power booster question
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power booster question
1969 f250 with power drums on all four corners. P.O. replaced the master cyll, and wheel cyllinders too. Pedal is firm, but takes one pump to bring it up. Not spongy at all.Does not bleed down when holding it. No noise from the booster (that i can hear while the engine is purring).
seems like quite a bit of vac to the booster. This booster looks like it may have been the original, rusty she is.
I think the booster is bad: pump the pedal up with the truck off, then hold it there and start it up, pedal stays in position, does not sink down like my 95 Bronco does.
Time for a new MC and booster assembly? If so, cheap autozone with lifetime warr? Should I get the adustable or non adjustable push rod? Does that matter?
Thanks.
seems like quite a bit of vac to the booster. This booster looks like it may have been the original, rusty she is.
I think the booster is bad: pump the pedal up with the truck off, then hold it there and start it up, pedal stays in position, does not sink down like my 95 Bronco does.
Time for a new MC and booster assembly? If so, cheap autozone with lifetime warr? Should I get the adustable or non adjustable push rod? Does that matter?
Thanks.
Logistics Pro
Joined: Oct 2000
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From: All over Texas
When my booster went there was no mistaking it. The thing blew an internal diaphram or whatever is inside and squealed like pig. Your problem doesn't sound like a bad booster since it's holding pressure. Have you tried bleeding the brakes?
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I have not bled them. The pedal does not feel like it needs it. I could be wrong though, it wouldnt be the first time. The truck stops good, it just takes a heavy foot.I still think the booster is out.
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Joined: Apr 2004
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From: Virginia Beach
If you need to pump it at all to get pressure you need to bleed the brakes, here's a quick test... put your foot on the brake but don't press down hard...if it slowly loses pressure you need to bleed the brakes.... just a suggestion, I once had the same problem... i agree with buzzard it doesn't sound like a booster.
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Pressure is good, the pedal just goes down close to the floor. The pedal is nice and firm, does not bleed down with light pressure on it, and holds the truck from moving forward at stoplights. My foot just seems like it goes too close to the floor, and it takes a fair bit of muscle to stop. Give the pedal one stroke and it comes up to a more comfortable position, with the same foot input to stop. I guess that I'm trying to say that I don't have to pump the brakes to get them to work, just a pump to move the brake lever up .
I ordered a booster with MC this morning. I got the one with the adjustible rod. If it's just bleeding that needs to be done, at least i'll have fresh fluid and new components when I'm done.
I ordered a booster with MC this morning. I got the one with the adjustible rod. If it's just bleeding that needs to be done, at least i'll have fresh fluid and new components when I'm done.
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Joined: Mar 2002
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From: Central Coast, Cali
I was having problems with my 69 f100 power brakes as well (drums). When I replaced the standard master cylinder with the power and adjusted and bled all the brakes, I felt no power assitance. I thought the boast was just garbage too but when I disconnected the master cylinder from the diaphram I saw I had a adjustment and backed it off. Now the peddle travels father before braking begins but i can use one toe to stop the 4 wheel drive long bed now.
If you already have an adjustment between the master and diphram you may want to tweak with it first. If you don;t have one now, get the one that does.
My idle rises a couple hundred rpms while the brakes are applied, but I think that is just a small vacuum leak. Any ideas on this?
Oh well, better than standard brakes anyway.
If you already have an adjustment between the master and diphram you may want to tweak with it first. If you don;t have one now, get the one that does.
My idle rises a couple hundred rpms while the brakes are applied, but I think that is just a small vacuum leak. Any ideas on this?
Oh well, better than standard brakes anyway.
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From: Brea CA
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If Your Pedal Is Low And Firm, You Need To Adjust The Brakes All The Way Around. Turn Adjuster Until You Lockup The Wheel. Use A Hook Or Wire To Push The Auto Adjuster Out The Way (most 69's Have Them) And Back Off Counting The 'clicks' Until Wheel Turns Relatively Free. Do The Same At All Four Wheels, Backing Off The Same Amount. Test Drive It May Stop Good Enough But The Booster Is Suspect. You Did The Booster Test Correctly By Pumping Off The Vacuum With The Engine Off And Pressing The Pedal While Starting And Feeling The Pedal Not Fall (which It Should Have). But You Should Double Check The Vacuum Amount At The Booster. You Need At Least 12 Inches.
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