G Body Manual brake problem
 

Having trouble with a spongy pedal, but no air in the system. It's got stock g body disc/drum brakes, with a Master Cyl for a 69 camaro manual disc/drum. I have removed the proportion valve. Relocated the master cyl rod pin up about 3/4" from the orig power location.

So now the problem is that I have a spongy pedal, with absolutely no air in the system. And it's giving me greif with staging more than anything, I have a 5200 flash stall converter, and 2400 rpm the car is trying to push the beams.

Is it possible the master is too small of a bore?

If not, any suggestions?

Re: G Body Manual brake problem
 

Get a gauge and check the brake pressure.

I'd try a manual brake master cylinder from an S-10, the brakes are very similar, it'll be a plastic/aluminum master cylinder, get a syringe type pressure bleeder, you'll find them at O'Rielly's. You've definitely got the wrong master cylinder, in my experience.

Re: G Body Manual brake problem
 

I used a master cylinder for an 80-81 Trans Am for my 81 Malibu.

I can't remember exactly the reasoning, but the brakes held to well over 4500 on the footbrake, with a converter that stalled to 6100.

Hope this helps.

Re: G Body Manual brake problem
 

Recently I did a conversion on a 66 chevy truck using a power brake booster, proportioning valve and dual master in a kit form based on a 69 camaro type unit. I spent hours trying to bleed the air out of the system using the old pump-it-up and hold the pedal pressure, then open the bleeder,without any sucess! Then I read the instructions on how to bleed that type system disc& drum and it said to open the closest bleeder and slowly push the pedal down to the floor and hold it , then close the bleeder. this centers the proportioning valve and lets the air move freely from the system. repeat the above directions paying attention to any air bubbles leaving each wheel, always check the fluid level to keep it full after each wheel is bled. Don'ty release the pedal till the bleeder is closed each time( remember no pumpin the brakes!

Re: G Body Manual brake problem
 

By the way the front disc b leeder should be at the top of the caliper and you should be able to gravity bleed the front disc brakes with just pushing the pedal to start the flow they way I described. Hope this helps

Re: G Body Manual brake problem
 

A big problem on these is when you remove the power brake can. The angle that the rod goes into the back of the master is off. Try to find an adapter plate that helps correct this angle.

I went with a Lamb unit. One great part of his is that the rod can't fall out of the back of the master.

Re: G Body Manual brake problem
 

Call Bruce Compton 208.362.3570. He has a few adapter plates and proper master cylinder kits ready to go.

Re: G Body Manual brake problem
 

Jody I have the same Lamb set-up but mine still feel "funky" staging? Do you run a 2-step? If so did it help? Mine feels like it wants to "slide in" when turning on the 2nd bulb.

Re: G Body Manual brake problem
 

Check out these links for the manual brake conversion.

http://www.maliburacing.com/manualbrake_jim.htm

http://www.maliburacing.com/manual_brake_conversion.htm

http://www.maliburacing.com/manualbrake_pete.htm

http://www.hotrodders.com/forum/g-bo...ics-67017.html

Re: G Body Manual brake problem
 

I think the best way is to use a Mopar (Strange is double the $$) master with a conversion plate to get the resivior angle correct. Make sure that the pedal ratio is 6:1 with a 1in bore master (dodge truck) and it should put you through the windshield. :D

Heres a link to a real trick master conversion plate i found on RJ...

http://www.racingjunk.com/Brakes/184...r-Adapter.html

And heres what I used to calculate my pedal ratio...

http://www.mpbrakes.com/uploads/docu...alratiopdf.pdf

I tried to use all GM stuff to convert from power to manual that I had from a 78 Malibu parts on my wagon and it was a complete fail...pedal feel was garbage and it was hanging the brakes up...complete disaster. And I had a "stock car turned drag car guy" friend give me a little tip on brakes...it doesnt hurt to have a little heat in them before u stage....he told me he rides the brakes in the lanes to build some heat so the car will hold better on the 2 step...I tried it and it works great.