Brake problems

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larry202br
Posts: 92
Joined: Wed Sep 15, 2010 2:54 pm

Brake problems

Post by larry202br »

I have a soft pedal on the first push. Pedal goes way down, unless you pump it once or twice. I've bled the lines, and re-bled the lines. This didn't happen until I rebuilt the rear wheel cylinders. I'll admit I exercised the MC a lot during the bleeding procedure.

I used both the vacuum and two-man bleeding procedure.

I rebuilt all four wheel cylinders, and installed new shoes. Adjusted shoes by tightening until I can't spin the wheel, and backed off 9 clicks.

What am I missing?

What are the symptoms of a bad master cyl?

Does anyone know if the late model FC master cyl will fit on a early model FC?
joe moore
Posts: 99
Joined: Sat Oct 19, 2013 2:20 pm

Re: Brake problems

Post by joe moore »

Larry go to Clark's catalog page 145 my 62 has the c1195r works fine also make sure you prime the unit before you bleed your brakes I used my kid to push the brake pedal while I bled them you really need two guys for this joe
1962 rampside #3957
Wagon Master
Posts: 474
Joined: Thu Jul 28, 2011 6:36 pm

Re: Brake problems

Post by Wagon Master »

In my opinion backing off 9 clicks from tight is your problem. If you pump the pedal 2 or 3 times quickly does the pedal come up and get firm? If so that's a sign that the first stroke moved the shoes out against the drums but used up a lot of the volume the master cylinder can put out. On the 2nd and 3rd pump you added more fluid and "caught' the shoes before they could fully retract, raising the pedal in it's stroke.
If no matter what you do the pedal is still low and soft, it's got to be air in the system or a defective master cylinder. They're a specialty piece but you can buy plugs that will screw into the flare ports at the master cylinder. Pull the line(s) and plug the master. Pedal high and firm your issue is in the system. Still low and soft it in the master, either defective or needs bench bleed. If you go that route MAKE SURE YOU GET THE PROPER FITTINGS so as not to damage the seats in the master.
Look in the shop manual for the procedure to adjust the master cylinder push rod. It shouldn't have changed but it should be checked. Just don't get it too tight.
GOOD LUCK
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terribleted
Posts: 4588
Joined: Sun Apr 18, 2010 2:36 pm
Location: Atlanta, GA
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Re: Brake problems

Post by terribleted »

The brakes should scrub some (a firm drag as the manual says) when properly adjusted. You may, like Wagon said, have them adjusted too loosely. Re-adjust, perhaps re-bleed, then replace master perhaps. If it is a single master cylinder, I recommend changing to dual cylinder for safety reasons unless factory stock for show purposes etc. is needed.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
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Located in Snellville, Georgia
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