1971 fj40 drums drag when vacum line is hooked to booster

Asked by GuruS3K5Y Jun 23, 2019 at 07:06 AM

Question type: Maintenance & Repair

So I have a 1971 fj40 with drums all around I've
replaced almost all the brake lines and have
replaced the master and all the wheel cylinders
and booster the booster has been replaced twice
now due to the issue but the issue has never gone
away so when I have the vacuum line attached to
the booster my pedal gets hard and my brakes
drag ever so slightly but I end up cooking them so I
currently have the vacuum line disconnected but I'd
like to know what's causing the booster to
pressurize and to do what it's doing id really like to
have my brake assist back

38,905

beatupchevy answered 4 years ago

remove the rod that depresses the master from the pedal , see if it stops , guess you'll have to put the rear in the air to see if they drag , perhaps for some reason something wore out and the booster is being slightly depressed

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GuruS3K5Y answered 4 years ago

Ok I'll give it a shot like I said the almost everything is new the booster isn't even a week old I did notice that when I drove it that when I stoped the truck did not roll freely but after I disconnected the booster vacuum line it rolls like it should I appreciate the help I'm so frustrated this is now the second booster and it's been to the shop multiple times for the issue with no headway I should have done it myself ugh

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