Master Cylinder Going Bad?

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Jul 23, 2002 | 04:02 PM

PRyan1983

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Master Cylinder Going Bad?

I have a 1984 F-150. When I press the brake pedal down when slowing down, the pedal begins to travel very slowly to the floor. When I am hauling a heavy load sometimes I have to pump the brakes to keep the pedal from going to the floor. The pedal will also do it sometimes while sitting still in drive, but very slowly. Is my master cylinder going bad? What is the problem. Any info will be appreciated.

Jul 23, 2002 | 06:57 PM

bgodkin

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From: Stanton, Suffolk England

Master Cylinder Going Bad?

Look under the dash where the rod connecting the brake pedal goes through the firewall. If the internal seals in the master cylinder are bad then alot of times it will have fluid leaking there. Is it losing fluid? if not then it may be leaking internally and not holding pressure. If there are no other fluid leaks on the truck and You are not losing fluid than I would say the master cylinder has had it.

Brad Godkin
1986 F350 XLT
CC/SRW 6.9 auto

Jul 24, 2002 | 02:14 PM

JJH

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From: Panama City United States

Master Cylinder Going Bad?

Yeap it is the Master cylinder. Had the same thing happen with my 84 f-150. Hey here is another question. I changed the power brake booster but now when you apply the brakes it makes a poping noise and you can feel it in the steering colum. What do you think about this problem?

Jul 24, 2002 | 06:16 PM

Mil1ion

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Master Cylinder Going Bad?

Was the pushrod adjustment done right?

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Jul 24, 2002 | 06:41 PM

JJH

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From: Panama City United States

Master Cylinder Going Bad?

Well the tag said in some cases the rod might need to be adjusted but how am I to know if it needed to adjusted? In other words I made no adjustments. Tell me how to do this and how to know which way to turn and how far!

Thanks JJH

Jul 24, 2002 | 08:39 PM

bgodkin

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Joined: Sep 2000

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From: Stanton, Suffolk England

Master Cylinder Going Bad?

I'd look in a manual for the adjustment but sounds to me like the push rod is too long.

Brad Godkin
1986 F350 XLT
CC/SRW 6.9 auto

Jul 25, 2002 | 03:12 PM

82Dave

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From: Ridge

Master Cylinder Going Bad?

The same thing happened to my 1982 Ford. Except my Brake light came on in the dash. You may want to check where the master cylinder meets the firewall or booster (if you have one). Usually they like to leak out of the seal if it is near to compleatly failing on you. Also just be prepared for some other brake parts like the Booster or Calipers to brake. Because when I replaced my master cylinder, the brake booster went the next day

. Also it may be worth it to check your wheel cylinders or proportioning valve. If they are leaking then it would be worth replacing them at this time since you have to bleed the system anyway

Dave