Weak brakes

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Jul 16, 2010 | 09:51 PM

johnson2007

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From: Bozeman, MT

Weak brakes

I have a 1979 F-150 with discs in the front and drums in the back. I have put a new master cylinder on, new pads all the way around, new cylinders on the rear, new rotors and calipers on the front, and the brakes still don't work that well. I can push the brake pedal as hard as I can and the brakes don't lock. The pedal doesn't go to the floor like there is a leak, but I can push the pedal until it hits the bracket and the pickup doesn't come to a screeching hault by any means. Anyone have any ideas? Thanks in advance.

Jul 16, 2010 | 10:00 PM

montana_highboy

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From: Big Sky Country

Did you bench bleed the master cylinder? then bleed the brakes at all four wheels? you may have to go around the truck 4-5 times to get all the air out of the lines.

Jul 16, 2010 | 10:07 PM

johnson2007

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From: Bozeman, MT

Ya the brakes are bled and I bench bled the master. This was a problem before I did all of the replacement parts so obviously it's a problem that was resolved with new parts.

Jul 16, 2010 | 10:16 PM

1969furd

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not to hijack, but when bleeding what is the order that you do this in?

Jul 16, 2010 | 10:32 PM

montana_highboy

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From: Big Sky Country

Quote:

Originally Posted by johnson2007

Ya the brakes are bled and I bench bled the master. This was a problem before I did all of the replacement parts so obviously it's a problem that was resolved with new parts.

My only other guess is you have a tiny leak in one of your brake lines and/or brake hoses and it's not large enough to notice an obvious drip, are you leaking from the proportioning valve maybe?

Quote:

Originally Posted by 1969furd

not to hijack, but when bleeding what is the order that you do this in?

Furthest to closest...RR, LR, RF, LF

Jul 16, 2010 | 10:53 PM

masterbeavis

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From: Eldorado Ca. USA

Bad proportioning valve? Not much else to go wrong. I have a friends truck with a similar issue. No leaks, the lines look good, new master cylinder have to pump the brakes to get them to work halfway decent, and they crap out, need to pump the brakes again, pedal to the floor etc. Not sure what to think about it...

Jul 16, 2010 | 10:59 PM

1969furd

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thanks Montana!!! masterbeavis might be bad valve, i found one on broncograveyard for 69 bucks shipped, will be installing that tomorrow

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Jul 18, 2010 | 09:18 PM

masterbeavis

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From: Eldorado Ca. USA

In my situation however the truck was loaded to the top of the camper shell with tools, but still it should have had enough braking power for everything to shift and bust into the camper shell.

Jul 18, 2010 | 09:21 PM

#10

dlburch

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From: Kansas

are the rear shoes properly adjusted out and the automatic adjusters working?

Jul 18, 2010 | 09:24 PM

#11

quaallen

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two words bleed em

Jul 18, 2010 | 09:42 PM

#12

masterbeavis

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From: Eldorado Ca. USA

I bled till I was blue in the face. I also learned that there was a little dingleberry you need to either push or pull on the valve (depending on which one you had) while bleeding the brakes. Still did not fix my problem... Still wonder whats wrong with the rig.

Jul 18, 2010 | 10:00 PM

#13

montana_highboy

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From: Big Sky Country

Quote:

Originally Posted by masterbeavis

I also learned that there was a little dingleberry you need to either push or pull on the valve (depending on which one you had) while bleeding the brakes.

Yep, on trucks equipped with front discs the metering rod on the proportioning valve needs to be pulled out to properly bleed the calipers, believe it or not Ford actually had a tool for this specific purpose...

Jul 19, 2010 | 01:33 AM

#14

supawah

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Joined: Jul 2010

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adjust the rear shoes!

i found this out the hard way on an 83 e150, you will NEVER have any pedal till you adjust the rear brake shoes, either manually...... OR set the energency brake, then reverse and stop, that's one click, do that about 20 more times and if your rear adjusters are free and working, and your rear actuater levers are NOT rounded off in that one spot, they will adjust. In other words, do it manually, from the back, through the slot, rotate the star wheel down.