Power brake install issues

Suspension, steering, brakes, wheels & tires

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Ohiotinkerer
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Power brake install issues

Postby Ohiotinkerer » Mon Apr 16, 2018 4:34 pm

Finally got to test out my power brakes this weekend and of course have a couple issues - been reading some prior posts and gotten some answers but still have a question or 2.........first one is I'm gonna need an adjustable rod since my brake lights are on all the time unless I pull the pedal up so what is the best one to get - was looking at Scott Drake and Wilwood leaning towards Drake and wondered if anyone else has used it..........second question is i about ate the steering wheel just in the driveway they are so touchy - I did start it with my foot on the brakes and the pedal dropped a little so the booster seems to be working - it's out of a 1970 bump with drums - vacuum hooked to the block on the manifold - so I know I have the correct one so I'm leaning towards my NOS Ford master cylinder either not working right or being wrong altogether.........can my original manual brake master cylinder be used in place of my new one or are they 2 completely different pieces - if they are the same I'll swap it back in and see if that's my problem......... :?
"Life is a garden - dig it"........... :thup:

1968 F100 Baseline 2wd - Rangoon Red - 360 2bbl - T18 - power steering and manual brakes
1997 Honda CBR 900RR
1977 MonArk 14 ft jon boat with a 1963 Johnson JW-18 3hp outboard

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sargentrs
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Re: Power brake install issues

Postby sargentrs » Mon Apr 16, 2018 4:57 pm

If you started with drum and all you did was add a booster you can use the same M/C. As for the sudden stop use a lighter foot and be glad they work that well. You can also back off on your adjusters a click or two and get a little softer stop. As for the brake lights, the switch on your pedal is adjustable so you can ease it off too.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: viewtopic.php?f=22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1964 Ford Fairlane 500. 289/Cruise-O-Matic, A/C, P/S.

Ohiotinkerer
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Re: Power brake install issues

Postby Ohiotinkerer » Mon Apr 16, 2018 6:41 pm

What makes me think something isn't right is i did use a soft foot.........the pedal went down and it felt like it wasn't doing anything and all at once it stopped hard....... :eek: ..........it doesn't feel anything like the 71 bump my dad had years back with the same setup which makes me think there's something up with the new mc........ :hmm:
"Life is a garden - dig it"........... :thup:

1968 F100 Baseline 2wd - Rangoon Red - 360 2bbl - T18 - power steering and manual brakes
1997 Honda CBR 900RR
1977 MonArk 14 ft jon boat with a 1963 Johnson JW-18 3hp outboard

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sargentrs
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Re: Power brake install issues

Postby sargentrs » Tue Apr 17, 2018 4:29 am

Could be. Try your old one. Real junk at the parts stores sometimes.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: viewtopic.php?f=22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1964 Ford Fairlane 500. 289/Cruise-O-Matic, A/C, P/S.

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Re: Power brake install issues

Postby dtcohen » Tue Apr 17, 2018 2:49 pm

Ohiotinkerer wrote:What makes me think something isn't right is i did use a soft foot.........the pedal went down and it felt like it wasn't doing anything and all at once it stopped hard....... :eek: ..........it doesn't feel anything like the 71 bump my dad had years back with the same setup which makes me think there's something up with the new mc........ :hmm:


Your pedal ratio may be off. I am not as familiar with f100's, but Jeep CJ's have a different brake pedal for manual vs power brakes. The power brake pedal has a lower ratio because less force is needed to actuate the brakes. When I converted my CJ-7 to power brakes I used the manual brake pedal to start with and had a similar experience. Once I changed over the power brake pedal with the correct ratio the brakes felt much better.

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Re: Power brake install issues

Postby vossy » Wed Apr 18, 2018 9:41 am

Are you confident you've bled the system thoroughly? Sounds to me like you might have some air in the lines... I fought my brake redo for weeks, trying to figure out why they would be mushy sometimes, and then firm up, quickly..

