Print Page | Close Window

Convert to power brakes?

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: Suspension, Steering, Brakes & Wheels
Forum Description: What makes it stop, turn, and smooths the ride
URL: https://theamcforum.com/forum/forum_posts.asp?TID=30077
Printed Date: Mar/28/2024 at 12:09pm
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com


Topic: Convert to power brakes?
Posted By: fmahannah
Subject: Convert to power brakes?
Date Posted: Jun/11/2011 at 3:46am
My 74 Javelin has manual brakes, disc front drum rear. I have always had power brakes and it just seems to take way too much pedal effort to stop the car. Pedal is very high in the car as well.

Is it possible to convert from manual to power brakes and if so what does it involve parts-wise?

Thanks!


-------------
74 Javelin AKA Ghost



Replies:
Posted By: ramblinrev
Date Posted: Jun/11/2011 at 7:33am
It's certainly possible. The ideal switch would be to get the bracket/booster/rod to the brake pedal assembly you need from a donor car, and add a new power disc brake master cylinder to that. You'll need to redo the lines to the master as well. Then a line to manifold vacuum and you should be in business.
 


-------------
74 Hornet Hatchback X twins (since 1977)
62 American Convertible (still worth the $50 I spent in 1973!) AMCRC #513, AMO #384
70 AMX 360 4-speed (since 1981)


Posted By: amx39068
Date Posted: Jun/11/2011 at 10:57am

Not hard at all.  Some bracketsand a couple of other odds and ends like of course the booster and power master cylinder that you can buy as a complete kit from most part supply houses plus some different upper pedal brackets and master cylinder adjustment stud but that should come already installed with the PB/MC kit.  If you can find a donor car in a bone yard it should have everything you need.

Also, post right here in the wanted section.  Sometimes folks prefer manual and pull the PB stuff off their cars.


-------------
Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: fmahannah
Date Posted: Jun/11/2011 at 11:23am
Thanks.  I am going to take it to a regular brake shop first to make sure everything is working the way it should. It's possible the pedal is hard and braking is bad because there is something wrong. I replaced the rear cylinders because they were leaking and bled everything, but it just does not seem to stop like it should.

Also, if I put the cam in that I want I might not have enough vacuum for power brakes without getting a vacuum reserve tank or whatever you call it.


-------------
74 Javelin AKA Ghost


Posted By: ramblinrev
Date Posted: Jun/11/2011 at 11:33am
Manual brakes can be working fine and still require a good bit of pedal pressure. Most of us drivers today are only used to power brakes and so part of it may be perception. Getting your system checked out is a good start. Then you can decide what you're comfortable with.

-------------
74 Hornet Hatchback X twins (since 1977)
62 American Convertible (still worth the $50 I spent in 1973!) AMCRC #513, AMO #384
70 AMX 360 4-speed (since 1981)


Posted By: FuzzFace2
Date Posted: Jun/11/2011 at 1:46pm
Originally posted by ramblinrev ramblinrev wrote:

Manual brakes can be working fine and still require a good bit of pedal pressure. Most of us drivers today are only used to power brakes and so part of it may be perception. Getting your system checked out is a good start. Then you can decide what you're comfortable with.
X2 and what I think it is. I have a 75 gremlin factory v8 car with man 4 wheel drums and does take a little more to stop than power. Drag car & 76 Gremlin both have man disc and again takes a little more than power but not bad.
If you are going for a cam that may not work with the power set up then I would get what you have checked out and stick with it.
Dave ----


-------------
TSM = Technical Service Manual

75 Gremlin X v8 for sale
70 Javelin 360/auto drag car
70 Javelin 360/T5 Street car


Posted By: amx39068
Date Posted: Jun/11/2011 at 9:38pm
Sounds like a bad master or unflushed fluid with some moisture in it to me.  Manual discs should be firm but not rock hard and should stop every bit the same as power brakes albeit with increased pedal pressure

-------------
Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: Midnight Rambler
Date Posted: Jun/12/2011 at 5:53am
Is there a brake pedal difference like on some of the Ramblers?

-------------

'66 American 440 Convertible 290/M-40/AMC 20 3.15/PS/PB
'04 Jeep Wrangler X Rocky Mountain Edition 4.0 5sp


Posted By: Fluffy73
Date Posted: Jun/12/2011 at 1:55pm
My old '74 Javelin had manual discs and it took twice as much pedal effort to stop than my Gremlin with manual drums. It's the nature of manual discs.  Drums are easier because you're only forcing fluid into a small wheel cylinder (like 13/16" diameter). But on a manual disc car, you've got to force fluid into the calipers' chamber which is 2 to 3 times larger than a wheel cylinder.
 
Either that, or you've got a pedal with two holes for the pushrod to connect to and somebody put it on the wrong hole.  Most cars I've seen have a pedal (and arm) that have provisions for manual or power brakes.


-------------
I am genetically incapable of being Politically Correct.


Posted By: fmahannah
Date Posted: Jun/12/2011 at 2:27pm
I will have to check the pedal ... the way some other parts on this car were messed up it would not surprise me that  it is connected wrong. Pedal is way high in the car, have to raise foot way up to get it on the pedal.

Firewall below master cylinder is missing paint so I know they had trouble since the last repaint, hard to tell what they did to it.


-------------
74 Javelin AKA Ghost


Posted By: ramblinrev
Date Posted: Jun/12/2011 at 9:09pm
Originally posted by fmahannah fmahannah wrote:

I will have to check the pedal ... the way some other parts on this car were messed up it would not surprise me that  it is connected wrong. Pedal is way high in the car, have to raise foot way up to get it on the pedal.

Firewall below master cylinder is missing paint so I know they had trouble since the last repaint, hard to tell what they did to it.
A high pedal is characteristic of manual brakes from those days. The same car with power brakes would likely have a lower pedal height. A leaking master cylinder would explain the missing paint, again, very common.

-------------
74 Hornet Hatchback X twins (since 1977)
62 American Convertible (still worth the $50 I spent in 1973!) AMCRC #513, AMO #384
70 AMX 360 4-speed (since 1981)



Print Page | Close Window

Forum Software by Web Wiz Forums® version 12.03 - http://www.webwizforums.com
Copyright ©2001-2019 Web Wiz Ltd. - https://www.webwiz.net