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  #16 (permalink)  
Old 06-15-2010, 05:35 PM
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Mike, I posted earlier that the bore is 1 inch. that seems to be standard in the aftermarket "corvette style" masters. is there a larger bore master that fits the universal 7 inch booster? also since you tested a few rpv's which brand was good? thanks

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  #17 (permalink)  
Old 06-16-2010, 08:49 AM
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You can get bore sizes in up to 1 3/16" in the corvette style MC. The bolt pattern is about the same on all of them. Check your pedal ratio, if you have a low numerical ratio, like 5:1, get the 1 1/8..if you have slightly higher, like 6 or 7:1, get the 1 3/16.

A 1" bore is usually a drum brake bore size, but some aftermarket brakes like Wilwood and Baer and PBR actually take less volume to run,but need a higher line pressure, so they use even smaller bores, like 7/8" or 15/16". Those early GM calipers need more volume, and less line pressure, hence the bigger bore.

The pedal ratio has alot to do with the feel of the brakes, and your perception of how they work. You'd be surprised at how many systems I've fixed just by reworking the pedal ratio to match the system..

What really surprises me is that there are only a few companies that will actually ask you what calipers and wheel cylinders you have before they sell you a master cylinder..

Call the guy who sold you the universal booster kit, tell him you need a bigger bore with an RPV in the rear brake outlet, or just take the master cylinder to your local parts house and match it up to another with a bigger bore...Just make sure you get one with the shallow pushrod hole in the piston, or one that has a pushrod hole spacer, to make it work with the booster. You would do well to check the clearance between the pushrod and piston bore when you install it.

Masterpower brake has master cylinders listed by bore size, so does CPP...You can call Brake Tech Solutions too, the guy who owns it is actually an engineer, who usually pays attention to the stuff he sells to folks...Ralph at ECI could probably help you too, if he's in a good mood that day.

SSBC has some good RPVs...If you can find a master with an RPV in the port you don't need to add one inline.

Here's a good place to do a little reading.
http://www.mpbrakes.com/technical-su...igurations.cfm

Later, mikey
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Old 07-05-2010, 03:46 PM
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Make a pressure bleeder.
http://www.arkansaspontiacs.org/tech...er%20story.htm
http://faculty.ccp.edu/faculty/dreed...eder/index.htm
I made on of these for less than $20.00 works perfect and its a 1 man job.
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Old 09-12-2010, 09:25 PM
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still having problems

I upgraded my front control arms and decide why not change the brakes also, so now i have new metric calipers and stainless braided front hoses, i also installed a 10 lb resisdual pressure valve in the rear brake line...... still no pedal. when I was trying to bleed the rears its like there is very little pressure to the fluid comming out of the bleeder and i still end up with the same symptom. the pedal will start to build up and you bleed one wheel and all the pedal you had is gone. it just goes to the floor. may be a bad master??? going to go with a larger bore just in case.
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Old 09-12-2010, 10:38 PM
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Did you adjust the booster to master cylinder pushrod to match the master cylinder?
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Old 09-13-2010, 04:36 AM
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Quote:
Originally Posted by enjenjo
Did you adjust the booster to master cylinder pushrod to match the master cylinder?
I will recheck, but when I installed it I took all the freeplay out of it.
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  #22 (permalink)  
Old 09-14-2010, 09:41 PM
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well I built a pressure bleeder today with a garden sprayer and it works great. no more air and the best pedal yet. I still have lots of pedal travel before they brakes actuate. no resistance in the pedal for over half of the stroke then it gets better but it is close to the floor . i will check the booster pushrod adjustment tomorrow. if you are fighting air do yourself a favor and build a pressure bleeder. it works.
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  #23 (permalink)  
Old 09-14-2010, 10:28 PM
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It's a good idea when using a pressurized vessel like a pressure sprayer to do brakes, to leave the brake fluid in the original container and run the siphon tube from the sprayer into the brake fluid container. This keeps the fluid from being as exposed to moisture as it would be otherwise, is less messy and you need much less fluid to work with, than would be needed if the fluid has to fill the entire sprayer to a level that the siphon tube stays immersed.

FWIW, I like the spring-loaded bleeder screws that replace the original bleeders.

They are opened 1/2 turn from closed then you merely pump the brake pedal. Run a piece of clear tubing from the end of the bleeder into a jar so you can see the bubbles and fluid. No worries about keeping the end of the hose tight to the standard bleeder and the end of the hose need not be immersed.
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  #24 (permalink)  
Old 09-14-2010, 10:37 PM
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Quote:
Originally Posted by cobalt327
It's a good idea when using a pressurized vessel like a pressure sprayer to do brakes, to leave the brake fluid in the original container and run the siphon tube from the sprayer into the brake fluid container. This keeps the fluid from being as exposed to moisture as it would be otherwise, is less messy and you need much less fluid to work with, than would be needed if the fluid has to fill the entire sprayer to a level that the siphon tube stays immersed.

FWIW, I like the spring-loaded bleeder screws that replace the original bleeders.

They are opened 1/2 turn from closed then you merely pump the brake pedal. Run a piece of clear tubing from the end of the bleeder into a jar so you can see the bubbles and fluid. No worries about keeping the end of the hose tight to the standard bleeder and the end of the hose need not be immersed.
I used a .5 gallon sprayer and one quart of fluid total. I had $15 invested including the fluid. I had no luck with the self bleeders, I pumped till my leg hurt and still had no pedal. I pressure bled the whole system in 10 mins. when I worked at the dealership we had a $800 pressure bleeder and i think my cheap, homemade one worked better.
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Old 09-15-2010, 02:36 AM
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Have you tried to isolate the problem to the rear or front of the system?
Take the system and brake it down into smaller pieces. The rears are easier.
Plug the front lines at the Prop valve and work the rears until you are satisfied you have the highest peddle you can get with the shoes adjusted to fit the drum.

With that complete you can either leave the rears connected (as you have them at there best) and correct the "problem" in the front of the system.
You may want to start with just one wheel and work out from there.

Ralph was in a good mood the last time I talked to him, but I didn't let him rest until the problem was corrected.

Brake it down you will fix the errors
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