When you press on the brakes slowly does the pedal goto the floor? And if you were to simulate an emergency stop, like mash on the brakes, does it firm up, right away? That's what mine would do.. and it ended up being a bad master cylinder, from the pull-a-part junkyard.. When I put in one from Oreilly, and re-bled it all (thanks to someone's advice on this forum) it was fixed, and the brakes are pretty perfect, now.

I'm pretty sure you can use the same master cylinder with power or without... What has to be different is the proportioning valve, but, I think that's just if you also did disc up front... If you just added the vac booster, then, the same MC should be fine, as far as I know...

As for the brake lights.. I just tacked a block of steel, to the the bracket that depresses the stop light switch, when the pedal is forward. For me, the adjustment on the brake light switch was no where near close enough to being able to be adjusted out to hit that bracket...

Funny thing is, that bracket looks like Ford might have originally designed it to be adjustable as well as the stop-light switch, as it's got a slot in it that looks like if it was bolted on you would be able to slide it forward or backward by loosening the bolt, but mine appears to be welded at the factory, to the underside of the dash...

Ohiotinkerer
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Re: Power brake install issues

Postby Ohiotinkerer » Wed Apr 18, 2018 2:53 pm

vossy wrote:Are you confident you've bled the system thoroughly? Sounds to me like you might have some air in the lines... I fought my brake redo for weeks, trying to figure out why they would be mushy sometimes, and then firm up, quickly..

When you press on the brakes slowly does the pedal goto the floor? And if you were to simulate an emergency stop, like mash on the brakes, does it firm up, right away? That's what mine would do.. and it ended up being a bad master cylinder, from the pull-a-part junkyard.. When I put in one from Oreilly, and re-bled it all (thanks to someone's advice on this forum) it was fixed, and the brakes are pretty perfect, now.

I'm pretty sure you can use the same master cylinder with power or without... What has to be different is the proportioning valve, but, I think that's just if you also did disc up front... If you just added the vac booster, then, the same MC should be fine, as far as I know...

As for the brake lights.. I just tacked a block of steel, to the the bracket that depresses the stop light switch, when the pedal is forward. For me, the adjustment on the brake light switch was no where near close enough to being able to be adjusted out to hit that bracket...

Funny thing is, that bracket looks like Ford might have originally designed it to be adjustable as well as the stop-light switch, as it's got a slot in it that looks like if it was bolted on you would be able to slide it forward or backward by loosening the bolt, but mine appears to be welded at the factory, to the underside of the dash...



Still having air it there is a possibility that I'm gonna recheck.......I got a lot out when I bled them due to replacing the lines from the MC to the block......the pedal feels like there's nothing for about an inch then it's full on brakes - it doesn't go to the floor..............also gonna redo the MC since it was new and I haven't changed one in a long time....it's a NOS Ford part that I picked up and all the seals looked great but if I bench bleed it and it still doesn't work I'm gonna throw the original back in for grins and giggles to see if it will work. As far as the lights i haven't looked at adjusting it.....the never ending winter up here has made it impossible for me to get anything done on it..........the snow in April is really getting old....... :x
"Life is a garden - dig it"........... :thup:

1968 F100 Baseline 2wd - Rangoon Red - 360 2bbl - T18 - power steering and manual brakes
1997 Honda CBR 900RR
1977 MonArk 14 ft jon boat with a 1963 Johnson JW-18 3hp outboard

ButtaBean
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Re: Power brake install issues

Postby ButtaBean » Fri Apr 20, 2018 4:22 pm

I added a power booster to my 67 bump and it does simular. Takes a very light touch at low speeds or it'll put your nose on the windshield.

Ohiotinkerer
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Re: Power brake install issues

Postby Ohiotinkerer » Sun Apr 22, 2018 11:58 pm

Finally a nice sunny day!!! Re-bench bled the MC and re-bled the lines and took it for a test drive and all is now good....... :D ......thanks for all the suggestions and help........much appriciated...... :thup:

:fr: :fr: :fr:
"Life is a garden - dig it"........... :thup:

1968 F100 Baseline 2wd - Rangoon Red - 360 2bbl - T18 - power steering and manual brakes
1997 Honda CBR 900RR
1977 MonArk 14 ft jon boat with a 1963 Johnson JW-18 3hp outboard


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