I've been reading my '70 Ford Truck Shop manual about brakes. In the section on the master cylinder, I see that there should be a residual pressure check valve on the port of the master for the rear brakes.
From the 1970 Truck Shop Manual.
I replaced my master cylinder about 2 1/2 years ago. At the time, I did not have this manual and did not know about this check valve. I have no idea if there was one in the rebuilt master that I installed. Is this normally part of a rebuild? If there isn't one in there could I add something like this to the rear brake line?
If your brake line screws directly into the master cylinder, then you don't have them and definitely need them. If your brake line screws into something that looks like a brass fitting adapter, then either somebody's replaced the residual valve with an adapter or you do have the proper residual valve. You'd probably have to pop the line off to check.
However, to answer your question....yes, you can easily use that one, it does the same thing as the MC-mounted version.
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-O-----O- Keith
'67 F-100 2WD SWB ~ '69 F-100 4WD SWB w/7" chop ~ 1975 F-250 Ranger XLT Supercab Camper Special My '67 restoration video -> Posting and you!<-a MUST watch for all!!
FORDification wrote:If your brake line screws directly into the master cylinder, then you don't have them and definitely need them. If your brake line screws into something that looks like a brass fitting adapter, then either somebody's replaced the residual valve with an adapter or you do have the proper residual valve. You'd probably have to pop the line off to check.
However, to answer your question....yes, you can easily use that one, it does the same thing as the MC-mounted version.
That is not correct. The brake line can screw into the master cylinder and the valve will still be in there. The valve is installed behind the brass seat for the flair of tehbrake tube. If you want to verify that it is there you can take a sheetmetal screw and thread it into the brass seat and then use the screw head to pry the seat out. The valve will be inside behind it. Remove the screw and clean up any burrs it makes and then put it back in the hole and by tightening the brake line it will reseat. I have never had one that wasn't in there and I know because I do have to remove them for 4 wheel disc brake conversions but you never know, it could have been a guys first day on the job at a rebuilder. If the valve is missing the brakes won't pump up. If they pump up it is there. Hawkrod
The other thing I noticed is that the rear brake line is fed by the rear chamber of the master, not the front. This is the way it was when I got the truck, when I replaced the master, I left it the way it was. ( I guess I should have gotten a manual sooner) So, if the check valve is in there, it is on the fronts and not the rears. Maybe that's my problem? I soaked the fittings on the master with penetrating oil and will try switching them after a few days of soaking.
Steve
1970 F350 DRW Factory 9' Platform/Stake, 360, T18.
Passed on to new care taker July, 2013
This is a drum/drum master bought from a reputable source. Seem's my problem is operator/installer related and not mechanical. I won't get to mess with it 'til the end of the week, but I'm feeling better now that I have something to try.
Steve
1970 F350 DRW Factory 9' Platform/Stake, 360, T18.
Passed on to new care taker July, 2013
Hawkrod wrote:That is not correct. The brake line can screw into the master cylinder and the valve will still be in there. The valve is installed behind the brass seat for the flair of tehbrake tube. If you want to verify that it is there you can take a sheetmetal screw and thread it into the brass seat and then use the screw head to pry the seat out. The valve will be inside behind it. Remove the screw and clean up any burrs it makes and then put it back in the hole and by tightening the brake line it will reseat. I have never had one that wasn't in there and I know because I do have to remove them for 4 wheel disc brake conversions but you never know, it could have been a guys first day on the job at a rebuilder. If the valve is missing the brakes won't pump up. If they pump up it is there. Hawkrod
I stand corrected....thanks Hawkrod.
____| \__
-O-----O- Keith
'67 F-100 2WD SWB ~ '69 F-100 4WD SWB w/7" chop ~ 1975 F-250 Ranger XLT Supercab Camper Special My '67 restoration video -> Posting and you!<-a MUST watch for all!!
It's under the seat for the flair on the tubing. You only need them on drums. To change it or to look if its there,
screw a sheetmetal screw in a few turns and just pry it out with a screwdriver. Leave the screw in and use it to
tap the seat back in. It won't leak. Jake
I got both nuts to break loose last night. It was raining and dark, but at least I know they should come apart when I have time and daylight in a couple days. It looks like I can just swap them at the master cylinder.
Steve
1970 F350 DRW Factory 9' Platform/Stake, 360, T18.
Passed on to new care taker July, 2013
:):):)