



Here I have the lines disconnected and the corvette m/c removed:



The brake line nuts for the master cylinders are different sizes. They are both ISO (metric) bubble flares.

The corvette m/c is:
front: M10 x 1
rear: M12 x 1

The F-body is:
front: M12 x 1
rear: M11 x 1.5 (a very odd size)

I found an adapter or two that I thought might work, but m11x1.5 is an odd size and the adapter for that was $25 alone. Plus, you would have to use an additional adapter before it so it would be a total of two adapters in line on the rear and one on the front. I decided to cut them off and flare them myself. I bought a bubble flare tool online for maybe $25 shipped. Practice making the flares on some extra 3/16" tubing before you do this.

I cut the old line as close to the flare as I could with a dremel:



Despite this, I still didn't have enough straight pipe to put the flaring tool on (don't forget to install the camaro-sized fittings, first!). I had to use a tube bender and my hands to straighten out the tubing so I could slide the nut back and then flare:



I was then able to fit the flaring tool on. Make sure to use the length checker that comes with the tool to make sure you have the right amount sticking out. If it's too long, the flare mushrooms weird and probably won't seat correctly. Use some brake fluid as lubricant during the process. Be sure to tighten the wingnuts on the tool with channel locks or pliers. It has to be extremely tight.



When you flare the new end, you have to lock it all the way down against the tool. I used pipes to get leverage since working in the engine bay is ridiculously inconvenient. If you don't tighten it enough, the flare won't be correct.



The end result is a perfect flare:



Another result of tightening it all the way...you can see how I bent the turning handle:



After the lines are done, bench bleed the master cylinder. The kits are about $8. I used the rounded handle end of a socket wrench to push the m/c bore.





While you're at it, you can measure the bore depth on the m/c and double check the length of the booster actuator rod. You need to know the length of the rod from the rubber resting point inside the booster to the end of the rod. Adjust as necessary.

When I went to install it, I found the bolt patterns were not identical. Close, but not perfect. Wouldn't fit on the booster studs. I measured both m/cs and the corvette has a slightly wider on center bolt pattern. A couple minutes with the drill and I opened up the holes, fit great then. I wrote down the specs in the garage, but I don't have them in front of me. The difference was very minor.

I also bent the lines back as close to normal as I could to make them fit easily.

After that, I was able to put on the m/c and tighten everything down:



Next step is to bleed the brakes. Of course when I did this, the two rear caliper bleeder screws were seized and I had to vise-grip them out. Carquest had new bleeder screws in stock for about $2 each. I think they are m10x1x30mm off the top of my head.

When I took it out for a test drive...I was not impressed! What the heck? It stopped like a minivan. Long pedal travel and no real "oomph". I took it to the industrial park and activated the ABS a few times. What a difference!!! After that the pedal was firm and it initiated the brakes sooner and harder. I think I still have a little air in the lines I didn't get out completely. I'll have to rebleed them later. But as for now, I think the conversion was a success!

Matthew

Nice write up! I am close on a new master myself, so this is timely.

What fluid did you use? Just being nosy.

Looks like a nice fit! I wonder what the rear bias is set like?

The only part I haven't figured out yet is the low fluid switch. The corvette used a pressure/spring type switch. Single wire but has a two prong connector. The camaro uses what appears to be a magnetized float inside the m/c. It has a two prong connector but I don't know what the wired side looks like.

Andy, I used regular Dot 3 off the parts store shelf.

The rear bias feels better than the old m/c. It doesn't nose dive as much. I think the camaro has larger rear discs so that may be a factor.

This was a lot of work. Took me several hours by the time it was all said and done. For ease of swap, a direct bolt on is definitely the way to go. If you don't mind experimenting, this isn't a bad project.

Matthew

Looks good Matt. When my master went in the 90 I had a heck of a time trying to find a rebuilt unit.

Thanks, Jeff. That was one of the reasons I did the conversion. I've heard of guys ordering one...then three days later they get an email that it's not available, try a different vendor, same deal. Wait a month for a m/c, etc. That's crazy.

Matthew

Nice clean installation! Good job on the flare fittings.

Joel

Thanks, Joel. I only made two practice flares before I started because I didn't have enough extra line. The key is a lot of pressure on the tool.

I have been having good luck with my 90 MC..

I do have a 94 unit I need to rebuild though

Matt,
I e-mailed you the brake warning light diagrams from your '89 and a 2002 F-body.. the magnetic switch on the F-body is designed to apply ground to the circuit however it may not be designed to flow current for a bulb, it may only be designed to ground a signal for the IPC. I think you could try it though, wire one side to a ground and the other to the factory harness for the brake warning...

Very possible you still have some air in the system, I'd bleed them again, I'd start with the rear, gravity bleed them, then have someone help you manually bleed them, then the front.. I'm guessing the air in the the rear...

-=Rick

Rick - thanks a lot! I got the diagrams, I'll post them up later. I'm gonna try to find a terminal adapter for the f-body switch then I'll play with the wiring.

Matthew

I never hooked it up in my 89.. in my 90 it will not stay connected

Good write up. I hope I never need it.

Quote:

No problem, it was late last night, so I looked at your question about the f-body diagram.. the switch goes to an LED in the cluster it looks like... my point I was trying to make is the magnetic level switch may not be designed to flow and real amount of current as with the '89 where it uses a regular bulb.. but it's worth trying.... I would test it out though first...

-=Rick

Quote:

Yep that's the game I played too. I finally ended up sending it out through Rock Auto to get it rebuilt.

Diagrams below.

Attach file:

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  1989_corvette_brake_warning.gif (0.00 KB)


  2002Fbody_brake_warning.gif (0.00 KB)

Update on this from today. I had to change my brake booster because the metal aftermarket crapped out. This time I used an AC Delco reman unit. Once I got in installed, I found out the m/c mounting studs were shorter than the aftermarket one. I checked my old 89 m/c and it fit fine. But the camaro m/c has a thicker mounting flange plus the spacer, and it wasn't even close. I ended up having to remove the m/c from the car and put it in a vise so I could grind down the mounting flange at least 1/4" or more. After that it mounted up fine, did not seem to affect the integrity of the mounting flange.

Overall after all the trouble to install this plus the booster issue, I wouldn't do this conversion again if I had the chance.

Hey Matthew,

Where did you find the correct flaee fittings? I am finally going to do this on my 90 z

Jeff - I contacted the salvage yard on ebay I got the master cylinder from and he mailed them to me for about $2.00.

Why not buy a new Corvette MC? i just ordered a Cardonne MC for $95 from PartsGeek

Quote:

Didn't exist at the time that I did the conversion, as stated in post #1.

LS1 Matt used is a bigger bore then OEM

With my potential rear upgrade I am going to need the added capacity

Quote:

There is no more nose dive when braking with my C5 front upgrade because of what Jeff mentioned. Car stops well with this m/c, but pedal feel is not as stiff as with the stock.

Snagged a LS1 Master, now I need to find my spacers

Hey Matthew,

do you have the old OEM Fittings? if so do you need them?

nice work

Quote:

I have the original 89 fittings somewhere, the f-body fittings were used for the m/c. They are different. If you need them let me know and I'll dig through the parts box.

Yes if you have the 89 ones I could use them. I need to see if I have some..