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Leaking wheel cylinders

triracer67

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Nov 29, 2010
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I just installed both rear wheel cylinders since the old ones were leaking badly. After two drives the new ones are leaking just as bad as the olds ones. It's a 67 small bearing axle. I did install front disc brakes recently and new 1974 f250 MC. So, is the MC pressure blowing up the wheel cylinders? I find it hard to believe both the new ones are bad since they bled find and held pressure for a bit. Thanks in advance!
 

jim3326

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I just installed both rear wheel cylinders since the old ones were leaking badly. After two drives the new ones are leaking just as bad as the olds ones. It's a 67 small bearing axle. I did install front disc brakes recently and new 1974 f250 MC. So, is the MC pressure blowing up the wheel cylinders? I find it hard to believe both the new ones are bad since they bled find and held pressure for a bit. Thanks in advance!
Are you sure it's not a bad axle seal?

Sent from my D6708 using Tapatalk
 

DirtDonk

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Shouldn't be enough pressure in any master cylinder to blow out perfectly good wheel cylinders. At least not one normally associated with use in this situation.
Using hydro-boost by any chance?
A larger master is probably pushing less pressure than a smaller one anyway, but if it's boosted that can change things.

Still should not be that close to their rating that it could cause them to leak. Were they new or rebuilt?

But definitely check what type of fluid it is. As Jim said, it could be the axle seals.
But they're practically new too, aren't they?

Paul
 

JSBX

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My son ran into this same problem right before OCBR. He had one leaking so he brought it to a shop to have both changed and they went through 4 new cylinders before they got two that did not leak. Maybe a bad batch. I think they were getting them from NAPA
 
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triracer67

triracer67

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It's definitely brake fluid, when I got home it was caught a few drops on my finger. I also just replaced the axle shaft seals, so, its dssapinting I have to tear back into the unit. I'm hoping the parts store will warrantee parts.
 

DirtDonk

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Well now I guess we can add yet another component to the "crap when new" category. Right up there with starter relays and voltage regulators and ignition switches.
What's the world coming to, when a simple machined cylinder and slug to fit, then a couple of rubber caps and done. Apparently not.

Back in the day, new or rebuilt cylinders were sort of a luxury. Everybody seemed to have a brake hone in their tool box and all the stores stocked rebuild kits. A couple of hours of work and you had four new-ish ready to go wheel cylinders.
Maybe that wasn't such a bad idea. But if it came back into popularity, they'd figure out a way to make them in correctly too I'm sure!

Good luck. Sorry you have to pull things apart again too.
Maybe you'll get lucky and find that the fitting is loose on the back side and not even have to take them apart!

Paul
 
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triracer67

triracer67

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Question for the experts. Should I install and pressurize the cylinder before putting the brakes back together? I installed the complete brakes and drums before I put any fluid through, could that cause the seals to fail, kind of like installing the MC.
 

Skiddy

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no, sometimes the ends will push out past the cylinders
 
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triracer67

triracer67

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Fortunately these are the only that are offered by our vendors, I have no issue paying for the best parts available.
 

73azbronco

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Go rockauto dot com, 73 ford bronco.

http://www.rockauto.com/en/catalog/...1105535,brake+&+wheel+hub,wheel+cylinder,1952

Under that at wheel cylinders you will find and economy section and daily driver section. Never buy economy, think cheapest crap to get the car out the door. I've never gone wrong using name brand, so acdelco, raybestos, wagner. Read the notes, some are professional, others say nothing. All are more than cheap from what I remember buying a cylinder 20 years ago and spending $50 per. Most expensive one is $10 these days.

Toms has them for $11, not sure what version they are.
 

Rustytruck

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Feb 24, 2002
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10,875
Just remember these wheel cylinders could be sitting on a shelf for years in someones warehouse. I don't think they get much call for them especially the 10" drum size both front and rear.
 

JAFO

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Dec 3, 2007
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Have to ask the simple question....you have the brake shoes adjusted nice and snug, so that you have a slight resistance when you spin the tire? If the brake shoes are adjusted too loose I guess the brake cylinder could open more than it is meant to and fluid leak past the rubber cups.

I am old. I have honed a many of cylinder and just replaced the cups and spring. Back in the day you just bought the rebuild kit for the brake cylinders and master cylinder.
 

PaveBronco

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Oct 30, 2012
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Rock Auto is a good place to find good manufacture part numbers, I then run those part numbers in Amazon Prime and get free shipping.
helps me save money so I can spend it on yet more Bronco parts.
 
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